JP2012199354A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize an electronic control device.SOLUTION: A heat generating electronic component 2a is mounted on a surface 3a of a circuit board 3. A lower heat generating electronic component than the electronic component 2a is mounted on a rear face 3b of the circuit board 3 at a location behind the electronic component 2a. Accordingly, the electronic component 2b can be used as a heat sink for the electronic component 2a and heat radiation property of heat generated in the electronic component 2a can be improved without separately providing a mechanism for radiating heat generated in the electronic component 2a. Further, because the electronic component 2b can be mounted on the reverse side of the electronic component 2a, a component mounting area of the circuit board 3 can be enlarged without increasing the circuit board 3 in size. As a result, downsizing of the electronic control device 1 can be achieved by downsizing of the circuit board 3.

Description

  The present invention relates to an electronic control device in which electronic components are mounted on both sides of a circuit board.

  For example, Patent Document 1 discloses a pedestal that comes into close contact with the electronic component from the back side of the wiring substrate to a case where a wiring substrate having electronic components mounted on the surface thereof is attached, and heat dissipation that continues to the pedestal. There is disclosed a technique in which a protrusion is provided and heat generated in the electronic component is diffused from the pedestal to the wide range of the case through the heat dissipation protrusion.

JP 2009-158796 A

  However, in such Patent Document 1, the pedestal and the radiating ridge portion will protrude inside the case, and at the position where the pedestal and the radiating ridge portion are provided, Since it becomes difficult to mount the electronic component on the back surface of the wiring board, the wiring board becomes larger correspondingly, and there is a possibility that the entire apparatus will be enlarged.

  In view of this, the electronic control device of the present invention has a second electronic component having a lower exothermic property than the first electronic component on the back side of the first electronic component having the exothermic property mounted on one surface of the circuit board. And the heat generated in the first electronic component is dissipated to the second electronic component.

  According to the present invention, the second electronic component mounted on the back side of the first electronic component can be used as a heat sink for the first electronic component, and the heat generated in the first electronic component is dissipated. Therefore, the heat radiation performance of the heat generated in the first electronic component can be improved without providing a separate structure.

  In addition, an electronic component can be mounted as the second electronic component on the back side of the first electronic component having heat generation, and the component mounting area of the circuit board can be increased without increasing the circuit board. In addition, the electronic control device can be downsized by downsizing the circuit board.

The disassembled perspective view which showed typically the schematic structure of the electronic controller which concerns on this invention. The disassembled perspective view which showed typically the schematic structure of the electronic controller which concerns on this invention. The perspective view which looked at the electronic control unit concerning the present invention from the back side. Sectional drawing along the AA line of FIG. Sectional drawing of the circuit board in the position along the BB line of FIG. Explanatory drawing which showed typically the part by which an electronic component is mounted among the surfaces of the circuit board of the electronic control apparatus which concerns on this invention. The top view which showed the surface of the circuit board of the electronic controller which concerns on this invention with the electronic component. Explanatory drawing which expanded a part of FIG. 5, and showed more concretely. Explanatory drawing which showed typically the principal part of 2nd Embodiment of the electronic controller which concerns on this invention. Explanatory drawing which showed typically the principal part of 3rd Embodiment of the electronic control apparatus which concerns on this invention. Explanatory drawing which showed typically the principal part of 4th Embodiment of the electronic control apparatus which concerns on this invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 to 3 are explanatory views schematically showing a schematic configuration of an electronic control device 1 according to the present invention, FIGS. 1 and 2 are exploded perspective views of the electronic control device 1, and FIG. It is the perspective view which looked at the control apparatus 1 from the back side.

  The electronic control device 1 is, for example, mounted on an automobile and used for controlling an engine, a transmission, a brake, and the like, and has a rectangular plate-like circuit board 3 on which a plurality of heat-generating electronic components 2 are mounted, A connector 4 attached to the circuit board 3 to electrically connect an electronic circuit formed on the circuit board 3 and an external device, a case 5 in which the circuit board 3 is housed and fixed, and a circuit board housed in the case 5 3 and an upper cover 6 that covers 3 and a seal member 7 that seals a joint portion between the case 5 and the cover 6.

  Examples of the electronic component 2 mounted on the circuit board 3 include an IC, a FET (field effect transistor), a MOSFET (oxide semiconductor field effect transistor), a transistor, a diode, and a resistor.

  The case 5 and the cover 6 constitute the casing 8 of the electronic control device 1. The case 5 has a substantially rectangular dish shape, and the cover 6 has a substantially rectangular plate shape.

  The case 5 is made of a metal material excellent in heat dissipation such as aluminum or iron, and has a substantially rectangular plate-like bottom wall 9, a side wall 10 erected on the outer periphery of the bottom wall 8, And a flange-like flange portion 11 provided over the entire circumference on the distal end side.

  A window 12 is formed through the bottom wall 9. One end of the connector 4 protrudes from the window 12 when the case 5 and the cover 6 are assembled. A sealing member 13 is disposed around the window portion 12, and the space between the window portion 12 and the connector 4 is liquid-tightly sealed.

  On the inner side surface of the bottom wall 9 of the case 5, there are first and second radiating bases 14, 15 for radiating heat generated by the electronic components 2 c, 2 d mounted on the outer peripheral side of the surface 3 a of the circuit board 3. Projected. These first and second radiating bases 14 and 15 are respectively provided so as to face the back part of the electronic component 2c or 2d in the back surface 3b of the circuit board 3 when the circuit board 3 is assembled. ing. And between the back surface 3b of the circuit board 3 and the 1st heat radiating base 14, and between the back surface 3b of the circuit board 3 and the 2nd heat radiating base 15, respectively, the 1st, 2nd heat radiating sheet 16, 17 is each. Is sandwiched. Here, the heat radiation sheets 16 and 17 may be, for example, heat radiation grease, and are not limited to sheet-like materials as long as they are so-called heat conductive materials.

  First and second radiating fins 18 and 19 are provided on the outer surface of the bottom wall 9 of the case 5 on the back side of the portion where the first and second radiating bases 14 and 15 are provided. . The first and second radiating fins 18 and 19 are provided to efficiently radiate the heat received by the radiating bases 14 and 15. In the present embodiment, the heat radiating fins 18 and 19 are provided along the longitudinal direction of the bottom wall 9 (the left-right direction in FIG. 1, FIG. 2, or FIG. 3).

  The flange portion 11 of the case 5 is formed with a seal groove 20 that is continuous over the entire circumference of the flange portion 11. A protrusion 21 (described later) provided on the cover 6 together with the seal member 7 is inserted into the seal groove 20. Therefore, the joint between the case 5 and the cover 6 is liquid-tightly sealed by the seal member 7 over the entire circumference.

  The case 5 is integrally provided with a pair of first and second brackets 22 and 23 for mounting the electronic control device 1 to a vehicle body (not shown). In the present embodiment, the through-hole 22a penetrating in the vertical direction provided in the first bracket 22 and the cutout groove 23a provided in the second bracket 23 to the side are provided to the vehicle body of the electronic control device 1. Is installed.

  The cover 6 is formed of a metal material or a resin material, and is assembled to the case 5 so as to cover the circuit board 3 accommodated and fixed in the case 5. The four corners of the cover 6 are fixed to the case 5 with screws 24.

  On the outer peripheral edge of the cover 6, the above-described protrusion 21 is formed so as to be continuous over the entire outer periphery of the cover 6. The ridge 21 engages with a seal groove 20 provided in the flange portion 11 of the case 5.

  A breathing filter 26 that adjusts the pressure difference between the inside and the outside of the housing 8 is attached to the through hole 25 formed in the cover 6. An outer peripheral wall 27 that suppresses the direct hit of water on the breathing filter 26 is formed on the outer peripheral edge of the through hole 25 so as to protrude over the entire periphery.

  The circuit board 3 is made of, for example, glass epoxy resin, and a connector 4 having two connection ports 4a and 4b connected to an external connector (not shown) on the back surface 3b serving as a mounting surface for the case 5 is attached. It has been.

  In addition, the circuit board 3 is fixed to the case 5 by screws 28 at a plurality of locations on the outer periphery. The circuit board 3 can be fixed to the case 5 with an adhesive.

  And as shown in FIG. 4, the electronic component 2a as a 1st electronic component is mounted in the center part of the surface 3a of the circuit board 3, and it becomes the back side of the electronic component 2a in the back surface 3b of a circuit board. An electronic component 2b as a second electronic component having lower heat generation than the electronic component 2a is mounted at the position. That is, the electronic component 2b is used as a heat sink by disposing the electronic component 2b having lower heat generation than the electronic component 2a on the back side of the electronic component 2a. As the electronic component 2a, an integrated circuit such as a CPU or an IC, or other components having high heat generation when the control device is operated can be used. The electronic component 2b includes an integrated circuit that operates less (less exothermic) than the integrated circuit used in the electronic component 2a, and various components that are less exothermic when the control device (electronic control device 1) is operating with respect to heat capacity. Can be used.

  5 to 8, the circuit board 3 has a conductor pattern 29 on a portion where the electronic component 2a is mounted in order to efficiently conduct heat generated in the electronic component 2a to the electronic component 2b. And a thermal via 30 is formed. The conductor pattern 29 includes an electronic circuit configuration conductor pattern 29a in which the terminals 31 of the electronic component 2 are electrically connected by solder or the like, and a heat dissipation conductor pattern 29b mainly for conducting heat generated in the electronic component 2. 29c, 29d, and 29e. In addition, the heat dissipating conductor patterns 29b, 29c, 29d, and 29e may be installed not only for heat dissipation but also as part of the conductor pattern 29a for electronic circuit configuration, particularly the GND pattern.

  Here, FIG. 5 is a cross-sectional view of the circuit board 3 at a position along the line BB in FIG. 1, and FIG. 6 schematically shows a portion of the surface 3a of the circuit board 3 where the electronic component 2a is mounted. FIG. 7 is a plan view showing the surface 3a of the circuit board 3 together with the electronic component 2a, and FIG. 8 is an explanatory diagram showing a part of FIG. 5 more specifically. .

  On the front surface 3a of the circuit board 3, a substantially rectangular heat-dissipating conductor pattern 29b is formed within the range of the same size as the lower surface of the electronic component 2a and is electrically connected to the lower surface of the electronic component 2a. Is formed. The back surface 3b of the circuit board 3 is formed with a pattern in a range of approximately the same size as the lower surface of the electronic component 2b, and is a substantially rectangular heat dissipating conductor that is electrically connected to the lower surface of the electronic component 2b. A pattern 29c is formed.

  As shown in FIG. 7, the conductor pattern 29a for electronic circuit configuration formed on the surface 3a of the circuit board 3 and connected to the terminal 31 of the electronic component 2a is electrically radiated to the lower surface of the electronic component 2a. The conductive pattern 29b is not electrically connected. Also, a conductor pattern (not shown) for constituting an electronic circuit formed on the back surface 3b of the circuit board 3 and connected to the terminal 31 of the electronic component 2b is electrically connected to the lower surface of the electronic component 2b as in FIG. It is formed so as not to be electrically connected to the heat dissipating conductor pattern 29c connected to. When the electronic components 2a and 2b have a heat sink on the back surface, when the heat sink is set to GND, the heat radiation conductor patterns 29b and 29c may be part of the GND pattern of the electronic circuit.

  In the portion of the circuit board 3 where the electronic components 2a and 2b are mounted, a plurality of layers (two layers in this embodiment) of heat radiation conductive patterns 29d and 29e are formed inside the circuit board 3. .

  Further, as shown in FIG. 6, a plurality of (20 in this embodiment) through holes 32 penetrating the circuit board 3 are formed in a portion where the electronic components 2 a and 2 b of the circuit board 3 are mounted. A plurality of thermal vias 30 are formed by performing copper plating on the inner peripheral surface of each through hole 32. The thermal vias 30 allow the heat dissipating conductor patterns 29b, 29c, 29d, 29e formed on the portion of the circuit board 3 where the electronic components 2a, 2b are mounted to be in the thickness direction of the circuit board 3 (up and down in FIG. 5). The conductive patterns 29b, 29c, 29d, and 29e for heat radiation at different positions (different layers) in the (direction) are electrically connected.

  In the present embodiment, the thermal via 30 is formed so as to penetrate the circuit board 3 in order to conduct the heat of the electronic component 2 a generated on the front surface 3 a of the circuit board 3 to the electronic component 2 b on the back surface 3 b of the circuit board 3. ing.

  One end of the thermal via 30 is electrically connected to the lower surface of one of the electronic components 2a or 2b, but the other end is not electrically connected to the lower surfaces of both the electronic components 2a and 2b. Is formed.

  More specifically, as shown in FIG. 8, in the thermal via 30 a having one end electrically connected to the lower surface of the electronic component 2 a, the land 33 on the other end side is an insulator on the back surface 3 b of the circuit board 3. It is covered with the substrate resist 34 and is not electrically connected to the heat dissipation conductor pattern 29b formed on the lower surface of the electronic component 2b and the back surface 3b of the circuit board 3. Further, in the thermal via 30b, one end of which is electrically connected to the lower surface of the electronic component 2b, the land 35 on the other end side is covered with the substrate resist 34, which is an insulator, on the surface 3a of the circuit board 3, and the electronic component 2a It is not electrically connected to the heat dissipating conductor pattern 29 b formed on the lower surface and the surface 3 a of the circuit board 3. Further, as shown in FIG. 6, the thermal via 30a and the thermal via 30b correspond to the electronic component 2a (one end is electrically connected to the electronic component 2a) and the electronic component 2b. Thermal via 30 b rows (one end of which is electrically connected to the electronic component 2 b) are alternately arranged on the circuit board 3. This is an arrangement for improving the heat dissipation by arranging the thermal via 30a and the thermal via 30b as close as possible. In addition, the thermal via 30a and the thermal via 30b are alternately arranged in diagonal lines or checkered patterns. Also good.

  8 is a heat sink attached to the lower surface of the electronic component 2a, and 37 in FIG. 8 is a heat sink attached to the lower surface of the electronic component 2b. Further, reference numeral 38 in FIG. 8 denotes solder. Also, the two types of arrows having different thicknesses shown in FIG. 8 schematically show the flow of heat generated in the electronic component 2a, and the thick arrows have a relatively large amount of heat transfer in that portion. A thin arrow indicates that the amount of heat transfer in that portion is relatively small.

  In this embodiment, the electronic component 2b is used as a heat sink by disposing the electronic component 2b having lower heat generation than the electronic component 2a on the back side of the electronic component 2a with the circuit board 3 interposed therebetween. It is possible to improve the heat dissipation performance of the heat generated in the electronic component 2a without separately providing the structure for radiating the heat of the electronic component 2a generated on the surface 3a side of the circuit board 3 on the back surface 3b side of the circuit board 3. Can be made.

  In addition, since the electronic component 2b is mounted on the back side of the heat-generating electronic component 2a, the substantial component mounting area of the circuit board 3 is increased without increasing the circuit board 3. The electronic control device 1 can be downsized by downsizing the circuit board 3.

  Since the circuit board 3 has a plurality of thermal vias 30 penetratingly formed at the position where the electronic component 2 a is mounted, the heat generated on the front surface 3 a of the circuit board 3 is thermally transferred to the back surface 3 b of the circuit board 3. Since it can be conducted through the via 30, heat can be efficiently radiated to the electronic component 2 b mounted on the back surface 3 b of the circuit board 3.

  If the heat capacity of the electronic component 2b is set to be larger than the heat capacity of the electronic component 2a, the heat generated by the electronic component 2a can be more reliably absorbed by the electronic component 2b. Further, the thermal via 30 may be filled with a heat dissipation material or the like to improve the thermal conductivity between the front surface 3a and the back surface 3b of the circuit board 3 and to improve the heat dissipation of the electronic component 2a. Moreover, you may comprise the electronic components 2a and 2b by several components, respectively.

  Here, the conductor pattern 29 and the thermal via 30 formed in the part where the electronic component 2a of the circuit board 3 is mounted can also be formed as shown in FIGS.

  In the electronic control device 50 of the second embodiment shown in FIG. 9, the thermal via 30 formed in the portion where the electronic component 2a is mounted is a so-called blind via that does not penetrate the circuit board 3, and the electronic The heat dissipating conductor pattern 29b electrically connected to the lower surface of the component 2a and the heat dissipating conductor pattern 29c electrically connected to the lower surface of the electronic component 2b are configured not to be electrically connected. Yes.

  More specifically, the heat dissipating conductor pattern 29b electrically connected to the lower surface of the electronic component 2a is electrically connected to the heat dissipating conductor pattern 29d formed inside the circuit board 30 through the thermal via 30. It is connected. The heat dissipating conductor pattern 29c electrically connected to the lower surface of the electronic component 2b is electrically connected to the heat dissipating conductor pattern 29e formed inside the circuit board 30 through the thermal via 30. . The heat dissipating conductor pattern 29c and the heat dissipating conductor pattern 29d formed inside the circuit board 30 are configured not to be electrically connected to each other.

  Note that the two types of arrows with different thicknesses shown in FIG. 9 schematically show the flow of heat generated in the electronic component 2a, and the thick arrows have a relatively large amount of heat transfer in that portion. A thin arrow indicates that the amount of heat transfer in that portion is relatively small.

  Further, in the electronic control device 52 of the third embodiment shown in FIG. 10, the thermal via 30 is formed not outside the electronic components 2a and 2b but outside the electronic components 2a and 2b, and the terminal 31 of the electronic component 2a is connected. A conductor pattern 29a having an electronic circuit configuration on the surface 3a side of the circuit board 3 is electrically connected to a thermal via 30 formed outside the electronic component 2a. The thermal via 30 penetrates the circuit board 3, and the electronic circuit configuration that is not electrically connected to the terminal 31 of the electronic component 2 b in the electronic circuit configuration conductor pattern 29 a formed on the back surface 3 b of the circuit board 3. Is electrically connected to the conductive pattern 29a. An electronic circuit configuration conductor pattern 29a formed on the back surface 3b of the circuit board 3 that is not electrically connected to the terminal 31 of the electronic component 2b is formed on the back surface 3b of the circuit board 3 Among the conductive patterns 29a, the electronic circuit constituting conductor pattern 29a electrically connected to the terminal 31 of the electronic component 2b is configured to be close to the conductive pattern 29a. In other words, the electronic circuit configuration conductor pattern 29a formed on the back surface 3b of the circuit board 3 that is not electrically connected to the terminal 31 of the electronic component 2b is configured to be close to the electronic component 2b. .

  Note that the two types of arrows with different thicknesses shown in FIG. 10 schematically show the flow of heat generated in the electronic component 2a, and the amount of heat transfer is relative in the electrically connected portions. In a portion that is not electrically connected and is not continuous, the amount of heat transfer is relatively small (a thin arrow portion).

  In the third embodiment, a part of the heat generated in the electronic component 2a is transmitted to the electronic component 2b on the back surface 3b side of the circuit board 3 through the thermal via 30 formed outside the electronic component 2a. Become.

  In the electronic control device 53 of the fourth embodiment shown in FIG. 11, the heat radiation conductor pattern 29b on the surface 3a of the circuit board 3 electrically connected to the lower surface of the electronic component 2a is connected via the thermal via 30 to the electronic The circuit board 3 is electrically connected to the heat dissipating conductor pattern 29c on the back surface 3b of the circuit board 3 electrically connected to the lower surface of the component 2b.

  Note that the arrows shown in FIG. 11 schematically show the flow of heat generated in the electronic component 2a.

DESCRIPTION OF SYMBOLS 1 ... Electronic control apparatus 2a ... Electronic component 2b ... Electronic component 3 ... Circuit board 5 ... Case 6 ... Cover

Claims (3)

A circuit board with electronic components mounted on both sides;
A first heat-generating electronic component mounted on one surface of the circuit board;
A second electronic component mounted on the other surface of the circuit board and having lower heat generation than the first electronic component located on the back side of the first electronic component;
An electronic control device, wherein heat generated in the first electronic component is radiated to the second electronic component.   The electronic control device according to claim 1, wherein the second electronic component has a larger heat capacity than the first electronic component.   The electronic control device according to claim 1, wherein the circuit board is provided with a plurality of thermal vias at a position where the first electronic component is mounted.

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