TWI595249B - Magnetic field sensing apparatus - Google Patents

Description

Magnetic field sensing device

The invention relates to a magnetic field sensing device.

With the popularity of portable electronic devices, the technology of an electronic compass capable of sensing the geomagnetic direction has received attention. When an electronic compass is applied to a small portable electronic device (such as a smart phone), in addition to the small volume requirement, the electronic compass is preferably capable of achieving three-axis sensing because the user When holding the phone in your hand, it may be held obliquely, and various holding angles may also occur. In addition, the electronic compass can also be applied to drones (such as remote control aircraft, remote control helicopters, etc.), and the electronic compass is also preferably capable of achieving three-axis sensing.

One conventional technique is to use a composite sensing element method to achieve three-axis sensing. Specifically, it utilizes two giant magnetoresistance (GMR) multilayer film structures (or tunneling magnetic structures) that are vertically arranged perpendicular to each other. A tunneling magnetoresistance (TMR) multilayer film structure is used with a Hall element to achieve three-axis sensing. However, since the sensing sensitivity of the Hall element is different from the sensing sensitivity of the giant magnetoresistive multilayer film structure (or the tunneling magnetoresistive multilayer film structure), this causes the accuracy on one axis to be different from the accuracy on the other two axes. . As a result, when the user rotates the portable electronic device to different angles, the sensing sensitivity to the same magnetic field is different, which causes troubles in use.

In the prior art, in order to achieve multi-axis sensing of a magnetic field, a process of two or more processes is generally used, that is, a process using two or more wafers to fabricate a multi-axial magnetic field sensing module, thus The process is complicated and it is difficult to reduce the manufacturing cost. In addition, this also makes it difficult to further reduce the magnetic field sensing device.

The present invention provides a magnetic field sensing device having a simplified structure and having a small volume.

An embodiment of the invention provides a magnetic field sensing device comprising a magnetic flux concentrator and a plurality of magnetic resistance units. The flux concentrator has a top surface, a bottom surface opposite to the top surface, and a plurality of side surfaces connecting the top surface and the bottom surface, and the magnetoresistive units are respectively disposed beside the side surfaces. The magnetoresistive units are electrically connected to at least one Wheatstone full bridge at three different times to separately measure magnetic field components in three different directions, and to output the at least one Wheatstone full bridge output respectively. Three signals corresponding to the magnetic field components in three different directions.

In an embodiment of the invention, at any one of three different times, the signal output by the at least one Wheatstone bridge is a differential signal corresponding to a magnetic field component of one of three different directions. The differential signals generated by the at least one Wheatstone full bridge corresponding to the magnetic field components of the remaining two of the three different directions are all zero.

In an embodiment of the invention, the magnetic field sensing device further includes a switching circuit electrically connected to the magnetoresistance units, wherein the at least one Wheatstone full bridge is three types of Wheatstone full bridges, and the switching circuit is different in three The magnetoresistance units are electrically connected to the three Wheatstone full bridges respectively. The three Wheatstone bridges respectively measure the magnetic field components in three different directions and respectively output the magnetic field components corresponding to the three different directions. Three signals.

In an embodiment of the invention, the magnetic field sensing device further includes a substrate, wherein the magnetic flux concentrator and the magnetoresistance units are disposed on the substrate, and the switching circuit is disposed in the substrate.

In an embodiment of the invention, the magnetic field sensing device further includes a plurality of magnetization direction setting elements respectively disposed adjacent to the magnetoresistance units to respectively set the magnetization directions of the magnetoresistance units, wherein the at least one Wheatstone The bridge is a fixed connection of the Wheatstone full bridge, and the magnetization direction setting components respectively set the magnetization directions of the magnetoresistance units into three different combinations at three different times, so that the Wheatstone is fully The bridge measures the magnetic field components of three different directions at three different times, and outputs three signals corresponding to the magnetic field components of three different directions.

In an embodiment of the invention, each of the magnetoresistive units includes at least one anisotropic magnetoresistance.

In an embodiment of the invention, the anisotropic magnetoresistance in each of the magnetoresistive elements extends in a direction parallel to the corresponding side surface and parallel to the top surface and the bottom surface.

In an embodiment of the invention, the sides are four sides, and the normal lines of the two adjacent sides are perpendicular to each other, and the three different directions are a first direction, a first a second direction and a third direction, the first direction and the second direction are on a plane parallel to the plurality of normals of the four sides, and are at an angle of 45 degrees with the normal lines, and the first direction and the second direction are perpendicular to each other And the third direction is perpendicular to the first direction and the second direction.

In an embodiment of the invention, the material of the flux concentrator comprises a ferromagnetic material having a magnetic permeability greater than 10.

In an embodiment of the invention, the residual flux of the flux concentrator is less than 10% of its saturation magnetization.

In an embodiment of the invention, the two diagonal lines of the bottom surface are respectively parallel to two of the three different directions, and the remaining one of the three different directions is perpendicular to the bottom surface.

In an embodiment of the invention, the magnetic field sensing device further includes a substrate, wherein the magnetic flux concentrator and the magnetoresistive units are disposed on the substrate, and the substrate is a semiconductor substrate, a glass substrate or a circuit substrate.

In an embodiment of the invention, the number of Wheatstone full bridges electrically connected to each of the three magnetoresistance units is one at three different times.

In the magnetic field sensing device of the embodiment of the present invention, a magnetic flux concentrator is employed to bend magnetic field components of three different directions to a direction senseable by the magnetoresistance units, and the magnetic field components of the three different directions are There are three different combinations of directions through these magnetoresistive units after bending. In this way, by electrically connecting the magnetoresistance units to at least one Wheatstone bridge at three different times, the magnetic field components in three different directions can be separately measured, and the at least one Wheatstone full bridge output can be measured. Three signals corresponding to the magnetic field components of three different directions, respectively. Therefore, the present invention The magnetic field sensing device of the embodiment can have a simplified structure and at the same time can realize three-axis magnetic field measurement, and thus can have a small volume.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧ Magnetic field sensing device

110‧‧‧Magnetic concentrator

120‧‧‧Switching circuit

130‧‧‧Substrate

112‧‧‧ top surface

114‧‧‧ bottom

116, 116a, 116b, 116c, 116d‧‧‧ side

200, 200a, 200a', 200b, 200c, 200d‧‧‧ magnetic resistance unit

300, 301, 302‧‧‧ anisotropic magnetoresistance

310‧‧‧ Shorting bar

320‧‧‧ Ferromagnetic film

400, 400a, 400a', 400b, 400c, 400d‧‧‧ magnetization direction setting components

401, 402‧‧‧Sub magnetization direction setting component

D‧‧‧ Extension direction

H‧‧‧External magnetic field

Hx, Hy, Hz, f1x, f2x, f3x, f4x, f1y, f2y, f3y, f4y, f1z, f2z, f3z, f4z‧‧‧ magnetic field components

I‧‧‧current

I1, I1', I2, I3, I4‧‧‧ current direction

M, M1, M1', M1x, M2, M2x, M3, M3y, M4‧‧‧ magnetization direction

V1, V2, V3, V4‧‧‧ contacts

Vx, Vy, Vz‧‧‧ output voltage

x, y, z‧‧ direction

+△R, -△R‧‧‧Change in resistance value

1A is a top plan view of a magnetic field sensing device according to an embodiment of the present invention.

1B is a schematic cross-sectional view of the magnetic field sensing device of FIG. 1A taken along line A-A.

2A and 2B are diagrams for explaining the operation of the anisotropic magnetoresistance of Fig. 1A.

3A to 3C respectively show deflection states of magnetic flux lines when the magnetic field components in the x, y, and z directions pass through the magnetic flux concentrator of FIG. 1A.

4A to 4C respectively illustrate magnetic field components near the side of the magnetic flux concentrator when the magnetic field components in the x, y, and z directions pass through the magnetic flux concentrator of FIG. 1A.

5A, 5B, and 5C are equivalent circuit diagrams of the magnetic field sensing device according to the first embodiment of the present invention when measuring a magnetic field component in the x direction.

6A, 6B, and 6C are equivalent circuit diagrams of the magnetic field sensing device according to the first embodiment of the present invention when measuring a magnetic field component in the y direction.

7A, 7B and 7C are equivalent circuit diagrams of the magnetic field sensing device according to the first embodiment of the present invention when measuring a magnetic field component in the z direction.

8 is a diagram showing the magnetoresistance of the three types of Wheatstone bridges of FIGS. 5A to 7C. An example of the direction in which the shorting bar of the element is set and the direction in which the magnetization direction is set.

Fig. 9 is a top plan view showing a magnetoresistive unit and a magnetization direction setting member according to another embodiment of the present invention.

FIG. 10 illustrates another embodiment of the magnetization direction setting member of FIG. 1A.

FIG. 11 illustrates still another embodiment of the magnetization direction setting member of FIG. 1A.

12A, 12B and 12C are equivalent circuit diagrams of the magnetic field sensing device according to the second embodiment of the present invention when measuring a magnetic field component in the x direction.

13A, 13B and 13C are equivalent circuit diagrams of the magnetic field sensing device according to the second embodiment of the present invention when measuring a magnetic field component in the y direction.

14A, 14B and 14C are equivalent circuit diagrams of the magnetic field sensing device according to the second embodiment of the present invention when measuring a magnetic field component in the z direction.

1A is a top view of a magnetic field sensing device according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the magnetic field sensing device of FIG. 1A taken along line A-A. Referring to FIG. 1A and FIG. 1B , the magnetic field sensing device 100 of the present embodiment includes a magnetic flux concentrator 110 and a plurality of magnetic resistance units 200 . The magnetic flux concentrator 110 has a top surface 112, a bottom surface 114 opposite to the top surface 112 (as shown in FIG. 1B), and a plurality of side surfaces 116 connecting the top surface 112 and the bottom surface 114. Beside these sides 116.

In the present embodiment, the material of the flux concentrator 110 includes a ferromagnetic material having a magnetic permeability greater than 10. In addition, the residual magnetism of the magnetic flux concentrator 110 is, for example, smaller than its saturation magnetic 10% of the amount. For example, magnetic flux concentrator 110 is a soft magnetic material such as a nickel-iron alloy, a cobalt iron or cobalt iron boron alloy, a ferrite magnet, or other high permeability material.

Further, in the present embodiment, each of the magnetoresistive units 200 includes at least one anisotropic magnetoresistance. 2A and 2B are diagrams for explaining the operation of the anisotropic magnetoresistance of Fig. 1A. Referring first to FIG. 2A, the anisotropic magnetoresistor 300 has a barber pole-like structure, that is, a plurality of shorting bars extending on the surface thereof with an inclination of 45 degrees with respect to the extending direction D of the anisotropic magnetoresistive resistor 300. (electrical shorting bar) 310, these shorting bars 310 are disposed on the ferromagnetic film 320 spaced apart from each other and in parallel, and the ferromagnetic film 320 is the main body of the anisotropic magnetoresistance 300, and the extending direction thereof is different. The direction in which the directional magnetoresistor 300 extends. Further, the opposite ends of the ferromagnetic film 320 may be formed in a tip shape.

The anisotropic magnetoresistor 300 can first set its magnetization direction by the magnetization direction setting component before starting to measure the external magnetic field, wherein the magnetization direction setting component is, for example, a coil, a wire, a metal piece or a metal piece that can generate a magnetic field by energization. conductor. In FIG. 2A, the magnetization direction setting element can generate a magnetic field along the extending direction D by energization so that the anisotropic magnetoresistor 300 has the magnetization direction M.

Next, the magnetization direction setting element is not energized, so that the anisotropic magnetoresistor 300 begins to measure the external magnetic field. When there is no external magnetic field, the magnetization direction M of the anisotropic magnetoresistor 300 is maintained in the extending direction D. At this time, a current I is applied to cause the current I to flow from the left end of the anisotropic magnetoresistor 300 to the right end, and the shorting bar The flow direction of the current I near 310 is perpendicular to the extending direction of the shorting bar 310, so that the shorting bar 310 is nearby. The current I flows in a direction of 45 degrees with the magnetization direction M, and the resistance value of the anisotropic magnetoresistor 300 is R.

When there is an external magnetic field H directed in a direction perpendicular to the extending direction D, the magnetization direction M of the anisotropic magnetoresistance 300 is deflected outward in the direction of the magnetic field H, so that the angle between the magnetization direction and the current I flowing near the shorting bar is larger than At 45 degrees, the resistance value of the anisotropic magnetoresistor 300 has a change of -ΔR, that is, becomes R-ΔR, that is, the resistance value becomes small, wherein ΔR is greater than zero.

However, as shown in FIG. 2B, when the extending direction of the shorting bar 310 of FIG. 2B is set at a direction 90 degrees from the extending direction of the shorting bar 310 of FIG. 2A (the extending direction of the shorting bar 310 of FIG. 2B is still And the extension direction D of the anisotropic magnetoresistor 300 is 45 degrees), and when there is an external magnetic field H, in addition, the magnetic field H still deflects the magnetization direction M outward in the direction of the magnetic field H, and the magnetization direction M and the short circuit The angle of the current I flowing in the vicinity of the rod 310 is less than 45 degrees, and the resistance value of the anisotropic magnetoresistor 300 becomes R + ΔR, that is, the resistance value of the anisotropic magnetoresistor 300 becomes large.

Further, when the magnetization direction M of the anisotropic magnetoresistance is set to the reverse direction shown in FIG. 2A by the magnetization direction setting element, the resistance value of the anisotropic magnetoresistor 300 of FIG. 2A after the external magnetic field H becomes R + ΔR. Further, when the magnetization direction M of the anisotropic magnetoresistance is set to the reverse direction shown in FIG. 2B by the magnetization direction setting element, the resistance value of the anisotropic magnetoresistor 300 of FIG. 2B after the external magnetic field H is It becomes R-△R.

In summary, when the direction in which the shorting bar 310 is set changes, the resistance value of the anisotropic magnetoresistor 300 changes from +ΔR to -ΔR in response to the change in the external magnetic field H. Or vice versa, and when the magnetization direction M set by the magnetization direction setting element is changed to the reverse direction, the resistance value of the anisotropic magnetoresistor 300 corresponding to the change of the external magnetic field H may change from +ΔR to -ΔR or vice versa. . When the direction of the external magnetic field H becomes reversed, the resistance value of the anisotropic magnetoresistor 300 corresponds to a change in the external magnetic field H from +ΔR to -ΔR or vice versa. However, when the current passing through the anisotropic magnetoresistor 300 becomes reversed, the resistance value of the anisotropic magnetoresistive resistor 300 maintains the same sign as the original external magnetic field H, that is, if it is originally +ΔR, After changing the current direction, it is still +ΔR. If it is originally -ΔR, it is still -ΔR after changing the current direction.

According to the above principle, it is possible to determine the anisotropic magnetic when the anisotropic magnetoresistor 300 receives a certain component of the external magnetic field by designing the magnetization direction M set by the extending direction or the magnetization direction setting element of the shorting bar 310. The direction in which the resistance value of the resistor 300 changes, that is, the resistance value becomes larger or smaller, for example, the amount of change is +ΔR or -ΔR.

Referring to FIG. 1A and FIG. 1B again, in the embodiment, the anisotropic magnetoresistance in each of the magnetoresistive units 200 extends in parallel with the corresponding side surface 116 and is parallel to the top surface 112 and the bottom surface 114. Specifically, the direction of extension of the anisotropic magnetoresistance in the magnetoresistive unit 200a is parallel to the side surface 116a, and the direction of extension of the anisotropic magnetoresistance in the magnetoresistive unit 200b is parallel to the side surface 116b, and the anisotropy in the magnetoresistive unit 200c The extending direction of the magnetic resistance is parallel to the side surface 116c, and the direction of extension of the anisotropic magnetoresistance in the magnetoresistive unit 200d is parallel to the side surface 116d.

3A to 3C respectively illustrate deflection states of magnetic flux lines when the magnetic field components in the x, y, and z directions pass through the magnetic flux concentrator 110 of FIG. 1A. Referring first to FIG. 1A, FIG. 1B and FIG. 3A, the magnetic field sensing device 100 of the present embodiment. The space in which it is located may be defined by a slanted coordinate system in which the x and y directions are respectively parallel to the two diagonals of the top surface 112 and the z direction is perpendicular to the top surface 112. Further, the x direction, the y direction, and the z direction are perpendicular to each other. In the present embodiment, the top surface 112 is, for example, square, and the four side surfaces 116 are perpendicular to the top surface 112, and any two adjacent side surfaces 116 are perpendicular to each other, that is, the normal lines of the adjacent two side surfaces 116 are perpendicular to each other. . In other words, the x and y directions fall on a plane parallel to the plurality of normals of the four sides 116 and are at an angle of 45 degrees to the normals.

As shown in FIG. 3A, when a magnetic field component Hx along the +x direction passes through the magnetic flux concentrator 110, the magnetic field lines of the magnetic field component Hx tend to be converted to be perpendicular to the magnetic flux line near the magnetic flux concentrator 110. The direction of the surface of the flux concentrator 110 (e.g., the sides 116a, 116b, 116c, and 116d). As a result, when there is an external magnetic field component Hx along the +x direction, a magnetic field is generated in the magnetoresistive units 200a, 200b, 200c, and 200d adjacent to the side faces 116a, 116b, 116c, and 116d, respectively, as shown in Fig. 4A. Components f1x, f2x, f3x, and f4x.

Referring to FIG. 3B and FIG. 4B, when a magnetic field component Hy along the +y direction passes through the magnetic flux concentrator 110, the magnetic field lines of the magnetic field component Hy tend to be converted into directions when passing through the vicinity of the magnetic flux concentrator 110. The direction perpendicular to the sides 116a, 116b, 116c, and 116d of the flux concentrator 110 is perpendicular. As a result, when there is an external magnetic field component Hy in the +y direction, a magnetic field is generated in the magnetoresistive units 200a, 200b, 200c, and 200d adjacent to the side faces 116a, 116b, 116c, and 116d, respectively, as shown in Fig. 4B. Components f1y, f2y, f3y, and f4y.

Referring again to FIG. 1B and FIG. 4C, when a magnetic field component Hz along the -z direction When passing through the flux concentrator 110, the magnetic field lines of the magnetic field component Hz tend to transition perpendicular to the sides 116a, 116b, 116c, and 116d of the flux concentrator 110 as they pass near the side 116 of the flux concentrator 110. direction. As a result, when there is a magnetic field component Hz of the external magnetic field along the -z direction, a magnetic field is generated in the magnetoresistive units 200a, 200b, 200c, and 200d beside the side faces 116a, 116b, 116c, and 116d, respectively, as shown in Fig. 4C. Components f1z, f2z, f3z, and f4z.

5A, FIG. 5B and FIG. 5C are equivalent circuit diagrams of the magnetic field sensing device according to the first embodiment of the present invention when measuring a magnetic field component in the x direction, and FIGS. 6A, 6B and 6C are first embodiments of the present invention. The equivalent circuit diagram of the magnetic field sensing device of the example when measuring the magnetic field component in the y direction, and FIGS. 7A, 7B and 7C are magnetic field components of the magnetic field sensing device according to the first embodiment of the present invention. Equivalent circuit diagram at the time. 1A, 5A to 5C, 6A to 6C, and 7A to 7C, the component configuration of the magnetic field sensing device 100 of the first embodiment is as shown in FIG. 1A and FIG. 1B, and the amount thereof is The equivalent circuit when measuring the magnetic field component Hx in the x direction is as shown in FIG. 5A to FIG. 5C, and the equivalent circuit when measuring the magnetic field component Hy in the y direction is as shown in FIG. 6A to FIG. 6C, and An equivalent circuit for measuring the magnetic field component Hz in the z direction is illustrated in FIGS. 7A to 7C.

In this embodiment, the magnetoresistive units 200 (including the magnetoresistive units 200a, 200b, 200c, and 200d) are electrically connected to at least one Wheatstone full bridge at three different times (in this embodiment, for example, FIG. 5A) To the first Wheatstone bridge in Fig. 5C, the second Wheatstone bridge in Figs. 6A to 6C, and the third Wheatstone bridge in Fig. 7A to 7C. To measure three different directions separately (ie Magnetic field components (eg, magnetic field components Hx, Hy, and Hz) in a first direction (eg, x-direction), a second direction (eg, y-direction), and a third direction (eg, z-direction), and such at least one Wheatstone bridge (For example, the aforementioned three Wheatstone full bridges) output three signals corresponding to magnetic field components (for example, magnetic field components Hx, Hy, and Hz) in three different directions (such as the x direction, the y direction, and the z direction). In other embodiments, the three different directions are not necessarily perpendicular to each other, and at least two directions may not be perpendicular to each other.

In the present embodiment, the bottom surface 114 is parallel to the top surface 112 and is, for example, also square. The two diagonal lines of the bottom surface 114 are respectively parallel to two of the three different directions (for example, the x direction and the y direction), and three The remaining one of the different directions (eg, the z direction) is perpendicular to the bottom surface 114.

In the present embodiment, the magnetic field sensing device 100 further includes a switching circuit 120 electrically connected to the magnetoresistive units 200a, 200b, 200c, and 200d. The switching circuit 120 respectively connects the magnetoresistive units 200a, 200b at three different times. 200c and 200d are electrically connected to the first Wheatstone full bridge as shown in Figures 5A to 5C, the second Wheatstone full bridge as shown in Figures 6A to 6C, and the third benefit of Figures 7A to 7C. Three types of Wheatstone bridges, such as the Stern Full Bridge, which measure the magnetic field components (such as the magnetic field components Hx, Hy, and Hz) in three different directions (such as the x-direction, y-direction, and z-direction). And output three signals corresponding to magnetic field components of three different directions (for example, magnetic field components Hx, Hy, and Hz).

In the present embodiment, the magnetic field sensing device 100 further includes a substrate 130, wherein the magnetic flux concentrator 110 and the magnetoresistive unit 200 are disposed on the substrate 130, and The switching circuit 120 is provided in the substrate 130. The substrate 130 is, for example, a semiconductor substrate (such as a germanium substrate), a glass substrate, or a circuit substrate, wherein the circuit substrate is, for example, a germanium substrate provided with a conductive line and having a surface covered with an insulating layer.

In this embodiment, at any one of three different times, the signal output by the at least one Wheatstone full bridge is a differential signal corresponding to a magnetic field component of one of three different directions, and at least A differential signal generated by a Wheatstone full bridge corresponding to the magnetic field components of the remaining two directions in three different directions is zero. For example, at the first time of three different times, as shown in FIG. 5A to FIG. 5C, the signals output by the first type of Wheatstone bridge correspond to three different directions (ie, x, a differential signal of the magnetic field component Hx in one of the y and z directions), such as the x direction, at which point the first type of Wheatstone bridge produces the remaining two directions in three different directions (ie, y The difference signals of the magnetic field components Hy and Hz in the z direction are both zero. In addition, at the second time of three different times, as shown in FIG. 6A to FIG. 6C, the signals output by the second Wheatstone bridge correspond to three different directions (ie, x, y, and a differential signal of the magnetic field component Hy in one direction (such as the y direction) in the z direction), at which time the second Wheatstone full bridge produces the remaining two directions in three different directions (ie, x and z) The differential signal of the magnetic field component Hx and Hz of the direction is 0. Furthermore, at the third time of three different times, as shown in FIG. 7A to FIG. 7C, the signals output by the third Wheatstone bridge correspond to three different directions (ie, x, y). And the differential signal of the magnetic field component Hz in one direction (such as the z direction) in the z direction), at which time the third Wheatstone bridge produces the remaining two directions in the three different directions (ie, x and Magnetic field component in the y direction) The difference signals of Hx and Hy are both zero.

Further, in the present embodiment, in any of the above three different times, the number of the Wheatstone full bridges electrically connected to the magnetoresistive units 200 is one.

Specifically, in the first time of three different times, referring to FIG. 5A first, when the external magnetic field has the magnetic field component Hx, the magnetic field component f1x is generated in the magnetoresistive units 200a, 200b, 200c, and 200d, respectively. , f2x, f3x, and f4x. In the present embodiment, the magnetic field sensing device 100 (please refer to FIG. 1A ) further includes a plurality of magnetization direction setting elements 400 disposed adjacent to the magnetoresistive units 200 . For example, the magnetization direction setting elements 400a, 400b, 400c, and 400d are disposed beside the magnetoresistive units 200a, 200b, 200c, and 200d, respectively. The magnetization direction setting element 400 may be disposed above, below or above and below the corresponding magnetoresistive unit 200 to set the magnetization direction of the magnetoresistive unit 200. The magnetic resistance units 200a, 200b, 200c, and 200d can be correspondingly provided by the arrangement described in the relevant paragraphs of FIGS. 2A and 2B (including the setting direction of the shorting bars 310 and the setting direction of the initial magnetization direction of the magnetoresistive unit 200). The resistance values of -ΔR, +ΔR, -ΔR, and +ΔR are varied in the magnetic field components f1x, f2x, f3x, and f4x, respectively. In this way, when a voltage difference is applied between the contact V2 and the contact V4, there is a voltage difference between the contact V1 and the contact V3, that is, the output voltage Vx, and the output voltage Vx is a differential signal. Its size will correspond to the magnitude of the magnetic field component Hx. Therefore, by knowing the magnitude of the output voltage Vx, the magnitude of the magnetic field component Hx can be inferred.

On the other hand, referring to FIG. 5B, when the external magnetic field has the magnetic field component Hy, the magnetic field component f1y is generated in the magnetoresistive units 200a, 200b, 200c, and 200d, respectively. F2y, f3y, and f4y. Since the direction of the magnetic field component f1y is the reverse of the magnetic field component f1x of FIG. 5A, the resistance change of the magnetoresistive element 200a becomes +ΔR. Further, since the direction of the magnetic field component f3y is the reverse of the magnetic field component f3x of Fig. 5A, the resistance change of the magnetoresistive element 200c becomes -ΔR. As a result, the magnetoresistive units 200a, 200b, 200c, and 200d generate resistance values of +ΔR, +ΔR, -ΔR, and -ΔR, respectively, corresponding to the magnetic field components f1y, f2y, f3y, and f4y. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 is 0, that is, the differential signal outputted at this time is zero.

Furthermore, referring to FIG. 5C, when the external magnetic field has a magnetic field component Hz, magnetic field components f1z, f2z, f3z, and f4z are generated in the magnetoresistive units 200a, 200b, 200c, and 200d, respectively. At this time, the magnetoresistive units 200a, 200b, 200c, and 200d generate resistance values of +ΔR, -ΔR, +ΔR, and -ΔR, respectively, corresponding to the magnetic field components f1z, f2z, f3z, and f4z. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 is 0, that is, the differential signal outputted at this time is zero.

Therefore, when the magnetoresistive units 200a, 200b, 200c, and 200d are electrically connected to the first Wheatstone bridge of the first type as shown in FIGS. 5A to 5C, the voltages of the magnetic field components Hy and Hz for the contacts V1 and V3 are If there is no contribution, the output voltage Vx at this time is only related to the magnetic field component Hx, so the first type of Wheatstone bridge can be used to measure the magnetic field component Hx in the x direction, and the first type of Wheatstone bridge is The magnetoresistive unit 200a is connected in series with the magnetoresistive unit 200c, the magnetoresistive unit 200b is connected in series with the magnetoresistive unit 200d, and the two series of the series are connected in parallel, and the contact V2 is electrically connected to the magnetoresistive unit. Between 200a and the magnetoresistive unit 200b, the contact V4 is electrically connected between the magnetoresistive unit 200c and the magnetoresistive unit 200d, and the contact V1 is electrically connected between the magnetoresistive unit 200a and the magnetoresistive unit 200c, and the contact is V3 is electrically connected between the magnetoresistive unit 200b and the magnetoresistive unit 200d.

In the second time of three different times, referring to FIG. 6A again, the switching circuit 120 electrically connects the magnetoresistive units 200a, 200b, 200c, and 200d into a second Wheatstone full bridge, and the second The whole bridge of Wheatstone is: the magnetoresistive unit 200a is connected in series with the magnetoresistive unit 200c, the magnetoresistive unit 200d is connected in series with the magnetoresistive unit 200b, and the two strings of the series are connected in parallel, and the contact V1 is electrically connected to Between the magnetoresistive unit 200a and the magnetoresistive unit 200d, the contact V3 is electrically connected between the magnetoresistive unit 200b and the magnetoresistive unit 200c, and the contact V2 is electrically connected between the magnetoresistive unit 200a and the magnetoresistive unit 200c. The contact V4 is electrically connected between the magnetoresistive unit 200d and the magnetoresistive unit 200b. The setting directions of the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d are all the same as those of FIGS. 5A to 5C, so when the external magnetic field has the magnetic field component Hx, the magnetoresistive units 200a, 200b, 200c, and 200d correspond to the magnetic field. The components f1x, f2x, f3x, and f4x also produce resistance values of -ΔR, +ΔR, -ΔR, and +ΔR, respectively. In this way, when a voltage difference is applied between the contact V1 and the contact V3, the voltage difference between the contact V2 and the contact V4 will be 0, that is, the output differential signal is 0.

On the other hand, referring to FIG. 6B, when the external magnetic field has the magnetic field component Hy, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, +ΔR corresponding to the magnetic field components f1y, f2y, f3y, and f4y, respectively. - ΔR and - ΔR change in resistance value. therefore, When a voltage difference is applied between the contact V1 and the contact V3, there is a voltage difference between the contact V2 and the contact V4, that is, the output voltage Vy, and the output voltage Vy is a differential signal, and the size thereof will be Corresponds to the magnitude of the magnetic field component Hy. Therefore, by knowing the magnitude of the output voltage Vy, the magnitude of the magnetic field component Hy can be inferred.

Furthermore, referring to FIG. 6C, when the external magnetic field has a magnetic field component Hz, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, -ΔR corresponding to the magnetic field components f1z, f2z, f3z, and f4z, respectively. The resistance values of +ΔR and -ΔR change. Therefore, when a voltage difference is applied between the contact V1 and the contact V3, the voltage difference between the contact V2 and the contact V4 is 0, that is, the differential signal outputted at this time is zero.

Therefore, when the magnetoresistive units 200a, 200b, 200c, and 200d are electrically connected to the second Wheatstone full bridge as shown in FIGS. 6A to 6C, the voltages output by the magnetic field components Hx and Hz for the contacts V2 and V4 are If there is no contribution, the output voltage Vy at this time is only related to the magnetic field component Hy, so the second Wheatstone full bridge can be used to measure the magnetic field component Hy in the y direction.

In the third time of three different times, referring to FIG. 7A again, the switching circuit 120 electrically connects the magnetoresistive units 200a, 200b, 200c, and 200d into a third Wheatstone full bridge, and a third type. The whole bridge of Wheatstone is: the magnetoresistive unit 200a is connected in series with the magnetoresistive unit 200d, the magnetoresistive unit 200b is connected in series with the magnetoresistive unit 200c, the two strings of the series are connected in parallel, and the contact V2 is electrically connected to Between the magnetoresistive unit 200a and the magnetoresistive unit 200b, the contact V4 is electrically connected between the magnetoresistive unit 200c and the magnetoresistive unit 200d, and the contact V1 is electrically connected between the magnetoresistive unit 200a and the magnetoresistive unit 200d. And the contact V3 is electrically connected to the magnetoresistive unit Between 200b and the magnetoresistive unit 200c. The setting directions of the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d are all the same as those of FIGS. 5A to 5C, so when the external magnetic field has the magnetic field component Hx, the magnetoresistive units 200a, 200b, 200c, and 200d correspond to the magnetic field. The components f1x, f2x, f3x, and f4x also produce resistance values of -ΔR, +ΔR, -ΔR, and +ΔR, respectively. In this way, when a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 will be 0, that is, the output differential signal is 0.

On the other hand, referring to FIG. 7B, when the external magnetic field has the magnetic field component Hy, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, +ΔR corresponding to the magnetic field components f1y, f2y, f3y, and f4y, respectively. - ΔR and - ΔR change in resistance value. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 will be 0, that is, the output differential signal is 0.

Furthermore, referring to FIG. 7C, when the external magnetic field has a magnetic field component Hz, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, -ΔR corresponding to the magnetic field components f1z, f2z, f3z, and f4z, respectively. The resistance values of +ΔR and -ΔR change. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, there is a voltage difference between the contact V1 and the contact V3, that is, the output voltage Vz, and the output voltage Vz is a differential signal. The size will correspond to the magnitude of the magnetic field component Hy. Therefore, by knowing the magnitude of the output voltage Vz, the magnitude of the magnetic field component Hz can be inferred.

Therefore, when the magnetoresistive units 200a, 200b, 200c, and 200d are electrically connected to the third Wheatstone full bridge as shown in FIGS. 7A to 7C, the voltages output by the magnetic field components Hx and Hy for the contacts V1 and V3 are Will not contribute, the output power at this time The pressure Vz is only related to the magnetic field component Hz, so the third Wheatstone full bridge can be used to measure the magnetic field component Hz in the z direction.

In this way, after the first time, the second time, and the third time, the magnetic field sensing device 100 can sequentially measure the magnetic field component Hx, the magnetic field component Hy, and the magnetic field component Hz of the external magnetic field. Know the magnitude and direction of the external magnetic field. When the magnetic field sensing device 100 continuously repeats the first, second, and third types of Wheatstone bridges in the first time, the second time, and the third time, the external and continuous monitoring can be performed continuously. The change in the magnetic field relative to the magnetic field sensing device 100, that is, for example, the direction of the magnetic field sensing device 100 relative to the geomagnetic field can be monitored.

8 is a diagram showing an example of a direction in which a shorting bar is disposed and a direction in which a magnetization direction is applied to the three types of Wheatstone full bridges of FIGS. 5A to 7C. Referring to FIG. 5A and FIG. 8, in the present embodiment, the shorting bars 310 of the magnetic resistance units 200a, 200b, 200c, and 200d all extend in the x direction, and the magnetization direction setting elements 400a, 400b, 400c, and 400d are respectively disposed on the magnetic resistance. The current directions of the units 200a, 200b, 200c, and 200d, and the magnetization direction setting elements 400a, 400b, 400c, and 400d, respectively, when setting the magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d are current directions I1, I2, respectively I3 and I4, and the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d are set to the magnetization directions M1, M2, M3, and M4, respectively. Wherein, the current direction I1 faces the xy direction, the current direction I2 faces the x+y direction, the current direction I3 faces the -x+y direction, the current direction I4 faces the -xy direction, the magnetization direction M1 faces the x+y direction, and the magnetization direction M2 faces the - In the x+y direction, the magnetization direction M3 faces the -xy direction, and the magnetization direction M4 faces the xy direction. via In the above setting, when the external magnetic field has the magnetic field component Hx, the magnetoresistance units 200a, 200b, 200c, and 200d can respectively generate resistance values of -ΔR, +ΔR, -ΔR, and +ΔR (Fig. 5A). The conditions illustrated in FIGS. 6A and 7A are also applicable to the conditions illustrated in FIGS. 5B, 5C, 6B, 6C, 7B, and 7C. However, the directions of extension of the magnetization directions M1 to M4, the current directions I1 to I4, and the short-circuit bars 310 of the magnetoresistive units 200a, 200b, 200c, and 200d are not limited to the example of FIG. 8, and FIG. 8 merely cites various changes. An example of this. For example, the shorting bar 310 of the magnetoresistive unit 200a in FIG. 8 can be changed to extend in the y direction, and at the same time, the current direction I1 is changed to the reverse direction, that is, to the direction of -x+y, so that the magnetization direction M1 can be made. In the reverse direction, it becomes the direction toward -xy. Under this setting, when there is a magnetic field component Hx as shown in Fig. 5A, the amount of change in the resistance value of the magnetoresistive element 200a is maintained at -ΔR. Therefore, under this setting, the measurement results of the magnetic field sensing device 100 are still consistent with the measurement results of FIGS. 5A to 7C. Other directions regarding the arrangement direction of the magnetoresistive units 200b, 200c, and 200d may be changed.

In addition, the combination of the resistance value changes illustrated in FIGS. 5A to 7C is only one example, and the combination of these resistance value changes can also be equivalently changed, as long as any of the three different times, the three benefits The signal output by the Stern Full Bridge is a differential signal corresponding to the magnetic field component of one of the three different directions. At this time, the three types of Wheatstone bridges correspond to the other two directions in three different directions. The differential signal of the magnetic field component is zero.

In addition, the order of appearance of the first time, the second time, and the third time is not limited, and may be any suitable arrangement direction. For example, it can also The second Wheatstone bridge, the first Wheatstone bridge and the third Wheatstone bridge are sequentially arranged to measure the magnetic field component Hy, the magnetic field component Hx and the magnetic field component Hz in sequence.

In the magnetic field sensing device 100 of the present embodiment, since a Wheatstone full bridge is used in one time, magnetic field components of three different directions can be respectively sensed at three different times, and thus the magnetic field sensing device 100 The structure is relatively simple and can have a small volume. Compared with the magnetic field sensing device that measures the magnetic field components of three different directions by using three Wheatstone full bridges, the volume of the magnetic field sensing device 100 of the present embodiment can be reduced to one third, so the size can be greatly reduced. The volume of the magnetic field sensing device 100 further reduces the manufacturing cost of the magnetic field sensing device 100.

Further, the magnetization direction setting elements 400a to 400d can initialize the magnetization direction arrangement of the magnetoresistive elements 200a to 200d so that the magnetoresistive elements 200a to 200d can be normally used after the impact of the strong external magnetic field. Further, by changing the current directions of the magnetization direction setting elements 400a to 400d to form different magnetization directions of the magnetoresistive units 200a to 200d, the dynamic system offset of the magnetoresistive units 200a to 200d can be measured (dynamic system) Offset). By subtracting the dynamic system offset from the measured value, the correct magnetic field component value can be obtained more quickly. Similarly, low frequency noise can be subtracted to make the measured magnetic field component values more accurate.

Fig. 9 is a top plan view showing a magnetoresistive unit and a magnetization direction setting member according to another embodiment of the present invention. Referring to FIG. 8 and FIG. 9 , the magnetoresistive unit 200 a in FIG. 8 is exemplified by an anisotropic magnetoresistance 300. However, the present invention is not limited thereto, and each of the magnetoresistive units 200 may have multiple Anisotropic magnetoresistor 300, for example For example, a plurality of anisotropic magnetoresistances 300 connected in series to increase the intensity of the output signal. For example, in FIG. 9, the magnetoresistive unit 200a' has an anisotropic magnetoresistor 301 and an anisotropic magnetoresistor 302, wherein the anisotropic magnetoresistor 301 is disposed in the same manner as the magnetoresistive unit 200a of FIG. The related arrangement of the anisotropic magnetoresistance 302 may be the same as or different from that of the anisotropic magnetoresistance 301, and is different in FIG. 9 as an example. In FIG. 9, the shorting bar 310 of the anisotropic magnetoresistor 302 extends in the y direction, and the magnetization direction setting element 400a' may include two sub magnetization direction setting elements respectively disposed above the anisotropic magnetoresistors 301 and 302. 401 and 402. The current direction I1' of the sub-magnetization direction setting element 402 is oriented in the -x+y direction, so that the initial magnetization direction of the anisotropic magnetoresistor 302 is set to the magnetization direction M1'. As a result, when there is an external magnetic field having a magnetic field component Hx as shown in FIG. 5A, the anisotropic magnetoresistance 301 and the anisotropic magnetoresistance 302 each generate a resistance value change of -ΔR, and the anisotropic magnetoresistance 301 The resistance value change in series with the anisotropic magnetoresistor 302 becomes -2ΔR, so that the output signal can be amplified.

FIG. 10 illustrates another embodiment of the magnetization direction setting member of FIG. 1A. Referring to FIG. 1A and FIG. 10, in the embodiment of FIG. 10, the magnetization direction setting elements 400b, 400a, 400d, and 400c may be electrically connected in series, so that current flows sequentially through the magnetization direction setting component 400b, At 400a, 400d, and 400c, magnetization directions M1, M2, M3, and M4 as shown in Fig. 8 can be generated in the magnetoresistive units 200a, 200b, 200c, and 200d, respectively.

FIG. 11 illustrates still another embodiment of the magnetization direction setting member of FIG. 1A. Please refer to FIG. 1A and FIG. 11. In the embodiment of FIG. 11, these magnetization direction setting elements The 400a, 400b, 400c, and 400d can be independently controlled, for example, by circuitry in the substrate 130. In this way, the magnetoresistive units 200a, 200b, 200c, and 200d can be connected by only one Wheatstone bridge, and the different magnetic field components Hx, Hy, and Hz are applied to the magnetoresistive units 200a, 200b, 200c, and 200d. The first time to the third time is a resistance value change of +ΔR or a resistance value change of -ΔR, which can be determined by controlling the current directions of the magnetization direction setting elements 400a, 400b, 400c, and 400d, respectively, and can be borrowed. The change in resistance value is changed from +?R to -?R or vice versa by changing the direction of the current in the opposite direction.

12A, FIG. 12B and FIG. 12C are equivalent circuit diagrams of the magnetic field sensing device according to the second embodiment of the present invention when measuring the magnetic field component in the x direction, and FIGS. 13A, 13B and 13C are second embodiments of the present invention. The equivalent circuit diagram of the magnetic field sensing device of the example when measuring the magnetic field component in the y direction, and FIGS. 14A, 14B and 14C are magnetic field components of the magnetic field sensing device according to the second embodiment of the present invention. Equivalent circuit diagram at the time. The magnetic field sensing device 100 of the second embodiment is a structure in which the magnetization direction setting elements 400a, 400b, 400c, and 400d of FIG. 11 are independently controlled, and the magneto resistance units 200a, 200b, 200c, and 200d are connected to Wheatstone. There is only one type of full bridge and it will not change.

In the present embodiment, the magnetization direction setting members 400a, 400b, 400c, and 400d respectively set the magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d into three different combinations at three different times to make the one. The Wheatstone bridge measures the magnetic field components Hx, Hy and Hz in three different directions at three different times, and outputs the magnetic field components Hx, Hy and Hz corresponding to three different directions. Three signals.

Specifically, in the first time of three different times, referring to FIG. 12A first, when the external magnetic field has the magnetic field component Hx, the permeation direction setting elements 400a, 400b, 400c, and 400d are respectively independently The combination of the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d to an appropriate direction (hereinafter referred to as the first combination) allows the magnetoresistive units 200a, 200b, 200c, and 200d to correspond to the magnetic field component f1x, F2x, f3x, and f4x produce resistance values of +ΔR, -ΔR, +ΔR, and -ΔR, respectively. For example, when the shorting bars of the magnetoresistive units 200a, 200b, 200c, and 200d in FIGS. 12A to 14C are all extended in the x direction as illustrated in FIG. 8, the first combination refers to the magnetization direction setting. The elements 400a, 400b, 400c, and 400d respectively set the magnetization directions M1x, M2x, M3, and M4 to the magnetoresistive elements 200a, 200b, 200c, and 200d, wherein the magnetization direction M1x is the reverse of the magnetization direction M1 of FIG. 8, and the magnetization direction M2x It is the reverse of the magnetization direction M2 of FIG. That is, the current direction of the magnetization direction setting member 400a in FIGS. 12A to 12C is opposite to the current direction of the magnetization direction setting member 400a in FIG. 8, and the current direction of the magnetization direction setting member 400b in FIGS. 12A to 12C The current direction is opposite to that of the magnetization direction setting element 400b in FIG.

In addition, unlike the first embodiment, the Wheatstone full bridge of the second embodiment has only one type and does not change. Such a Wheatstone full bridge is, for example, a magnetic resistance unit 200a and a magnetoresistive unit 200d connected in series, and magnetic The resistor unit 200b is connected in series with the magnetoresistive unit 200c, and the two series of the series are connected in parallel. The contact V2 is electrically connected between the magnetoresistive unit 200a and the magnetoresistive unit 200b, and the contact V4 is electrically connected to the magnetoresistive resistor. unit Between 200c and the magnetoresistive unit 200d, the contact V1 is electrically connected between the magnetoresistive unit 200a and the magnetoresistive unit 200d, and the contact V3 is electrically connected between the magnetoresistive unit 200b and the magnetoresistive unit 200c. However, in other embodiments, this kind of Wheatstone full bridge that does not change may also be a Wheatstone full bridge as shown in FIGS. 5A to 5C, such as Wheatstone as shown in FIGS. 6A to 6C. Bridge or other appropriate form of Wheatstone Bridge.

In the structure of the Wheatstone full bridge of FIG. 12A, and the magnetoresistive units 200a, 200b, 200c, and 200d respectively generate resistance values of +ΔR, -ΔR, +ΔR, and -ΔR, When a voltage difference is applied between the contact V2 and the contact V4, there is a voltage difference between the contact V1 and the contact V3, that is, the output voltage Vx, and the output voltage Vx is a differential signal, and the size thereof will be Corresponds to the magnitude of the magnetic field component Hx. Therefore, by knowing the magnitude of the output voltage Vx, the magnitude of the magnetic field component Hx can be inferred.

Referring again to FIG. 12B, when the external magnetic field has the magnetic field component Hy, the magnetoresistive elements 200a, 200b, 200c, and 200d generate -ΔR, -ΔR, -Δ corresponding to the magnetic field components f1y, f2y, f3y, and f4y, respectively. The resistance values of R and -ΔR vary. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 is 0, that is, the differential signal outputted at this time is zero.

Referring to FIG. 12C, when the external magnetic field has a magnetic field component Hz, the magnetoresistive elements 200a, 200b, 200c, and 200d generate -ΔR, +ΔR, and +ΔR corresponding to the magnetic field components f1z, f2z, f3z, and f4z, respectively. And the resistance value of -ΔR changes. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the electric power between the contact V1 and the contact V3 The differential voltage is 0, that is, the differential signal output at this time is zero.

Therefore, in the combination of the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d of FIGS. 12A to 12C (i.e., the first combination described above), the magnetic field components Hy and Hz are output for the contacts V1 and V3. The voltage does not contribute, and the output voltage Vx at this time is only related to the magnetic field component Hx, so the combination of the magnetization directions can be used to measure the magnetic field component Hx in the x direction.

In the second time of three different times, referring to FIG. 13A first, when the external magnetic field has the magnetic field component Hx, the magnetization direction setting elements 400a, 400b, 400c, and 400d respectively independently apply the magnetoresistance units. The combination of the initial magnetization directions of 200a, 200b, 200c, and 200d to another suitable direction (hereinafter referred to as the second combination) allows the magnetoresistive units 200a, 200b, 200c, and 200d to correspond to the magnetic field components f1x, f2x, F3x and f4x respectively produce changes in the resistance values of -ΔR, -ΔR, -ΔR, and -ΔR. Compared with FIG. 12A, the current direction of the magnetization direction setting member 400a of FIG. 13A is opposite to the current direction of the magnetization direction setting member 400a of FIG. 12A, and thus the initial magnetization direction M1 of the magnetoresistive unit 200a of FIG. 13A is the same as that of FIG. 12A. The initial magnetization direction M1x of the resistor unit 200a is reversed, so the magnetoresistive unit 200a of FIG. 12A has a resistance value change of +ΔR, but the magnetoresistive element 200a of FIG. 13A is a resistance value change of -ΔR. Similarly, Compared with FIG. 12A, the current direction of the magnetization direction setting member 400c of FIG. 13A is opposite to the current direction of the magnetization direction setting member 400c of FIG. 12A, and thus the initial magnetization direction M3y of the magnetoresistive unit 200c of FIG. 13A is the same as that of FIG. 12A. The initial magnetization direction M3 of the resistance unit 200c is opposite, so the magnetoresistive unit 200c of FIG. 12A has a resistance value of +ΔR. The change is made, but the magnetoresistive unit 200c of Fig. 13A is a resistance value change that produces -ΔR. In addition, the current direction of the magnetization direction setting element 400b of FIG. 13A is maintained the same as the current direction of the magnetization direction setting element 400b of FIG. 12A, and the current direction of the magnetization direction setting element 400d of FIG. 13A is maintained and the magnetization direction setting element of FIG. 12A. The current direction of 400d is the same.

In addition, the Wheatstone Full Bridge of Figure 13A is the same as the Wheatstone Full Bridge of Figure 12A and has not changed. In the structure of the Wheatstone full bridge of FIG. 13A, and the magnetoresistive units 200a, 200b, 200c, and 200d respectively generate resistance values of -ΔR, -ΔR, -ΔR, and -ΔR, When a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 is 0, that is, the differential signal outputted at this time is zero.

Referring again to FIG. 13B, when the external magnetic field has the magnetic field component Hy, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, -ΔR, and +Δ corresponding to the magnetic field components f1y, f2y, f3y, and f4y, respectively. The resistance values of R and -ΔR vary. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, there is a voltage difference between the contact V1 and the contact V3, that is, the output voltage Vy, and the output voltage Vy is a differential signal, and its magnitude It will correspond to the magnitude of the magnetic field component Hy. Therefore, by knowing the magnitude of the output voltage Vy, the magnitude of the magnetic field component Hy can be inferred.

Referring to FIG. 13C, when the external magnetic field has a magnetic field component Hz, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, +ΔR, and -ΔR corresponding to the magnetic field components f1z, f2z, f3z, and f4z, respectively. And the resistance value of -ΔR changes. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the electric power between the contact V1 and the contact V3 The differential voltage is 0, that is, the differential signal output at this time is zero.

Therefore, in the combination of the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d of FIGS. 13A to 13C (ie, the second combination described above), the magnetic field components Hx and Hz are output for the contacts V1 and V3. The voltage does not contribute, and the output voltage Vy at this time is only related to the magnetic field component Hy, so the combination of the magnetization directions can be used to measure the magnetic field component Hy in the y direction.

In the third time of three different times, referring to FIG. 14A first, when the external magnetic field has the magnetic field component Hx, the magnetization direction setting elements 400a, 400b, 400c, and 400d respectively independently apply the magnetoresistance units. The combination of the initial magnetization directions of 200a, 200b, 200c, and 200d to another suitable direction (hereinafter referred to as the third combination, that is, the combination of magnetization directions M1, M2, M3, and M4) allows these magnetoresistive units 200a, 200b, 200c, and 200d generate resistance values of -ΔR, +ΔR, +ΔR, and -ΔR, respectively, corresponding to the magnetic field components f1x, f2x, f3x, and f4x. Compared with FIG. 12A, the current direction of the magnetization direction setting member 400a of FIG. 14A is opposite to the current direction of the magnetization direction setting member 400a of FIG. 12A, and thus the initial magnetization direction M1 of the magnetoresistive unit 200a of FIG. 14A is the same as that of FIG. 12A. The initial magnetization direction M1x of the resistor unit 200a is reversed, so the magnetoresistive unit 200a of FIG. 12A has a resistance value change of +ΔR, but the magnetoresistive unit 200a of FIG. 14A is a resistance value change of -ΔR. Similarly, Compared with FIG. 12A, the current direction of the magnetization direction setting member 400b of FIG. 14A is opposite to the current direction of the magnetization direction setting member 400b of FIG. 12A, and thus the initial magnetization direction M2 of the magnetoresistive unit 200b of FIG. 14A is the same as that of FIG. 12A. The initial magnetization direction M2x of the resistance unit 200b is opposite, so The magnetoresistive unit 200b of Fig. 12A has a resistance value change of -ΔR, but the magnetoresistive element 200b of Fig. 14A is a resistance value change of +ΔR. Further, the current direction of the magnetization direction setting element 400c of FIG. 14A is maintained the same as the current direction of the magnetization direction setting element 400c of FIG. 12A, and the current direction of the magnetization direction setting element 400d of FIG. 14A is maintained and the magnetization direction setting element of FIG. 12A. The current direction of 400d is the same.

In addition, the Wheatstone Full Bridge of Figure 14A is the same as the Wheatstone Full Bridge of Figure 12A and has not changed. In the structure of the Wheatstone full bridge of FIG. 14A, and the magnetoresistive units 200a, 200b, 200c, and 200d respectively generate resistance values of -ΔR, +ΔR, +ΔR, and -ΔR, When a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 is 0, that is, the differential signal outputted at this time is zero.

Referring again to FIG. 14B, when the external magnetic field has the magnetic field component Hy, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, +ΔR, and -Δ corresponding to the magnetic field components f1y, f2y, f3y, and f4y, respectively. The resistance values of R and -ΔR vary. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, the voltage difference between the contact V1 and the contact V3 is 0, that is, the differential signal outputted at this time is zero.

Referring to FIG. 14C, when the external magnetic field has a magnetic field component Hz, the magnetoresistive elements 200a, 200b, 200c, and 200d generate +ΔR, -ΔR, and +ΔR corresponding to the magnetic field components f1z, f2z, f3z, and f4z, respectively. And the resistance value of -ΔR changes. Therefore, when a voltage difference is applied between the contact V2 and the contact V4, there is a voltage difference between the contact V1 and the contact V3, that is, the output voltage Vz, which is a differential signal. Its size will correspond to the magnitude of the magnetic field component Hz. Therefore, by knowing the magnitude of the output voltage Vz, the magnitude of the magnetic field component Hz can be inferred.

Therefore, in the combination of the initial magnetization directions of the magnetoresistive units 200a, 200b, 200c, and 200d of FIGS. 14A to 14C (i.e., the above-described third combination), the magnetic field components Hx and Hy are outputted for the contacts V1 and V3. The voltage does not contribute, and the output voltage Vz at this time is only related to the magnetic field component Hz, so the combination of the magnetization directions can be used to measure the magnetic field component Hz in the z direction.

In this way, after the first time, the second time, and the third time, the magnetic field sensing device 100 can sequentially measure the magnetic field component Hx, the magnetic field component Hy, and the magnetic field component Hz of the external magnetic field. Know the magnitude and direction of the external magnetic field. When the magnetic field sensing device 100 continuously repeats the first, second, and third combinations of the setting directions of the magnetization directions of the first time, the second time, and the third time, the external and external monitoring can be continuously and instantaneously The change in the magnetic field relative to the magnetic field sensing device 100, that is, for example, the direction of the magnetic field sensing device 100 relative to the geomagnetic field can be monitored. In addition, the order of appearance of the first time, the second time, and the third time is not limited, and may be any suitable arrangement direction.

In summary, in the magnetic field sensing device of the embodiment of the present invention, a magnetic flux concentrator is employed to bend the magnetic field components of three different directions to the direction that the magnetoresistance units can sense, and the three different The direction of the magnetic field component is three different combinations of directions through the magnetoresistance elements after bending. In this way, by electrically connecting the magnetoresistive units to at least one Wheatstone bridge at three different times, the magnetic field components in three different directions can be separately measured, and the at least one Wheatstone is fully The bridge outputs three signals corresponding to the magnetic field components of the three different directions, respectively. Therefore, the magnetic field sensing device of the embodiment of the present invention can have a simplified structure and at the same time can realize three-axis magnetic field measurement, and thus can have a small volume.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100: magnetic field sensing device 110: magnetic flux concentrator 130: substrate 112: top surface 116, 116a, 116b, 116c, 116d: side surfaces 200, 200a, 200b, 200c, 200d: magnetoresistive units 400, 400a, 400b, 400c , 400d: magnetization direction setting component x, y, z: direction

Claims (12)

A magnetic field sensing device includes: a magnetic flux concentrator having a top surface, a bottom surface opposite to the top surface, and a plurality of sides connecting the top surface and the bottom surface; and a plurality of magnetoresistive units respectively disposed on Next to the sides, wherein the magnetoresistive units are electrically connected to at least one Wheatstone full bridge at three different times to respectively measure magnetic field components in three different directions, and to make the at least one Wheatstone full bridge Three signals respectively corresponding to the magnetic field components of the three different directions are output, wherein, in any of the three different times, the number of the Wheatstone full bridges electrically connected to the magnetoresistive units is one. The magnetic field sensing device of claim 1, wherein at any one of the three different times, the signal output by the at least one Wheatstone bridge corresponds to one of the three different directions. A differential signal of the magnetic field component of the direction, wherein the differential signals generated by the at least one Wheatstone full bridge corresponding to the magnetic field components of the remaining two of the three different directions are all zero. The magnetic field sensing device of claim 1, further comprising a switching circuit electrically connected to the magnetoresistive units, wherein the at least one Wheatstone full bridge is three types of Wheatstone full bridges, the switching circuit The three magneto-resistive units are electrically connected to the three Wheatstone full bridges at the three different times, and the three Wheatstone full bridges respectively measure the magnetic field components of the three different directions, and respectively output corresponding to the The three signals of the magnetic field components in three different directions. The magnetic field sensing device of claim 3, further comprising a substrate, wherein the magnetic flux concentrator and the magnetoresistive units are disposed on the substrate, and the switching circuit is disposed in the substrate. The magnetic field sensing device of claim 1, further comprising a plurality of magnetization direction setting elements respectively disposed adjacent to the magnetoresistance units to respectively set magnetization directions of the magnetoresistive units, wherein the at least one The Wheatstone full bridge is a fixed connection of the whole Wheatstone bridge, and the magnetization direction setting components respectively set the magnetization directions of the magnetoresistance units into three different combinations at the three different times. The Wheatstone full bridge is configured to measure the magnetic field components of the three different directions at the three different times, and respectively output the three signals corresponding to the magnetic field components of the three different directions. The magnetic field sensing device of claim 1, wherein each of the magnetoresistive units comprises at least one anisotropic magnetoresistance. The magnetic field sensing device of claim 6, wherein the anisotropic magnetoresistance in each of the magnetoresistive elements extends in a direction parallel to the corresponding side surface and parallel to the top surface and the bottom surface. The magnetic field sensing device of claim 1, wherein the sides are four sides, and the normal lines of the two adjacent sides are perpendicular to each other, and the three different directions are a first direction and a second a direction and a third direction, the first direction and the second direction are on a plane parallel to the plurality of normal lines of the four sides, and are at a 45 degree angle with the normal lines, the first direction and the The second directions are perpendicular to each other, and the third direction is perpendicular to the first direction and the second direction. The magnetic field sensing device of claim 1, wherein the material of the magnetic flux concentrator comprises a ferromagnetic material having a magnetic permeability greater than 10. The magnetic field sensing device of claim 1, wherein the magnetic flux concentrator has a residual magnetization less than 10% of its saturation magnetization. The magnetic field sensing device of claim 1, wherein the two diagonal lines of the bottom surface are respectively parallel to two of the three different directions, and the remaining one of the three different directions is perpendicular to the bottom surface. . The magnetic field sensing device of claim 1, further comprising a substrate, wherein the magnetic flux concentrator and the magnetoresistive units are disposed on the substrate, and the substrate is a semiconductor substrate, a glass substrate or a circuit substrate .