Semiconductor module and electronic device using same

Abstract

To provide a semiconductor module and an electronic device using the same, capable of effectively using a mounting area of a substrate.SOLUTION: A motor relay module 147 includes a motor relay element 127, a sealing portion 310, a drain terminal 305, a source terminal 306, and a gate terminal 307. The motor relay element 127 is composed of a drain 302, a source 303, and a gate 304. The sealing portion has a rectangular shape in plan view, and molds the motor relay element 127. The drain terminal 305 is connected to the drain 302. The source terminal 306 is connected to the source 303. The gate terminal 307 is connected to the gate 304. The drain terminal 305, the source terminal 306, and the gate terminal 307 are exposed on a short side of the sealing portion 310.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a semiconductor module and an electronic device using the same. [Background technology]

[0002] Conventionally, there has been known a mechanically and electrically integrated electric drive device. For example, in Patent Document 1, a power conversion circuit is made redundant, and a positive power supply path and a negative power supply path are disposed adjacent to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-55488 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the high-side MOSFET, the low-side MOSFET, and the phase relay MOSFET are all substantially square-shaped and arranged in a straight line, which makes it difficult to arrange other elements, such as a current detection element, in close proximity to the MOSFETs.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a semiconductor module that can effectively utilize the mounting area of ​​a substrate, and an electronic device using the same. [Means for solving the problem]

[0006] The semiconductor module of the present invention includes a switching element (127-129, 227-229) consisting of a drain (302), a source (303) and a gate (304), a sealing portion (310), a drain terminal (305, 315, 335) connected to the drain, a source terminal (306, 316) connected to the source, and a gate terminal (307, 317, 337) connected to the gate. The sealing portion is formed in a rectangular shape in a plan view and molds the switching element. The drain terminal, the source terminal and the gate terminal are exposed on the short side of the sealing portion. A non-potential terminal (338) is provided at least at one of the corners of the sealing portion, and the non-potential terminal is exposed at two sides of the sealing portion. This allows the mounting area of ​​the board to be used efficiently. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram showing a steering system according to a first embodiment. [Diagram 2] FIG. 2 is a side view showing the drive device according to the first embodiment. [Diagram 3] 3 is a view taken in the direction of the arrow III in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 2 is a side view showing the ECU with the cover removed according to the first embodiment. [Figure 6] FIG. 2 is a circuit diagram of a drive device according to the first embodiment. [Figure 7] 2 is a plan view showing a surface of the main board on the heat sink side according to the first embodiment. FIG. [Figure 8] FIG. 2 is a diagram showing an arrangement of upper and lower arm modules, a motor relay module, a shunt resistor, and a snubber circuit element according to the first embodiment. [Figure 9] FIG. 4 is a cross-sectional view illustrating the height of a component according to the first embodiment. [Figure 10] FIG. 11 is a plan view showing a motor relay module according to a second embodiment. [Figure 11] FIG. 11 is a plan view showing a motor relay module according to a third embodiment. [Figure 12]FIG. 13 is a plan view showing a motor relay module according to a fourth embodiment. [Figure 13] FIG. 13 is a plan view showing a motor relay module according to a fifth embodiment. [Figure 14] FIG. 13 is a plan view showing a motor relay module according to a sixth embodiment. [Figure 15] FIG. 13 is a plan view showing a motor relay module according to a seventh embodiment. [Figure 16] FIG. 16 is a view taken in the direction of the arrow XVI in FIG. [Figure 17] FIG. 13 is a plan view showing a motor relay module according to an eighth embodiment. [Figure 18] FIG. 18 is a view taken in the direction of the arrow XVIII in FIG. 17. [Figure 19] 11A and 11B are cross-sectional views for explaining the height of a component according to a reference example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic device according to the present invention will now be described with reference to the accompanying drawings. In the following, substantially identical components in a number of embodiments will be designated by the same reference numerals, and the description thereof will be omitted.

[0009] (First embodiment) Hereinafter, the electronic device will be described with reference to the drawings. In the following, in a number of embodiments, substantially the same configurations are given the same reference numerals and descriptions thereof will be omitted. An electronic control device according to a first embodiment is shown in Figs. 1 to 9.

[0010] As shown in Fig. 1, the drive device 1 includes a motor 80 and an ECU 10, and is applied to an electric power steering device 8, which is a steering device for assisting the steering operation of a vehicle. Fig. 1 shows the overall configuration of a steering system 90 including the electric power steering device 8. The steering system 90 includes a steering wheel 91, which is a steering member, a steering shaft 92, a pinion gear 96, a rack shaft 97, wheels 98, the electric power steering device 8, etc.

[0011] The steering wheel 91 is connected to a steering shaft 92. A torque sensor 93 that detects steering torque is provided on the steering shaft 92. The torque sensor 93 is divided into two systems internally, and the detected values ​​of each system are input to corresponding connectors 156, 256. A pinion gear 96 is provided at the tip of the steering shaft 92. The pinion gear 96 meshes with a rack shaft 97. A pair of wheels 98 are connected to both ends of the rack shaft 97 via tie rods or the like.

[0012] When a driver turns a steering wheel 91, a steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into linear motion of a rack shaft 97 by a pinion gear 96. A pair of wheels 98 are steered to an angle according to the amount of displacement of the rack shaft 97.

[0013] The electric power steering device 8 includes a drive unit 1, and a reduction gear 89 as a power transmission unit that reduces the speed of rotation of a motor 80 and transmits the reduced speed to a rack shaft 97. The electric power steering device 8 of this embodiment is a so-called "rack assist type", but may be a so-called "column assist type" in which the rotation of the motor 80 is transmitted to a steering shaft 92.

[0014] 2 to 5, motor 80 is a three-phase brushless motor. Motor 80 outputs a part or all of the torque required for steering, and is driven by power supplied from a battery (not shown) to rotate reduction gear 89 forward and reverse. Motor 80 has first motor winding 180 and second motor winding 280.

[0015] Hereinafter, the combination of components related to the energization control of the first motor winding 180 will be referred to as the first system, and the combination of components related to the energization control of the second motor winding 280 will be referred to as the second system. Components of the first system L1 will be mainly numbered in the 100s, and components of the second system L2 will be mainly numbered in the 200s, with the last two digits of the numbers being the same for components that are substantially similar between the first and second systems, and explanations will be omitted as appropriate. Additionally, in the drawings, etc., the subscript "1" will be added to components related to the first system L1, and the subscript "2" will be added to components related to the second system L2 as appropriate.

[0016] The drive device 1 is a so-called "mechatronically integrated type" in which the ECU 10 is integrally provided on one side of the motor 80 in the axial direction, but the motor 80 and the ECU 10 may be provided separately. The ECU 10 is arranged coaxially with the axis Ax of the shaft 870 on the opposite side of the output shaft of the motor 80. Here, "coaxial" means that errors and deviations related to, for example, assembly and design are allowed. Note that the "mechatronically integrated" in the drive device 1 of this embodiment is different from, for example, simply providing an approximately rectangular parallelepiped ECU close to the motor 80. By making it a mechatronically integrated type, the ECU 10 and the motor 80 can be efficiently arranged in a vehicle with limited mounting space. Hereinafter, the axial direction of the motor 80 is regarded as the axial direction of the drive device 1, and is simply referred to as the "axial direction".

[0017] The motor 80 includes a motor case 830, a motor frame 840, a stator 860, and a rotor 865. The stator 860 is fixed to the motor case 830, and the motor windings 180, 280 are wound around the stator 860. The rotor 865 is provided radially inside the stator 860 and is rotatable relative to the stator 860.

[0018] Shaft 870 is fitted into rotor 865 and rotates integrally with rotor 865. Shaft 870 is rotatably supported by motor case 830 and motor frame 840 by bearings 871, 872. The end of shaft 870 on the ECU 10 side is inserted into shaft hole 849 formed in motor frame 840 and exposed on the ECU 10 side. A magnet 875 is provided on the end of shaft 870 on the ECU 10 side.

[0019] The motor case 830 is formed in a generally cylindrical shape with a bottom, which is composed of a bottom portion 831 and a cylindrical portion 832, and the ECU 10 is provided on the opening side. A bearing 871 is provided on the bottom portion 831. A stator 860 is fixed to the cylindrical portion 832.

[0020] The motor frame 840 has a frame portion 841, a heat sink 845, a connector connection portion 846, and the like, and is formed of a material with good thermal conductivity, such as aluminum. The frame portion 841 is press-fitted into the radially inner side of the motor case 830, and is generally contained within a projection area (hereinafter referred to as "motor silhouette" as appropriate) obtained by projecting a cylindrical portion 832 of the motor case 830 in the axial direction. A flange portion 842 is formed on the outer periphery of the frame portion 841, and abuts against a step portion 833 formed on the inner wall of the cylindrical portion 832. In addition, an extension member connection portion 843 is formed on the outer side of the heat sink 845 of the frame portion 841.

[0021] The connector connection portion 846 is provided in an upright position approximately in the center of the side surface of the heat sink 845 on the side from which the motor windings 180, 280 are not taken out.

[0022] The ECU 10 has a main board 31, a sub-board 32, power system connection components 101, 201, signal system connection components 106, 206, a connector unit 50, and a cover 60. The main board 31 is fixed to a heat sink 845 by fastening members 399 such as screws. The sub-board 32 is fixed to the connector unit 50. The boards 31, 32 are larger than the heat sink 845 when projected in the axial direction, and are formed to extend to the outside of the heat sink 845.

[0023] Switching elements and the like constituting an inverter circuit are mounted on a surface 391 of the main board 31 on the heat sink 845 side, and are provided so as to be able to dissipate heat to the heat sink 845. Components such as an aluminum electrolytic capacitor are mounted on the surface of the main board 31 opposite the heat sink 845. The arrangement of components on the main board 31 will be described later.

[0024] Components such as a choke coil and a capacitor that configure a filter circuit, and a communication driver are mounted on the sub-board 32. The main board 31 and the sub-board 32 are connected by power system connection components 101, 201 and signal system connection components 106, 206. The power system connection components 101, 201 are arranged side by side outside the element mounting area. The signal system connection components 106, 206 are arranged side by side outside the element mounting area, on the opposite side of the element mounting area from the power system connection components 101, 201.

[0025] The connector unit 50 has a base portion 51, vehicle system connectors 152, 252, and steering system connectors 156, 256. The base portion 51 is formed in a generally rectangular shape in a plan view. A groove portion 511 is formed along the outer edge of the surface of the base portion 51 opposite to the motor 80. The base portion 51 also has a fixing portion 516. A through bolt 519 is inserted into the fixing portion 516 and screwed into a connector connection portion 846 of the motor frame 840. This fixes the connector unit 50 to the motor frame 840. The connection position in the axial direction between the connector connection portion 846 of the motor frame 840 and the fixing portion 516 of the connector unit 50 is between the main board 31 and the sub-board 32.

[0026] The connectors 152, 156, 252, 256 are formed with their frontages facing outward in the axial direction. The vehicle system connectors 152, 252 are integrated hybrid connectors that integrate a power system connector connected to a vehicle power source and ground, and a communication system connector connected to a vehicle communication network 99 (see FIG. 1), such as a CAN (Controller Area Network). The steering system connectors 156, 256 are connected to the torque sensor 93.

[0027] The cover 60 is formed in a generally cylindrical shape with a bottom, and houses the boards 31, 32, the heat sink 845, etc. in the interior. A generally rectangular hole 61 is formed in the bottom of the cover 60. The connectors 152, 156, 252, 256 are inserted into the hole 61. An end 611 of the hole 61 is bent inward. The end 611 is inserted into a groove 511 of the connector unit 50 to which an adhesive member such as an adhesive is applied. This makes it possible to prevent water droplets and dust from entering between the connector unit 50 and the cover 60.

[0028] In this embodiment, four openings are provided for the vehicle system connectors 152, 252 and the steering system connectors 156, 256, and the base portion 51 extends beyond a projection area obtained by projecting the cylindrical portion 832 of the motor case 830 in the axial direction. In other words, the connector unit 50 does not fit within the motor silhouette.

[0029] The extension member 70 has a base 71, an annular protrusion 72, a cover insertion groove 73, a fixing portion 74, etc., and is integrally formed of resin or the like. The extension member 70 is formed in an annular shape as a whole, and is disposed on the ECU 10 side of a frame portion 841 of a motor frame 840, radially outside a heat sink 845. In other words, the heat sink 845 is formed on the inner peripheral side of the extension member 70, protruding toward the ECU 10 side. At least a part of the outer edge of the extension member 70 is located outside the motor silhouette.

[0030] The annular projection 72 is provided on the motor 80 side surface of the base 71 so as to protrude along the inner circumferential surface, and is inserted into the tubular portion 832 of the motor case 830. A cover insertion groove 73 is formed along the outer edge on the surface of the extension member 70 opposite the motor 80. The end of the opening side of the cover 60 is inserted into the cover insertion groove 73 to which an adhesive material such as an adhesive has been applied. This makes it possible to prevent water droplets, dust, and the like from entering between the extension member 70 and the cover 60. The fixing portion 74 is formed so as to protrude radially inward from the inner circumferential wall of the extension member 70. A collar is inserted into the fixing portion 74, and the fixing portion 74 is fixed to the frame portion 841 by a screw 79.

[0031] 6 shows the circuit configuration of the drive device 1. In this embodiment, since the circuit configuration of the first system L1 is the same as the circuit configuration of the second system L2, the first system L1 will be described and the description of the second system L2 will be omitted as appropriate.

[0032] Inverter circuit 120 is a three-phase inverter in which upper arm elements 121-123 connected to the high potential side and lower arm elements 124-126 connected to the low potential side are bridge-connected. The high potential side of inverter circuit 120 is connected to a power source such as a battery via power relay elements 111 and 112, and the low potential side is connected to ground.

[0033] A connection point between the paired U-phase upper arm element 121 and lower arm element 124 is connected to one end of a U-phase winding 181 via a motor relay element 127 and a motor terminal 191. A connection point between the paired V-phase upper arm element 122 and lower arm element 125 is connected to one end of a V-phase winding 182 via a motor relay element 128 and a motor terminal 192. A connection point between the paired W-phase upper arm element 123 and lower arm element 126 is connected to one end of a W-phase winding 183 via a motor relay element 129 and a motor terminal 193. The other ends of the windings 181 to 183 are wired.

[0034] Shunt resistors 131, 132, 133, which are current detection elements that detect the current of each phase of the motor winding 180, are provided on the low potential sides of the lower arm elements 124, 125, 126. In addition, snubber circuit elements 134-139 for reducing noise are connected in parallel to the upper arm elements 121-123 and the lower arm elements 124-126. The snubber circuit elements 134-139 are composed of a capacitor and a resistor connected in series. Hereinafter, in the drawings etc., in order to distinguish between capacitors and resistors, the subscript "ca" is added to the capacitors and the subscript "r" is added to the resistors and they are hatched.

[0035] Power is supplied to the inverter circuit 120 via power relay elements 111 and 112. In this embodiment, the upper arm elements 121-123, the lower arm elements 124-126, the motor relay elements 127-129, and the power relay elements 111 and 112 are all MOSFETs, but may be IGBTs, thyristors, or the like. The power relay elements 111 and 112 are connected in series such that the orientation of the parasitic diodes is reversed. This prevents a reverse current from flowing when the battery is mistakenly connected in reverse, thereby protecting the ECU 10.

[0036] FIG. 7 shows a surface 391 of the main board 31 on the side of the heat sink 845. As shown in FIG. 7, the electronic device 30 has the main board 31 and various electronic components mounted on the main board 31. The main board 31 is mounted with the upper and lower arm modules 141-143, 241-243, the relay modules 147-149, 247-249, the shunt resistors 131-133, the snubber circuit elements 134-139, 234-239, the power relay modules 161, 162, 261, 262, the microcomputers 170, 270, and the integrated circuit components 175, 275, etc. Hereinafter, the main board 31 is simply referred to as the "board" as appropriate. In FIG. 7, the holes to which the terminals are connected are appropriately labeled with the symbols of the corresponding members. In addition, in FIG. 7, the substrate 31 is illustrated as a circle, and the holes and the like associated with the fastening members 399 are omitted, but the shape of the substrate is not limited to a circle and may be different.

[0037] In this embodiment, the upper arm element 121 and the lower arm element 124 of the U phase are packaged together as an upper and lower arm module 141. Similarly, the upper arm element 122 and the lower arm element 125 of the V phase are packaged together as an upper and lower arm module 142. The upper arm element 123 and the lower arm element 126 of the W phase are packaged together as an upper and lower arm module 143.

[0038] Similarly, in the second system, the upper arm element 221 and the lower arm element 224 of the U phase are packaged together as an upper and lower arm module 241. The upper arm element 222 and the lower arm element 225 of the V phase are packaged together as an upper and lower arm module 242. The upper arm element 223 and the lower arm element 226 of the W phase are packaged together as an upper and lower arm module 243. In other words, the upper and lower arm modules 141-143 and 241-243 are so-called "2-in-1 modules" in which two elements are packaged.

[0039] The motor relay modules 147-149, 247-249 are so-called "1-in-1 modules" in which the motor relay elements 127-129, 227-229 are individually packaged. The power relay elements 111, 112 are 1-in-1 modules similar to the motor relay module 147, and the semiconductor modules in which the power relay elements 111, 112, 211, 212 are packaged are referred to as power relay modules 161, 162, 261, 262.

[0040] Two sets of snubber circuit elements 134-139, 234-239 are provided for each upper and lower arm module 141-143, 241-243. The snubber circuit elements 134-136, 234-236 provided in parallel with the upper arm elements 121-123, 221-223 are arranged on the board center line C side of the upper and lower arm modules 141-143, 241-243. The snubber circuit elements 137-139, 237-239 connected in parallel with the lower arm elements 124-126, 224-226 are arranged on the opposite side of the board center line C of the upper and lower arm modules 141-143, 241-243.

[0041] The board 31 is divided by the board center line C into a first system area RL1 where components related to the first system L1 are mounted, and a second system area RL2 where components related to the second system L2 are mounted. Here, the direction perpendicular to the board center line C is defined as the x direction, and the direction along the board center line C is defined as the y direction. In addition, in the y direction, the side where the power system connection components 101, 201 are provided is defined as the "power end", and the side where the signal system connection components 106, 206 are provided is defined as the "control end".

[0042] In the first system area RL1, the power system connection part 101, the power relay modules 161, 162, the parts related to the UVW phases, the microcomputer 170 and the integrated circuit part 175, and the signal system connection part 106 are arranged in this order from the power end side. Similarly, in the second system area RL2, the power system connection part 201, the power relay modules 261, 262, the parts related to the UVW phases, the microcomputer 270 and the integrated circuit part 275, and the signal system connection part 206 are arranged in this order from the power end side. The power relay modules 161, 162 are arranged side by side with their longitudinal directions aligned with the x-direction.

[0043] The upper and lower arm modules 141 to 143 are arranged generally parallel to the board center line C. The upper and lower arm modules 141 to 143, the motor relay modules 147 to 149, and the motor terminals 191 to 193 are arranged in this order from the board center line C side.

[0044] The arrangement of elements for each phase is shown in Fig. 8. Fig. 8 shows a schematic internal configuration of the motor relay module 147, and for the sake of explanation, the sealing portion 310 is shown with a matte finish. This also applies to the figures relating to the embodiments described below. The U-phase, V-phase, and W-phase in the first system and the U-phase, V-phase, and W-phase in the second system have roughly the same arrangement of elements, so the U-phase in the first system will be mainly described as an example.

[0045] The upper and lower arm module 141 is formed in a generally square shape in a plan view. The motor relay module 147 is formed in a generally rectangular shape in a plan view with a long side length approximately equal to the length of one side of the upper and lower arm module 141 and a short side length shorter than the length of one side of the upper and lower arm module 141. Here, if the y direction (i.e., the vertical direction on the paper) is defined as the width direction, it can be said that the motor relay module 147 is formed narrow.

[0046] The motor relay module 147 is disposed adjacent to the outer edge side of the board of the upper and lower arm module 141 so that the short side faces the upper and lower arm module 141. In this embodiment, the motor relay module 147 is formed narrower than the upper and lower arm module 141, so that a space capable of mounting components other than the motor relay module 147 can be secured in the module mounting area Rm, which is an area obtained by extending the upper and lower arm module 141 in the x direction.

[0047] In the first system L1, on the outer edge side of the board in the module mounting area Rm, the motor relay module 147, the snubber circuit element 137, and the shunt resistor 131 are arranged in this order from the power end side. On the other hand, in the second system L2, on the outer edge side of the board in the module mounting area Rm, the motor relay module 247, the snubber circuit element 237, and the shunt resistor 231 are arranged in this order from the control end side (see FIG. 7). The shunt resistor 131 is arranged so that its longitudinal direction is the x-direction.

[0048] The snubber circuit elements 134 are arranged side by side in the y direction on the board center line C side of the upper and lower arm modules 141, with the longitudinal directions of the resistors and capacitors facing the upper and lower arm modules 141. In the first system L1, the snubber circuit elements 134 are arranged in the order of resistors and capacitors from the control end side on the board center line C side of the module mounting area Rm. In the second system L2, the snubber circuit elements 234 are arranged in the order of resistors and capacitors from the power end side on the board center line C side of the module mounting area Rm (see FIG. 7).

[0049] The snubber circuit element 137 has its short side facing the upper and lower arm module 141 , and is arranged in the order of a capacitor and a resistor from the upper and lower arm module 141 side.

[0050] The motor relay module 147 includes a land 301 , a drain 302 , a source 303 , a gate 304 , a drain terminal 305 , a source terminal 306 , a gate terminal 307 , a conductive clip 308 , and the like, molded by a sealing portion 310 .

[0051] In the motor relay module 147, a source terminal 306 is formed along one short side, and a drain terminal 305 and a gate terminal 307 are formed along the other short side. The motor relay module 147 is arranged so that the source terminal 306 faces the upper and lower arm module 141 side, and the drain terminal 305 and the gate terminal 307 face the outer edge side of the substrate.

[0052] The drain terminal 305 is formed integrally with the land 301. The source 303 and the source terminal 306 are connected by a conductive clip 308. The conductive clip 308 is made of a material having good electrical conductivity, such as copper, and is wider than the wire 309. The gate terminal 307 is connected to the gate 304 by the wire 309.

[0053] In this embodiment, a drain terminal 305 and a gate terminal 307 are formed on one short side of the sealing portion 310, and a source terminal 306 is formed on the other short side. The drain electrode is formed on the back surface of the chip, whereas the source 303 has a smaller electrode area than the drain 302. Therefore, the gate terminal 307 is disposed on the drain terminal 305 side so that the number of source terminals is greater than the number of drain terminals, and the source 303 and the source terminal 306 are connected by a wide conductive clip 308. This makes it possible to reduce the resistance on the source side.

[0054] The sealing portion 310 is formed in a generally rectangular shape in a plan view. The length of the long side of the sealing portion 310 is desirably 1.5 times or more the short side. Alternatively, the length of the short side may be 2 / 3 or less the long side. The sealing portion 310 is made of a resin having a relatively high thermal conductivity, similar to the upper and lower arm module 141. The thermal conductivity is preferably 2.2 W / m·K or more. By using a resin having a high thermal conductivity for the sealing portion 310, it is possible to omit a surface electrode that is exposed on the surface opposite to the substrate 31 to dissipate heat, and therefore the size of the motor relay module 147 can be reduced.

[0055] 19, when the thermal conductivity of the mold resin of the motor relay module 947 is relatively low and a surface electrode 948 is provided, the thickness is greater than that of the upper and lower arm modules 141. If there is a difference in thickness between the elements mounted on the substrate 31, the heat sink 945 needs to be formed in a shape that matches the elements, which makes the processing complicated. Also, in order to insulate the surface electrode from the heat sink 945, an insulating distance needs to be secured between the motor relay module 947 and the heat sink 945.

[0056] 9, in this embodiment, the sealing portion 310 of the motor relay module 147 is made of a resin with high thermal conductivity, similar to the upper and lower arm module 141, and no surface electrodes are provided that are exposed from the sealing portion 310. This allows the upper and lower arm module 141 and the motor relay module 147 to have approximately the same thickness.

[0057] In addition, the thickness of the heat generating elements (in this embodiment, the shunt resistor 131 and the snubber circuit elements 134, 137) that are arranged adjacent to the upper and lower arm module 141 and the motor relay module 147 and require heat dissipation in the direction opposite to the substrate 31 is made smaller than that of the upper and lower arm module 141 and the motor relay module 147.

[0058] This makes it unnecessary to secure an insulating distance from the heat sink 845, and makes it possible to reduce unevenness on the heat dissipation surface 848 of the heat sink 845, making processing easier. Note that Fig. 9 is a diagram for explaining the mounting height of each element on the surface of the substrate 31 facing the heat sink 845, and does not necessarily match the actual arrangement. Also, in Figs. 9 and 19, hatching of each element has been omitted to avoid complication.

[0059] As described above, the motor relay module 147 of the present embodiment includes a switching element, a sealing portion 310, a drain terminal 305, a source terminal 306, and a gate terminal 307. The switching element of the present embodiment is a motor relay element 127 that can switch between connection and disconnection between the inverter circuit 120 and the motor terminal 191.

[0060] The motor relay element 127 is composed of a drain 302, a source 303, and a gate 304. The sealing portion 310 is formed in a rectangular shape in a plan view, and molds the motor relay element 127. The drain terminal 305 is connected to the drain 302. The source terminal 306 is connected to the source 303. The gate terminal 307 is connected to the gate 304. The drain terminal 305, the source terminal 306, and the gate terminal 307 are exposed on the short side of the sealing portion 310. This allows peripheral components such as the shunt resistor 131 and the snubber circuit element 137 to be mounted in positions adjacent to the motor relay module 147, and the mounting area of ​​the substrate 31 can be effectively used. The same applies to the other relay modules, and the configuration related to the motor relay module 147 will be mainly described below.

[0061] The motor relay module 147 is mounted on the substrate 31, and is provided so as to be able to dissipate heat to the heat sink 845 from the surface opposite to the substrate 31. This allows the heat generated by energization to be dissipated appropriately.

[0062] Drain terminals 305 and gate terminals 307 are arranged on one side of sealing portion 310. Source terminals 306 are arranged on one side of sealing portion 310 opposite drain terminals 305 and gate terminals 307. This makes it possible to reduce the resistance on the source side by increasing the number of source terminals 306 connected to sources 303 having a smaller electrode area compared to drains 302 having electrodes formed on the back surface of the chip.

[0063] The electronic device 30 of this embodiment includes relay modules 147-149, 247, and 249, upper and lower arm modules 141-143, and 241-243, peripheral components, and a board 31. Below, the first system L1 will be explained, and the second system L2 will be omitted.

[0064] The upper and lower arm modules 141-143 are formed as one module by upper arm elements 121-123 and lower arm elements 124-126 of the same phase that constitute the inverter circuit 120. The peripheral components include at least one of shunt resistors 131-133 and snubber circuit elements 134-139. The upper and lower arm modules 141-143, motor relay modules 147-149, and peripheral components are mounted on the substrate 31.

[0065] On the same surface 391 of the substrate 31, the upper and lower arm modules 141-143, the motor relay modules 147-149, and the motor terminals 191-193 are arranged in this order from the substrate center line C toward the outside. The shunt resistors 131-133 and the snubber circuit elements 137-139, which are part of the peripheral components, are arranged side by side with the motor relay modules 147-149 in the region between the upper and lower arm modules 141-143 and the motor terminals 191-193. The relay modules 147-149 are arranged so that their short sides face the upper and lower arm modules 141-143. This makes it possible to reduce the substrate area occupied by the inverter circuit 120 and the peripheral circuits.

[0066] The upper and lower arm modules 141 to 143 and the motor relay modules 147 to 149 have the same mounting height. Here, the "mounting height" refers to the height when the elements are mounted on the substrate 31, and "equal mounting height" means that heat can be dissipated to the heat dissipation surface 848 that is approximately parallel to the substrate 31, and a difference in height is allowed to the extent that the difference can be absorbed by the heat dissipation gel 849 or the like, and is considered to be "equal mounting height". The same degree is also allowed for "equal mounting height" described below.

[0067] The mounting height of the shunt resistors 131 to 133 and the snubber circuit elements 134 to 139 is equal to or lower than the upper and lower arm modules 141 to 143. This eliminates the need to form a step on the heat dissipation surface 848, making it easier to process the heat sink 845.

[0068] Second embodiment The second embodiment is shown in Fig. 10. The second to eighth embodiments differ from the above embodiment mainly in the relay module, and this point will be mainly described.

[0069] 10, in a motor relay module 351, a land 301, a drain 302, a source 303, a gate 304, a drain terminal 315, a source terminal 316, a gate terminal 317, a conductive clip 308, etc. are molded by a sealing part 310. In the motor relay module 351, the drain terminal 315 is formed along one short side, and the source terminal 316 and the gate terminal 317 are formed along the other short side. Even with this configuration, the same effects as those of the above embodiment can be obtained.

[0070] Third embodiment The third embodiment is shown in Fig. 11. In a motor relay module 352 shown in Fig. 11, a land 301, a drain 302, a source 303, a gate 304, a drain terminal 315, a source terminal 316, a gate terminal 317, a conductive clip 308, and the like are molded by a sealing part 310. In Fig. 11, the gate terminal is disposed on the source terminal side as in the second embodiment, but the gate terminal may be disposed on the drain terminal side as in the first embodiment.

[0071] In the motor relay module 352, the shunt resistor 318 and the board pattern 319 connected to the shunt resistor 318 are integrally molded in the sealing portion 310. That is, in this embodiment, the motor relay module 352 has a built-in shunt resistor 318, which is an element related to current detection. This makes it possible to reduce the mounting area compared to a case where the shunt resistor is provided separately. Also, it is possible to improve the heat dissipation of the shunt resistor 318. Also, the same effects as those of the above embodiment are achieved.

[0072] (Fourth embodiment) The fourth embodiment is shown in Fig. 12. In a relay module 353 shown in Fig. 12, a land 301, a drain 302, a source 303, a gate 304, a drain terminal 315, a source terminal 316, a gate terminal 317, a shunt resistor 318, etc. are molded by a sealing portion 310.

[0073] In this embodiment, the source 303 and the source terminal 316 are connected by a shunt resistor 318 instead of the conductive clip 308. That is, the shunt resistor 318 also functions as the conductive clip. This makes it possible to further reduce the mounting area. In addition, the same effects as those of the above embodiment are achieved.

[0074] Fifth embodiment The fifth embodiment is shown in Fig. 13. In a motor relay module 354 shown in Fig. 13, a land 301, a drain 302, a source 303, a gate 304, a drain terminal 315, a source terminal 316, a gate terminal 317, a conductive clip 308, a heat dissipation terminal 321, etc. are molded by a sealing portion 310.

[0075] The heat dissipation terminal 321 is formed along the side on which the terminals 315 to 317 are not formed, and is connected to the wiring pattern 322 connected to the shunt resistor 318. This allows the heat generated in the shunt resistor 318 to be dissipated from the motor relay module 354 side via the wiring pattern 322 and the heat dissipation terminal 321.

[0076] The motor relay module 354 of this embodiment has a heat dissipation terminal 321 connected to a wiring pattern 322 connected to the shunt resistor 318. This allows the heat generated in the shunt resistor 318 to be dissipated more efficiently. In addition, the same effects as those of the above embodiment are achieved.

[0077] Sixth embodiment The sixth embodiment is shown in Fig. 14. In a motor relay module 355 shown in Fig. 14, a land 301, a drain 302, a source 303, a gate 304, a drain terminal 335, a source terminal 306, a gate terminal 337, a conductive clip 308, and a non-potential terminal 338 are molded in a sealing portion 310.

[0078] In this embodiment, non-potential terminals 338 are provided on both sides of the arranged source terminals 306, and non-potential terminals 338 are provided on both sides of the arranged drain terminals 335 and gate terminals 337. The non-potential terminals 338 mean that they are not assigned a potential related to their main function, such as a gate terminal, and may have a secondary function, such as heat dissipation. By making the terminals provided at the four corners of the sealing portion 310 non-potential terminals 338, it is possible to improve the solder joint life of the terminals assigned a potential related to their main function. Note that some of the corner terminals do not need to be non-potential terminals.

[0079] Further, drain terminals 335 are arranged on both sides of the gate terminal 337. This can improve the solder joint life of the gate terminal 337. In the motor relay module of the above embodiment, other terminals such as drain terminals may be arranged on both sides of the gate terminal. Although not shown, in the upper and lower arm module, the terminals provided at the four corners of the sealing portion may be non-potential terminals.

[0080] In this embodiment, the motor relay module 355 has a non-potential terminal 338 formed at at least one corner of the rectangular sealing portion 310. This makes it possible to maintain the function of the motor relay module 355 even if a joint failure occurs at the corner.

[0081] In the motor relay module 355, other terminals are arranged on both sides of the gate terminal 337 related to transmission and reception of the drive signal. In other words, the gate terminal 337 is assigned to a terminal other than a corner pin, which is a terminal provided at a corner. The terminals arranged on both sides of the gate terminal 337 are not limited to the drain terminal 335, and may be non-potential terminals or the like. This makes it possible to maintain at least transmission and reception of the drive signal even if a poor connection occurs at the corner.

[0082] Seventh embodiment The seventh embodiment is shown in Figures 15 and 16. In a motor relay module 356 shown in Figures 15 and 16, a land 301, a drain 302, a source 303, a gate 304, a drain terminal 305, a source terminal 306, a gate terminal 307, a large conductive clip 341, etc. are molded by a sealing portion 310.

[0083] In the motor relay module 356, the source 303 and the source terminal 306 are connected by a large conductive clip 341. For example, the conductive clip 308 in the first embodiment is narrower than the source 303 (see FIG. 8), whereas the large conductive clip 341 is wider than the source 303 and is formed so as to cover the entire surface of the source 303. In this embodiment, the large conductive clip 341 is formed in a flat plate shape extending from the source terminal 306 to the drain terminal 305 side, and is cut out so as not to overlap with the gate 304.

[0084] 16, the large conductive clip 341 has a protruding portion 342 that protrudes toward the source 303 and is connected to the source 303. The minimum thickness Hr of the sealing portion 310 where the large conductive clip 341 is provided is thicker than the diameter of the filler in the mold resin to enable resin molding. The minimum thickness Hr is set to a value that ensures insulation equal to or greater than the switching withstand voltage.

[0085] In this embodiment, the large conductive clip 341 that connects the source 303 and the source terminal 306 is formed to cover the entire surface of the electrode part of the source 303. This makes it possible to reduce the resistance on the source side compared to the case where a connection is made with a clip narrower than the electrode part of the source 303.

[0086] The minimum thickness Hr of the sealing portion 310 is greater than the filler diameter. In this embodiment, a large conductive clip 341 is used, and the thickness of the sealing portion 310 is minimum at the location where the large conductive clip 341 is provided. By making the minimum thickness Hr greater than the filler diameter, it is possible to perform appropriate resin molding. In the above embodiment, the minimum thickness Hr of the sealing portion 310 is also greater than the filler diameter. Moreover, the same effects as those of the above embodiment are achieved.

[0087] Eighth embodiment The eighth embodiment is shown in Figures 17 and 18. The eighth embodiment differs from the seventh embodiment in the large conductive clip 345, and this point will be mainly described. As shown in Figures 17 and 18, in a motor relay module 357 of this embodiment, the large conductive clip 345 has a uniform thickness and abuts against the source 303 at a recess 346.

[0088] In this embodiment, the large conductive clip 345 has a uniform thickness and is connected to the source 303 at a recess 346 provided in the middle. This allows the large conductive clip 345 to be formed using a material with a uniform thickness. In addition, the same effects as those of the above embodiment are achieved.

[0089] In the embodiment, main board 31 corresponds to the "board", motor relay modules 147-149, 237-239, 351-357 correspond to the "semiconductor modules" and "relay modules", motor relay elements 127-129, 227-229 correspond to the "switching elements" and "relay elements", shunt resistors 131-133, 231-233, 318 correspond to the "current detection elements" and "peripheral components", snubber circuit elements 134-139, 234-239 correspond to the "noise removal elements" and "peripheral components", motor terminals 191-193, 291-293 correspond to the "output terminals", gate terminal 337 corresponds to the "drive signal terminal", and large conductive clips 341, 345 correspond to the "wiring members".

[0090] (Other embodiments) In the above embodiment, in all relay modules, the shunt resistors and snubber circuit elements are arranged side by side as peripheral components. In other embodiments, in some motor relay modules, the peripheral components may not be arranged side by side. In other embodiments, the shunt resistors or snubber circuit elements may not be arranged side by side with the motor relay modules. In addition, the peripheral components may be other than the shunt resistors and snubber circuit elements. In addition, it is not necessary for all relay modules to have the same shape, and the shape of some relay modules may be different from that of other modules.

[0091] In the above embodiment, two inverter circuits and a motor relay module are mounted on the board. In other embodiments, the number of systems is not limited to two, and may be one system or three or more systems. In the above embodiment, the electronic device is applied to a motor drive circuit. In other embodiments, the electronic device may be applied to a circuit other than the motor drive circuit, such as a power generation circuit or a DC-DC converter.

[0092] In the above embodiment, the inverter circuit and the microcomputer are mounted on the same board. In other embodiments, the inverter circuit and electronic components related to control such as the microcomputer may be mounted on different boards. Also, the sub-board on the connector side may be omitted and there may be only one board. Also, regardless of the number of boards, the configuration of the drive circuit may be different from that of the above embodiment.

[0093] In the above embodiment, the steering device is an electric power steering device. In other embodiments, the steering device may be a steer-by-wire device, and the drive device may be used as a steering device that steers the wheels, or as a reaction device that applies a reaction force to the steering wheel. The drive device may also be applied to devices other than the steering device. As described above, the present invention is not limited to the above embodiment, and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0094] 30 Electronic device 31 Main circuit board (circuit board) 127~129, 227~229...Motor relay elements (switching elements, relay elements) 147~149, 247~249, 351~357 Motor relay module (semiconductor module, relay module) 302 Drain 303 Source 304: Gate 310: Sealing part 305, 315, 335...Drain terminal 306, 316 Source terminal 307, 317, 337 Gate terminal

Claims

1. A switching element (127-129, 227-229) consisting of a drain (302), a source (303) and a gate (304); A sealing portion (310) formed in a rectangular shape in a plan view and molding the switching element; A drain terminal (305, 315, 335) connected to the drain; a source terminal (306, 316) connected to the source; A gate terminal (307, 317, 337) connected to the gate; Equipped with the drain terminal, the source terminal, and the gate terminal are exposed to a short side of the sealing portion, A semiconductor module, comprising: a non-potential terminal (338) provided at at least one corner of the sealing portion, the non-potential terminal being exposed at two sides of the sealing portion.

2. 2. The semiconductor module according to claim 1, which is mounted on a substrate (31) and is provided so as to be capable of dissipating heat to a heat sink (845) from a surface opposite to the substrate.

3. 3. The semiconductor module according to claim 1, wherein drain terminals or non-potential terminals are arranged on both sides of the gate terminal.

4. the drain terminal and the gate terminal are arranged on one side of the sealing portion, 4. The semiconductor module according to claim 1, wherein the source terminals are arranged on one side of the sealing portion opposite to the drain terminal and the gate terminal.

5. 5. The semiconductor module according to claim 1, wherein a wiring member (341, 345) connecting the source and the source terminal is formed so as to cover the entire surface of the electrode portion of the source.

6. 6. The semiconductor module according to claim 5, wherein the wiring member (345) is connected to the source at a recess (346) provided in an intermediate portion thereof.

7. 7. The semiconductor module according to claim 1, wherein the minimum thickness of the sealing portion is greater than a diameter of the filler.

8. 8. The semiconductor module according to claim 1, further comprising a built-in element for current detection.

9. 9. The semiconductor module according to claim 1, wherein the switching element is a relay element capable of switching between connection and disconnection of an inverter circuit (120, 220) and an output terminal (191-193, 291-293).

10. A relay module (147 to 149, 247 to 249) which is a semiconductor module according to claim 9; upper and lower arm modules (141-143, 241-246) each including upper arm elements (121-123, 221-223) and lower arm elements (124-126, 224-226) of the same phase that configure the inverter circuit; A peripheral component including at least one of a current detection element (131 to 133, 231 to 233) and a noise removal element (134 to 139, 234 to 239); a substrate (31) on which the upper and lower arm modules, the relay module, and the peripheral components are mounted; Equipped with On the same surface (391) of the substrate, The upper and lower arm modules, the relay modules, and the output terminals are arranged in this order from the center line of the board toward the outside, An electronic device in which at least a portion of the peripheral components are arranged side by side with the relay module between the upper and lower arm modules and the output terminal.

11. The electronic device according to claim 10 , wherein the relay module is arranged such that a short side of the relay module faces the upper and lower arm modules.

12. The electronic device according to claim 10 or 11, wherein the upper and lower arm modules and the relay module have the same mounting height.

13. The electronic device according to any one of claims 10 to 12, wherein the peripheral components have a mounting height equal to or lower than the upper and lower arm modules.

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