JP2011075576A - Current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an integrated circuit having a miniaturized current sensor in an integrated circuit package. <P>SOLUTION: The integrated circuit includes: a lead frame portion having a plurality of leads; a first current conductor portion including at least two of the plurality of leads; a substrate having a first surface and an opposing second surface, the first surface proximate to the first current conductor portion and the second surface distal from the first current conductor portion; one or more magnetic field transducers disposed on the first surface of the substrate; and a second current conductor portion deposited on the first surface of the substrate, disposed proximate to the one or more magnetic field transducers, and coupled to the first current conductor portion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates generally to current sensors, and more particularly to miniaturized current sensors in integrated circuit packages.

  As is known in the art, one type of conventional current sensor uses a magnetic field transducer (eg, Hall effect or magnetoresistive transducer) in the vicinity of the current conductor. The magnetic field transducer generates an output signal having a magnitude proportional to the magnetic field induced by the current flowing through the current conductor.

  Some typical Hall effect current sensors include a gapped toroid flux concentrator where the Hall effect element is positioned within the toroid gap. The Hall effect device and toroid are assembled in a housing, which can be mounted on a printed circuit board. In use, individual current conductors such as wires are passed through the center of the toroid. Such devices tend to be undesirably large both in terms of height and circuit board area.

  Other Hall effect current sensors include a Hall effect element mounted on a dielectric material, such as a circuit board. One such current sensor is described in European patent application EP 0867725. Yet another Hall effect current sensor includes a Hall effect element mounted on a substrate, for example a silicon substrate, as described in European Patent Application No. EP1111693.

  Various parameters characterize current sensor performance, including sensitivity and linearity. Sensitivity is related to the magnitude of the change in output voltage from the Hall effect transducer in response to the sensed current. Linearity is related to the degree to which the output voltage from the Hall effect transducer changes in direct proportion to the sensed current.

  The sensitivity of a current sensor is related to various factors. One important factor is the flux convergence of the magnetic field generated near the current conductor and sensed by the Hall effect element. For this, some current sensors use a flux concentrator. Another important factor, especially for current sensors where a flux concentrator is not used, is the physical separation between the Hall effect element and the current conductor.

European Patent Application No. EP 0867725 European Patent Application No. EP1111693 US Patent Application Publication No. 2005/0045359

  In accordance with the present invention, an integrated circuit current sensor includes a first lead frame having at least two lead wires coupled to provide a current conductor portion and one or more magnetic field transducers. A substrate having a first surface proximal to the current conductor portion and a second surface distal to the current conductor portion. In one particular embodiment, the substrate is disposed having a first surface of the substrate above the current conductor portion and a second surface of the substrate above the first surface. . In this particular embodiment, the substrate is oriented upside down in the integrated circuit with respect to the conventional orientation.

  In this particular configuration, the current sensor is provided with one or more magnetic field transducers positioned in close proximity to the current conductor portion, resulting in improved sensitivity. In addition, the current sensor is provided in a small integrated circuit package.

  According to another aspect of the invention, a method of manufacturing an integrated circuit includes providing a lead frame having a plurality of leads, wherein at least two of the plurality of leads are coupled together to provide a current. Forming a conductor portion and etching the current conductor portion to provide the current conductor portion with a cross-section having a predetermined shape. In one particular embodiment, the predetermined shape is T-shaped. In another embodiment, the predetermined shape is a rectangular shape with a minimum dimension that is less than the thickness of most of the lead frame.

  In this particular configuration, the current conductor portion is provided such that more magnetic flux density is concentrated on the surface of the current conductor portion. Thus, a magnetic field transducer mounted near the current conductor portion receives the increased magnetic field and results in a current sensor with improved sensitivity.

  According to another aspect of the present invention, the integrated circuit includes a lead frame portion having a plurality of lead wires, and the first current conductor portion includes at least two of the plurality of lead wires. The integrated circuit also includes a substrate having a first surface and an opposite second surface, the first surface being proximal to the first current conductor portion, and the second surface being the first surface. Distant from the current conductor. One or more magnetic field transducers are disposed on the first surface of the substrate. The integrated circuit further includes a second current conductor portion coated on the first surface of the substrate and disposed proximal to the one or more magnetic field transducers and coupled to the first current conductor portion. Including.

  According to another aspect of the present invention, an integrated circuit includes a lead frame having a plurality of lead wires and a current conductor portion having a coupling of at least two of the plurality of lead wires. The integrated circuit also includes a substrate having a first surface and an opposite second surface. The first surface of the substrate is proximal to the current conductor portion and the second surface of the substrate is distal from the current conductor portion. Each one of the lead wires has a respective length and each one of the lead wires is selected to be closer to the first surface of the substrate than the second surface of the substrate over the entire length of the lead wire. It has a curved part in the direction. The integrated circuit also includes an insulating layer disposed between the substrate and the current conductor portion of the lead frame, and one or more magnetic field transducers disposed on the first surface of the substrate.

  According to yet another aspect of the invention, an integrated circuit includes a lead frame portion having a first current conductor portion having a plurality of lead wires and comprising at least two of the plurality of lead wires. The integrated circuit also includes a substrate having a first surface and an opposite second surface. The first surface of the substrate is proximal to the first current conductor portion and the second surface of the substrate is distal from the first current conductor portion. The integrated circuit also includes one or more magnetic field transducers disposed on the first surface of the substrate. The integrated circuit further includes a second current conductor portion coated proximal to the first surface of the substrate and disposed proximal to the one or more magnetic field transducers. The second current conductor portion is coupled to the first current conductor portion. The integrated circuit further includes an insulating layer disposed between the second current conductor portion and the first surface of the substrate.

  According to yet another aspect of the invention, an integrated circuit includes a lead frame having a plurality of lead wires and a current conductor portion comprising at least two of the plurality of lead wires. The integrated circuit further includes a substrate having a first surface and an opposite second surface, wherein the first surface is proximal to the current conductor portion and the second surface is distal from the current conductor portion. is there. The integrated circuit further includes one or more magnetic field transducers disposed on the first surface of the substrate and an insulating layer disposed between the substrate and the current conductor portion of the lead frame. . The insulating layer comprises an intervening insulating layer comprising a ceramic layer, a lead frame insulating layer associated with the lead frame, a lead frame thermal insulating layer, a lead frame covering insulating layer, or a lead frame oxide insulating layer, or At least one of the substrate insulation layers comprising at least one of a substrate covering insulation layer or a substrate oxide insulation layer associated with the substrate is included.

  According to still another aspect of the present invention, an integrated circuit includes a lead frame portion having a plurality of lead wires and a current conductor portion including at least two of the plurality of lead wires. The integrated circuit also includes a substrate having a first surface and an opposite second surface. The first surface is proximal to the current conductor portion and the second surface is distal from the current conductor portion. The integrated circuit also includes one or more magnetic field sensing elements disposed proximate the current conductor portion. The integrated circuit also includes a current sensing circuit disposed on the first surface of the substrate and coupled to the one or more magnetic field sensing elements. The current sensing circuit is adapted to provide an output signal indicative of the current flowing through the current conductor. The integrated circuit also includes an overcurrent circuit disposed on the first surface of the substrate. The overcurrent circuit is adapted to sense a voltage drop associated with the current and is further adapted to provide an output signal in response to the voltage drop. The output signal from the overcurrent circuit indicates that the current sensed by the overcurrent circuit is above a predetermined current.

  According to still another aspect of the present invention, an integrated circuit includes a lead frame having a plurality of lead wires and a first current conductor portion including at least two of the plurality of lead wires. The integrated circuit also includes a shunt conductor portion having at least two of the plurality of lead wires. The integrated circuit further includes a substrate having a first surface and an opposite second surface. The first surface of the substrate is proximal to the first current conductor portion and the second surface of the substrate is distal from the first current conductor portion. The integrated circuit also includes one or more magnetic field transducers disposed on the first surface of the substrate.

  According to yet another aspect of the invention, a current sensor includes a lead frame having a plurality of lead wires. The first current conductor portion includes at least two of the plurality of lead wires. The current sensor also includes a substrate having a first surface and an opposite second surface. The first surface is proximal to the first current conductor portion and the second surface is distal from the first current conductor portion. The current sensor may be one or more magnetic field transducers disposed on the first surface of the substrate and proximal to the one or more magnetic field transducers. And an electromagnetic shield disposed between the one current conductor portion. The electromagnetic shield has at least one feature selected to reduce eddy currents induced in the electromagnetic shield.

  In accordance with yet another aspect of the present invention, a current sensor includes a lead frame having a plurality of leads and a substrate having a first surface and an opposite second surface. One or more magnetic field transducers are coated on the first surface of the substrate. The current sensor also includes an electromagnetic shield disposed proximal to the one or more magnetic field transducers. The electromagnetic shield has at least one feature selected to reduce eddy currents induced in the electromagnetic shield.

  The foregoing features of the invention, as well as the invention itself, may be more fully understood from the following detailed description of the drawings.

According to a first aspect, in an integrated circuit, a lead frame portion having a plurality of lead wires, a first current conductor portion including at least two of the plurality of lead wires, a first surface, and an opposite first A substrate having two surfaces, wherein the first surface is proximal to the first current conductor portion and the second surface is distal from the first current conductor portion; One or a plurality of magnetic field transducers disposed on the first surface of the substrate, and a second current conductor portion coated on the first surface of the substrate, wherein the one Or a second current conductor portion disposed proximal to the plurality of magnetic field transducers and coupled to the first current conductor portion. In a second aspect, the at least two of the plurality of lead wires provide a current path through the lead frame portion. In a third aspect, the at least two of the plurality of lead wires provide a current path through the second current conductor portion. In a fourth aspect, the substrate has the first surface of the substrate above the first current conductor portion and the second surface above the first surface. Arranged. In a fifth aspect, at least a portion of the second current conductor portion has a T-shaped cross section. In a sixth aspect, at least a portion of the second current conductor portion has a rectangular cross section having a minimum dimension smaller than the thickness of the lead frame portion. In a seventh aspect, the apparatus further includes at least one amplifier disposed on the substrate.

In an eighth aspect, in an integrated circuit, the lead frame having a plurality of lead wires, the lead frame having a current conductor portion including at least two of the plurality of lead wires, the first surface, A substrate having an opposite second surface, wherein the first surface is proximal to the current conductor portion, the second surface is distal from the current conductor portion, and each of the lead wires One having a respective length such that each one of the lead wires is closer to the first surface of the substrate than the second surface of the substrate over the entire length of the lead wire. A substrate having a curved portion in a selected direction, an insulating layer disposed between the substrate and the current conductor portion of the lead frame, and disposed on the first surface of the substrate. With one or more magnetic field transducers Provided. In a ninth aspect, the insulating layer is made of a polymer tape. In a tenth aspect, the insulating layer is composed of a ceramic layer. In an eleventh aspect, the insulating layer includes an insulating material disposed on the current conductor portion. In a twelfth aspect, the insulating material comprises at least one of a polymer tape, a polymer, a ceramic, or an oxide. In a thirteenth aspect, the insulating layer includes an insulating material disposed on the substrate. In a fourteenth aspect, the insulating material comprises at least one of a polymer tape, a polymer, a ceramic, a nitride, or an oxide. In a fifteenth aspect, the current conductor portion includes the at least two couplings of the plurality of lead wires.

In a sixteenth aspect, in an integrated circuit, a lead frame portion having a plurality of lead wires, the lead frame portion having a first current conductor portion including at least two of the plurality of lead wires; A substrate having a first surface and an opposite second surface, wherein the first surface is proximal to the first current conductor portion, and the second surface is the first current conductor portion. Distal to the substrate, one or more magnetic field transducers disposed on the first surface of the substrate, and a second coated proximally of the first surface of the substrate A second current conductor portion disposed proximal to the one or more magnetic field transducers and coupled to the first current conductor portion; and the second current conductor portion An insulating layer disposed between the conductor portion and the first surface of the substrate. In the seventeenth aspect, the insulating layer is composed of a polymer tape. In an eighteenth aspect, the insulating layer is composed of a ceramic layer. In a nineteenth aspect, the insulating layer includes an insulating material disposed on the lead frame. In a twentieth aspect, the insulating material comprises at least one of a polymer tape, a polymer, a ceramic, or an oxide. In a twenty-first aspect, the insulating layer comprises an insulating material disposed on the first surface of the substrate. In a twenty-second aspect, the insulating material comprises at least one of a polymer tape, a polymer, a ceramic, a nitride, or an oxide. In a twenty-third aspect, the material of the insulating layer comprises at least one of a polymer, a ceramic, a nitride, or an oxide.

In a twenty-fourth aspect, in an integrated circuit, a lead frame having a plurality of lead wires, the lead frame having a current conductor portion including at least two of the plurality of lead wires, a first surface, A substrate having an opposite second surface, wherein the first surface is proximal to the current conductor portion and the second surface is distal from the current conductor portion; and the substrate One or a plurality of magnetic field transducers disposed on the first surface, and an insulating layer disposed between the substrate and the current conductor portion of the lead frame. The layer is an intervening insulating layer comprising a ceramic layer, or a lead frame insulating layer associated with the lead frame, the lead frame sprayed insulating layer, the lead frame covering insulating layer, or the lead frame acid A lead frame insulating layer, or a substrate insulating layer associated with the substrate, comprising at least one of a substrate covering insulating layer or a substrate oxide insulating layer, At least one of the following. In a twenty-fifth aspect, a second current conductor portion coated proximally of the first surface of the substrate is disposed proximal to the one or more magnetic field transducers, and the current A second current conductor portion coupled to the conductor portion is further included.

In a twenty-sixth aspect, in an integrated circuit, a lead frame portion having a plurality of lead wires, a current conductor portion including at least two of the plurality of lead wires, a first surface and an opposite second surface A substrate having the first surface proximal to the current conductor portion and the second surface distal to the current conductor portion; and proximal to the current conductor portion One or more magnetic field sensing elements disposed; and a current sensing circuit disposed on the first surface of the substrate and coupled to the one or more magnetic field sensing elements, A current sensing circuit is a current sensing circuit adapted to provide an output signal indicative of current flowing through the current conductor portion and an overcurrent circuit disposed on the first surface of the substrate. And the overcurrent circuit is associated with a current. Adapted to sense a voltage drop, and further adapted to provide an output signal in response to the voltage drop, wherein the output signal has a current sensed by the overcurrent circuit greater than a predetermined current. And an overcurrent circuit that indicates the above. In a twenty-seventh aspect, the first surface of the substrate includes at least two conductive regions coupled to the overcurrent circuit, and the current conductor portion is adapted to contact the at least two conductive regions. At least two features. In a twenty-eighth aspect, the first surface of the substrate includes at least two conductive regions coupled to the overcurrent circuit. Further comprises at least two wire coupling portions coupled between the at least two conductive regions and the current conductor portion. In a twenty-ninth aspect, the apparatus further comprises a second substrate disposed in proximity to the current conductor portion, and the one or more magnetic field sensing elements are disposed on the second substrate. In a thirtieth aspect, the overcurrent circuit is coupled to the current conductor portion, the voltage drop is associated with the current flowing through the current conductor portion, and the output signal passes through the current conductor portion. It indicates that the current flowing through is higher than a predetermined current. In a thirty-first aspect, the output signal generated by the overcurrent circuit is a digital output signal having first and second states, and one of the first and second states is that the current is the predetermined value. The other of the first and second states indicates that the current is lower than the predetermined current. In a thirty-second aspect, the current conductor portion is a first current conductor portion, and the integrated circuit is further a second current conductor portion coated on the first surface of the substrate. A second current conductor portion disposed proximate to the one or more magnetic field transducers and coupled to the first current conductor portion and flowing through the first current conductor portion At least part of the current also flows through the second current conductor. In a thirty-third aspect, when the plurality of lead wires are normally mounted on an uppermost surface of a circuit board, the substrate includes the first surface of the substrate above the current conductor portion, and the substrate. And the second surface of the substrate overlying the first surface of the substrate.

In a thirty-fourth aspect, in a current sensor, a lead frame having a plurality of lead wires, a first current conductor portion including at least two of the plurality of lead wires, and the one of the plurality of lead wires. A substrate having a shunt conductor portion comprising at least two couplings, a first surface and an opposite second surface, wherein the first surface is proximate to the first current conductor portion; A substrate having a surface that is distal from the first current conductor and one or more magnetic field transducers disposed on the first surface of the substrate. In a thirty-fifth aspect, the first current conductor portion and the shunt conductor portion are each adapted to pass a portion of current, and the shunt conductor portion is selected to provide a selected resistance. And the resistance is selected to pass a selected portion of the current. In a thirty-sixth aspect, each one of the lead wires is selected to be closer to the first surface of the substrate than the second surface of the substrate over the length of the lead wire. Have a curved portion. In a thirty-seventh aspect, the first current conductor portion includes the at least two other couplings of the plurality of lead wires, and the one or more magnetic field transducers include the first current conductor. Disposed proximally of the section. In a thirty-eighth aspect, a second current conductor portion coated on the first surface of the substrate is disposed in the vicinity of the one or more magnetic field transducers, The apparatus further includes a second current conductor portion coupled to the current conductor portion. In a thirty-ninth aspect, the semiconductor device further includes an insulating layer disposed between the first surface of the substrate and the first current conductor portion. In the fortieth aspect, a magnetic flux shield is further provided as a whole between the shunt conductor portion and the one or more magnetic field transducers. In a forty-first aspect, the magnetic flux concentrator disposed on the shunt conductor portion is further provided. In a forty-second aspect, at least a portion of the first current conductor portion has a T-shaped cross section. In a forty-third aspect, at least a part of the first current conductor portion has a rectangular cross-sectional area having a minimum dimension smaller than the thickness of the lead frame. In a forty-fourth aspect, the apparatus further comprises at least one amplifier disposed on the substrate.

In a forty-fifth aspect, in a current sensor, a lead frame having a plurality of lead wires, a first current conductor portion including at least two of the plurality of lead wires, a first surface, and an opposite second A substrate having a plurality of surfaces, wherein the first surface is proximal to the first current conductor portion and the second surface is distal from the first current conductor portion; One or more magnetic field transducers disposed on the first surface of the substrate; proximal to the one or more magnetic field transducers; and the first surface of the substrate and the first An electromagnetic shield disposed between one current conductor portion, the electromagnetic shield having at least one feature selected to reduce eddy currents induced in the electromagnetic shield. In a forty-sixth aspect, the electromagnetic shield is substantially flat and has a shape selected to reduce the path length of a closed loop current path in the electromagnetic shield. In a 47th aspect, the electromagnetic shield includes a slot. In a forty-eighth aspect, the electromagnetic shield includes a central member and a plurality of non-overlapping members coupled to the central member. In a forty-ninth aspect, the electromagnetic shield includes a plurality of alternating fitting members. In a fifty aspect, the position of the at least one feature relative to the one or more magnetic field transducers is selected to reduce the effect of the eddy currents on the one or more magnetic field transducers. In a fifty-first aspect, each one of the lead wires is selected to be closer to the first surface of the substrate than the second surface of the substrate over the entire length of the lead wire. Have a curved portion. In a fifty-second aspect, the first current conductor portion includes the at least two couplings of the plurality of lead wires, and the one or more magnetic field transducers are provided on the first current conductor portion. Proximally disposed. In a 53rd aspect, it is the 2nd current conductor part coat | covered on the said 1st surface of the said board | substrate, It is arrange | positioned in the vicinity of the said one or several magnetic field transducer, The said 1st The apparatus further includes a second current conductor portion coupled to the current conductor portion. In a fifty-fourth aspect, the semiconductor device further includes an insulating layer disposed between the first surface of the substrate and the first current conductor portion. In a fifty-fifth aspect, at least a portion of the first current conductor portion has a T-shaped cross section. In a fifty-sixth aspect, at least a part of the first current conductor portion has a rectangular cross section having a minimum dimension smaller than the thickness of the lead frame. The fifty-seventh aspect further comprises at least one amplifier disposed on the substrate. In a 58th aspect, a shunt conductor portion comprising the at least two couplings of the plurality of lead wires is further provided. In a 59th aspect, the first current conductor portion and the shunt conductor portion are each adapted to pass a portion of a current, and the shunt conductor portion is selected to provide a selected resistance. And the resistance is selected to pass a selected portion of the current.

According to a sixtyth aspect, in the current sensor, a lead frame having a plurality of lead wires, a substrate having a first surface and an opposite second surface, and the first surface of the substrate are disposed on the first surface. One or more magnetic field transducers and an electromagnetic shield disposed proximate to the one or more magnetic field transducers, selected to reduce eddy currents induced in the electromagnetic shields An electromagnetic shield having at least one feature. In a sixty-first aspect, the electromagnetic shield is substantially flat and has a shape selected to reduce the path length of a closed loop current path in the electromagnetic shield. In a sixty-second aspect, the electromagnetic shield includes a slot. In a 63rd aspect, the electromagnetic shield includes a central member and a plurality of non-overlapping members coupled to the central member. In a sixty-fourth aspect, the electromagnetic shield includes a plurality of alternating fitting members. In a 65th aspect, the position of the at least one feature relative to the one or more magnetic field transducers is selected to reduce the effect of the eddy current on the one or more magnetic field transducers.

1 is an isometric view of a current sensor according to the present invention. FIG. It is a graph which shows the relationship between the position over the Hall effect element of the current sensor of FIG. 1, and a magnetic field. FIG. 6 is an isometric view of another embodiment of a current sensor according to the present invention. It is the schematic of the circuit formation part of the current sensor of FIG. FIG. 6 is an isometric view of yet another embodiment of a current sensor according to the present invention. FIG. 6 is an isometric view of yet another embodiment of a current sensor according to the present invention. FIG. 6 is an isometric view of yet another embodiment of a current sensor according to the present invention. FIG. 6 is an isometric view of yet another embodiment of a current sensor according to the present invention. FIG. 8 is a further isometric view of the current sensor of FIG. 7 modified to include an insulating layer and an electromagnetic shield. FIG. 6 is an isometric view of an alternative lead frame having a thinner current conductor portion, according to a further aspect of the present invention. FIG. 10 is a cross-sectional view of an alternative embodiment of the current conductor portion of FIG. 9. FIG. 6 is an isometric view of yet another embodiment of a current sensor according to the present invention. FIG. 11 is an isometric view of an alternative configuration of the current sensor of FIG. FIG. 11 is an isometric view of another alternative configuration of the current sensor of FIG. FIG. 11 is an isometric view of another alternative configuration of the current sensor of FIG. It is sectional drawing of the current sensor of FIG. 9 is an isometric view of an alternative configuration of the current sensor of FIGS. 7 and 8. FIG. It is sectional drawing of the current sensor of FIG. FIG. 14B is a schematic diagram of an exemplary circuit that can be used with the current sensor of FIGS. 13, 13A, 14 and 14A, including a current sensing circuit and an overcurrent circuit. 9 is an exploded isometric view of another alternative configuration of the current sensor of FIGS. 7 and 8. FIG. FIG. 11 is an isometric view of another alternative configuration of the current sensor of FIG. 9 is an exploded isometric view of another alternative configuration of the current sensor of FIGS. 7 and 8. FIG. It is a top view of the electromagnetic shield which can form a part of current sensor. FIG. 6 is a top view of another electromagnetic shield that can form part of a current sensor. FIG. 6 is a top view of yet another electromagnetic shield that can form part of a current sensor. FIG. 6 is a top view of yet another electromagnetic shield that can form part of a current sensor. FIG. 23 is a cross-sectional view illustrating a stacked structure of an exemplary current sensor having one of the electromagnetic shields of FIGS. 19 to 22.

Referring to FIG. 1, an exemplary current sensor 10 according to the present invention includes a lead frame 12 having a plurality of lead wires 12a-12h. Lead wires 12a and 12b are coupled to lead wires 12c and 12d to form a current path or current conductor having a narrow portion 14 having a width w1. The current sensor 10 also includes a substrate 16 having a first surface 16a and a second surface 16b opposite to the first surface 16a. The substrate 16 includes a magnetic field transducer 18, which in some embodiments is diffused into the first surface 16a or disposed on the first surface 16a. It may be an effect element 18. The substrate 16 can be composed of a semiconductor material, such as silicon, or in alternative embodiments, the substrate 16 can be composed of an insulating material.

  More specifically, the substrate 16 is such that the Hall effect element 18 is current sensitive so that the first surface 16a is proximal to the current conductor portion 14 and the second surface 16b is distal to the current conductor portion 14. It is disposed on the lead frame 12 so as to be in the vicinity of the conductor portion 14. In the illustrated embodiment, the substrate 16 has an upside down orientation (ie, the first surface 16a is directed downward) with respect to the conventional direction in which the substrate is mounted in an integrated circuit package.

  The substrate 16 has bond pads 20a-20c on the first surface 16a, to which bond wires 22a-22c are bonded. The coupling wires are further coupled to the lead wires 12e, 12f, and 12h of the lead frame 12.

  An insulator 24 separates the substrate 16 from the lead frame 12. The insulator 24 can be provided in various forms. For example, in one embodiment, the first portion of the insulator 24 comprises a 4 μm thick layer of BCB resin material that is coated (deposited, evaporated, deposited) directly on the first surface 16 a of the substrate 16. Including. The second portion of the insulator 24 may include a layer of underfill material coated on the lead frame 12, such as Staychip ™ NUF-2071E (Cookson Electronics Equipment, New Jersey). Such a configuration provides insulation greater than 1000 volts between the substrate 16 and the lead frame 12.

  It should be understood that the current conductor portion 14 is only a portion of the entire path through which current flows. For example, the current having the direction indicated by arrow 26 is electrically coupled in parallel here and flows in the illustrated leads 12c, 12d, through the current conductor 14 and again in parallel here. The lead wires 12a and 12b which are connected to each other.

  In this configuration, the Hall effect element 18 is disposed in a predetermined position with respect to the conductor portion 14 in the vicinity of the current conductor portion 14, thereby generating a current passing through the current conductor portion 14 in the direction indicated by the arrow 26. The applied magnetic field is in a direction substantially aligned with the maximum response axis of the Hall effect element 18. Hall effect element 18 generates a voltage output that is proportional to the magnetic field and thus proportional to the current flowing through current conductor portion 14. The illustrated Hall effect element 18 has a maximum response axis that is substantially aligned with the z-axis 34. Since the magnetic field generated in response to the current is circular around the current conductor portion 14, as shown, the Hall effect element 18 is immediately beside the current conductor portion 14 (ie, along the y-axis 32). Slightly offset), where the magnetic field is directed substantially along the z-axis 34. This position results in a greater voltage output from the Hall effect element 18 and thus improved sensitivity. However, a Hall effect element having a maximum response axis aligned in another direction, or another type of magnetic field sensor, such as a magnetoresistive element, may be in a different position with respect to the current conductor portion 14, for example (along the z-axis 34). It can also be arranged on the current conductor part 14 (in the direction).

  Although a single Hall effect element 18 is illustrated on the first surface 16a of the substrate 16, it is understood that a plurality of Hall effect elements may be used as shown in the embodiments of FIGS. I want to be. Further circuits, such as amplifiers, can also diffuse into, or be disposed on, or supported by the first and / or second surfaces 16a, 16b of the substrate 16. it can. An exemplary circuit of this type is shown in FIG.

  In the embodiment of FIG. 1, the proximity of the Hall effect element 18 and the current conductor 14 is such that the Hall effect element 18 is on the first substrate surface 16 a positioned closer to the current conductor portion 14 than the second surface. It is realized by providing. In other embodiments, this advantageous proximity provides a Hall effect element 18 on the second substrate surface 16b and is substantially aligned with the second surface 16b, as shown in FIGS. In this way, the current conductor portion 14 is formed.

  Referring now to FIG. 2, a graph 50 relates to an x-axis 30 (FIG. 1) and y-axis 32 (FIG. 1) in the plane of the Hall effect element 18 (FIG. 1) for current through the current conductor portion 14 of about 10A. ) Along the Hall element 18 in the direction of the z-axis 34 (FIG. 1). The center (not shown) of the Hall effect element 18 corresponds to 300 microns on the abscissa 52. The decimal part 54 corresponds to a magnetic flux.

The magnetic flux curve 56 corresponds to a change in magnetic flux on the z-axis 34 with respect to a position along the x-axis 30. The magnetic flux curve 58 corresponds to the change in magnetic flux on the z axis 34 relative to the position along the y axis 32.
The magnetic flux curves 56, 58 can be characterized as being substantially flat near the Hall element centered at 300 μm. Therefore, the output of the Hall effect element 18 sensitive to the magnetic field in the direction of the z axis 34 is relatively insensitive to the position of the Hall effect element 18 along the x axis 30 and the y axis 32.

  The exemplary Hall effect element 18 has dimensions along the x-axis 30 and y-axis 32 on the order of 200 microns, so that the Hall effect element 18 is in the region between 200 microns and 400 microns on the abscissa 52. is there. A 50 micron change in the position of the Hall effect element 18 along the x-axis 30 or the y-axis 32 results in little change in the magnetic field sensed by the Hall effect element. Accordingly, the position of the Hall effect element on the x-axis 30 and the y-axis 32 can vary with manufacturing position tolerances without a substantial effect on the sensitivity of the current sensor 10 (FIG. 1).

  The width w1 (FIG. 1) of the current conductor portion 14 in the x direction 30 relative to the dimension of the Hall effect element 18 in the x direction 30 is the magnetic flux in the z direction 34 relative to the position along the Hall effect element 18 in the x direction 30. Greatly affects density uniformity. In particular, as the current conductor portion 14 becomes longer with respect to the width of the Hall effect element 18 in the x direction 30 (ie, as the width w1 (FIG. 1) increases), the curve 56 remains substantially flat. The distance gets longer.

  The width w1 (FIG. 1) includes the desired sensitivity of the current sensor 10 (FIG. 1) and the desired reduction in performance variations due to manufacturing variations in the relative positions of the current path 14 and the Hall effect element 18. However, it is selected according to various factors that are not limited thereto. In general, it should be understood that the selection of a width w 1 that is equivalent to the width of the Hall effect element 18 provides the maximum sensitivity of the current sensor 10. However, it should also be understood that the selection of a width w 1 that is greater than the width of the Hall effect element 18 minimizes performance variations due to manufacturing tolerances in the Hall element position arrangement in the x direction 30.

  Referring now to FIG. 3, another exemplary current sensor 70 according to the present invention includes a lead frame 72 having a plurality of lead wires 72a-72h and a current conductor portion 74 having a width w2. The current sensor also includes a substrate 76 having a first surface 76a and an opposite second surface 76b. The substrate 76 is diffused into the first surface 76a, or disposed on or supported by the first surface 76a, and the first and second Hall effect elements 78a, 78b. Have The substrate 76 is disposed on the lead frame 72 such that the Hall effect element 78 is in the vicinity of the current conductor 74. In the illustrated embodiment, the substrate 76 has an upside down orientation (ie, the first surface 76a is directed downward) with respect to the conventional orientation of the substrate mounted in the integrated circuit package. An insulator (not shown) can separate the substrate 76 from the lead frame 72. The insulator may be the same as or similar to the insulator 24 shown in FIG.

  In this configuration, both Hall effect elements 78 a, 78 b are disposed in the vicinity of the current conductor portion 74 at a predetermined position with respect to the current conductor portion 74, thereby causing the current conductor portion 74 to move in the direction indicated by the arrow 86. The magnetic field generated by the passing current is in a direction substantially aligned with the maximum response axis of the Hall effect elements 78a, 78b. Here, each Hall effect element 78 a, 78 b has a maximum response axis aligned with the z-axis 94. Thus, as shown, the Hall effect elements 78a, 78b are disposed on either side of the current conductor portion 74 (ie, slightly offset along the y-axis 92) where the magnetic field is on the z-axis 94. Aimed along. In one embodiment, the Hall effect elements 78a, 78b are offset (along the y-axis 92) by a substantially equal and opposite amount with respect to the current conductor portion 74. However, a Hall effect element having a maximum response axis aligned in another direction, or another type of magnetic field sensor, such as a magnetoresistive element, may be placed in another position with respect to the current conductor 74, such as (z It can also be arranged above (in the direction of the axis 94).

  In operation, current flows in the parallel coupled leads 72c, 72d and exits through the current conductor portion 74 and also from the parallel coupled leads 72a, 72b. The current flowing through the current conductor 74 generates a magnetic field that is sensed by the Hall effect elements 78a and 78b. As described above, the Hall effect elements 78a and 78b are in the vicinity of the current conductor portion 74 and are in a predetermined position with respect to the current conductor portion 74. Therefore, the magnetic field generated by the current is generated by the Hall effect elements 78a and 78b. Substantially aligned with the maximum response axis. This arrangement results in a larger voltage output from the Hall effect elements 78a, 78b and thus improved sensitivity.

  It should be understood that the magnetic fields received by the first and second Hall effect elements 78a, 78b are directed in opposite directions and are aligned along the z-axis 94, respectively. Therefore, when the polarity is given in the same direction, the polarities of the outputs of the two Hall effect elements 78a and 78b are reversed. There are several advantages when the output from one of the Hall effect elements 78a, 78b is inverted, for example using an inverting amplifier, and then summed with the other output of the Hall effect elements 78a, 78b, ie, summed differentially. Realized.

  As an initial advantage, the outputs of the two Hall effect elements 78a, 78b are twice the magnitude of the voltage output from a single Hall effect element in the presence of the same current when the difference is added as described above. Provides voltage output. Therefore, the current sensor 70 has twice the sensitivity of the current sensor 10 of FIG.

  As a second advantage, the current sensor 70 is relatively insensitive to fluctuations in the position of the Hall effect elements 78a and 78b in the direction of the y-axis 92. This is because when moving in the direction of the y-axis 92, the voltage output from one of the Hall effect elements 78a, 78b tends to increase, and the voltage output from the other of the Hall effect elements 78a, 78b tends to decrease. Because there is. Therefore, the difference addition of the two outputs is relatively unchanged.

  The lead frame 72 is shown having flat lead wires 72a-72h suitable for surface mounting on a circuit board, but a lead frame having a curved lead wire such as the lead frame 12 of FIG. 1 is used. Please understand that you can. Also, although two Hall effect elements 78a, 78b are shown, more or less than two Hall effect elements can be used.

  Referring now to FIG. 4, an adder circuit 100 suitable for performing the differential signal addition described with reference to FIG. 3 is shown coupled to two Hall effect elements 102a, 102b. The Hall effect elements 102a and 102b may be the same as or similar to the Hall effect elements 78a and 78b of FIG. Here, the Hall effect elements 102a and 102b are rotated by 90 ° with respect to the other Hall effect element as indicated by the vectors on the Hall effect elements 102a and 102b. Accordingly, the Hall effect elements 102a and 102b generate output voltages 103a and 103b having the same polarity in response to the reverse magnetic fields 112a and 112b. Output voltage 103a is coupled to amplifier 104a configured in a non-inverting configuration, and output voltage 103b is coupled to amplifier 104b configured in an inverting configuration. Accordingly, the amplifier output voltages 106a and 106b move in the opposite voltage direction in response to the magnetic fields 112a and 112b. The amplifier output voltages 106a, 106b are differentially coupled to the amplifier 108 to produce a differential addition or difference of the output voltages 106a, 106b. Thus, the output voltages 106a, 106b add up to provide a larger output voltage 110 at the output of the amplifier 108.

  The adder circuit 100 can be used in the current sensor 70 of FIG. 3, in which case the Hall effect elements 102a and 102b correspond to the Hall effect elements 78a and 78b. In one particular embodiment, the summing circuit 100 is diffused into or disposed on the first surface 76a of the substrate 76. In another embodiment, the summing circuit 100 is diffused into or disposed on the second surface 76b of the substrate 76, while the Hall effect elements 78a, 78b are the first surface 76b. Located on surface 76a and coupled to other circuit components via a plurality of passages (vias) and the like.

  Referring now to FIG. 5, like elements of FIG. 1 are shown with like reference numerals, and another exemplary current sensor 120 is connected to a second surface 126b opposite the first surface 126a. A substrate 126 having Here, four Hall effect elements 128a-128d are diffused into the first surface 126a of the substrate 126 or disposed on the first surface 126a. As shown in the figure, the substrate 126 has first and second Hall effect elements 128a and 128b on one side of the current conductor portion 14 along the y-axis 142, respectively. Positioned with respect to the lead frame 12 such that 128c, 128d is on the opposite side of the current conductor portion 14 along the y-axis 42. In one embodiment, the Hall effect elements 128a, 128b are equal to the amount by which the Hall effect elements 128c, 128d are offset from the current conductor portion 14 (along the y-axis 142) and in the opposite direction. From (along the y-axis 142).

  In this configuration, the Hall effect elements 128a to 128d are disposed in a predetermined position with respect to the conductor portion 14 in the vicinity of the current conductor portion 14, and thereby the current passing through the current conductor portion 14 in the direction indicated by the arrow 86. Is in a direction substantially aligned with the maximum response axis of the Hall effect elements 128a-128d. Here, each Hall effect element 128 a-128 d has a maximum response axis aligned with the z-axis 144. In the illustrated embodiment, as shown, the Hall effect elements 128a, 128b are on the opposite side of the current conductor portion 144 from the Hall effect elements 128c, 128d (ie, slightly along the y-axis 142). Offset), where the magnetic field is directed along the z-axis 144. However, a Hall effect element having a maximum response axis aligned in another direction, or another type of magnetic field sensor, such as a magnetoresistive element, may be placed in another position with respect to the current conductor part 14, eg, (z It can also be arranged above (in the direction of the axis 144). The first and second Hall effect elements 128a, 128b are exposed to a magnetic field in one direction along the z-axis 144, and the third and fourth Hall effect elements 128c, 128d are reversed along the z-axis 144. It should be understood that it is exposed to a magnetic field in the direction.

  The four Hall effect elements 128a-128d can be coupled to an electronic circuit configured as a summing circuit as understood by those skilled in the art to achieve several advantages. The adder circuit can include, for example, two adder circuits 100 of FIG. In one embodiment, the adder circuit combines the first two of the Hall effect elements 128a-128d with a first adder circuit, such as the adder circuit 100 of FIG. The second two can be combined with a second adder circuit such as adder circuit 100. Another amplifier can be used to add the output of the first adder circuit with the output of the second adder circuit. As a first advantage, the four Hall effect elements 128a-128d coupled to the summing circuit as described are a single Hall effect element in the presence of the same current, eg, the Hall effect element of FIG. Provides a voltage output that is four times the magnitude of the voltage output from 18. Therefore, the current sensor 120 has a sensitivity four times that of the current sensor 10 of FIG.

  As a second advantage, the current sensor 120 is relatively insensitive to variations in the position of the Hall effect elements 128a-128d in the direction of the y-axis 142. This is because the voltage output from two of the four Hall effect elements 128a-128d tends to increase when moved in the direction of the y-axis 142, and the other of the four Hall effect elements 128a-128d. This is because the voltage output from the two tends to decrease. Thus, when coupled as an adder circuit, the circuit output is relatively unchanged with respect to the y-axis position of the Hall effect element.

  Referring now to FIG. 6, an exemplary current sensor 150 according to the present invention includes a lead frame 152 having a plurality of lead wires 152a-152h and a current conductor portion 154. The current sensor 150 also includes a substrate 166 having a first surface 166a and a second surface 166b opposite to the first surface 166a. The substrate 166 has a Hall effect element 158 diffused into the first surface 166a or disposed on the first surface 166a. The substrate 166 is disposed on the lead frame 152 such that the Hall effect element 158 is in the vicinity of the current conductor 154. The substrate 166 has an upside down orientation (ie, the first surface 166a is directed downward) with respect to the conventional direction in which the substrate is mounted within the integrated circuit package. The substrate 166 is a flip chip having solder balls 160a-160c on the first surface 166a of the substrate 166. Solder balls 160a-160c are directly coupled to lead wires 152e-152h as shown. An insulator 164 separates the substrate 166 from the lead frame 152. The insulator 164 may be the same as or similar to the insulator 24 shown in FIG.

  In this configuration, the Hall effect element 158 is disposed in the vicinity of the current conductor portion 154 at a predetermined position with respect to the conductor portion 154, thereby generating a current passing through the current conductor portion 154 in the direction indicated by the arrow 168 The applied magnetic field is in a direction substantially aligned with the maximum response axis of the Hall effect element 158. Hall effect element 158 has a maximum response axis aligned with z-axis 174. Thus, as shown, the Hall effect element 158 is disposed directly beside the current conductor portion 14 (ie, with a slight offset along the y-axis 172), where the magnetic field is along the z-axis 174. Directed. However, a Hall effect element having a maximum response axis aligned in another direction, or another type of magnetic field sensor, such as a magnetoresistive element, may be placed in a different position with respect to the current conductor portion 154, for example (z It can also be arranged above (in the direction of the shaft 174).

  The operation of the current sensor 150 is similar to the above-described operation of the current sensor 10 of FIG. A Hall effect element 158 in the vicinity of the current conductor 154 provides a greater output voltage from the Hall effect element 158 and thus improved sensitivity.

  Although only one Hall effect element 158 is illustrated on the first surface 166a of the substrate 166, it should be understood that multiple Hall effect elements may be used with the present invention. Other circuits, such as amplifiers, may be diffused into or coupled to the first and / or second surfaces 166a, 166b of the substrate 166 or supported by the surfaces 166a, 166b.

  Although three solder balls 160a-160c are shown, any number of solder balls can be provided, including dummy solder balls for stabilizing the substrate 166. Also, although solder balls 160a-160c are illustrated, gold bumps, eutectic or lead-containing solder bumps, lead-free solder bumps, gold stud bumps, polymer conductive bumps, anisotropic conductive paste, Alternatively, other connection methods can be used, including but not limited to conductive films.

  Referring now to FIG. 6A, elements similar to those in FIG. 6 are shown having similar reference numerals, and an exemplary current sensor 180 according to the present invention includes a flux concentrator 182 and a flux concentrating layer 184. . The flux concentrator is positioned proximal to the Hall effect sensor 158 and adjacent to the first surface 166a of the substrate 166. The magnetic flux concentrating layer 184 is disposed on the second surface 166b of the substrate 166 (or on top adjacent to the second surface 166b).

  In operation, each of the flux concentrator 182 and the flux concentrating layer 184 tends to converge the magnetic flux generated by the current passing through the current conductor portion 154 so that the current sensor 180 is more than the current sensor 150 of FIG. Try to have high sensitivity.

  The magnetic flux concentrator 182 and the magnetic flux concentrating layer 184 can each be composed of various materials including, but not limited to, ferrite, permalloy, and iron. An adhesive layer (not shown), for example a titanium or chrome layer, may be present and will be understood by those skilled in the art.

  Although the magnetic flux concentrator 182 is illustrated as having a cubic shape, in other embodiments, the magnetic flux concentrator can have another shape, such as a polyhedral shape, an elliptical shape, or a spherical shape. Although both magnetic flux concentrator 182 and magnetic flux converging layer 184 are shown, in other embodiments, only one of magnetic flux concentrator 182 or magnetic flux converging layer 184 can be provided. Further, although the magnetic flux concentrator 182 and the magnetic flux converging layer 184 are illustrated in relation to one magnetic field converter 158, the magnetic flux concentrator 182 and the magnetic flux converging layer 184 include a plurality of magnetic field converters 158. It should be understood that the invention can be applied to the configurations illustrated in FIGS. 1, 3, and 5, for example.

  Referring now to FIG. 7, another exemplary current sensor 200 according to the present invention includes a lead frame 202 having a plurality of leads 202a-202h. The current sensor 200 also includes a substrate 206 having a first surface 206a and a second surface 206b opposite to the first surface 206a. The substrate 206 has a Hall effect element 208 diffused into the first surface 206a or disposed on the first surface 206a. A conductive fastener (clip) 204 having a current conductor portion 204a is coupled to the leads 202a-202d. The mechanism of the conductive fastener 204 is shown in FIG. Here, it should be noted that the conductive fastener is formed with a curved portion so that the conductive fastener 204 extends over the first surface 206 a of the substrate 206. The substrate 206 is disposed on the lead frame 202 so that the Hall effect element 208 is in the vicinity of the current conductor portion 204a. In the illustrated embodiment, the substrate 206 has a conventional mounting orientation with the first surface 206a facing up. Substrate 206 has bond pads 212a-212c on first surface 206a, to which bond wires 210a-210c are bonded. The coupling wires 210a to 210c are further coupled to the lead wires 202e, 202f, and 202h. An insulator 214 can be provided to isolate the substrate 206 from the conductive fastener 204. Insulator 214 may be the same as or similar to insulator 24 shown in FIG.

  In this configuration, the Hall effect element 208 is disposed in the vicinity of the current conductor portion 204 a extending over the first surface 206 a of the substrate 206. The Hall effect element 208 is disposed at a predetermined position with respect to the conductor portion 204 a so that the magnetic field generated by the current passing through the current conductor portion 204 a in the direction indicated by the arrow 216 is the maximum response of the Hall effect element 208. The direction is substantially aligned with the axis. Hall effect element 208 has a maximum response axis aligned with z-axis 224. In the illustrated embodiment, as shown, the Hall effect element 208 is disposed immediately next to the current conductor portion 204a (ie, with a slight offset along the y-axis 222), where the magnetic field is Oriented along the z-axis 224. However, a Hall effect element having a maximum response axis aligned in another direction, or another type of magnetic field sensor, such as a magnetoresistive element, can be disposed at another position with respect to the current conductor portion 204a, for example ( It can be essentially aligned with current conductor portion 204a (up or down) (in the direction of z-axis 224).

  In operation, current flows through the parallel coupled leads 202c, 202d, through the conductive fastener 204, through the current conductor portion 204a, and exits the parallel coupled leads 202a, 202b. The current flowing through the current conductor portion 204 a generates a magnetic field that is sensed by the Hall effect element 208. Hall effect element 208 generates a voltage output that is proportional to the magnetic field and thus proportional to the current flowing through current conductor portion 204a. As described above, the Hall effect element 208 is in the immediate vicinity of the current conductor portion 204a and is in a predetermined position with respect to the current conductor portion 204a, so that the magnetic field generated by the current is the maximum response axis of the Hall effect element 208. Substantially aligned. This position results in a larger voltage output from the Hall effect element 208 and thus improved sensitivity.

  Although only one Hall effect element 208 is shown on the second surface 206b of the substrate 206, it should be understood that multiple Hall effect elements may be used. In particular, an embodiment having two Hall effect elements may be similar to the current sensor 70 of FIG. 3, and an embodiment having four Hall effect elements may be similar to the current sensor 120 of FIG. Also, additional circuitry, such as an amplifier, can be diffused into or coupled to the first and / or second surfaces 206a, 206b of the substrate 206.

  It should be understood that the conductive fastener 204 can be formed from a variety of materials in a variety of ways. In one particular embodiment, the conductive fastener 204 is stamped from, for example, a copper sheet. In another embodiment, the conductive fastener 204 is formed from a foil, such as a copper foil. In yet another embodiment, the conductive fastener 204 is formed by an etching process. The conductive fasteners 204 allow for the conventional mounting orientation of the substrate 206 and at the same time bring the current conductor portion 204a very close to the Hall effect element 208.

  The conductive fastener 204 can be provided with a thickness that is selected according to the amount of current that passes through the conductive fastener 204. Thus, if a current sensor adapted to sense relatively high current is desired, the conductive fastener can be relatively thick and a current sensor adapted to sense relatively low current is desired. If so, the conductive fastener 204 can be relatively thin. In another embodiment, if a current sensor adapted to sense relatively high currents is desired, a plurality of conductive fasteners 204 can be stacked in contact with other conductive fasteners, and optionally It is possible to provide an increased effective thickness that is thicker than that of one of the conductive fasteners 204 and thus carry more current.

  In the embodiment of FIG. 7, the proximity of the Hall effect element 208 and the current conductor portion 204a is such that the Hall effect is on the first substrate surface 206a positioned closer to the current conductor portion 204a than the second surface 206b. This is accomplished by providing element 208. In other embodiments, this advantageous proximity is provided by providing a Hall effect element 208 on the second substrate surface 206b and forming the current conductor portion 204a to be substantially aligned with the second surface 206b. Realized.

  Referring now to FIG. 8, like elements of FIG. 7 are shown with like reference numerals and conductive fasteners 204 are illustrated prior to being coupled to leads 202a-202d. The conductive fastener 204 includes a current conductor portion 204a, a transition region 204b, a curved region 204c, and a coupling region 204d. The coupling region 204d includes two portions 204e and 204f that couple to the lead wires 202a to 202d. The transition region 204b can be lifted relative to the current conductor portion 204a to avoid contact with the substrate 206.

  Although Hall effect elements are shown and described in connection with embodiments of the present invention, it should be understood that other types of magnetic field sensors can be used. For example, a magnetoresistive element can be used instead of the Hall effect element. However, the conventional magnetoresistive element has a maximum response axis perpendicular to the maximum response axis of the conventional Hall effect element. Those skilled in the art should know how to position one or more magnetoresistive elements with respect to the current conductor according to embodiments of the present invention to achieve the same results as the Hall effect element embodiments described herein. You will understand.

  In some embodiments, an insulating layer 220 can be disposed between the conductive fastener 204 and the first surface 206a of the substrate 206. Insulating layer 220 may be formed from a variety of materials including, but not limited to, silicon dioxide and polymers. In some embodiments, an electromagnetic shield 222 may also be disposed between the conductive fastener 204 and the first surface 206a of the substrate 206. The electromagnetic shield 222 can be disposed in the vicinity of the Hall effect element 208 and below or above the insulating layer 220. For example, in the other configuration shown in FIG. 23, there can be two insulating layers, one above the electromagnetic shield 222 and one below the electromagnetic shield 222.

  The electromagnetic shield 222 tends to reduce the influence of the electromagnetic field on the Hall effect element 208, which makes the current sensor 200 less accurate, i.e. sensitive to electrical influences other than the magnetic field generated by the current. There is a tendency to make it. It should be understood that it is desirable to have a Hall effect element 208 that is sensitive only to magnetic fields and not to electromagnetic fields. The electromagnetic shield 222 is described in more detail below in connection with FIGS.

  Although the electromagnetic shield 222 is illustrated in connection with the current sensor 200 of FIGS. 7 and 8, any of the current sensors described herein, including flip chip and non-flip chip configurations, may be associated with the associated Hall effect. It should be understood that the electromagnetic shield 222 may be the same as or similar to the electromagnetic shield 222 disposed in the vicinity of the element.

  Referring now to FIG. 9, a lead frame 250 is shown having the same shape as the lead frame 72 of FIG. 3 and the lead frame 152 of FIG. The lead frame 250 has a plurality of thinned portions 252 a to 252 n, which are thinner than the other portions of the lead frame 250. Thinner portions can be provided by various processes, including but not limited to chemical etching and stamping.

  The current conductor portion 254 has a surface 254a and a thickness t1 that may be the same as or similar to the thickness of the other thinned portions 252b-252n. The other part of the lead frame has a thickness t2. In one particular embodiment, the thickness t1 of the current carrying portion 254 is the same as the thickness of the other thinned portions 252b-252n, and the thickness t1 is approximately half of the thickness t2. In one embodiment, the current conductor portion 254 has an essentially rectangular cross section with a thickness t1.

  When the current passing through the current conductor portion 254 exists, for example, the current conductor portion 254 thinner than the current conductor portion 74 of FIG. 3 is near the surface 254a, and the current conductor portion 74 of FIG. It should be understood that it has a higher current density than it has near 74a. That is, the current is compressed closer to the surface 254a than in the thicker current conductor portion. As a result, the magnetic field generated by the current has a higher magnetic flux density near the surface 254a.

  Thus, when the lead frame 250 is used in place of the lead frame 72 of FIG. 3, the Hall effect elements 78a, 78b are subjected to a larger magnetic field, resulting in a more sensitive current sensor.

  Other thinned portions 252b-252n provide other advantages. For example, when the lead frame 250 is molded into a plastic enclosure body, the other thinned portions 252b-252n tend to lock the lead frame 250 more securely within the molded body.

The thickness t1 is selected according to various factors including, but not limited to, the maximum current to be passed through the current conductor portion 254.
It should be understood that the thinned portion can also be applied to other lead frames shown above in embodiments other than the embodiment of FIG. 3 to achieve the same advantages.

  Referring now to FIG. 9A, an alternative current conductor portion 270 suitable as an alternative to the current conductor portion 254 of FIG. 9 is a T-shaped cross section when viewed from the cross section taken along line 9A-9A of FIG. Have The T-shape has a surface 270a and a first thickness t3 and a second thickness t4. The thickness t3 may be the same as or similar to the thickness t1 in FIG. 9, and the thickness t4 may be the same as or similar to the thickness t2 in FIG. In one particular embodiment, thickness t3 is approximately half of thickness t4.

  For substantially the same reason as described above in connection with FIG. 9, the magnetic field generated in response to the current passing through the current conductor portion 270 is near the surface 270a and the current conductor portion 270 has a uniform thickness. Higher than in the case of having t4.

  Although current conductor portion 254 (FIG. 9) and current conductor portion 270 have been described as having rectangular and T-shaped cross sections, respectively, other cross-sectional shapes can be provided to achieve the above advantages. Should be understood.

  Referring now to FIG. 10, another exemplary current sensor 300 according to the present invention is provided as a combination of a plurality of leads 302a-302h and a first current conductor portion 304a and a second current conductor portion 304b. And a lead frame 302 (also referred to herein as a lead frame portion). The current sensor 300 also includes a substrate 306 having a first surface 306a and a second surface 306b opposite to the first surface 306a. The substrate 306 has a Hall effect element 308 that is diffused into, or disposed on, or supported by the first surface 306a. The substrate 306 is disposed on the lead frame 302 so that the Hall effect element 308 is in the vicinity of the current conductor 304. In the illustrated embodiment, the substrate 306 has an upside down orientation (ie, the first surface 306a is directed downward) with respect to the conventional orientation of the substrate mounted in the integrated circuit package. The substrate 306 is a flip chip having solder balls 320a-320e on the first surface 306a of the substrate 306. Solder balls 320a-320e are directly coupled to lead wires 302e-302h. An insulating layer 330 can separate the substrate 306 from the lead frame 302. The insulating layer 330 may be the same as or similar to the insulator 24 shown in FIG.

  In one particular embodiment, the second current conductor portion 304b is coated directly on the first surface 306a of the substrate 306 and the insulating layer 330 is not used. The second current conductor portion 304b can be coated by any conventional integrated circuit coating technique, including but not limited to sputtering and electroplating. In other embodiments, the second current conductor portion 304b is a conductive structure that is remote from the first surface 306a of the substrate 306, but proximal to the first surface 306a, and the insulating layer 330 is the first The two current conductor portions 304 b and the first surface 306 a of the substrate 306 are disposed.

As shown, it should be understood that the Hall effect element 308, the insulating layer 330, the second current conductor portion 304b, and the first current conductor portion are under the substrate 306.
In these configurations, the Hall effect element 308 is disposed in the vicinity of the current conductor portion 304 at a predetermined position with respect to the current conductor portion 304, so that the magnetic field generated by the current 316 passing through the current conductor portion 304 is , In a direction substantially aligned with the maximum response axis of the Hall effect element 308. Here, the Hall effect element 308 has a maximum response axis aligned with the z-axis 326. Thus, as shown, the Hall effect element 308 is disposed beside the current conductor portion 304 (ie, slightly offset along the y-axis 324), where the magnetic field is along the z-axis 326. Directed. However, a Hall effect element having a maximum response axis aligned in another direction, or another type of magnetic field sensor, such as a magnetoresistive element, may be placed in a different position with respect to the current conductor part 304, eg, (z (In the direction of axis 326).

  Insulating layer 330 may be an intervening insulating layer or a substrate insulating layer associated with substrate 306. In some embodiments where the insulating layer 330 is an intervening insulating layer, the insulating layer 330 is a ceramic intervening insulating layer.

  In some embodiments, where the insulating layer 330 is a substrate insulating layer associated with the substrate 306, the insulating layer 330 is a substrate tape insulating layer formed by a taping process. The substrate tape insulating layer can be composed of a tape that is affixed to a substrate, including but not limited to a polymer tape, such as a Kapton ™ tape.

  In yet another embodiment where the insulating layer 330 is a substrate insulating layer associated with the substrate 306, the insulating layer 330 is a substrate covering insulating layer formed by a coating process. The coating processes used to form the insulating layer 330 include, but are not limited to, screen printing processes, spin coating processes, sputtering processes, plasma enhanced chemical vapor deposition (PECVD) processes, and low pressure chemical vapor deposition (LPCVD) processes. A variety of processes can be included without limitation. The screen printing process can provide a substrate insulating layer composed of a variety of materials, including but not limited to polymers and ceramic materials. The spin coating process is composed of various materials including but not limited to polymers such as polyimide (eg trade name Pyralin ™) and bisbenzocyclobutene (BCB) (eg trade name Cyclotene ™). A substrate insulating layer can be provided. The sputtering process can result in a substrate insulating layer composed of a variety of materials, including but not limited to nitrides and oxides. The PECVD process can result in a substrate insulating layer composed of a variety of materials, including but not limited to nitrides and oxides. The LPCVD process can result in a substrate insulating layer composed of a variety of materials, including but not limited to nitrides and oxides.

  In still other embodiments, where the insulating layer 330 is a substrate insulating layer associated with the substrate 306, the insulating layer 330 is a substrate oxide insulating layer formed by an oxide generation process. The substrate oxide insulating layer can be made of, for example, silicon dioxide.

  In operation, current 316 flows in parallel coupled leads 302c, 302d and exits current conductor section 304 and also exits coupled leads 302a, 302b in parallel. The current flowing through the current conductor 304 generates a magnetic field that is sensed by the Hall effect element 308. As described above, the Hall effect element 308 is in the immediate vicinity of the current conductor 304 and is in a predetermined position with respect to the current conductor 304, where the magnetic field generated by the current is the maximum response axis of the Hall effect element 308. Substantially aligned. This arrangement results in a greater voltage output from the Hall effect element 308 and thus greater sensitivity.

In this configuration, it should be understood that the current 316 flowing through the current conductor portion 304 is shunted between the first and second current conductor portions 304a, 304b, respectively.
The lead frame 302 is shown as having curved lead wires 302a-302h suitable for surface mounting to a circuit board, but other shapes, including but not limited to through-hole leads having a linear shape, may be used. It should be understood that a lead frame having a lead can be used.

  Although only one Hall effect element 308 is shown on the first surface 306a of the substrate 306, it should be understood that multiple Hall effect elements may be used with the present invention. Also, other circuits, such as amplifiers, can be diffused into or coupled to the first and / or second surfaces 306a, 306b of the substrate 306 or supported by the surfaces 306a, 306b. .

  Although five solder balls 320a-320e are shown, any number of solder balls can be provided, including dummy solder balls for stabilizing the substrate 306. Also, although solder balls 320a-320e are shown, gold bumps (bumps), eutectic or lead-containing solder bumps, lead-free solder bumps, gold stud bumps, polymer conductive bumps, anisotropic conductive Other connection methods may also be used, including but not limited to conductive pastes, conductive films, or wire bonds.

  Although the substrate 306 is illustrated in a flip-chip configuration, in other embodiments, the substrate 306 can be mounted in a conventional manner, and when the integrated circuit 300 is mounted on the top surface of the circuit board, the first One surface 306a overlies the second surface 306b. In these configurations, the first and second current conductor portions 304a, 304b, respectively, are on the first surface 306a of the substrate 306, respectively.

  Referring now to FIG. 11, like elements of FIG. 10 are shown with like reference numerals, providing a current conductor portion 354 that is different from the current conductor portion 304 of FIG. This is different from the current sensor 300 of FIG. The current conductor portion 354 includes a first current conductor portion 354a and a second current conductor portion 304b. Unlike the lead frame 302 having the first current conductor portion 304a shown in FIG. 10, the lead frame 352 having the first current conductor portion 354a does not form a continuous current path. In this configuration, it should be understood that all current 316 flowing through the current conductor portion 354 passes through the second current conductor portion 304b. Thus, the current 316 passes closer to the Hall effect element 308 than in the current sensor 300 of FIG. 10, resulting in higher sensitivity.

  As described above in connection with FIG. 10, the substrate 306 is illustrated in a flip chip configuration, but in other embodiments, the substrate 306 can be mounted conventionally and the integrated circuit 300 is a circuit board. When mounted on the top surface of the first surface 306a, the first surface 306a is over the second surface 306b. In these configurations, the first and second current conductor portions 354a, 304b are each on the first surface 306a of the substrate 306.

  Referring now to FIG. 12, like elements of FIG. 10 are shown with like reference numerals and have only a current conductor portion 304a (ie, there is no current conductor portion 304b (FIG. 10)). By providing the portion 304, the current sensor 400 is different from the current sensor 300 of FIG. The lead frame 302 having the first current conductor portion 304a forms a continuous current path. It should be understood that in this configuration, all current 316 passes through current conductor portion 304a.

  An insulating layer 402 is disposed between the current conductor portion 304 a and the first surface 306 a of the substrate 306. In some embodiments, the insulating layer 402 is an intervening insulating layer, such as a ceramic layer, as described above in connection with FIG. In other embodiments, the insulating layer 402 is a substrate insulating layer associated with the substrate. In other embodiments, the insulating layer 402 is a lead frame insulating layer associated with the lead frame 302. It should be understood that the insulating layer 402 can extend beyond the substrate 306 in a direction along the y-axis 324 when associated with a lead frame. This configuration provides improved reliability because the edge of the substrate 306 is unlikely to contact the lead frame 302.

The intervening insulating layer and the substrate insulating layer have been described above with reference to FIG.
In some embodiments, where the insulating layer 402 is a lead frame insulating layer associated with the lead frame 302, the insulating layer 402 is a lead frame tape insulating layer formed by a taping process. The leadframe tape insulation layer can be composed of tape that is affixed to a leadframe, including but not limited to polymer tape, such as Kapton ™ tape.

  In other embodiments, where the insulating layer 402 is a lead frame insulating layer associated with the lead frame 302, the insulating layer 402 is a lead frame sprayed insulating layer formed by a thermal spray process. The lead frame sprayed insulation layer may be a polymer, such as polyimide (eg trade name Pyralin ™), bisbenzocyclobutene (BCB) (eg trade name Cyclotene ™), a thermally sprayed dielectric (eg trade name 3MScotch ™). ) Insulating spray 1601 and Loctite ™ ShadowCure ™ 3900), or sprayed ceramic coatings, but can be composed of a variety of materials.

  In other embodiments, where the insulating layer 402 is a lead frame insulating layer associated with the lead frame 302, the insulating layer 402 is a lead frame covering insulating layer formed by a covering process. The leadframe coating insulation layer can be formed by a variety of processes, including but not limited to screen printing processes. The screen printing process can result in a leadframe covering insulation layer composed of a variety of materials including, but not limited to, polymers and ceramics. In yet another embodiment, the leadframe coating insulation layer is formed by a vacuum coating process. In these embodiments, the leadframe covering insulating layer can be composed of, for example, a polymer, such as parylene.

  In yet another embodiment, where the insulating layer 402 is a lead frame insulating layer associated with the lead frame 302, the insulating layer 402 is a lead frame oxide insulating layer formed by an oxide generation process. The lead frame oxide insulating layer can be composed of, for example, a sputtered oxide layer coated on the lead frame 302.

  Referring now to FIG. 13, another exemplary current sensor 450 includes a lead frame 452 (also referred to herein as a lead frame portion) having a plurality of lead wires 452a-452h and a current conductor portion 454. The lead frame 452 may be similar to the lead frame 302 of FIG. Current sensor 450 also includes a substrate 456 having a first surface 456a and a second surface 456b opposite to the first surface 456a. The substrate 456 includes a Hall effect element 458 that is diffused into, or disposed on, or supported by the first surface 456a. The substrate 456 is disposed on the lead frame 452 such that the Hall effect element 458 is in the vicinity of the current conductor 454. In the illustrated embodiment, the substrate 456 has an upside down orientation (ie, the first surface 456a is directed downward) with respect to the conventional orientation of the substrate mounted in the integrated circuit package. Substrate 456 is configured as a flip chip having solder balls 460a-460e on first surface 456a of substrate 456. Solder balls 460a-460e are directly coupled to lead wires 452e-452h. An insulating layer 470 can separate the substrate 456 from the lead frame 452. The insulating layer 470 may be the same as or similar to the insulating layer 24 shown in FIG. The insulating layer 470 can cover a substantial portion of the surface 456a. The insulating layer has regions 470a, 470b that lack insulating material, as will become more apparent from the discussion of FIG. 13A below.

  The current conductor portion 454 has two features 454a, 454b (also referred to herein as ridges (bumps)) that extend upward from the current conductor portion 454 in the direction of the z-axis 476. The raised portions 454a, 454b have dimensions and shapes selected to provide an electrical contact between the current conductor portion 454 and the first surface 456a of the substrate 456. In particular, the two ridges 454a, 454b provide electrical contacts to metallization features (not shown) on the first surface 456a of the substrate 456 and are also disposed on the first surface 456a of the substrate 456. Provide electrical coupling to installed circuitry (not shown). The electrical coupling and circuitry coupled thereto will be discussed in more detail below in connection with FIG.

  The lead frame 452 having the first current conductor portion 454 forms a continuous current path. It should be understood that in this configuration, most of the current 466 passes through the current conductor 454 and some small amount of current 466 flows through the raised portions 454a and 454b into the circuit described above on the substrate 456. However, it should be understood that the circuit described above can be designed to draw only a small amount of current 466. Accordingly, almost all of the current 466 passes through the current conductor portion 454.

  In some embodiments, the insulating layer 470 is an intervening insulating layer, such as a ceramic layer. In other embodiments, the insulating layer 470 is a substrate insulating layer associated with the substrate. In other embodiments, the insulating layer 470 is a lead frame insulating layer associated with the lead frame 452.

The intervening insulating layer, the substrate insulating layer, and the lead frame insulating layer have been described above with reference to FIG.
The ridges 454a, 454b are circuits adapted to detect an overcurrent condition, i.e., to detect a current passing through the current conductor 452a that is greater than a predetermined current level or current threshold. It will become apparent from the following discussion in conjunction with FIGS. 13A and 15 that a connection coupling the current conductor portion 454 can be provided. To this end, the circuit can detect a voltage difference between the first ridge 454a and the second ridge 454b that is greater than a predetermined voltage drop or voltage threshold.

  Although only one current conductor portion 454 is shown, it should be understood that a second current conductor portion may be used. The second current conductor portion may be the same as or similar to the second current conductor portion 304b of FIG. 10, and may be similarly disposed on the first surface 456a of the substrate 456 or on the insulator 470. .

  Referring now to FIG. 13A, like elements of FIG. 13 are shown having like reference numerals, the current conductor portion 454 includes a raised portion 454a that insulates the current conductor portion 454. Bonding to first surface 456a of substrate 456 through region 470a of layer 470.

  The Hall effect element 458 is disposed in the first surface 456a of the substrate 456 or on the first surface 456a. Another circuit 480 that is electrically coupled to the ridge 454a may be disposed in or on the first surface 456a of the substrate 456. An exemplary circuit 480 is described below in connection with FIG.

  In other embodiments, the current conductor portion 454 is connected to the region 470a of the insulating layer 470, such as by using a wire coupling portion 478, shown here as an imaginary line, to show an alternative configuration to the raised portion 454a. To the first surface 456a of the substrate 456. It should be understood that a second wire joint (not shown) can be used in place of the other ridge 454b of FIG. It will be appreciated that the wire coupling portion 478 appears to terminate in the substrate 456 immediately above the current conductor portion 454, but the termination may be to the side of the current conductor portion 454.

  Referring now to FIG. 14, another exemplary current sensor 500 includes a lead frame 502 having a plurality of leads 502a-502h. Although only leads 502c and 502d are shown for clarity, it should be understood that other leads 502a-502h are configured in a conventional lead configuration. The current sensor 500 also includes a substrate 506 having a first surface 506a and a second surface 506b opposite to the first surface 506a. The substrate 506 has a Hall effect element 508 diffused into the first surface 506a or disposed on the first surface 506a. A conductive fastener 503 having a current conductor portion 504 is coupled to the leads 502a-502d. The current conductor portion 504 includes two raised portions 504a and 504b.

  The conductive fastener 503 is formed with a curved portion such that the conductive fastener 503 extends over the first surface 506a of the substrate 506. The substrate 506 is disposed on the lead frame 502 such that the Hall effect element 508 is in the vicinity of the current conductor portion 504. In the illustrated embodiment, the substrate 506 has a conventional mounting orientation with the first surface 506a facing up. An insulator 514 (also referred to herein as an insulating layer) can insulate the substrate 506 from the conductive fastener 503. The insulator 514 has two regions 514a, 514b that are devoid of any insulating material. The insulator 514 may be similar to the insulator 24 shown in FIG.

  It should be understood that when the integrated circuit 500 is assembled, the ridges 504a, 504b align with and extend into the regions 514a, 514b of the insulating layer 514 that lack the insulating material. The raised portions 504a, 504b have dimensions and shapes selected to provide an electrical contact between the current conductor portion 504 and the first surface 506a of the substrate 506. In particular, the two ridges 504a, 504b provide electrical contacts to metallization features (not shown) on the first surface 506a of the substrate 506, and are also disposed on the first surface 506a of the substrate 506. Provide electrical coupling to installed circuitry (not shown). The electrical coupling and circuitry coupled thereto will be discussed in more detail below in connection with FIG.

  Although a conductive fastener 503 is illustrated having a current conductor portion 504 that includes ridges 540a, 540b, in other configurations, other current conductor portions, such as a linear current including two features or ridges. It should be understood that conductor portions can also be used.

  Although only one current conductor portion 504 is shown, it should be understood that a second current conductor portion may be used. The second current conductor portion may be the same as or similar to the second current conductor portion 304b of FIG. 10, and may be similarly disposed on the first surface 506a of the substrate 506 or on the insulator 514. .

  Referring now to FIG. 14A, like elements of FIG. 14 are shown with like reference numerals, the current conductor portion 504 includes a raised portion 504a that insulates the current conductor portion 504. Coupled to substrate 506 through region 514 a of layer 514.

  The Hall effect element 508 is disposed in the surface 506a of the substrate 506 or on the surface 506a. Another circuit 530 that is electrically coupled to the raised portion 504a may be disposed in or on the substrate 506a of the substrate 506. An exemplary circuit 530 is described below in connection with FIG.

  In other embodiments, the current conductor portion 504 is connected to the region 514a of the insulating layer 514, such as by using a wire joint 532, shown here as an imaginary line, to show an alternative configuration to the raised portion 504a. To the first surface 506a of the substrate 506. It should be understood that a second wire bond (not shown) can be used in place of the other ridge 504b of FIG. It should be understood that the wire coupling portion 532 appears to terminate in the substrate 506 under the current conductor portion 506, but the termination may be to the side of the current conductor portion 506.

  Referring now to FIG. 15, exemplary circuit 550 may be the same as or similar to circuit 480 used in current sensor 450 of FIG. 13A or circuit 530 used in current sensor 500 of FIG. 14A. Circuit 550 can be coupled to Hall effect element 552. Hall effect element 552 may be the same as or similar to Hall effect element 458 of FIGS. 13 and 13A, or Hall effect element 508 of FIGS. 14 and 14A.

  Hall effect element 552 is coupled to current sensing circuit 554, which includes dynamic offset cancellation circuit 553. Dynamic offset cancellation circuit 553 provides DC offset adjustment for DC voltage errors associated with Hall effect element 552.

  Dynamic offset cancellation circuit 553 is coupled to amplifier 556, which amplifies the offset adjusted Hall output signal. Amplifier 556 is coupled to filter 558, which may be a low pass filter, a high pass filter, a band pass filter, and / or a notch filter. Filter 558 is selected according to various factors including, but not limited to, the desired response time and the frequency spectrum of noise associated with Hall effect element 552, dynamic offset cancellation circuit 553, and amplifier 556. . In one particular embodiment, filter 558 is a low pass filter. Filter 558 is coupled to output driver 560, which provides current sensor output signal 571 to node 572 for transmission to other electronic circuitry (not shown). As described more fully below, the current sensor output signal indicates the magnitude of the current passing through the conductor.

  Trim control circuit 564 is coupled to node 570. Node 570 can receive a trim signal, which typically allows trimming of various current sensor parameters during manufacturing. To this end, trim control circuit 564 includes one or more counters that are enabled (enabled) by an appropriate signal applied to node 570.

  Trim control circuit 564 is coupled to a quiescent output voltage (Qvo) circuit 562. The quiescent output voltage is the voltage of the output signal 571 when the current sensed by the Hall effect element 552 is zero. Nominally, for a unipolar supply voltage, Qvo is equal to Vcc / 2. By providing the appropriate trim signal via node 570 to a first trim control circuit counter within trim control circuit 564, trim control circuit 564 then controls a digital to analog converter (DAC) within Qvo circuit 562, Qvo can be trimmed (adjusted).

  Trim control circuit 564 is further coupled to sensitivity adjustment circuit 566. Sensitivity adjustment circuit 566 allows the gain of amplifier 556 to be adjusted to adjust the sensitivity of current sensor 550. Applying an appropriate trim signal to a second trim control circuit counter within trim control circuit 564 via node 570, which then trims the sensitivity by controlling the DAC within sensitivity adjustment circuit 566. Can do.

  Trim control circuit 564 is further coupled to sensitivity temperature compensation circuit 568. Sensitivity temperature compensation circuit 568 allows adjustment of the gain of amplifier 556 to compensate for gain variations due to temperature. An appropriate trim signal is provided via node 570 to a third trim control circuit counter within trim control circuit 564, which then controls the DAC within sensitivity temperature compensation circuit 568, thereby providing a sensitivity temperature compensation circuit. 568 can be trimmed.

  Here, the Hall effect element 552 is disposed in the vicinity of the current conductor portion 604 shown apart from the Hall effect element 552 for easy understanding. The current conductor portion 604 may be the same as or similar to the current conductor portion 454 of FIGS. 13 and 13A formed by coupling integrated circuit leads or the current conductor portion 504 of FIGS. 14 and 14A. In operation, current 584 enters node 574 of current sensor 550, passes through current conductor portion 604, exits node 576, where it passes through switch 580 and load 586, both of which are external to integrated circuit 550. It may be. The switch 580 may be a relay or a field effect transistor (FET), for example.

  It is desirable to stop the current 584 upon detection of an overcurrent condition, such as a short circuit, which typically results in an undesirably high current 584 that can damage the integrated circuit 550 or other related circuitry. is there. For this reason, the overcurrent circuit 590 can detect an overcurrent state.

  Overcurrent circuit 590 includes a comparator 591 coupled to receive current sensor output signal 571 and also coupled to voltage reference 592. Output 593 of comparator 591 is coupled to logic gate 594. Logic gate 594 is coupled to a gate driver, which generates a control signal 597 at node 578 of circuit 550. Node 578 is coupled to the control node of switch 580 and is operable to open switch 580 and stop current 584 in response to detection of an overcurrent condition by Hall effect element 552.

  Logic gate 594 is also coupled to fault circuit 598, which generates fault output signal 599 at node 588 of integrated circuit 550. Fault output signal 599 indicates an overcurrent condition, current 584 exceeds a predetermined current.

  It should be understood that amplifier 591 and voltage reference 592 are responsive to current sensor output signal 571, which is responsive to the signal generated by Hall effect element 552. It should be understood that the Hall effect element 552 has a relatively slow response time. Thus, if the switch 580 is controlled only in the manner described above in response to the signal generated by the Hall effect element 552, any rapid overcurrent condition will accumulate before the switch 580 can be opened. Circuit 550 or load 586 can be damaged. The circuit described below can provide a faster response speed to overcurrent conditions.

  Comparator 600 and voltage reference 602 are coupled to current conductor portion 604 of integrated circuit 550. As described above, the current conductor portion 604 is the same as or similar to the current conductor portion 454 of FIGS. 13 and 13A and the current conductor portion 504 of FIGS. 14 and 14A formed by coupling integrated circuit leads. It's okay. The coupling from current conductor 604 to voltage reference 602 and comparator 600 includes, but is not limited to, ridges 454a and 454b in FIGS. 13 and 13A and ridges 504a and 504b in FIGS. 14 and 14A. It can be provided in various forms.

  In operation, a voltage appears across the current conductor 604 in response to the current 584 because the current conductor 604 has an associated resistance. When the current 584 is sufficiently large, the output signal 601 of the comparator 600 changes state, thereby causing the control signal 597 to change state, opening the switch 580 and stopping the current. The opening of switch 580 in this manner occurs more rapidly than when switch 580 is opened only by comparator 591 in response to a signal generated by Hall effect element 592.

  15 may be integrated in a current sensor in association with a current sensor such as current sensor 450 of FIGS. 13 and 13A and current sensor 500 of FIGS. 14 and 14A. It will be understood by those skilled in the art that a simple circuit is shown.

It should be understood that in other embodiments, the switch 580 can be integrated within the current sensor circuit 550.
Referring now to FIG. 16, another exemplary current sensor 650 is similar to the current sensor 500 of FIG. 14, but the current sensor 650 includes a second substrate 655, described more fully below. Current sensor 650 includes a lead frame 652 having a plurality of lead wires 552a-552h. The current sensor 650 also includes a substrate 656 having a first surface 656a and a second surface 656b opposite to the first surface 656a. A conductive fastener 654 having a current conductor portion 655 is coupled to the leads 652a-652d. The current conductor portion 605 includes two raised portions 655a and 655b. A second substrate 666 having a magnetic field sensing element such as a magnetoresistive element (not shown) disposed thereon may be disposed on the current conductor portion 655. The magnetic field sensing element on the second substrate 666 can be coupled to the first surface 656a of the substrate 656 using wire couplings 668a, 668b, and the like.

  The conductive fastener 654 is formed with a curved portion such that the conductive fastener 654 extends over the first surface 656a of the substrate 656. In the illustrated embodiment, the substrate 656 has a conventional mounting orientation with the first surface 656a facing up. An insulator 664 (also referred to herein as an insulating layer) can insulate the substrate 656 from the conductive fastener 654. The insulator 664 has two regions 664a, 664b that are devoid of any insulating material. The insulator 664 may be similar to the insulator 24 shown in FIG.

  Shown in assembled form, the ridges 655a, 655b align with and extend into regions 664a, 664b of the insulating layer 664 that lack the insulating material. The raised portions 655a, 655b have dimensions and shapes selected to provide an electrical contact between the current conductor portion 655 and the first surface 656a of the substrate 656. In particular, the two ridges 655 a, 655 b provide electrical contacts to metallization features (not shown) on the first surface 656 a of the substrate 656, and are also disposed on the first surface 656 of the substrate 656. Provide electrical coupling to installed circuitry (not shown). Electrical coupling, and the circuitry coupled thereto, was discussed in more detail above in connection with FIG.

  Although a conductor fastener 654 is shown having a current conductor portion 655 that includes ridges 655a, 655b, in other configurations, other current conductor portions, eg, linear current conductors that include two features or ridges. It should be understood that parts may be used.

  Although only one current conductor portion 655 is shown, it should be understood that a second current conductor portion may be used. The second current conductor portion may be the same as or similar to the second current conductor portion 304b of FIG. 10, and may be similarly disposed on the first surface 656a of the substrate 656 or on the insulator 664. .

  The current sensor 650 has two substrates 656 and 666. The current sensor 650 can provide two substrates, along with providing a current carrying conductor, eg, 655, in the vicinity of the magnetic field sensing element and / or an overcurrent circuit as described above in connection with FIG. It shows only one configuration including The other two substrate configurations are named “Arrangements for an Integrated Sensor”, agent reference number ALLEG-162PUS, inventor Michael C. Doogue, Vijay Mangtani, and William P. Taylor, U.S. Patent Application No. 11/335944, filed January 20, 2006. Any of the configurations described herein can be combined with current carrying conductors and / or overcurrent circuits.

  The current sensor 450 in FIGS. 13 and 13A, the current sensor 500 in FIGS. 14 and 14A, the current sensor 550 in FIG. 15, and the current sensor 650 in FIG. 16 are respectively current conductor portions 454, 504, 604, and 655; Shown with coupling between the associated overcurrent circuit represented by circuit 590 of FIG. However, in other embodiments, other current sensors similar to current sensors 450, 500, 550, and 650 provide coupling between current conductors 454, 504, 604, and 655 and associated overcurrent circuits. No, i.e., no ridges or wire joints. That is, referring to the current sensor 550 of FIG. 15, the current conductor 604 of FIG. 15 is not coupled to the node 574 or 576 of FIG. In these embodiments, overcurrent circuit 590 (FIG. 15) remains coupled to nodes 574 and 576, and nodes 574 and 576 couple to other circuit elements in addition to current sensor 550. For example, in some configurations, the nodes 574, 576 can be coupled to circuit traces on the circuit board, which carry the same current that passes through the current conductor portion 604 (FIG. 15). In these configurations, the overcurrent circuit 590 can sense a voltage drop due to the current passing through the circuit trace, providing essentially the same effect, and the overcurrent circuit 590 is as described above. Provides similar functionality.

  Referring now to FIG. 17, like elements of FIG. 10 are shown having like reference numerals, and the current sensor 700 has a lead frame 702 (having a plurality of lead wires 702a-702h and a shunt conductor portion 706). (Also referred to as a lead frame portion in this specification). Similarly to the current sensor 300 of FIG. 10, the current sensor 700 includes a current conductor portion 304 provided as a combination of the first current conductor portion 304a and the second current conductor portion 304b. Accordingly, the lead frame 702 has two couplings of the lead wires 702a, 702b to the lead wires 702c, 702d. The first coupling is provided by the current conductor portion 304 and the second coupling is provided by the shunt conductor portion 706.

  In some embodiments, the current sensor 700 is disposed between a first flux concentrator 708 disposed on the shunt conductor portion 706 and generally between the shunt conductor portion 706 and the Hall effect element 308. It can also include a second magnetic flux concentrator 710, sometimes referred to as a magnetic shield (magnetic flux shield or shield portion). Each of the first and second magnetic flux concentrators 708, 710 can be constructed from a variety of soft magnetic materials, including but not limited to ferrite, permalloy, or nickel iron alloy. The magnetic flux concentrators 708 and 710 can be applied in various forms. For example, the flux concentrator can be coated on the lead frame 706 by a coating process.

  The flux concentrator 708 can be formed by a direct electroplating process on the lead frame 702 or by the use of Kapton tape affixed to the shunt conductor portion 706, the other side of the Kapton tape being laminated or tape It may have a soft magnetic material that may be formed by the process. The shield part 710 can be disposed in the lead frame and fixed with an adhesive during package assembly.

  In operation, current conductor portion 304 provides a current path for a portion of current 316 and shunt conductor portion 706 provides another current path for another portion of current 316. It should be understood that the current sensor 700 is sensitive to the current 316 that is related to a portion of the current 316 that flows through the current conductor portion 304. As a result, the current sensor 700 can have a lower sensitivity to the current 316 than the current sensor 300 of FIG. 10 that does not have the shunt conductor portion 706. Thus, the current sensor 700 can operate over a larger range of current without saturating the circuit coupled to the Hall effect element 308 (eg, the circuit 554 of FIG. 15). The larger range of current is not only due to the effect on the Hall effect element 308 provided by the shunt conductor 706, but the lead frame 702 having the shunt conductor 706 can withstand a larger amount of current without overheating. This is also due to the fact that the lead frame 702 can have a lower total resistance current path than the lead frame 302 of FIG.

  Although the aforementioned portion of the current 316 flowing through the current conductor portion 304 and flowing through the shunt conductor portion 706 tends to provide the results described above, a portion of the current 316 flowing through the shunt conductor portion 706 is shown. It should also be understood that the section generates a magnetic field near the Hall effect element 308, which tends to be opposite to the magnetic field generated by a portion of the current 316 flowing through the current conductor section 304. In some embodiments, a reverse magnetic field may be undesirable. Each of the first and second flux concentrators 708, 710 tends to converge or shield the magnetic field generated by a portion of the current 316 flowing through the shunt conductor portion 706, and thus the first and second Each of the flux concentrators 708, 710 tends to keep the magnetic flux away from the Hall effect element 308.

  The separation distance between the shunt conductor 706 and the Hall effect element 308 controls and / or minimizes the effect on the Hall effect element 308 from the magnetic field generated by a portion of the current 316 flowing through the shunt conductor 706. You can choose to do. It will be appreciated that larger separation distances tend to reduce the effect.

  The size setting of the shunt conductor portion 706 in a manner that affects the resistance of the shunt conductor portion 706 is such that the current 316 flowing through the shunt conductor portion 706 is more than the part of the current 316 flowing through the current conductor portion 304. Can affect the department. Therefore, the size and shape of the shunt conductor portion 706 can be selected to provide a selected resistance. Thus, the dimensioning can affect the overall sensitivity of the current sensor 700.

  Referring now to FIG. 18, this figure has elements similar to those shown in FIG. 8, and the current sensor 750 has leads 752a-752d (752a, 752b not shown, respectively) of the lead frame 752, A conductive fastener 754 having a current conductor portion 756 coupled to the lead wires 202a, 202b of FIG. The conductive fastener 754 also includes a shunt conductor portion 758 having similar function and operating characteristics as described above with respect to the shunt conductor portion 706 of FIG. The integrated circuit 750 also has first and second flux concentrators 764, 766, respectively, that have similar functions and operating characteristics as the first and second flux concentrators 758, 760 described above with reference to FIG. One or more of the above can also be included.

  Similar to the configuration described in connection with FIGS. 7 and 8, the conductive fastener 754 has a shape designed to extend over the first surface 760a of the substrate 760. A magnetic field sensing element 762, eg, a Hall effect element, is disposed in or on the first surface 760a of the substrate 760.

  Although the shunt conductor portions 706, 758 and flux concentrators 708, 710, 764, 766 of FIGS. 17 and 18 are illustrated in connection with a particular current sensor configuration, similar shunt conductor portions and similar It should be understood that the flux concentrator can be included in any of the flip chip or non-flip chip configurations shown herein.

  Referring now to FIG. 19, the electromagnetic shield 800 may be the same as or similar to the electromagnetic shield 212 of FIG. The electromagnetic shield 800 is generally disposed over the Hall effect element 880, and the Hall effect element 880 may be the same as or similar to the Hall effect element 208 of FIG. The electromagnetic shield 800 includes a first portion 802 and a second portion 804 separated by a slit 806. First portion 802 and second portion 804 are coupled by conductive region 808. A coupling pad 810 allows the electromagnetic shield 800 to be coupled to a DC voltage, such as a ground voltage.

  The electromagnetic shield 800 can be formed from a metal layer during the manufacture of a current sensor, eg, the current sensor 200 of FIG. The metal layer can be composed of various materials, such as aluminum, copper, gold, titanium, tungsten, chromium, or nickel.

  It should be understood that AC eddy currents 812, 814 can be induced in the electromagnetic shield 800 in the presence of an AC magnetic field (eg, a magnetic field surrounding a current carrying conductor). Eddy currents 812 and 814 are generated as a closed loop as shown. The closed loop eddy currents 812, 814 tend to produce a magnetic field in the vicinity of the electromagnetic shield 800 that is smaller than the magnetic field that induces the eddy currents 812, 814. Thus, if the electromagnetic shield 800 is placed close to a Hall effect element, eg, the Hall effect element 208 of FIG. 8, the Hall effect element 208 receives a smaller magnetic field than normally received, resulting in a less sensitive current sensor, This is generally undesirable. Further, if the magnetic field associated with the eddy current is not uniform or not symmetrical about the Hall effect element 208, the Hall effect element 208 may generate an undesirable offset voltage.

  Slit 806 tends to reduce the size (ie, diameter or path length) of the closed loop through which eddy currents 812, 814 travel. The reduced size of the closed loop through which the eddy currents 812, 814 travel results in smaller eddy currents 812, 814 and a smaller local effect on the eddy current induced AC magnetic field. Thus, the sensitivity of current sensors in which Hall effect element 816 and electromagnetic shield 800 are used is not significantly affected by smaller eddy currents.

  Further, by placing the shield 800 with respect to the Hall effect element 816 as shown so that the slit 806 extends above the Hall effect element 816, the magnetic field associated with any one of the eddy currents 812, 814 is It should be understood that there is a tendency to generate a magnetic field that passes through the Hall effect element 816 in two directions and cancels over at least a portion of the area of the Hall effect element 816.

  Referring now to FIG. 20, the electromagnetic shield 850 may be the same as or similar to the electromagnetic shield 212 of FIG. The electromagnetic shield 850 includes four portions 852-858 separated by four slits 860-866. The four portions 852-858 are joined by a conductive region 876. A coupling pad 878 allows the electromagnetic shield 850 to be coupled to a DC voltage, such as a ground voltage.

  It should be understood that eddy currents 868-874 can be induced in the electromagnetic shield 850 in the presence of a magnetic field. It should be understood that due to the four slits 860-866, the dimensions (ie, diameter or path length) of the closed loop eddy currents 866-874 tend to be smaller than the dimensions of the closed loop eddy currents 812, 814 of FIG. The reduced size of the closed loop through which the eddy currents 868-874 travel has a smaller eddy current 868-874 and a smaller local effect on the eddy current-induced AC magnetic field than that caused by the shield 800 of FIG. Please understand that it will bring. Accordingly, the sensitivity of the current sensor in which the Hall effect element 880 and the electromagnetic shield 850 are used is less affected by the small eddy currents 868-874 than the sensitivity of the current sensor using the shield 800 of FIG.

  In addition, the magnetic field associated with any one of the eddy currents 868-874 by placing the shield 850 relative to the Hall effect element 880 as shown such that the slits 860-866 extend above the Hall effect element 880. Should tend to generate a magnetic field that passes through the Hall effect element 880 in two directions and cancels over at least a portion of the area of the Hall effect element 880.

  Referring now to FIG. 21, the electromagnetic shield 900 may be the same as or similar to the electromagnetic shield 212 of FIG. The electromagnetic shield 900 includes a shield 902 having interdigitated members, the member 902a being just an example. The interdigitating member is coupled to the coupling pad 906 via the conductor portion 904, which allows the electromagnetic shield 900 to be coupled to a DC voltage, such as a ground voltage.

  It should be understood that the electromagnetic shield 900 can support eddy currents having a much smaller dimension (ie, path length diameter) than the electromagnetic shield 850 of FIG. 20 or the electromagnetic shield 800 of FIG. Thus, the electromagnetic shield 900 tends to have a much smaller negative impact on the sensitivity of the current sensor than that described above.

Referring now to FIG. 22, the electromagnetic shield 950 may be the same as or similar to the electromagnetic shield 212 of FIG. The electromagnetic shield 950 includes a shielding portion 952 having a plurality of members, and the member 952a is merely an example. The member is coupled to a coupling pad 956 via a conductive portion 954, which allows the electromagnetic shield 950 to be coupled to a DC voltage, such as a ground voltage.
The advantages of electromagnetic shield 950 will be apparent from the discussion above.

  Referring now to FIG. 23, a side view of a portion of the current sensor 1000 includes a substrate 1002 having a first surface 1002a and a second surface 1002b. A Hall effect element 1004 is disposed on or in the first surface 1002a of the substrate 1002. An insulating layer 1006 is disposed under the first surface 1002a of the substrate 1002.

  An electromagnetic shield 1008 is disposed under the insulating layer 1006. The electromagnetic shield may be the same as or similar to one of the electromagnetic shields 800, 850, 900, 950 of FIGS. The electromagnetic shield 1008 includes a shield portion 1010, a conductor portion 1012, and a bond pad 1014, which may be the same as or similar to the similar structure in FIGS. A bond wire 1016, or another bonding method, can bond the bond pad 1014 to the first surface 1002a of the substrate 1002, in particular to a metal layer (not shown) on the first substrate 1002a of the substrate 1002. However, in some embodiments this is not the case, this bonding is made by a part of the integrated circuit manufacturing process, for example a metal layer coated as a base process and an additional metal layer, in which case the bonding wire 1016 Can be omitted.

  The current sensor 1000 can also include another insulating layer 1018 disposed below the electromagnetic shield 1008. Furthermore, the current sensor 1000 can include a current conductor portion 1020 disposed under the insulating layer 1018. The current conductor portion 1020 may be the same as or similar to the various current conductor portions described herein, eg, the current conductor portion 304b of FIG.

Although the current sensor 1000 is illustrated in a flip chip configuration, in other embodiments, the structure can be inverted to provide a non-flip chip configuration.
Having described preferred embodiments of the invention, it will now be apparent to those skilled in the art that other embodiments incorporating their concepts may be used. Accordingly, these embodiments should not be limited to the disclosed embodiments, but should be limited only by the spirit and scope of the appended claims. All references cited herein are hereby incorporated by reference in their entirety.

Claims (7)

In integrated circuits,
  A lead frame portion having a plurality of lead wires;
  A first current conductor portion comprising at least two of the plurality of lead wires;
  A substrate having a first surface and an opposite second surface, wherein the first surface is proximal to the first current conductor portion, and the second surface is the first current conductor portion. A substrate distal to the substrate,
  One or more magnetic field transducers disposed on the first surface of the substrate;
  A second current conductor portion coated on the first surface of the substrate, the second current conductor portion being disposed proximal to the one or more magnetic field transducers and coupled to the first current conductor portion; , A second current conductor portion.   The integrated circuit of claim 1, wherein the at least two of the plurality of leads provide a current path through the lead frame portion.   The integrated circuit of claim 1, wherein the at least two of the plurality of leads provide a current path through the second current conductor portion.   The substrate is disposed to have the first surface of the substrate above the first current conductor portion and the second surface above the first surface. Item 14. The integrated circuit according to Item 1.   The integrated circuit of claim 1, wherein at least a portion of the second current conductor portion has a T-shaped cross section.   The integrated circuit of claim 1, wherein at least a portion of the second current conductor portion has a rectangular cross section having a minimum dimension that is less than a thickness of the lead frame portion.   The integrated circuit of claim 1, further comprising at least one amplifier disposed on the substrate.

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