JP2015208200A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device that enables a main circuit and a control circuit to be formed on one insulation substrate, and that can facilitate weight saving and cost reduction, and that can be manufactured with ease.SOLUTION: A power supply device comprises: an insulation substrate 2 formed of an insulation material; a plurality of electronic components 3 provided on the insulation substrate 2; a transformer 5 for transformation provided on the insulation substrate 2; and wiring 4 formed on the insulation substrate 2. The wiring 4 includes large-current wiring 4a, medium-current wiring 4b, and small-current wiring 4c. Among the large-current wiring 4a, the medium-current wiring 4b, and the small-current wiring 4c, the large-current wiring 4a is formed to have the largest thickness. The medium-current wiring 4b is formed to have a thickness smaller than that of the large-current wiring 4a. The small-current wiring 4c is formed to have a thickness smaller than that of the medium-current wiring 4b.

Description

  The present invention relates to a power supply device including an insulating substrate, a transformer and an electronic component provided on the insulating substrate, and wiring formed on the insulating substrate.

  Some power supply devices such as a DC-DC converter include a main circuit board in which an electronic component and a transformer are mounted on an insulating board, and a control circuit board provided separately from the main circuit board (described below). Patent Document 1). On the main circuit board, for example, a main circuit for transforming a DC voltage is formed. In addition, a control circuit that controls the operation of the electronic components included in the main circuit is formed on the control circuit board. The main circuit board and the control circuit board are electrically connected to each other by a metal connecting member.

  The main circuit includes a primary side circuit connected to the primary coil of the transformer and a secondary side circuit connected to the secondary coil. For example, when a DC voltage is stepped down using a transformer, a large current (large current) flows through the wiring of the secondary circuit, and a smaller current (medium) than the wiring of the secondary circuit flows through the wiring of the primary circuit. Current) flows. Also, less current (small current) flows in the wiring of the control circuit than in the wiring of the primary circuit. As described above, the power supply device has three types of wirings: a large current wiring through which a large current flows, a middle current wiring through which a medium current flows, and a small current wiring through which a small current flows.

  In recent years, it has been studied to integrate a main circuit board and a control circuit board and form the main circuit and the control circuit on one board. If the main circuit board and the control circuit board are integrated, the connecting member and the like are not necessary, and the number of components can be reduced.

JP 2012-15226 A

  However, when the main circuit and the control circuit are formed on one insulating substrate, the following problems are likely to occur. That is, in this case, the three types of wirings are formed on the same insulating substrate. When forming the wiring, a step of forming a metal layer on the insulating substrate, a step of forming a predetermined wiring pattern by photolithography or the like, and an etching step are performed. Therefore, it seems that the manufacturing process can be simplified if the thicknesses of the three types of wirings are all made uniform and the three types of wirings are simultaneously formed. Here, if the thicknesses of the three types of wiring are unified with the thickness of the large current wiring, a wiring having a narrow wiring pitch like a small current wiring is formed by a thick metal layer. When the etching process is performed, the small current wiring easily falls down. If the thicknesses of the three types of wiring are unified with the thickness of the large current wiring, the medium current wiring and the small current wiring are formed thicker than necessary, which increases the weight of the power supply device and reduces the manufacturing cost. It becomes easy to rise.

  Further, if the thicknesses of the three types of wirings are unified with the thicknesses of the small current wirings, the pattern widths of the large current wirings and the medium current wirings are significantly increased, and the substrate area tends to be large. Also, when the thickness of the three types of wiring is unified to the thickness of the medium current wiring, the same problem as above, that is, the small current wiring tends to collapse during the etching process, or the pattern width of the large current wiring Problems such as a significant increase in thickness and an increase in substrate area arise.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a power supply device that can form a main circuit and a control circuit on a single insulating substrate, is easy to reduce weight and cost, and is easy to manufacture. is there.

One embodiment of the present invention is an insulating substrate including an insulating material;
A plurality of electronic components provided on the insulating substrate;
A transformer for voltage transformation provided on the insulating substrate;
Wiring formed on the insulating substrate,
The wiring includes a large current wiring having a relatively large current value, a medium current wiring in which the current value is smaller than the large current wiring, and a small current wiring in which the current value is smaller than the medium current wiring. Yes,
A main circuit for performing power conversion is formed by a part of the plurality of electronic components, the large current wiring, the medium current wiring, and the transformer, and the main circuit among the plurality of electronic components. A control circuit for controlling the main circuit is formed by the electronic components other than the electronic components constituting the and the small current wiring,
Of the large current wiring, the medium current wiring, and the small current wiring, the large current wiring is the thickest, the medium current wiring is thinner than the large current wiring, and the small current wiring The wiring is in the power supply device characterized in that the wiring is thinner than the medium current wiring.

  In the power supply device, the thickness of the large current wiring is the largest among the large current wiring, the medium current wiring, and the small current wiring. Therefore, a sufficiently large current can be passed through the large current wiring. Further, since the thickness of the medium current wiring is thinner than that of the large current wiring, the thickness of the medium current wiring is not increased more than necessary, and the amount of metal material necessary for forming the medium current wiring can be reduced. . Therefore, the weight of the power supply device can be reduced and the manufacturing cost can be reduced.

  In the above power supply device, the thickness of the small current wiring is made thinner than that of the medium current wiring. Therefore, the thickness of the small current wiring is not increased more than necessary, and the amount of the metal material necessary for forming the small current wiring can be reduced. Therefore, the power supply device can be reduced in weight and the manufacturing cost can be reduced. In addition, although the wiring pitch of the small current wiring is often narrow, if the thickness of the small current wiring is reduced as described above, even if the wiring pitch is narrow, when the etching process is performed during manufacturing, the small current wiring is small. Problems such as the wiring falling down can be suppressed.

  As described above, according to the present invention, the main circuit and the control circuit can be formed on one insulating substrate, and it is possible to provide a power supply device that can be easily reduced in weight and cost and can be easily manufactured.

Sectional drawing of the power supply device in Example 1. FIG. FIG. 3 is a plan view of the power supply device according to the first embodiment, in which wiring is omitted. 1 is a circuit diagram of a power supply device according to Embodiment 1. FIG. 1 is a plan view of a MOSFET in Embodiment 1. FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. The figure following FIG. The figure following FIG. The figure following FIG. The circuit diagram of the power supply device which performs synchronous rectification in Example 1. FIG. Sectional drawing of the power supply device in Example 2. FIG. The principal part expanded sectional view of the power supply device in Example 3. FIG. FIG. 6 is a schematic plan view of a power supply device according to a fourth embodiment. FIG. 10 is a schematic plan view of a power supply device according to a fourth embodiment in which the layout of the large current region, the medium current region, the small current region, and the transformer is changed.

  The power supply device can be an in-vehicle power supply device to be mounted on a vehicle such as an electric vehicle or a hybrid vehicle.

Example 1
Embodiments according to the power supply apparatus will be described with reference to FIGS. As shown in FIG. 1, the power supply device 1 of this example includes an insulating substrate 2 made of an insulating material, a plurality of electronic components 3 provided on the insulating substrate 2, and a transformer for transformation provided on the insulating substrate 2. A transformer 5 and wiring 4 formed on the insulating substrate 2 are provided.

  The wiring 4 includes a large current wiring 4a, a medium current wiring 4b, and a small current wiring 4c. The current value flowing through the large current wiring 4a is larger than the current value flowing through either the medium current wiring 4b or the small current wiring 4c. The value of current flowing through the medium current wiring 4b is smaller than that of the large current wiring 4a. Further, the value of the current flowing through the small current wiring 4c is smaller than that of the medium current wiring 4b.

  As shown in FIGS. 1 to 3, a main circuit 11 for performing power conversion is formed by a part of the plurality of electronic components 3, the large current wiring 4 a, the medium current wiring 4 b, and the transformer 5. ing. A control circuit 12 for controlling the main circuit 11 is formed by the electronic components 3 other than the electronic components 3 constituting the main circuit 11 among the plurality of electronic components 3 and the small current wiring 4c.

  As shown in FIG. 1, among the large current wiring 4a, the medium current wiring 4b, and the small current wiring 4c, the large current wiring 4a has the largest thickness. The medium current wiring 4b is thinner than the large current wiring 4a. The small current wiring 4c is thinner than the medium current wiring 4b.

  The power supply device 1 of this example is an in-vehicle power supply device to be mounted on an electric vehicle or a hybrid vehicle.

  As shown in FIG. 3, the power supply device 1 of this example is a DC-DC converter that steps down the voltage of the high-voltage DC power supply 80 and charges the low-voltage DC power supply 81. The power supply device 1 includes a plurality of MOSFETs 3a, a filter capacitor 3e, a current sensor 3g, a rectifier diode 3b, a choke coil 3d, and a smoothing capacitor 3f as electronic components 3. An H bridge circuit is formed by the plurality of MOSFETs 3a. By turning on and off the MOSFET 3a, the DC voltage of the high-voltage DC power supply 80 is converted into an AC voltage, and this AC voltage is applied to the primary coil 51 of the transformer 5.

  The secondary coil 52 of the transformer 5 is connected to the diode bridge 39. The diode bridge 39 includes a plurality of rectifier diodes 3b. In this example, the secondary current of the secondary coil 52 is full-wave rectified by the diode bridge 39 and the rectified current is smoothed using the choke coil 3d. Moreover, the smoothed capacitor 3f is used to smooth the rectified voltage.

  As shown in FIG. 3, a primary side circuit 111 connected to the primary coil 51 is configured by the MOSFET 3a, the filter capacitor 3e, and the wiring (medium current wiring 4b). The secondary side circuit 112 connected to the secondary coil 52 is configured by the plurality of rectifier diodes 3b, the choke coil 3d, the rectifier diode 3f, and the wiring 4 (large current wiring 4a). The primary circuit 111, the secondary circuit 112, and the transformer 5 form the main circuit 11 described above.

  In this example, since the voltage on the primary side is stepped down using the transformer 5, the current value flowing through the wiring 4 of the secondary circuit 112 is larger than the current value flowing through the wiring 4 of the primary circuit 111.

  In this example, the control circuit 12 controls the switching operation of the MOSFET 3a. A current sensor 3g is provided in the medium current wiring 4b constituting the primary circuit 111. The control circuit 12 uses the current sensor 3g to measure the current value flowing through the medium current wiring 4b and feeds it back to the switching operation of the MOSFET 3a.

  In this example, the output voltage of the secondary side circuit 112 is measured by the control circuit 12. The measured voltage is fed back to the switching operation of the MOSFET 3a.

  On the other hand, as shown in FIG. 1, the insulating substrate 2 of this example includes three divided plates 21, one common plate 22, and an adhesive layer 23 that bonds these divided plates 21 and the common plate 22. . Of the three divided plates 21 (21a to 21c), the first divided portion 21a is provided with a large current wiring 4a. The secondary side circuit 112 is formed on the first divided plate 21a. In addition, a medium current wiring 4b is formed on the second divided plate 21b. The primary side circuit 111 is formed on the second divided plate 21b. Further, a small current wiring 4c is formed on the third divided plate 21c. The control circuit 12 is formed on the third divided plate 21c.

  A rectifier diode 3b is connected to the large current wiring 4a. Further, the MOSFET 3a is connected to the medium current wiring 4b. A microcomputer 3c is connected to the small current wiring 4c.

  In this example, three types of wirings 4 of a large current wiring 4a, a medium current wiring 4b, and a small current wiring 4c are formed of copper. A current of 30 A or more flows through the large current wiring 4a. The thickness of the large current wiring 4a is 1.0 to 3.0 mm. In addition, a current of 30 A or less flows through the medium current wiring 4b. The thickness of the medium current wiring 4b is 0.3 to 1.0 mm. Further, a current of 1 A or less flows through the small current wiring 4c. The thickness of the small current wiring 4c is 35 to 70 μm.

  As shown in FIG. 1, the rectifier diode 3 b includes a diode body 31 in which a diode element (not shown) is sealed, and an anode terminal 32 and a cathode terminal 33 protruding from the diode body 31. The diode main body 31 is placed on the large current wiring 4a. The anode terminal 32 and the cathode terminal 33 are each connected to the large current wiring 4a.

  As shown in FIGS. 1 and 4, the MOSFET 3 a includes a MOS element 342, a MOS body part 341 that seals the MOS element 342, a gate terminal 343 and a source terminal 344 that protrude from the MOS body part 341, and a MOS body. And a drain terminal 345 provided on the bottom surface of the portion 341. As shown in FIG. 1, a drain terminal 345 is interposed between the MOS main body 341 and the medium current wiring 4b. The drain terminal 345, the gate terminal 343, and the source terminal 344 are each connected to the medium current wiring 4b.

  As shown in FIGS. 1 and 2, the control circuit 12 includes a microcomputer 3c, a plurality of other electronic components 3, and a small current wiring 4c.

As shown in FIG. 1, each of the wirings 4 a, 4 b, 4 c is formed on one main surface 24 of the two main surfaces 24, 25 of the insulating substrate 2. Further, the other-side metal layer 7 is formed on the other main surface 25. A via 15 is formed in the insulating substrate 2 so as to penetrate in the thickness direction (Z direction) of the insulating substrate 2. Two vias 4 (4b, 4c) having different thicknesses are electrically connected by the two vias 15 (151, 152) and the other surface side metal layer 7.
The “main surface” means a surface of the surface of the insulating plate 2 excluding the side surface 290.

  Although not shown, the small current wiring 4c and the large current wiring 4a are similarly connected. Thus, the control circuit 12 can detect the output voltage of the secondary circuit 11 (see FIG. 3).

  As shown in FIG. 2, the insulating substrate 2 of this example has a rectangular shape when viewed from the Z direction. The control circuit 12, the primary side circuit 111, and the secondary side circuit 112 are arranged in the longitudinal direction (X direction) of the insulating substrate 2. A transformer 5 is provided between the primary side circuit 111 and the secondary side circuit 112. The primary circuit 111 includes four MOSFETs 3a. The four MOSFETs 3 a are arranged in the short direction (Y direction) of the insulating substrate 2. The secondary circuit 112 includes four rectifier diodes 3b. The four rectifier diodes 3b are arranged in the Y direction.

Next, the manufacturing method of the power supply device 1 of this example is demonstrated. First, as shown in FIG. 5, a large current temporary substrate 211 in which the large current wiring 4a is formed on the first divided plate 21a, a medium current temporary substrate 212 in which the medium current wiring 4b is formed on the second divided plate 21b, A small current temporary substrate 213 having a small current wiring 4c formed on the third divided plate 21c is prepared. Then, the temporary substrates 211 to 213, the adhesive layer 23, and the common plate 22 are stacked.
The temporary substrates 211 to 213 and the common plate 22 are formed by performing a metal foil bonding process, a photolithography process, and an etching process, respectively. In the metal foil bonding step, a metal foil (copper foil) is bonded to each divided plate 21. In the photolithography process, a photosensitive resist is applied on the copper foil, and exposure and development are performed to form a predetermined wiring pattern. In the etching step, a portion of the metal foil exposed from the photosensitive resist is removed. Thereby, the temporary substrates 211 to 213 and the common plate 22 are formed.

  After the temporary substrates 211 to 213, the adhesive layer 23, and the common plate 22 are stacked, as shown in FIG. 6, these are pressed in the Z direction using the pressurizer 16. As a result, the temporary substrates 211 to 213 are bonded to the common plate 22.

  Next, as shown in FIG. 7, a through hole 155 is formed in the insulating substrate 7. The through hole 155 can be formed by irradiating laser light. It can also be formed by photolithography and etching.

  Thereafter, a plating step is performed to form a conductor portion 156 in the through hole 155 as shown in FIG. Thereby, the via 15 is formed. In this example, the through hole 155 is filled with the conductor portion 156 so-called filled via, but the conductor portion 156 may be formed only on the inner peripheral surface of the through hole 155.

  Thereafter, a solder resist (not shown) is applied to the side on which the wirings 4 (4a to 4c) are formed, and exposure and development processes are performed to expose only the portions of the wiring 4 that need to be soldered. Next, the electronic component 3 is mounted on each wiring 4 and soldered. The power supply device 1 of this example is manufactured by performing the above steps.

  The effect of this example will be described. As shown in FIG. 1, in this example, the thickness of the large current wiring 4a is the largest among the large current wiring 4a, the medium current wiring 4b, and the small current wiring 4c. Therefore, a sufficiently large current can be passed through the large current wiring 4a. Further, since the thickness of the medium current wiring 4b is thinner than that of the large current wiring 4a, the thickness of the middle current wiring 4b is not increased more than necessary, and the amount of metal material necessary for forming the middle current wiring 4b is reduced. can do. Therefore, the weight of the power supply device 1 can be reduced, and the manufacturing cost can be reduced.

  In this example, the thickness of the small current wiring 4c is made thinner than that of the medium current wiring 4b. Therefore, the thickness of the small current wiring 4c is not increased more than necessary, and the amount of metal material necessary for forming the small current wiring 4c can be reduced. Therefore, the power supply device 1 can be reduced in weight and the manufacturing cost can be reduced. In addition, the small current wiring 4c often has a narrow wiring pitch. However, if the thickness of the small current wiring 4c is reduced as described above, the etching process of the small current wiring 4c is performed even if the wiring pitch is narrow. Sometimes, it is possible to suppress problems such as the small current wiring 4c falling.

  In the power supply device 1 of this example, there are three types of wirings 4, that is, a large current wiring 4 a, a medium current wiring 4 b, and a small current wiring 4 c, and current values flowing through these three types of wiring 4 are greatly different from each other. . Therefore, the effect by making the thickness of each wiring 4 (4a-4c) mutually different is large.

  In this example, the via 15 and the back surface side metal layer 7 electrically connect two types of wirings 4 (medium current wiring 4b and small current wiring 4c) having different thicknesses. Although it is difficult to directly connect two types of wirings 4 (4b, 4c) having different thicknesses, if they are connected using the via 15 and the back-side metal layer 7 as in this example, they can be easily connected. can do.

  As described above, according to this example, the main circuit and the control circuit can be formed on one insulating substrate, and it is possible to provide a power supply device that can be easily reduced in weight and cost and can be easily manufactured.

  In this example, the value of the current flowing through the secondary circuit 112 is larger than that of the primary circuit 111 (see FIG. 3), but the present invention is not limited to this. That is, as in the case where the DC voltage is boosted, the current value flowing through the primary circuit 111 may be larger than that of the secondary circuit 112. In this case, the wiring 4 included in the primary side circuit 111 becomes the high current wiring 4a, and the wiring 4 included in the secondary side circuit 112 becomes the medium current wiring 4b.

  In this example, the secondary current is rectified using the rectifier diode 3b, but the present invention is not limited to this. For example, as shown in FIG. 9, the secondary current may be rectified using a rectifying MOSFET 3h. In this case, so-called synchronous rectification is performed in which the switching operation of the rectifying MOSFET 3h is performed using the control circuit 12.

  In this example, as the MOSFET 3a and the rectifier diode 3b, a so-called discrete electronic component 3 in which a single element is sealed is used. However, even if an electronic component 3 in which a plurality of elements are sealed to form a module is used. Good.

  Moreover, in this example, although the wiring 4 was formed in one main surface 24 of the insulating substrate 2, this invention is not limited to this. For example, the wiring 4 may be formed on each of the main surfaces 24 and 25 of the insulating substrate 2. Further, the wiring 4 may be formed inside the common plate 22 or the divided plate 21.

  Moreover, in this example, as shown in FIG. 1, each temporary board | substrate 211-213 is adhere | attached on one main surface 221 among the two main surfaces 221 and 222 of the common board 22, but this invention corresponds to this. It is not limited. That is, the temporary substrate may be bonded to the two main surfaces 221 and 222 of the common plate 22. Alternatively, the wiring 4 may be formed in at least one of the two main surfaces 221 and 222 of the common plate 22 and the inside, and the temporary substrates may be bonded to the two main surfaces 221 and 222, respectively.

(Example 2)
In this example, as shown in FIG. 10, a plurality of other-surface-side metal layers 7 are formed on the insulating plate 2. In this example, as in the first embodiment, a plurality of electronic components 3 are fixed to one main surface 24 of the two main surfaces 24 and 25 of the insulating substrate 2 via wirings 4. Further, the other surface side metal layer 7 is formed on the other main surface 25. Part of the plurality of electronic components 3 (MOSFET 3a and rectifier diode 3b) is a high heat generating component 30. The high heat generating component 30 has a heat generation amount higher than that of the electronic component 3 (microcomputer 3c) constituting the control circuit 12. A part of the other surface side metal layer 7 is formed at a position overlapping the high heat-generating component 30 when viewed from the Z direction. The cooler 17 is in contact with the other surface side metal layer 7.

  Part of the heat generated from the high heat-generating component 30 is transmitted through the insulating layer 2 and is radiated from the other surface side metal layer 7. Thus, the high heat generating component 30 is configured to be cooled. Of the plurality of other-surface-side metal layers 7, the conductive other-surface-side metal layer 7 a for electrically connecting the wirings 4 b and 4 c is covered with an insulating film 19. Thereby, the other side metal layer 7a for conduction and the cooler 17 are insulated.

The effect of this example will be described. In this example, since the high heat generation electronic component 30 and the other surface side metal layer 7 are configured to overlap each other when viewed from the Z direction, the heat generated from the high heat generation electronic component 30 is transferred to the insulating layer 2. It is possible to dissipate heat from the other-surface-side metal layer 7. Therefore, the cooling efficiency of the high heat generating electronic component 30 can be improved.
In addition, the configuration and operational effects are the same as those of the first embodiment.

  In this example, the large current wiring 4 a and the medium current wiring 4 b are not connected to the other surface side metal layer 7 by the via 15, but they may be connected by the via 15. In this case, the heat generated from the highly heat-generating electronic component 30 is transmitted through the conductor portion 156 having a high thermal conductivity in the via 15 and is radiated from the other surface side metal layer 7. Therefore, the cooling efficiency of the high heat generating electronic component 30 can be further increased. In this case, since the wirings 4a and 4b and the other surface side metal layer 7 are electrically connected via the vias 15, the other surface side metal layer 7 and the cooler 17 are insulated from each other so that they can be insulated. It is necessary to interpose the film 19.

(Example 3)
In this example, as shown in FIG. 11, a temperature sensor 18 is provided on the other surface side metal layer 7. The temperature sensor 18 is configured to measure the temperature of the other side metal layer 7. The control circuit 12 of this example controls the duty of the switching operation of the MOSFET 3a so that the current flowing through the main circuit 11 is reduced when the measured temperature rises above a predetermined value. Thereby, it is suppressed that the temperature of the high heat generation electronic component 30 (MOSFET 3a, rectifier diode 3b) rises too much.
In addition, the configuration and operational effects are the same as those of the first embodiment.

Example 4
In this example, the layout of each circuit formed on the insulating substrate 2 is changed. As shown in FIG. 12, in this example, a primary circuit 111 that is a circuit through which a medium current flows, a transformer 5, and a secondary circuit 112 that is a circuit through which a large current flows are arranged in this order to form the main circuit 11. It is. Then, the control circuit 12 is formed at a position adjacent to the main circuit 11 in the direction (Y direction) orthogonal to the direction (X direction) in which the primary side circuit 111, the transformer 5 and the secondary side circuit 112 are arranged. It is.

Also, the layout shown in FIG. 13 can be used. In this power supply device 1, a control circuit 12 and a secondary side circuit 112, which is a circuit through which a large current flows, are arranged. A primary side circuit that is a circuit in which a medium current flows in a position adjacent to the control circuit 12 in a direction (Y direction) orthogonal to a direction (X direction) in which the control circuit 12 and the secondary side circuit 112 are arranged. 111 is formed. A transformer 5 is provided at a position adjacent to the secondary circuit 112 in the Y direction.
In addition, the configuration and operational effects are the same as those of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Power supply device 11 Main circuit 12 Control circuit 2 Insulation board 3 Electronic component 4 Wiring 4a Large current wiring 4b Medium current wiring 4c Small current wiring 5 Transformer

Claims (4)

An insulating substrate (2) made of an insulating material;
A plurality of electronic components (3) provided on the insulating substrate (2);
A transformer (5) for voltage transformation provided on the insulating substrate (2);
Wiring (4) formed on the insulating substrate (2),
The wiring (4) includes a large current wiring (4a) having a relatively large current value, a medium current wiring (4b) in which the current value is smaller than that of the large current wiring (4a), and the current value. There is a small current wiring (4c) smaller than the medium current wiring (4b),
The main electronic component (3) among the plurality of electronic components (3), the large current wiring (4a), the medium current wiring (4c), and the transformer (5) are used for power conversion. A circuit (11) is formed, and the electronic component (3) other than the electronic component (3) constituting the main circuit (11) among the plurality of electronic components (3) and the small current wiring A control circuit (12) for controlling the main circuit (11) is formed;
Of the large current wiring (4a), the medium current wiring (4b), and the small current wiring (4c), the large current wiring (4a) has the largest thickness, and the medium current wiring (4b) Is thinner than the large current wiring (4a), and the small current wiring (4c) is thinner than the middle current wiring (4b).   The plurality of electronic components (3) are fixed to one main surface (24) of the two main surfaces (24, 25) of the insulating substrate (2), and the other main surface (25) is the other surface. A side metal layer (7) is formed, and the plurality of electronic components (3) included in the main circuit (11) generate more heat than the electronic components (3) included in the control circuit (12). There is a high heat generating electronic component (30), and the high heat generating electronic component (30) and the other surface side metal layer (7) overlap when viewed from the thickness direction of the insulating substrate (2). 2. The structure according to claim 1, wherein the other surface side metal layer (7) is configured to dissipate heat generated from the highly heat-generating electronic component (30) and conducted through the insulating substrate (2). The power supply device (1) described.   The power supply device (1) according to claim 2, wherein a temperature sensor (14) for detecting the temperature of the other surface side metal layer (7) is provided on the other surface side metal layer (7). ).   A via (15) penetrating the insulating substrate (2) is formed in the insulating substrate (2), and the thickness of the via (15) and the other surface side metal layer (7) is reduced. The power supply device (1) according to claim 2 or 3, wherein two different types of wirings (4) are electrically connected.

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