Switching element driving unit

Abstract

The invention provides a switching element driving unit, which can ensure the insulation between a driver and a cooler and shorten the connection distance between the driver and a semiconductor switching element even when the semiconductor switching element formed by a wide band gap semiconductor is used. A switching element drive unit (30) is provided with a circuit board (1), a semiconductor switching element (102a) comprising a wide-band-gap semiconductor, a cooler (4), and a driver (103a). The driver (103a) is surface-mounted on a second surface (32) on the opposite side from a first surface (31), which is the surface of the circuit board (1) on the side on which the cooler (4) is disposed.

Description

This application is a divisional application of an invention patent application with the invention name “Switching element driving unit”, the international application date of April 3, 2017, and the application number of 201780089164.8 (the international application number is PCT / JP2017 / 013909). Technical Field

[0001] The present invention relates to a switching element driving unit including a semiconductor switching element formed of a wide bandgap semiconductor and a driver for driving the semiconductor switching element, and more particularly to the arrangement of the driver. Background Art

[0002] In order to achieve miniaturization of a power conversion device having a semiconductor switch element and a driver, a structure is proposed in which electronic components such as a transformer and a reactor and a semiconductor switch element are installed in a housing with high cooling efficiency. For example, there is a method as follows: a storage body is provided, the storage body has a recess for storing a relatively high electronic component, a refrigerant flow path is provided on a side portion of the recess, a relatively low semiconductor switch element is installed on the upper surface of the side portion, and a circuit substrate is installed on the upper surface of the electronic component and the semiconductor switch element (Japanese Patent Gazette No. 5823020, Japanese Patent Gazette No. 5535292).

[0003] In such a structure, for electronic components and semiconductor switch elements of different heights, the cooling efficiency of the electronic components is improved while the height of each component is made consistent with the circuit substrate, so that there is no waste of space, so the space utilization rate is good and high-density installation can be achieved. In addition, the electronic components and semiconductor switch elements are arranged below the circuit substrate, so the projected area of ​​the power conversion device can be reduced. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent No. 5823020 Patent Document 2: Japanese Patent No. 5535292 Summary of the invention Technical problem to be solved by the invention

[0005] However, as semiconductor switching elements, if wide-gap GaN (Gallium Nitride) and SiC (Silicon Carbide) that can operate at high speed are used, in order to ensure stability for high-speed operation, it is necessary to shorten the connection distance between the semiconductor switching element and the driver mounted on the circuit substrate in a surface-mounted manner. If the connection distance between the semiconductor switching element and the driver is to be shortened, it is necessary to shorten the pins connecting the semiconductor switching element and the circuit substrate. Therefore, the cooling surface of the semiconductor switching element needs to be close to the circuit substrate, and the cooler that cools the cooling surface needs to be close to the circuit substrate. On the other hand, in order to ensure insulation between the driver and the housing (cooler), it is necessary to configure the driver at a position where the insulation distance from the cooler is ensured. Therefore, it is necessary to configure the driver outside the projection area where the cooler is projected onto the surface of the circuit substrate on the side where the cooler is configured. As a result, the connection distance between the semiconductor switching element and the driver has to be lengthened, making it difficult to ensure the stability of the operation of the semiconductor switching element.

[0006] In addition, in order to stabilize the operation of semiconductor switch elements composed of wide-bandgap semiconductors, surface-mount packages without pins for semiconductor packages are becoming more and more common. In addition, the thinning of semiconductor switch elements is constantly being promoted for miniaturization. The cooler for cooling the thin semiconductor switch elements using the above-mentioned surface mounting is arranged close to the circuit substrate. In order to ensure the insulation distance between the cooler and the driver, it is necessary to arrange the driver outside the projection area of ​​the cooler onto the surface of the circuit substrate on the side where the cooler is arranged. As a result, the connection distance between the semiconductor switch element and the driver has to be longer, making it difficult to ensure the stability of the operation of the semiconductor switch element.

[0007] In addition, wide bandgap semiconductors have the characteristic of making chips smaller compared to Si (silicon) semiconductors, and can make packages smaller. As a result, the semiconductor switch element becomes smaller relative to the cooler, and if the insulation distance with the cooler is to be ensured, the connection distance with the semiconductor switch element becomes longer. Therefore, a switching element driving unit is desired that can ensure insulation between a driver and a cooler and shorten the connection distance between the driver and the semiconductor switching element even when a semiconductor switching element formed of a wide bandgap semiconductor is used. Technical solutions adopted to solve technical problems

[0009] The switching element driving unit involved in the present invention includes: a circuit substrate having a circuit pattern; a semiconductor switching element, which is connected to the circuit substrate and is composed of a wide bandgap semiconductor; a cooler, which cools the semiconductor switching element while being insulated from the semiconductor switching element; and a driver, which drives the semiconductor switching element, and the driver is surface-mounted on a second surface opposite to the first surface of the circuit substrate on which the cooler is arranged. Effects of the Invention

[0010] According to the switch element driving unit involved in the present invention, the semiconductor switch element is insulated from the cooler, so it is necessary to insulate the part of the driver that is connected to the semiconductor switch element from the cooler. By mounting the driver that drives the semiconductor switch element composed of a wide bandgap semiconductor on the second surface opposite to the first surface of the circuit substrate on the side where the cooler is arranged in a surface-mounted manner, since the circuit substrate is arranged between the driver and the cooler, the insulation between the driver and the cooler can be ensured. In addition, the driver is arranged on the opposite side of the cooler and sandwiches the circuit substrate in the middle, so the configuration position of the driver can be determined regardless of the configuration position of the cooler. Therefore, the driver can be arranged near the semiconductor switch element, shortening the connection distance between the driver and the semiconductor switch element, and ensuring stability for high-speed operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 and 2 are a plan view and a side view of the switching element driving unit according to the first embodiment of the present invention. Figure 2 This is a circuit diagram of a power conversion device including a plurality of switching element driving units according to the first embodiment of the present invention. Figure 3 1 and 2 are a plan view and a side view of a switching element driving unit according to Embodiment 2 of the present invention. Figure 4 1 and 2 are a plan view and a side view of a switching element driving unit according to a third embodiment of the present invention. Figure 5 1 and 2 are a plan view and a side view of a switching element driving unit according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0012] Implementation method 1. The switching element driving unit 30 according to the first embodiment will be described with reference to the drawings. Figure 1 The figure on the upper side is a plan view of the switching element driving unit 30 according to the first embodiment as viewed from the second surface 32 side of the circuit substrate 1. Figure 1The lower figure is a side view of the switching element driving unit 30 as viewed from the side. Figure 2 3 is a circuit diagram of a power conversion device including four switching element driving units 30 .

[0013] Figure 2 The power conversion device shown is an example of a power conversion device having a switching element driving unit 30, and is an insulated full-bridge DC / DC converter. The power conversion device has an insulated transformer 104, a single-phase inverter 102 connected to a primary winding 104a of the transformer 104, and a rectifier circuit 105 connected to a secondary winding 104b of the transformer 104.

[0014] The single-phase inverter 102 has four semiconductor switching elements 102a to 102d configured as a full bridge. Each semiconductor switching element 102a to 102d uses a FET (Field Effect Transistor) and is composed of a wide-gap semiconductor GaN (Gallium Nitride) having reverse conduction characteristics from the source to the drain. The single-phase inverter 102 converts the DC voltage Vin of the input power supply 101 into an AC voltage and supplies it to the primary winding 104a of the transformer 104. In addition, each semiconductor switching element may have a diode connected in reverse parallel between the source and the drain, and the diode may be composed of a wide-gap semiconductor. In addition, each semiconductor switching element may use a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor) composed of a wide-gap semiconductor. As a wide-gap semiconductor, SiC (Silicon Carbide), diamond-based materials, etc. may be used.

[0015] The rectifier circuit 105 includes four rectifier elements (semiconductor elements) diodes 105a to 105d forming a full bridge. The output of the rectifier circuit 105 is connected to an output filter reactor 106 and an output capacitor 107 , and the filtered DC voltage Vout is output to a load 108 .

[0016] In addition, the power conversion device includes a control circuit 109 for controlling the semiconductor switch element. The control circuit 109 is insulated from the main circuits such as the single-phase inverter 102. The detection signal of the input voltage Vin is input to the control circuit 109 via the insulating element 112a, and the detection signal of the output voltage Vout is input to the control circuit 109 via the insulating element 112b. The control circuit 109 generates gate signals 110a to 110d for turning on and off each semiconductor switch element 102a to 102d and controls the conduction duty ratio (conduction period) of each semiconductor switch element 102a to 102d so that the output voltage Vout becomes the target voltage. Here, each gate signal 110a to 110d is input to the driver 103a to 103d via the insulating element 111a to 111d. The insulating elements 111a to 111d use an optical coupler or a magnetic coupler. Each driver 103a to 103d includes a semiconductor switch element such as a FET, and each semiconductor switch element generates a gate drive signal according to each gate signal 110a to 110d. Each gate drive signal is input to a gate terminal of each semiconductor switch element 102a to 102d.

[0017] Next, the switching element driving unit 30 will be described. Figure 1 2 shows a mounting structure of a switching element driving unit 30 including one pair of semiconductor switching elements and a driver among four pairs of semiconductor switching elements 102a to 102d and drivers 103a to 103d. Figure 1 The semiconductor switching element 102a and the driver 103a are shown in the example of FIG.

[0018] The switch element driving unit 30 includes a circuit substrate 1 having a circuit pattern. In the present embodiment, the circuit pattern is printed on a substrate such as glass epoxy resin in the circuit substrate 1. The circuit substrate 1 includes a plurality of circuit pattern layers of two or more layers. The circuit substrate 1 is in the form of a flat plate and includes a first surface 31 on one side and a second surface 32 on the other side. Figure 1 2 shows a case where one switching element driving unit 30 includes one circuit substrate 1 , but a plurality of switching element driving units 30 may include one common circuit substrate 1 .

[0019] The semiconductor switch element 102a is a surface-mounted chip in the form of a plate (in this example, a rectangular plate). One side of the semiconductor switch element 102 is a surface-mounted surface, and is provided with a connection terminal pad that is soldered to the circuit pattern of the circuit substrate 1. In this embodiment, connection terminal pads for a gate terminal, a source terminal, and a drain terminal are provided. The other side of the semiconductor switch element 102a is a cooling surface, and is provided with a cooling pad.

[0020] The surface mounting surface of the semiconductor switch element 102a is mounted on the first surface 31 of the circuit substrate 1 in a surface mounting manner, and the gate terminal, source terminal, and drain terminal of the semiconductor switch element 102a are connected to the circuit pattern of the circuit substrate 1. The cooler 4 is mounted on the cooling surface of the semiconductor switch element 102a. Therefore, the heat of the semiconductor switch element 102a is transferred to the cooler 4 without passing through the circuit substrate 1. Therefore, the heat conduction efficiency from the semiconductor switch element 102a to the cooler 4 can be improved.

[0021] In this embodiment, an insulating sheet 3 as an insulating member is sandwiched between the cooling surface of the semiconductor switch element 102a and the mounting surface of the cooler 4. Even if the cooler 4 is connected to the housing of the power conversion device for heat conduction, etc., insulation between the housing and the semiconductor switch element 102a can be ensured. The insulating sheet 3 is attached to the entire mounting surface of the cooler 4. The insulating sheet 3 can ensure insulation between the cooler 4 and the circuit substrate 1, and can ensure an insulation distance between the cooler 4 and the driver 103a arranged on the opposite side of the circuit substrate 1.

[0022] In addition, when the cooling surface of the semiconductor switch element 102a is insulated, the insulating sheet 3 may not be interposed. In addition, a heat sink for dissipating heat from the semiconductor switch element 102a may be provided between the semiconductor switch element 102a and the insulating sheet 3. The cooler 4 may be a water-cooled type having a water path, or an air-cooled type having a cooling fan for cooling through air. In this example, the outer shape of the cooler 4 is a rectangular parallelepiped.

[0023] The semiconductor switch element 102a is composed of a wide bandgap semiconductor, and thus can be miniaturized more than the conventional case where it is composed of a Si (silicon) semiconductor. Therefore, the cooling surface of the semiconductor switch element 102a becomes narrower than the mounting surface of the cooler 4, and the semiconductor switch element 102a is covered by the cooler 4. The cooling surface of the semiconductor switch element 102a is mounted at the center of the mounting surface of the cooler 4. Thus, the diffusion of heat transferred from the semiconductor switch element 102a to the cooler 4 can be improved.

[0024] A space without semiconductor switch element 102a is generated between the first surface 31 of the circuit substrate 1 and the mounting surface of the cooler 4. If the driver 103a can be arranged in this space, the connection distance between the driver 103a and the semiconductor switch element 102a can be shortened. However, the semiconductor switch element 102a is thinned due to the wide bandgap semiconductor, so the interval in the space becomes narrower. Therefore, it is difficult to arrange the driver 103a in the space between the circuit substrate 1 and the cooler 4 while ensuring the insulation distance from the cooler 4.

[0025] Therefore, the driver 103 a is surface mounted on the second surface 32 on the opposite side to the first surface 31 which is the surface of the circuit board 1 on which the cooler 4 is arranged.

[0026] According to this structure, the circuit substrate 1 is arranged between the driver 103a and the cooler 4, so that the insulation between the driver 103a and the cooler 4 can be ensured. In addition, the driver 103a is arranged on the opposite side of the cooler 4 with the circuit substrate 1 in between, so the arrangement position of the driver 103a can be determined regardless of the arrangement position of the cooler 4. Therefore, the driver 103a can be arranged near the semiconductor switch element 102a, the connection distance between the driver 103a and the semiconductor switch element 102a can be shortened, and the stability for high-speed operation can be ensured.

[0027] In this embodiment, the driver 103a is an active element disposed closest to the semiconductor switch element 102a driven by the driver 103a. Here, the active element refers to an element that amplifies or converts energy other than a signal into signal energy, such as a transistor (semiconductor switch element), among the components that are components of the electronic circuit and have independent inherent functions. Active elements do not include passive elements such as resistors, coils, capacitors, and wiring. In addition, the driver 103a is an active element as described above and has a semiconductor switch element.

[0028] According to this configuration, the driver 103a can be arranged closest to the semiconductor switch element 102a, thereby shortening the connection distance between the driver 103a and the semiconductor switch element 102a and ensuring stability for high-speed operation.

[0029] When the first surface 31 and the second surface 32 of the circuit board 1 are viewed in the normal direction, the driver 103a is arranged so that at least a part overlaps with the cooler 4. According to this structure, the driver 103a can be arranged near the semiconductor switch element 102a and close to the position where it overlaps with the cooler 4 when viewed in the normal direction. In addition, the various components of the switch element drive unit 30 can be compactly gathered, so that miniaturization can be achieved.

[0030] When viewed in the normal direction of the first surface 31 and the second surface 32 of the circuit substrate 1, the driver 103a is arranged so as not to overlap with the semiconductor switch element 102a. In the present embodiment, the driver 103a is not mounted on the surface of the area of ​​the second surface 32 on the opposite side of the area of ​​the first surface 31 on which the semiconductor switch element 102a is mounted, and the driver 103a is mounted on the surface of the area of ​​the second surface 32 close to the area of ​​the second surface 32 on the opposite side. According to this structure, it is difficult for the semiconductor switch element 102a and the driver 103a to transfer heat to each other through the circuit substrate 1, and insulation can be ensured except for the connection portion.

[0031] When viewed in the normal direction of the circuit board 1 , the interval between the driver 103 a and the semiconductor switch element 102 a is narrower than the width of the driver 103 a and the width of the semiconductor switch element 102 a . The semiconductor switch element 102a and the driver 103a are connected via a through hole 11 penetrating the circuit substrate 1. The through hole 11 is provided at the end portion of the region of the circuit substrate 1 on which the semiconductor switch element 102a is mounted on the surface, which is located on the driver 103 side. A conductor is embedded in the through hole 11, and the first surface 31 side of the through hole 11 is connected to a gate terminal or the like provided on the surface mounting surface of the semiconductor switch element 102a, and the second surface 32 side of the through hole 11 is connected to a terminal of the driver 103a via a connection pattern 12 provided on the second surface 32. The driver 103a is an active element having the shortest connection distance to the semiconductor switch element 102a.

[0033] In the present embodiment, the gate terminal and the source terminal of the semiconductor switch element 102 a are connected to the driver 103 a , and two through holes 11 and two connection patterns 12 are provided.

[0034] Implementation method 2. Next, the switching element driving unit 30 involved in Embodiment 2 is described. The description of the same structural parts as those in Embodiment 1 is omitted. The basic circuit structure of the power conversion device and the switching element driving unit 30 involved in this embodiment is the same as that in Embodiment 1, but the configuration structure of the switching element driving unit 30 is different from that in Embodiment 1. Figure 3 The figure on the upper side is a plan view of the switching element driving unit 30 according to the second embodiment as viewed from the second surface 32 side of the circuit substrate 1. Figure 3 The lower figure is a side view of the switching element driving unit 30 as viewed from the side.

[0035] This embodiment is also the same as the first embodiment, and the driver 103a is mounted on the second surface 32 on the opposite side of the first surface 31 of the circuit substrate 1 on the side where the cooler 4 is arranged in a surface mounting manner. In addition, the driver 103a is an active element arranged closest to the semiconductor switch element 102a driven by the driver 103a. In addition, the driver 103a is an active element with the shortest connection distance to the semiconductor switch element 102a.

[0036] In this embodiment, unlike the first embodiment, the semiconductor switch element 102a is mounted on the second surface 32 in a surface-mounted manner. The semiconductor switch element 102a has a cooling pad on the surface mounted on the circuit substrate 1 in a surface-mounted manner. In addition, the cooler 4 is mounted on the area of ​​the first surface 31 on the opposite side of the area of ​​the second surface 32 on which the semiconductor switch element 102a is surface-mounted. Thus, the heat of the semiconductor switch element 102a is transferred to the cooler 4 via the circuit substrate 1.

[0037] According to this structure, the heat of the semiconductor switch element 102a can be transferred to the cooler 4 on the opposite side through the circuit substrate 1 for cooling. In addition, physical interference between the cooler 4 and the driver 103a can be avoided, and the driver 103a can be arranged in the vicinity of the semiconductor switch element 102a to minimize the connection distance. The semiconductor switch element 102a and the driver 103a do not need to be connected through the through hole 11 as in the first embodiment, and the structure of the circuit substrate can be suppressed from becoming complicated.

[0038] The center of the mounting surface of the cooler 4 is arranged on the opposite side of the semiconductor switch element 102a with the circuit substrate 1 sandwiched therebetween. An insulating sheet 3 as an insulating member is sandwiched between the cooler 4 and the first surface 31. A through hole 13 penetrating the circuit substrate 1 is provided in the region of the circuit substrate 1 where the cooling pad of the semiconductor switch element 102a is arranged. The through hole 13 is filled with a thermally conductive material such as resin or metal. Therefore, the heat of the semiconductor switch element 102a can be efficiently transferred to the cooler 4 through the through hole 13.

[0039] Since the circuit substrate 1 can ensure insulation between the driver 103a and the cooler 4, the driver 103a is mounted on the area of ​​the second surface 32 opposite to the area of ​​the first surface 31 on which the cooler 4 is mounted. Therefore, when viewed in the normal direction of the first surface 31 and the second surface 32 of the circuit substrate 1, the driver 103a is arranged so that at least a portion overlaps with the cooler 4.

[0040] The distance between the driver 103a and the semiconductor switch element 102a mounted on the second surface 32 in a surface mounting manner is narrower than the width of the driver 103a and the width of the semiconductor switch element 102a. The semiconductor switch element 102a has a gate terminal and a source terminal connection terminal 22 extending from the rectangular plate-shaped main body 6 to the driver 103a side. The two connection terminals 22 of the semiconductor switch element 102a are connected to the terminals of the driver 103a via two connection patterns 12 provided on the second surface 32.

[0041] As described above, even if the semiconductor switch element 102a has a cooling surface on the same surface as the surface mounting surface, insulation between the driver 103a and the cooler 4 can be ensured. At the same time, there is no need to sacrifice the cooling of the semiconductor switch element 102a composed of a wide bandgap semiconductor. The connection distance between the semiconductor switch element 102a and the driver 103a can be shortened, thereby achieving stable high-speed switching.

[0042] Implementation method 3. Next, the switching element driving unit 30 involved in Embodiment 3 is described. The description of the same structural parts as those in Embodiment 1 is omitted. The basic circuit structure of the power conversion device and the switching element driving unit 30 involved in this embodiment is the same as that in Embodiment 1, but the configuration structure of the switching element driving unit 30 is different from that in Embodiment 1. Figure 4 The figure on the upper side is a plan view of the switching element driving unit 30 according to the third embodiment as viewed from the second surface 32 side of the circuit substrate 1. Figure 4 The lower figure is a side view of the switching element driving unit 30 as viewed from the side.

[0043] This embodiment is also the same as the first embodiment, and the driver 103a is mounted on the second surface 32 on the opposite side of the first surface 31 of the circuit substrate 1 on the side where the cooler 4 is arranged in a surface mounting manner. In addition, the driver 103a is an active element arranged closest to the semiconductor switch element 102a driven by the driver 103a. In addition, the driver 103a is an active element with the shortest connection distance to the semiconductor switch element 102a.

[0044] In this embodiment, unlike the first embodiment, the semiconductor switch element 102a has a rectangular plate-shaped main body 6 and a pin 21 extending linearly from one side of the main body 6. The pin 21 is inserted into the through hole 14 penetrating the circuit substrate 1 from the first surface 31 side and is mounted on the circuit substrate 1 with solder or the like. The main body 6 extends along the normal direction of the first surface 31 on the first surface 31 side of the circuit substrate 1. The cooler 4 is mounted on one side of the main body 6.

[0045] According to this structure, the main body 6 is arranged to extend along the normal direction of the first surface 31, so that the main body 6 can be separated from the first surface 31, and the cooler 4 can be installed on the cooling surface of one side of the main body 6. Therefore, when using the semiconductor switch element 102a packaged with the pin 21, the cooler 4 can be arranged on the first surface 31 side of the circuit substrate 1, and the physical interference between the driver 103a mounted on the second surface 32 in a surface mounting manner and the cooler 4 can be avoided, and the driver 103a is arranged at the nearest position of the pin 21 of the semiconductor switch element 102a mounted on the circuit substrate 1, thereby shortening the connection distance between the driver 103a and the semiconductor switch element 102a. In addition, since the cooler 4 and the main body 6 can be separated from the first surface 31, the insulation of the cooler 4 and the circuit substrate 1 can be ensured, and the insulation distance between the cooler 4 and the driver 103a arranged on the opposite side of the circuit substrate 1 can be ensured.

[0046] The mounting surface of the cooler 4 is wider than the cooling surface of the semiconductor switch element 102a, but the mounting surface of the cooler 4 is arranged closer to the side separated from the first surface 31 relative to the cooling surface of the semiconductor switch element 102a. That is, the portion of the mounting surface of the cooler 4 that is not mounted on the cooling surface of the semiconductor switch element 102a is the portion on the side separated from the first surface 31. Therefore, the interval between the cooler 4 and the first surface 31 can be ensured, the main body 6 can be brought close to the first surface 31, and the connection distance between the semiconductor switch element 102a and the driver 103a can be shortened.

[0047] An insulating sheet 3 as an insulating member is sandwiched between the mounting surface of the cooler 4 and the cooling surface of the semiconductor switch element 102a. A screw 7 is inserted into a through hole provided in the main body 6 from the opposite side of the cooler 4 and screwed into a nut provided in the cooler 4, thereby fixing the cooler 4 to the semiconductor switch element 102a.

[0048] In this embodiment, three pins 21 of a gate terminal, a source terminal, and a drain terminal are provided, and three through holes 14 are provided. The pins 21 of the gate terminal and the source terminal are connected to the terminals of the driver 103a via two connection patterns 12 provided on the second surface 32. In addition, the pins 21 of the source terminal and the drain terminal are connected to a circuit pattern (not shown) provided on the circuit substrate 1.

[0049] The driver 103a is arranged on the side where the cooler 4 is provided with respect to the mounting portion of the pin 21 mounted on the circuit substrate 1, and when viewed in the normal direction of the first surface 31 and the second surface 32 of the circuit substrate 1, the driver 103a is arranged so that at least a part of it overlaps with the cooler 4. Thus, the components of the switching element driving unit 30 can be compactly gathered and miniaturized.

[0050] As described above, the semiconductor switch element 102a is a package with a pin 21. Even when the pin 21 is shortened and is to be installed on the circuit substrate 1, insulation between the driver 103a and the cooler 4 can be ensured without sacrificing the cooling of the semiconductor switch element 102a composed of a wide bandgap semiconductor. The connection distance between the semiconductor switch element 102a and the driver 103a can be shortened, thereby achieving stable high-speed switching.

[0051] Implementation method 4. Next, the switching element driving unit 30 involved in Embodiment 4 is described. The description of the same structural parts as those in Embodiment 1 is omitted. The basic circuit structure of the power conversion device and the switching element driving unit 30 involved in this embodiment is the same as that in Embodiment 1, but the configuration structure of the switching element driving unit 30 is different from that in Embodiment 1. Figure 5 The figure on the upper side is a plan view of the switching element driving unit 30 according to the fourth embodiment as viewed from the second surface 32 side of the circuit substrate 1. Figure 5 The lower figure is a side view of the switching element driving unit 30 as viewed from the side.

[0052] This embodiment is also the same as the first embodiment, and the driver 103a is mounted on the second surface 32 on the opposite side of the first surface 31 of the circuit substrate 1 on the side where the cooler 4 is arranged in a surface mounting manner. In addition, the driver 103a is an active element arranged closest to the semiconductor switch element 102a driven by the driver 103a. In addition, the driver 103a is an active element with the shortest connection distance to the semiconductor switch element 102a.

[0053] In this embodiment, unlike the first embodiment, the semiconductor switch element 102a has a rectangular plate-shaped main body 6 and a pin 21 extending from one side of the main body 6 and then bent. The pin 21 is inserted into the through hole 14 penetrating the circuit substrate 1 from the first surface 31 side and mounted on the circuit substrate 1. The main body 6 is spaced apart from the first surface 31 and extends in a direction parallel to the first surface 31. The cooler 4 is mounted on the surface opposite to the surface of the main body 6 on the first surface 31 side.

[0054] According to this structure, the main body 6 is spaced apart from the first surface 31 and extends in a direction parallel to the first surface 31, so the cooler 4 can be mounted on the surface opposite to the surface on the first surface 31 side of the main body 6. Therefore, in the case of using a semiconductor switch element 102a with a pin 2 package, the cooler 4 can be arranged on the first surface 31 side of the circuit substrate 1, and physical interference between the driver 103a mounted on the second surface 32 in a surface mounting manner and the cooler 4 can be avoided, and the driver 103a is arranged at the nearest position to the pin 21 of the semiconductor switch element 102a mounted on the circuit substrate 1, thereby shortening the connection distance between the driver 103a and the semiconductor switch element 102a. In addition, the main body 6 is arranged between the cooler 4 and the circuit substrate 1, and the cooler 4 can be arranged separately from the circuit substrate 1, so that the insulation between the cooler 4 and the circuit substrate 1 can be ensured, and the insulation distance between the cooler 4 and the driver 103a arranged on the opposite side of the circuit substrate 1 can be ensured. An insulating sheet 3 as an insulating member is sandwiched between the mounting surface of the cooler 4 and the cooling surface of the semiconductor switch element 102a. The screw 7 is inserted into the through hole provided in the main body 6 from the opposite side of the cooler 4 and screwed with the nut portion provided in the cooler 4, thereby fixing the cooler 4 to the semiconductor switch element 102a. The circuit substrate 1 is provided with a through hole 15 for preventing the screw 7 from contacting the circuit substrate 1 or for installing the screw 7 from the second surface 32 side. In addition, the screw 7 and the circuit substrate 1 can be separated to form a structure without the through hole 15.

[0056] As in the third embodiment, three pins 21 of the gate terminal, the source terminal, and the drain terminal are provided, and three through holes 14 are provided. Each pin 21 is bent at a right angle, and the surface of the main body 6 is arranged parallel to the first surface 31. The pins 21 of the gate terminal and the source terminal are connected to the terminals of the driver 103a via two connection patterns 12 provided on the second surface 32. In addition, the pins 21 of the source terminal and the drain terminal are connected to a circuit pattern (not shown) provided on the circuit substrate 1.

[0057] The driver 103a is arranged on the side where the main body 6 is provided with respect to the mounting portion of the pin 21 mounted on the circuit substrate 1, and when viewed in the normal direction of the first surface 31 and the second surface 32 of the circuit substrate 1, the driver 103a is arranged so that at least a part of it overlaps with the cooler 4. Thus, the various components of the switching element driving unit 30 can be compactly gathered and miniaturized.

[0058] As described above, the semiconductor switch element 102a is a package with a pin 21. Even when the pin 21 is shortened and is to be installed on the circuit substrate 1, insulation between the driver 103a and the cooler 4 can be ensured without sacrificing the cooling of the semiconductor switch element 102a composed of a wide bandgap semiconductor. The connection distance between the semiconductor switch element 102a and the driver 103a can be shortened, thereby achieving stable high-speed switching.

[0059] [Other embodiments] Finally, other embodiments of the present invention will be described. In addition, the configurations of the embodiments described below are not limited to being applied individually, and can be applied in combination with the configurations of other embodiments as long as no contradiction occurs. (1) In the above embodiments, the insulating elements 111a to 111d are described as elements independent of the drivers 103a to 103d. However, the drivers 103a to 103d may be insulating drivers including the insulating elements 111a to 111d.

[0061] In this case, when the control circuit 109 connected to the insulating elements 111a to 111d and the cooler 4 are not insulated, the input terminals of the insulating elements 111a to 111d provided in the drivers 103a to 103d connected to the control circuit 109 and the cooler 4 are indirectly connected via the housing, the control circuit 109, etc., and may not be insulated. However, the portions other than the input terminals of the drivers 103a to 103d are insulated from the cooler 4.

[0062] (2) In each of the above embodiments, a case where one driver drives one semiconductor switch element is described as an example. However, one driver may drive a plurality of semiconductor switch elements. For example, one driver may drive two semiconductor switch elements connected in parallel, or one driver may drive two semiconductor switch elements connected in series ( Figure 2 In this case, a switching element driving unit 30 includes a driver, a plurality of semiconductor switching elements driven by the driver, and a single or multiple coolers for cooling the plurality of semiconductor switching elements, and the configuration structure of the driver, semiconductor switching elements, and cooler is set based on the same technical concept as the above-mentioned embodiments.

[0063] Specifically, a driver is mounted on the second surface opposite to the first surface of the circuit substrate on the side where the single or multiple coolers are arranged in a surface mounting manner, and the driver is an active element arranged closest to the multiple semiconductor switch elements driven by the driver. In addition, when observed in the normal direction of the first and second surfaces of the circuit substrate, the driver is arranged so that at least a part overlaps with the single or multiple coolers. Corresponding to the first embodiment, the multiple semiconductor switch elements are mounted on the first surface in a surface mounting manner, and have a cooling surface on the surface opposite to the surface mounted on the circuit substrate in a surface mounting manner, and the single or multiple coolers are installed on the cooling surface of the multiple semiconductor switch elements, and the heat of the multiple semiconductor switch elements is transferred to the single or multiple coolers without passing through the circuit substrate. Corresponding to the second embodiment, the multiple semiconductor switch elements are mounted on the second surface in a surface mounting manner, and have cooling pads on the surface mounted on the circuit substrate in a surface mounting manner, and the single or multiple coolers are installed in the area of ​​the first surface opposite to the area of ​​the second surface where the multiple semiconductor switch elements are mounted on the surface, and the heat of the multiple semiconductor switch elements is transferred to the single or multiple coolers via the circuit substrate.

[0064] Corresponding to the third embodiment, the plurality of semiconductor switch elements each have a plate-shaped main body and pins extending linearly from one side of the main body, the pins are inserted into through holes penetrating the circuit substrate from the first surface side and mounted on the circuit substrate, the main body extends along the normal direction of the first surface on the first surface side of the circuit substrate, and a single or multiple coolers are mounted on the cooling surface of each side of the main body. Corresponding to the fourth embodiment, the plurality of semiconductor switch elements each have a plate-shaped main body and pins extending from one side of the main body and then bent, the pins are inserted into through holes penetrating the circuit substrate from the first surface side and mounted on the circuit substrate, the main body is spaced apart from the first surface and extends in a direction parallel to the first surface, and a single or multiple coolers are mounted on the surface opposite to the surface of each of the main bodies on the first surface side.

[0065] (3) In each of the above-mentioned embodiments, the power conversion device is as follows Figure 2 The case of an insulated full-bridge DC / DC converter as shown is described as an example. However, as long as it is a power conversion device with a switching element driving unit, it can be any type of power conversion device. For example, as long as the main circuit of the power conversion device is insulated, it can be an LLC method, a half-bridge type DC / DC converter, etc. In addition, the power conversion device can be an AC / DC converter such as a semibridgeless AC / DC converter, a totem pole type AC / DC converter, an inverter for driving a motor, etc.

[0066] (4) In the above-mentioned embodiments, the semiconductor switch element 102a and the driver 103a are directly connected through wiring such as pins and circuit patterns. However, passive components such as resistors, capacitors, and ferrite beads may be inserted into the connection path between the semiconductor switch element 102a and the driver 103a. In addition, the ferrite beads act as inductors such as coils arranged to surround the wiring, and are passive components that remove noise components, and may be chip-type. The present invention can freely combine the various embodiments within the scope of the invention, or appropriately modify or omit the various embodiments. Description of symbols 1 Circuit board 3 Insulation components 4 Cooler 6 Main body 21 pins 22Connection terminals 30 Switching element drive unit Page 1 of 31 32 Page 2 102aSemiconductor switching element 103a drive.

Claims

1. A switching element driving unit, characterized in that: include: a circuit substrate having a circuit pattern; A semiconductor switch element connected to the circuit substrate and composed of a wide bandgap semiconductor; a cooler for cooling the semiconductor switch element while being insulated from the semiconductor switch element; as well as a driver mounted on a second surface of the circuit board opposite to the first surface on which the cooler is arranged in a surface-mounted manner, and driving the semiconductor switch element; The semiconductor switch element has a plate-shaped main body and a pin extending linearly from one side of the main body, the pin being inserted from the first surface side into a through hole penetrating the circuit substrate and mounted on the circuit substrate, the main body extending along a normal direction of the first surface on the first surface side of the circuit substrate, the pin penetrating the circuit substrate being connected to a terminal of the driver via a circuit pattern provided on a second surface of the circuit substrate, The driver is arranged so as not to overlap with the semiconductor switch element when viewed in the normal direction of the first surface and the second surface of the circuit substrate. The cooler is mounted on a cooling surface on one side of the main body. The normal direction of the cooling surface of the main body is orthogonal to the normal directions of the first surface and the second surface of the circuit substrate. A portion of the mounting surface of the cooler that is not mounted on the cooling surface of the main body is located on a side separated from the first surface.

2. The switching element driving unit according to claim 1, characterized in that: The driver is an active element disposed closest to the semiconductor switch element driven by the driver.

3. The switching element driving unit according to claim 1 or 2, characterized in that: The driver is an active element having the shortest connection distance to the semiconductor switch element driven by the driver.

4. The switching element driving unit according to claim 1 or 2, characterized in that: The driver is arranged so that at least a portion of the driver overlaps with the cooler when viewed in a normal direction of the first surface and the second surface of the circuit board.

5. The switching element driving unit according to claim 1 or 2, characterized in that: An insulating member is provided between the cooler and the semiconductor switching element.

6. The switching element driving unit according to claim 1 or 2, characterized in that: The driver drives at least two of the semiconductor switching elements.

7. The switching element driving unit according to claim 6, characterized in that: The driver drives the two semiconductor switching elements connected in series to form a half bridge.

8. The switching element driving unit according to claim 1 or 2, characterized in that: The wide bandgap semiconductor is gallium nitride GaN.

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