JP2017079493A - DC-DC converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC-DC converter superior in heat radiation performance of a transformer capable of reducing conductor loss.SOLUTION: A transformer 100 includes: a primary winding 101; and plate-like secondary windings 102A and 102B, the winding axial direction X-X of which extends parallel to a plane direction on one plane of a base member. The plate-like secondary windings 102A and 102B of the transformer 100 includes: connection parts 123A and 123B; heat radiation parts 124A and 124B; and terminal parts 125Aa and 125Ba. The connection parts 123A and 123B is extended from winding parts 121A and 121B of the plate-like secondary windings 102A and 102B toward a base member. The heat radiation parts 124A and 124B are thermally coupled with the base member so as to transmit the heat.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a DC-DC converter, and more particularly, to a DC-DC converter including a transformer that performs voltage conversion.

Vehicles such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles are equipped with a high voltage storage battery for driving power, an inverter, a DC-DC converter, and a low voltage storage battery as an auxiliary power source for a low voltage load. Yes.
The DC-DC converter converts a DC high voltage output of a high voltage storage battery into a DC low voltage output and supplies power to a low voltage load such as a vehicle light or a radio. The DC-DC converter is a high voltage circuit unit that converts a high DC voltage of a high voltage storage battery into an AC high voltage, a transformer that converts an AC high voltage into an AC low voltage, and an AC low voltage that is converted into a DC low voltage. A low-voltage circuit unit that outputs the voltage-converted voltage.

A transformer for converting an AC high voltage to an AC low voltage includes a primary winding, a secondary winding, and a magnetic core. This transformer has an unavoidable loss due to its configuration, that is, a conductor loss of the winding. (So-called copper loss) and core loss (so-called iron loss) of the magnetic core exist. Transformer loss that increases as the conversion power increases mostly becomes heat, raising the self-temperature of the transformer, as well as the ambient temperature of the part where the transformer is mounted and the temperature of the circuit components connected to the transformer. To raise.
For this reason, in the DC-DC converter, it is necessary to increase heat dissipation by attaching the transformer to a heat dissipation member formed of a conductive material having excellent heat conductivity such as aluminum.

In a conventional DC-DC converter, a transformer is arranged so that a primary winding and a plate-like secondary winding are sandwiched by a U-shaped magnetic core, and the winding axis direction of the transformer is set as a heat dissipation member. A structure is known that is attached to a heat radiating member in a state of being directed perpendicularly to one surface.
In this structure, the terminal portion of the plate-like secondary winding is pulled out substantially parallel to one surface of the heat radiating member, and the leading end side of the drawn portion is bent at a substantially right angle and extended toward the heat radiating member. Is bent substantially at a right angle to be substantially parallel to one surface of the heat radiating member to form a terminal portion, and the terminal portion is fixed to the heat radiating member (for example, see Patent Document 1).

JP 2013-26597 A

  In patent document 1, as for a plate-shaped secondary winding, parts other than the terminal part do not contact a heat radiating member, and only the terminal part is contacting the heat radiating member. For this reason, the area where the plate-like secondary winding contacts the heat radiating member is small, and the heat dissipation is poor. Further, since the length from the winding part to the terminal part is long, the conductor loss is large.

  The DC-DC converter according to the present invention includes a primary winding, a plate-like secondary winding, and a winding of the primary winding and the plate-like secondary winding across the primary winding and the plate-like secondary winding. A transformer having a pair of magnetic cores disposed on both sides in the axial direction, and a base member having one surface thermally coupled to the transformer and dissipating heat generated from the transformer. The axial direction is arranged on the base member so as to be substantially parallel to the in-plane direction of one surface of the base member, and the plate-like secondary winding extends from the winding portion and at least both ends of the winding portion. A terminal lead part, the terminal lead part has a connection part, a heat dissipation part, and a terminal part connected to another circuit, and the connection part of the terminal lead part is an end of the winding part. The heat radiating part is bent from the connection part so as to be substantially parallel to one surface of the base member. It is, are thermally conductively thermally coupled to one surface of the base member.

  According to the present invention, in the transformer, the winding axis direction of the primary winding and the plate-like secondary winding is arranged substantially parallel to the in-plane direction of one surface of the base member, and the connection of the plate-like secondary winding is performed. The portion extends toward the base member, and the heat radiating portion is bent from the connection portion and thermally coupled to the base member over the entire surface. For this reason, the length of a connection part can be shortened and the heat dissipation effect can be improved. Moreover, since the distance from a coil | winding part to a terminal part can be made small by shortening the length of a connection part, conductor loss can be reduced.

An example of the block circuit diagram of a DC-DC converter. An example of the block diagram of the power converter circuit part of the DC-DC converter in FIG. 1 is an external perspective view showing an embodiment of a transformer used in a DC-DC converter of the present invention. 4A and 4B are diagrams of the transformer illustrated in FIG. 3, in which FIG. 3A is a bottom view of a mounting surface on a base member, FIG. 3B is a side view as viewed from the magnetic core 103 </ b> A side in FIG. A side view, (D) is a side view of (C) viewed from the lower surface side. FIG. 4 is an exploded perspective view of the transformer illustrated in FIG. 3. It is a perspective view which shows the state which mounted the transformer on the base member, (A), (B) is the figure seen from a different angle, respectively. The disassembled perspective view which shows one Embodiment of the DC-DC converter of this invention. The exploded perspective view showing Embodiment 2 of a transformer. The external appearance perspective view which shows Embodiment 3 of a transformer. FIG. 10 is a diagram of the transformer illustrated in FIG. 9, (A) is a left side view, (B) is a front view, (C) is a right side view, and (D) is a bottom view of (C). FIG. 10 is an exploded perspective view of the transformer illustrated in FIG. 9. The disassembled perspective view which shows Embodiment 4 of a transformer. The disassembled perspective view which shows Embodiment 5 of a transformer. The disassembled perspective view which shows Embodiment 6 of a transformer. The disassembled perspective view which shows Embodiment 7 of a transformer. The disassembled perspective view which shows Embodiment 8 of a transformer. FIG. 17 is an enlarged perspective view of a plate-like secondary winding of the transformer illustrated in FIG. 16, where (A) is a view from above, and (B) is a view from below. FIG. 18 is a development view before processing the plate-like secondary winding illustrated in FIG. 17. The disassembled perspective view which shows Embodiment 9 of a transformer. FIG. 20 is an example of a configuration diagram of a power conversion circuit unit of a DC-DC converter to which the transformer illustrated in FIG. 19 is applied. The disassembled perspective view which shows Embodiment 10 of a transformer. FIG. 22 is an example of a configuration diagram of a power conversion circuit unit of a DC-DC converter to which the transformer illustrated in FIG. 21 is applied.

--Embodiment 1--
[Circuit Configuration of DC-DC Converter 10]
1 shows an example of a block circuit diagram of a DC-DC converter, and FIG. 2 shows an example of a configuration diagram of a power conversion circuit unit in the block circuit diagram of the DC-DC converter in FIG.
Below, it illustrates as a DC-DC converter for vehicles.
The DC-DC converter 10 includes a high voltage side circuit unit 200, a low voltage side circuit unit 300, a transformer 100, and a control circuit unit 400.

A DC high-voltage power supply of several hundred volts supplied from the vehicle side is first input to the high-voltage side circuit unit 200 as shown in FIG. In the high voltage side circuit unit 200, after passing through the DC high voltage power supply filter circuit 210, the high voltage switching circuit 220 converts the AC voltage into a high voltage.
As shown in FIG. 2, the DC high-voltage power supply filter circuit 210 includes an X capacitor Cx interposed between the phases of the input high voltage side and the input low voltage side, and 2 interposed between the respective phases and the chassis. It has two Y capacitors Cy and smoothes the DC high-voltage power supply supplied from the vehicle side. Further, the high voltage switching circuit 220 is configured as a so-called full bridge type including four MOS-FETs H1, H2, H3, and H4 connected in a bridge type. Each MOS-FET is provided with a snubber capacitor in parallel.

  The four MOS-FETs H1, H2, H3, and H4 of the high-voltage switching circuit 220 are optimally controlled by the phase shift PWM control by taking in the elements such as the output load amount and the input voltage by the control circuit unit 400. By performing phase shift PWM control, an alternating high voltage can be generated on the primary side of the transformer 100 (T). The connection of the MOS-FET is an example, and the connection is not limited to the above, and may be realized by another connection method.

  The alternating high voltage power supply is supplied to the primary side of the transformer 100 (T) and transmitted to the secondary side. Here, the transformer 100 (T) has an insulating structure on the primary side and the secondary side, and is set to an optimum winding ratio from the relationship between the input power source and the output power source. Note that a resonance choke coil Lr for performing a soft switching operation is provided at the input stage of the transformer 100 (T), and a combined inductance of the resonance choke coil Lr and the leakage inductance of the transformer 100 (T) is used. The zero voltage switching of the MOS-FET constituting the high voltage switching circuit 220 is made possible. However, the resonance choke coil Lr is not necessarily required, and a circuit configuration in which these are omitted may be used.

  The AC power transmitted to the secondary side is input to the low voltage side circuit unit 300. The low voltage side circuit unit 300 passes the low voltage rectifier circuit 310 and converts AC power into DC power. As shown in FIG. 2, the low voltage rectifier circuit 310 includes rectifier MOSFETs S1, S2, S3, and S4, a choke coil LO, a smoothing capacitor CO, and an active clamp capacitor Cc. Rectification is performed and surge absorption is achieved by the active clamp method. The switching timing of the rectifying MOSFETs S 1, S 2, S 3, and S 4 is coordinated with the phase shift PWM control pulse that takes in elements such as the output load amount and the input voltage by the control circuit unit 400 and supplies the elements to the high voltage switching circuit 220. Is done. The configuration of the low voltage rectifier circuit 310 is not necessarily the same as that of the synchronous rectification method, and may be a diode rectification method, regardless of whether an active clamp method is adopted.

  Further, in order to remove switching noise associated with AC conversion, the low voltage power supply filter circuit 320 is passed through and finally supplied to the vehicle side as a DC low voltage power supply of tens of volts. The low voltage power supply filter circuit 320 includes L1 and C1 illustrated in FIG. However, the low-voltage power supply filter circuit is not necessarily required, and it may be determined whether or not to adopt it according to product specifications.

The control circuit unit 400 generates a switching signal to be supplied to the high voltage switching circuit 220 and the low voltage rectifier circuit 310, and controls the operation of the entire DC-DC converter.
The control circuit unit 400 is mainly composed of a high voltage system control circuit unit 410 and a low voltage system control circuit unit 420, and the high voltage system control circuit unit 410 and the low voltage system control circuit unit 420 are electrically insulated. The configuration is taken.
The high voltage system control circuit unit 410 includes a switching element drive circuit 411 that supplies a switching signal to be supplied to the high voltage switching circuit. The high voltage system control circuit unit 410 includes a current sensor circuit 412, a voltage sensor circuit 413, and a temperature sensor circuit 414, and voltage / current from a sensor (not shown) provided in the high voltage side circuit unit 200.・ Extract information necessary for stable control such as temperature.

  The low voltage system control circuit unit 420 includes a switching element drive circuit 421 that supplies a switching signal to be supplied to the low voltage rectifier circuit 310. Further, the low voltage system control circuit unit 420 includes a current sensor circuit 422, a voltage sensor circuit 423, and a temperature sensor circuit 424, and information necessary for stable control such as voltage, current, and temperature of the low voltage side circuit unit 300. Take out. Further, the low voltage system control circuit unit 420 includes a control circuit power supply circuit 425, a communication circuit 426 that communicates with a vehicle-side control unit (not shown), and a vehicle signal processing circuit 427 that processes a signal supplied from the vehicle side. And a calculation / operation control circuit (DSP / CPU) 428 that calculates switching signals based on information collected by these components and performs integrated operation control. The configuration of the control circuit unit 400 is not limited to the above contents.

[Trance]
FIG. 3 is an external perspective view showing an embodiment of a transformer used in the DC-DC converter of the present invention, as viewed from the direction of the mounting surface on the base member (see FIG. 6). 4 is a view of the transformer shown in FIG. 3, FIG. 4 (A) is a bottom view showing a mounting surface on the base member, and FIG. 4 (B) is a view from the magnetic core 103A side in FIG. 4C is a front view, and FIG. 4D is a side view of FIG. 4C viewed from the lower surface side. FIG. 5 is an exploded perspective view of the transformer illustrated in FIG. 3. FIG. 5 is an exploded perspective view of the transformer illustrated in FIG. 3.
The transformer 100 includes a primary winding 101, a pair of plate-like secondary windings 102A and 102B, a bobbin (winding frame) 104, and a pair of magnetic cores 103A and 103B.
The bobbin 104 is formed of an insulating material, and is a member for insulating the primary winding 101 and the plate-like secondary windings 102A and 102B. The primary winding 101 and the plate-like secondary windings 102A and 102B are attached to the bobbin 104 so that their winding axis directions XX (see FIG. 5D) are on the same axis.

  The primary winding 101 is formed by winding an enamel stranded wire (Litz wire) a plurality of times. The primary winding 101 includes a winding part 111 and a pair of drawing parts 112 drawn from both ends of the winding part 111. A conductive metal terminal 113 for connecting to another circuit is attached to the leading end of each drawing portion 112 using, for example, a fusing method or the like. As described above, the high voltage switching circuit 220 is connected to the conductive metal terminal 113 of the primary winding 101. The lead-out portion 112 of the primary winding 101 is usually covered with an insulating tube (not shown), but the insulating tube is not always necessary. Moreover, the primary winding 101 can also be comprised with a plate-shaped member instead of a strand wire.

The plate-like secondary windings 102A and 102B are formed by, for example, pressing a copper plate.
The plate-like secondary winding 102A has a winding part 121A and two terminal lead parts 122Aa and 122Ab, and is wound around the winding axis by one turn in the winding part 121A.
Referring to FIG. 5, the terminal lead part 122Aa includes a connection part 123A extending from one end of the winding part 121A, a heat dissipation part 124A, and a terminal part 125Aa connected to the heat dissipation part 124A. The terminal lead portion 122Ab includes a connection portion 123A extending from the other end of the winding portion 121A, a heat dissipation portion 124A, and a terminal portion 125Ab connected to the heat dissipation portion 124A. The terminal portion 125Aa extends linearly from the heat radiating portion 124A, and the terminal lead portion 122Aa is bent substantially perpendicular to the winding portion 121A. The terminal portion 125Ab extends linearly from the heat radiating portion 124A, and the terminal lead portion 122Ab is bent substantially perpendicular to the winding portion 121A on the side opposite to the terminal lead portion 122Aa. The terminal portions 125Aa and 125Ab are portions for connection to other circuits, and are connected to the low voltage rectifier circuit 310 as described above. Through holes 126 are formed in the terminal portions 125Aa and 125Ab.

  Referring to FIG. 5, the plate-like secondary winding 102 </ b> B has a winding part 121 </ b> B and two terminal lead parts 122 </ b> Ba and 122 </ b> Bb, and the winding part 121 </ b> B is wound by one turn around the winding axis. Has been. The terminal lead portion 122Ba includes a connection portion 123B extending from one end of the winding portion 121B, a heat dissipation portion 124B, and a terminal portion 125Ba connected to the heat dissipation portion 124B. The terminal portion 125Bb extends linearly from the heat radiating portion 124B, and the terminal lead portion 122Bb is bent substantially perpendicular to the winding portion 121B on the side opposite to the terminal lead portion 122Ba. The terminal portions 125Ba and 125Bb are portions for connection to other circuits, and are connected to the low voltage rectifier circuit 310 as described above. Through holes 126 are formed in the terminal portions 125Ba and 125Bb.

The pair of magnetic cores 103A and 103B are disposed outside the plate-like secondary windings 102A and 102B in the winding axis direction XX between the primary winding 101 and the plate-like secondary windings 102A and 102B. The Each of the magnetic cores 103A and 103B has a substantially rectangular shape with a narrow central portion in plan view.
4A is a longitudinal surface of the magnetic cores 103A and 103B, and this surface 103L is a surface parallel to the upper surface of the base 21 described later. Also, reference numeral 103S in FIG. 4B denotes a short surface of the magnetic cores 103A and 103B.

  Each connection portion 123A of the terminal lead portions 122Aa and 122Ab of the plate-like secondary winding 102A extends substantially vertically toward the side surface 103L in the longitudinal direction of the magnetic cores 103A and 103B. The terminal lead-out portion 122Ab of the plate-like secondary winding 102A extends to the bottom surface (base member placement surface) side of the magnetic core 103A and is pulled out to the outside of the magnetic core 103A. The terminal lead-out portion 122Aa of the plate-like secondary winding 102A is on the bottom surface (base member mounting surface) side of the bobbin 104, the plate-like secondary winding 102B, and the other magnetic core 103B to which the primary winding 101 is attached. It is extended and pulled out of the magnetic core 103B.

  Each connection portion 123B of the terminal lead portions 122Ba and 122Bb of the plate-like secondary winding 102B extends substantially vertically toward the side surface 103L in the longitudinal direction of the magnetic cores 103A and 103B. The terminal lead portion 122Ba of the plate-like secondary winding 102B extends to the bottom surface (base member placement surface) side of the magnetic core 103B, and is pulled out to the outside of the magnetic core 103B. The terminal lead-out portion 122Bb of the plate-like secondary winding 102B extends to the bottom surface (base member mounting surface) side of the bobbin 104 to which the primary winding 101 is attached, the plate-like secondary winding 102A, and the magnetic core 103A. And extended outside the magnetic core 103A.

  The terminal portion 125Ab of the plate-like secondary winding 102A and the terminal portion 125Bb of the plate-like secondary winding 102B are outside the magnetic core 103A, and the terminal portion 125Ab of the terminal lead-out portion 122Ab is connected to the terminal lead-out portion 122Bb. It is laminated on the upper surface of the terminal portion 125Bb (see FIG. 3). The through holes 126 provided in the terminal portion 125Ab and the terminal portion 125Bb are arranged concentrically and attached to the one surface 21 on the base member 20. The laminated terminal portion 125Ab and terminal portion 125Bb serve as center tap terminals.

That is, the terminal lead portions 122Aa and 122Ab of the plate-like secondary winding 102A of the transformer 100 and the terminal lead portions 122Ba and 122Bb of the plate-like secondary winding 102B are the primary winding 101 and the plate-like secondary winding 102A. , 102B are arranged in parallel to the winding axis direction XX. The terminal portion 125Ab of the terminal lead portion 122Aa of the plate-like secondary winding 102A that becomes the center tap terminal of the transformer 100 and the terminal portion 125Bb of the terminal lead portion 122Bb of the plate-like secondary winding 102B are stacked. It has become.
The bottom surfaces of the terminal lead portion 122Aa of the plate-like secondary winding 102A and the terminal lead portions 122Ba, 122Bb of the plate-like secondary winding 102B form substantially the same plane. The laminated structure of the terminal portion 125Ab of the terminal lead portion 122Ab of the plate-like secondary winding 102A and the terminal portion 125Bb of the terminal lead portion 122Bb of the plate-like secondary winding 102B is laminated as the upper layer side. There is no problem.

[Transformer mounting structure]
6A is a perspective view showing a state in which the transformer is mounted on the base member, and FIG. 6B is a view seen from an angle different from that in FIG. 6A. FIG. 7 is an exploded perspective view showing an embodiment of the DC-DC converter of the present invention.
The transformer 100 is mounted on a base member 20 formed of a conductive material having excellent thermal conductivity, such as an aluminum-based metal.
In the transformer 100, the bottom surfaces of the heat radiation portions 124A of the terminal lead portions 122Aa and 122Ab of the plate-like secondary windings 102A and 102B and the heat radiation portions 124B of the terminal lead portions 122Ba and 122Bb are not attached to the one surface 21 of the base member 20, respectively. The sheet-like heat conductive member having insulation shown in the figure is interposed on the base member 20 and coupled to the base member 20 so as to be capable of heat conduction.
Note that the through holes 126 provided in the terminal lead-out portions 122Aa and 122Ab of the transformer 100 are used for circuit connection.

  As shown in FIG. 7, on one surface 21 of the base member 20, the MOS-FETs H <b> 1, H <b> 2, H <b> 3, H <b> 4 and the rectifying MOSFETs S <b> 1, S <b> 2, S <b> 3, S <b> 4 can conduct heat to the base member 20. Mounted on. Connection leads of the rectifying MOSFETs S 1, S 2, S 3, and S 4 are connected to a low voltage rectifier circuit board 310 A that constitutes the low voltage rectifier circuit 310. The MOS-FETs H1, H2, H3, and H4 are pressed against the one surface 21 of the base member 20 by the leaf spring 411. Connection leads of the MOS-FETs H1, H2, H3, and H4 are connected to the control circuit board 400A. Electronic components constituting the control circuit unit 400 and the high-voltage side circuit unit 200 shown in FIG. 1 are mounted on the control circuit board 400A.

  The heat radiation portions 124A of the terminal lead portions 122Aa and 122Ab of the plate-like secondary windings 102A and 102B of the transformer 100 and the heat radiation portion 124B of the terminal lead portions 122Ba and 122Bb heat the base member 20 together with the low voltage rectifier circuit board 310A. Combined. As described above, the terminal portion 125Ab of the plate-like secondary winding 102A of the transformer 100 and the terminal portion 125Bb of the plate-like secondary winding 102B are the center tap terminals of the secondary winding and are stacked. Is connected to the filter coil L1.

  In this state, the winding axis direction XX of the transformer 100 is substantially parallel to the one surface 21 of the base member 20. Further, the winding portions 121A and 121B of the plate-like secondary windings 102A and 102B are substantially perpendicular to the one surface 21 of the base member 20. Accordingly, the connection portions 123A and 123B of the terminal lead portions 122Aa, 122Ab, 122Ba, and 122Bb extend substantially perpendicular to the one surface 21 of the base member 20, and the heat dissipation portions 124A and 124B The member 20 is thermally coupled.

[Effect of the embodiment]
The transformer 100 of the DC-DC converter 10 of the first embodiment described above includes the plate-like secondary windings 102A and 102B. The plate-like secondary winding 102A has a winding part 121A and a pair of terminal lead parts 122Aa and 122Ab extended from at least both ends of the winding part 121A. The terminal lead portion 122Aa includes a connection portion 123A, a heat dissipation portion 124A, and a terminal portion 125Aa connected to another circuit. The terminal lead-out portion 122Ab is configured similarly. The connection part 123A of the terminal lead parts 122Aa and 122Ab extends from the end of the winding part 121A toward the base member 20, and the heat dissipation part 124A is substantially parallel to the one surface 21 of the base member 20 from the connection part 123A. And is thermally coupled to the one surface 21 of the base member 20 so as to conduct heat. The connection part 123B of the terminal lead parts 122Ba and 122Bb extends from the end of the winding part 121B toward the base member 20, and the heat dissipation part 124B is substantially parallel to the one surface 21 of the base member 20 from the connection part 123B. And is thermally coupled to the one surface 21 of the base member 20 so as to conduct heat.

According to the DC-DC converter 10 of the first embodiment, the following effects can be obtained.
(1) The winding axis direction XX of the transformer 100 is substantially parallel to the one surface 21 of the base member 20, and the terminal lead portions 122Aa, 122Ab, 122Ba, 122Bb of the plate-like secondary windings 102A, 102B. The connection portions 123 </ b> A and 123 </ b> B extend substantially perpendicular to the one surface 21 of the base member 20. For this reason, the length of the connection parts 123A and 123B of the plate-like secondary windings 102A and 102B can be shortened. Thereby, the amount of heat radiated onto the base member 20 from the connection portions 123A and 123B of the plate-like secondary windings 102A and 102B can be increased. As a result, it is possible to suppress the adverse effect that the electronic component assembled to the base member 20 receives from the heat generated from the transformer 100.

(2) A heat dissipating part that can be used as a heat dissipating part in the terminal lead parts 122Aa, 122Ab, 122Ba, 122Bb as the lengths of the connecting parts 123A, 123B of the plate-like secondary windings 102A, 102B become shorter. The lengths of 124A and 124B can be increased. Since the heat radiating portions 124A and 124B are thermally coupled to the base member 20 so as to conduct heat, the heat radiating effect of the transformer 100 can be increased.

(3) The connecting portions 123A and 123B of the plate-like secondary windings 102A and 102B are substantially perpendicular to the long side surface 103L (see FIG. 4A) of the magnetic cores 103A and 103B, that is, the short side This side surface 103S extends substantially parallel to the side surface 103S (see FIG. 4B). For this reason, the connection parts 123A and 123B are turned more than the structure extending substantially parallel to the longitudinal side surface 103L (see FIG. 4A) of the magnetic cores 103A and 103B, that is, the turn of the plate-like secondary winding. The lengths of the connection portions 123A and 123B can be shortened compared to the configuration in which the connection portion is formed by bending 90 degrees from the end. Thereby, the effect of said (1) and (2) can be enlarged further. Moreover, since the lengths of the connecting portions 123A and 123B are shortened, conductor loss can be reduced.

(4) The split portions are configured such that the terminal portions 125Aa and 125Ba and the center taps 122Ab and 122Bb are arranged on both sides of the primary winding 101 in the winding axis direction XX. Rectifying MOS-FETs constituting the low voltage rectifier circuit 310 are connected to the terminal portions 125Aa and 125Ba of the plate-like secondary windings 102A and 102B, and the choke coil LO is connected to the terminal portions 122Aa and 122Bb which are center taps. Is done. A large current flows through the rectifying MOS-FET and the choke coil LO, and the amount of heat generation is large and large. Therefore, each wiring becomes complicated and the wiring length becomes long. In the above embodiment, since the plate-like secondary windings 102A and 102B have a divided structure, the wiring pattern can be divided and the heat concentration can be dispersed. As a result, the heat dissipation efficiency can be improved.

(5) The plate-like secondary windings 102A and 102B of the transformer 100 are connected to the terminal lead portions 122Aa, 122Ab, 123Ba, and 123Bb provided at both ends of the winding portions 121A and 121B, and the heat dissipating portions 124A. , 124B can be made substantially equal. For this reason, wiring resistance, ie, a conductor loss, can be made equal.

(6) In addition to the above (5), the length of each of the heat dissipating parts 124A, 124B can be made substantially the same, and the heat dissipating effect of each plate-like secondary winding 102A, 102B can be made uniform. There is no need to provide a region for increasing heat dissipation as described above, and as a result, a low-cost DC-DC converter with high heat dissipation efficiency can be obtained.
It should be noted that the transformer 100 shown in the above embodiment can be applied with various modifications as shown in the following embodiment.

--Embodiment 2--
FIG. 8 is an exploded perspective view of a transformer 100A according to the second embodiment of the present invention.
The transformer 100A according to the second embodiment is different from the transformer 100 according to the first embodiment in that the terminal portions 125Ca, 125Cb, 125Da, and 125Db of the terminal lead portions 122Ca, 122Cb, 122Da, and 122Db are different from the heat dissipation portions 124C and 124D, respectively. It is the point which has.

  Terminal lead portions 122Ca, 122Cb, 122Da, 122Db are formed at both ends of the plate-like secondary windings 102C, 102D of the transformer 100A. The terminal lead part 122Ca has a connection part 123C, a heat dissipation part 124C, and a terminal part 125Ca, and the terminal lead part 122Cb has a connection part 123C (not shown), a heat dissipation part 124C, and a terminal part 125Cb. have. The terminal lead part 122Da has a connection part 123D, a heat dissipation part 124D, and a terminal part 125Da. The terminal lead part 122Db has a connection part 123D (not shown), a heat dissipation part 124D, and a terminal part 125Db. Have. The terminal portions 125Ca, 125Cb, 125Da, and 125Db are formed with steps that bend upward from the heat dissipating portions 124C and 124D, which is a direction away from the upper surface of the base member 20, respectively.

The terminal portions 125Ca, 125Cb, 125Da, and 125Db are attached to the upper surface of a boss (not shown) formed on the base member 20 via an insulating member (not shown), for example. Each of the terminal portions 125Ca, 125Cb, 125Da, and 125Db may be thermally coupled to the base member 20 so as to conduct heat by using a heat conductive member as an insulating member. In this state, the heat radiating portion 124C of the terminal lead portions 122Ca and 122Cb and the heat radiating portion 124D of the terminal lead portions 122Da and 122Db are thermally coupled to the base member 20 so as to conduct heat.
Other configurations in the second embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
According to the second embodiment, the same effects as those of the first embodiment are obtained.
The terminal portions 125Ca, 125Cb, 125Da, and 125Db have different steps from the heat radiating portions 124C and 124D, respectively, or part of the terminal portions 125Ca, 125Cb, 125Da, and 125Db. Alternatively, a step may be provided only on the surface.

--Embodiment 3--
9 to 11 are exploded perspective views of the transformer 100B according to the third embodiment of the present invention, and correspond to FIGS.
9 is an external perspective view showing a third embodiment of the transformer 100B, FIG. 10 is a diagram of the transformer 100B shown in FIG. 9, FIG. 10 (A) is a left side view, and FIG. 10 (B) is a diagram. FIG. 10C is a right side view and FIG. 10D is a bottom view of FIG. 10C. FIG. 11 is an exploded perspective view of the transformer shown in FIG.
The transformer 100B of the third embodiment is different from the transformer 100 of the first embodiment in that the heat radiation portions 124E and 124F of the terminal lead portions 122Ea, 122Eb, 122Fa, and 122Fb and the terminal portions 125Ea, 125Eb, 125Fa, and 125Fb are respectively implemented. This is that the terminal lead portions 122Aa, 122Ab, 122Ba, and 122Bb of the first form are formed wider than the heat radiation portions 124A and 124B and the terminal portions 125Aa, 125Ab, 125Ba, and 125Bb.

  Terminal lead portions 122Ea and 122Eb or 122Fa and 122Fb are formed at both ends of the plate-like secondary windings 102E and 102F of the transformer 100B, respectively. The terminal lead part 122Ea includes a connection part 123E, a heat dissipation part 124E, and a terminal part 125Ea. The terminal lead part 122Eb includes a connection part 123E (not shown), a heat dissipation part 124E, and a terminal part 125Eb. Have. The terminal lead portion 122Fa includes a connection portion 123F (not shown), a heat radiating portion 124F, and a terminal portion 125Fa. The terminal lead portion 122Fb includes a connection portion 123F, a heat radiating portion 124F, and a terminal portion 125Fb. Have. The terminal portions 125Ea, 125Eb, 125Fa, and 125Fb have shapes different from the terminal lead portions 122Aa, 122Ab, 122Ba, and 122Bb illustrated in the first embodiment, respectively. In particular, the heat dissipating parts 124E and 124F and the terminal parts 125Ea, 125Eb, 125Fa, and 125Fa are wider than the heat dissipating parts 124A and 124B and the terminal parts 125Aa, 125Ab, 125Ba, and 125Bb of the first embodiment. Is formed.

On the bottom surface side of the transformer 100B, at least the mounting area occupied by the magnetic cores 103A and 103B of the transformer 100B is normally an invalid space that cannot be used for purposes other than transformer mounting. In this space, by increasing the area of the heat radiation portions 124E and 124F of the transformer 100B, the space that has not been used can be effectively utilized, and the heat radiation efficiency to the base member 20 can be improved.
Other configurations in the third embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
According to the third embodiment, the same effect as that of the first embodiment can be obtained, and in particular, the heat dissipation efficiency can be improved.

--Embodiment 4--
FIG. 12 is an exploded perspective view of a transformer 100C according to the fourth embodiment of the present invention.
The transformer 100C of the fourth embodiment is different from the transformer 100 of the first embodiment in that the terminal lead portion 122Ga is bent in the same direction as the terminal portion 122Gb and the terminal lead portion 122Ha is bent in the same direction. is there.

  Terminal lead portions 122Ga and 122Gb or 122Ha and 122Hb are formed at both ends of the plate-like secondary windings 102G and 102H of the transformer 100C, respectively. The terminal lead part 122Ga has a connection part 123G, a heat dissipation part 124G, and a terminal part 125Ga, and the terminal lead part 122Gb has a connection part 123G (not shown), a heat dissipation part 124G, and a terminal part 125Gb. Have. The heat radiation part 124G and the terminal part 125G of the terminal lead parts 122Ga and 122Gb are bent substantially perpendicularly toward the magnetic core 103A side with respect to the winding part 121G. The terminal lead part 122Ha has a connection part 123H, a heat dissipation part 124H, and a terminal part 125Ha, and the terminal lead part 122Hb has a connection part 123H, a heat dissipation part 124H (not shown), and a terminal part 125Hb. Have. The heat radiation part 124H and the terminal part 125H of the terminal lead parts 122Ha and 122Hb are bent substantially perpendicularly toward the magnetic core 103A side with respect to the winding part 121H. The terminal part 125Gb of the terminal lead part 122Gb and the terminal part 125Ha of the terminal lead part 122Ha are laminated to form a center tap terminal.

That is, all of the terminal lead portions 122Ga and 122Gb of the plate-like secondary winding 102G and the terminal lead portions 122Ha and 122Hb of the plate-like secondary winding 102H are directed toward the magnetic core 103A, and the winding portion 102G, It is bent substantially perpendicular to 102H.
In the fourth embodiment, none of the terminal lead portions 122Ga and 122Gb and the terminal lead portions 122Ha and 122Hb extend outside the magnetic core 103B. For this reason, the mounting area of the transformer 100C can be reduced accordingly, and high-density mounting can be achieved.
The DC-DC converter 10 including the transformer 100C of the fourth embodiment also has the same effect as that of the first embodiment. However, since the terminal lead portions 122Ga, 122Gb, 122Ha, and 122Hb are all bent in the same direction, the wiring is more complicated than that of the first embodiment.
Other configurations in the fourth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

--Embodiment 5--
FIG. 13 is an exploded perspective view of a transformer 100D according to the fifth embodiment of the present invention.
The difference between the transformer 100D of the fifth embodiment and the transformer 100 of the first embodiment is that the terminal portions 125Ia, 125Ja of the terminal shape portions 122Ia, 122Ib, 122Ja, 122Jb are different from the heat dissipation portion 124I or the heat dissipation portion 124J, respectively. It is a point that is bent at a substantially right angle.

  Terminal lead portions 122Ia and 122Ib or 122Ja and 122Jb are formed at both ends of the plate-like secondary windings 102I and 102J of the transformer 100D, respectively. The terminal lead part 122Ia has a connection part 123I, a heat dissipation part 124I, and a terminal part 125Ia. The terminal lead part 122Ib has a connection part 123I (not shown), a heat dissipation part 124I, and a terminal part 125Ib. Have. The terminal lead portion 122Ja includes a connection portion 123J, a heat dissipation portion 124J, and a terminal portion 125Ja. The terminal lead portion 122Jb includes a connection portion 123J (not shown), a heat dissipation portion 124J, and a terminal portion 125Jb. Have.

The terminal part 125Ib of the terminal lead part 122Ib and the terminal part 125Jb of the terminal lead part 122Jb are laminated to form a center tap terminal.
The terminal portion 125Ia is bent substantially at a right angle with respect to the heat radiating portion 124I, and the terminal portion 125J is bent substantially at a right angle with respect to the heat radiating portion 124J. Further, notches 127 are formed at the tips of the terminal portions 125Ia and 125Ja instead of the through holes 126 of the first embodiment.
Other configurations in the fifth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

The heat radiating portion 124I of the terminal lead portion 122Ib and the heat radiating portion 124J of the terminal lead portion 122Jb are placed on the base member 20 with the terminal portion 125Ib or the terminal portion 125Jb interposed through an insulating heat conductive member (not shown). It is thermally coupled to one surface 21 of the base member 20. On the other hand, the terminal portion 125Ia of the terminal lead portion 122Ia and the terminal portion 125Ja of the terminal lead portion 122Ja are attached to a support member (not shown) provided in the base member 20. If the support member is a conductive member, an insulating member is interposed between the two members. The control circuit board 400A, the low-voltage rectifier circuit board 310A, or a support member that supports the capacitor module in which the X capacitor Cx and the Y capacitor Cy are accommodated may be attached. In this state, the heat radiating portion 124I of the terminal lead portion 122Ia and the heat radiating portion 124J of the terminal lead portion 122Ja are thermally coupled to the one surface 21 of the base member 20 so as to be able to conduct heat.
In the fifth embodiment, the same effect as in the first embodiment is obtained.
The terminal portions 125Ib and 125Jb may be bent with respect to the heat radiating portion 124I or 124J. The bending angle is not limited to 90 °, and may be set arbitrarily.
Further, the through holes 126 may be replaced with the notches 127 for the terminal portions 125Ib and 125Jb. About each terminal part 125Ia, 125Ib, 125Ja, 125Jb, the presence or absence of bending, the bending angle, whether to make a through hole or notch, etc. may be arbitrarily selected and applied.

--Embodiment 6--
FIG. 14 is an exploded perspective view of a transformer 100E according to the sixth embodiment of the present invention.
The difference between the transformer 100E of the sixth embodiment and the transformer 100 of the first embodiment is that the transformer 100E includes only one plate-like secondary winding 102K.

Similar to the transformer 100 of the first embodiment, the transformer 100E includes a primary winding 101, a bobbin 104, and a pair of magnetic cores 103A and 103B. However, the transformer 100E includes only one plate-like secondary winding 102K disposed between the one magnetic core 103A and the primary winding 101 in the winding axis direction XX. The plate-like secondary winding 102K has a winding part 121K and terminal lead parts 122Ka and 122Kb provided at both ends of the winding part 121K.
The terminal lead-out portion 122Ka includes a connection portion 123K, a heat dissipation portion 124K, and a terminal portion 125Ka, and the terminal lead-out portion 122Kb includes a connection portion 123K (not shown), a heat dissipation portion 124K, and a terminal portion 125Kb. Have. The plate-like secondary winding 102K is basically the same as the plate-like secondary winding 102A of the first embodiment. The transformer 100E does not have a center tap drawn from the middle part of the outer periphery of the winding part 121K.
Other configurations in the sixth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
The transformer 100E of the sixth embodiment also has the same effect as that of the first embodiment.
The plate-like secondary winding 102K may be disposed between the other magnetic core 103B and the primary winding 101.

--Embodiment 7--
FIG. 15 is an exploded perspective view of a transformer 100F according to the seventh embodiment of the present invention.
Similarly to the transformer 100E of the sixth embodiment, the transformer 100F of the seventh embodiment is different from the transformer 100 of the first embodiment in that it includes only one plate-like secondary winding 102L.
However, the heat radiation part 124L of the terminal lead part 122La of the plate-like secondary winding 102L of the seventh embodiment is formed to have a large width and a large area.

The plate-like secondary winding 102L includes a winding part 121L and terminal lead parts 122La and 122Lb formed at both ends of the winding part 121L. The terminal lead-out portion 122La has a connection portion 123L, a heat dissipation portion 124L, and a terminal portion 125La, and the terminal lead-out portion 122Lb has a connection portion 123L (not shown), a heat dissipation portion 124L, and a terminal portion 125Lb. . The plate-like secondary winding 102L is basically the same as the plate-like secondary winding 102G of the fourth embodiment shown in FIG. 12, and this transformer 100F is also in the middle of the outer periphery of the winding part 121L. It does not have a center tap drawn from the part.
Other configurations in the seventh embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
The transformer 100F of the seventh embodiment also has the same effect as that of the first embodiment.
The plate-like secondary winding 102L may be disposed between the other magnetic core 103B and the primary winding 101.

--Eighth embodiment--
FIG. 16 is an exploded perspective view of a transformer 100G according to Embodiment 8 of the present invention, and FIG. 17 is an enlarged perspective view of a plate-like secondary winding 102M of the transformer 100G shown in FIG. A) is a view seen from above, and FIG. 17B is a view seen from below.
The transformer 100G includes a primary winding 101, a bobbin 104, a plate-like secondary winding 102M, and a pair of magnetic cores 103A and 103B.

  The plate-like secondary winding 102M has a pair of winding portions 121Ma and 121Mb. Winding part 121Ma and winding part 121Mb are connected by connecting part 128. The bobbin 104 is disposed between the winding part 121Ma and the winding part 121Mb of the plate-like secondary winding 102M. That is, the winding part 121Ma is attached to one winding frame part 104a of the bobbin 104 to which the primary winding 101 is attached, and the winding part 121Mb is attached to the other winding frame part 104b. The winding portions 121Ma and 121Mb of the primary winding 101 and the plate-like secondary winding 102M have the same winding axis direction XX. The connecting part 128 is a center tap terminal and is connected to another circuit.

  As shown in FIGS. 17A and 17B, a terminal shape portion 122Ma bent substantially perpendicular to the winding portion 121Ma is formed on one end side of the winding portion 121Ma. A terminal shape portion 122Mb bent substantially perpendicular to the winding portion 121Mb is formed on one end side of the winding portion 121Mb. The terminal shape portion 122Ma has a connection portion 123Ma, a heat dissipation portion 124Ma, and a terminal portion 125Ma, and the terminal shape portion 122Mb has a connection portion 123Mb, a heat dissipation portion 124Mb, and a terminal portion 125Mb. The terminal shape portions 122Ma and 122Mb extend on the bottom surface side of the bobbin 104 and the other magnetic core 103B, and are drawn out of the other magnetic core 103B.

  The other end of the terminal lead portion 122Ma and the other end of the terminal lead portion 122Mb are connected by a connecting portion 128. The connecting portion 128 is bent substantially perpendicular to the winding portions 121Ma and 121Mb and on the side opposite to the terminal lead portions 122Ma and 122Mb. The connecting portion 128 extends on the bottom surface side of one magnetic core 103A and is folded back outside the one magnetic core 103A. A through-hole 126 is formed in the connecting portion 128 at a portion that is folded back to the outside of the one magnetic core 103A. The lower surface of the connecting portion 128 is provided in the same plane as the lower surfaces of the terminal lead portions 122Ma and 122Mb, and can conduct heat to the one surface 21 of the base member 20 like the heat radiating portions 124Ma and 124Mb of the terminal lead portions 122Ma and 122Mb. Thermally coupled.

18 is a development view of the plate-like secondary winding 102M shown in FIG. 17 before processing.
The unrolled secondary winding 102Mp before processing has a winding part 121Map wound around one side and a winding part 121Mbp wound around one side. A terminal lead portion 122Map is connected to one end side of the winding portion 121Map. A terminal lead portion 122Mbp is connected to one end side of the winding portion 121Mbp. The other end side of the winding part 121Map and the other end side of the winding part 121Mbp are connected by a connecting part 128p.

The terminal lead portion 122Map has a connection portion 123Map, a heat dissipation portion 124Map, and a terminal portion 125Map, and the terminal lead portion 122Mbp has a connection portion 123Mbp, a heat dissipation portion 124Mbp, and a terminal portion 125Mbp.
A through hole 126 is formed in each of the terminal portions 125Map and 125Mbp. Two through holes 126 are arranged in the longitudinal direction near the center in the longitudinal direction of the connecting portion 128p.

The developed plate-like secondary winding 102Mp is formed in the above shape by punching or the like.
The expanded plate-like secondary winding 102Mp is bent by a press bending process at a bent portion P1 which is a boundary portion between the heat radiation portion 124Map of the terminal lead-out portion 122Map and the connection portion 123Map, and the heat radiation portion 124Map and the terminal portion 125Map Is raised at a right angle. The developed plate-like secondary winding 102Mp is bent in the reverse direction at the bent portion P2 between the pair of through holes 126 of the connecting portion 128p. As for the connection part 128p, the both sides of the bending part P2 are closely_contact | adhered by the press bending process of multiple times. Then, the developed plate-like secondary winding 102Mp is bent by press bending at a bent portion P3 which is a boundary portion between the heat radiation portion 124Mbp of the terminal lead portion 122Mbp and the connection portion 123Mbp, and the heat radiation portion 124Mbp and the terminal portion 125Mbp. Stand up at a right angle. As a result, the plate-like secondary winding 102M shown in FIGS. 17A and 17B is formed.

Other configurations in the eighth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.
The transformer 100G of the eighth embodiment has the same configuration as that of the first embodiment, and therefore has the same effect as that of the first embodiment.
The connecting portion 128 may be formed in a different direction from the terminal lead portions 122Ma and 122Mb.

--Embodiment 9--
19 is an exploded perspective view of a transformer 100H according to Embodiment 9 of the present invention, and FIG. 20 is a configuration diagram of a power conversion circuit unit of the DC-DC converter 10 to which the transformer 100H illustrated in FIG. 19 is applied. It is an example.
The power conversion circuit unit of the DC-DC converter 10 illustrated in FIG. 20 has a plurality of secondary windings of the transformer 100H (T) as compared to the circuit unit illustrated in FIG. This is different in that it is connected in parallel. In FIG. 20, the winding start side terminals w1 and w4, the center tap terminals w2 and w5, and the winding end side terminals w3 and w6 of the secondary winding are respectively connected. In FIG. 20, “●” is added to the winding start side.

  As shown in FIG. 19, in the transformer 100H, a plurality of plate shapes (illustrated as two in FIG. 19) between one magnetic core 103A and the primary winding 101 in the winding axis direction XX. Secondary windings 102N and 102O are disposed, and a plurality of (second illustrated as two in FIG. 19) plate-like secondary windings 102P and 102Q are disposed between the other magnetic core 103B and the primary winding 101. ing.

The primary winding 101 and the plate-like secondary winding 102N are attached to the bobbin 104A with the same winding axis direction XX. A plate-like secondary winding 102O is arranged between the plate-like secondary winding 102N and one magnetic core 103A. Between the plate-like secondary winding 102N and the plate-like secondary winding 102O, a bobbin 104B is arranged to insulate the plate-like secondary winding 102N from the plate-like secondary winding 102O.
Similarly, the primary winding 101 and the plate-like secondary winding 102P are attached to the bobbin 104A with the same winding axis direction XX. A plate-shaped secondary winding 102Q is disposed between the plate-shaped secondary winding 102P and the other magnetic core 103B. Between the plate-like secondary winding 102P and the plate-like secondary winding 102Q, a bobbin 104C for insulating the plate-like secondary winding 102P and the plate-like secondary winding 102Q is disposed.
The primary winding 101 and the plate-like secondary windings 102N, 102O, 102P, and 102Q have the same winding axis direction XX.

  The plate-like secondary winding 102N has a winding part 121N and terminal lead parts 122Na and 122Nb. The terminal lead-out part 122Na has a connection part 123N, a heat dissipation part 124N, and a terminal part 125Na, and the terminal lead-out part 122Nb has a connection part 123N (not shown), a heat dissipation part 124N, and a terminal part 125Nb. The terminal lead portion 122Nb extends on the bottom side of the bobbin 104B, the plate-like secondary winding 102O, and one of the magnetic cores 103A, and is drawn out of the one of the magnetic cores 103A. The terminal lead portion 122Na extends on the bottom surface side of the bobbin 104B and extends on the bottom surface side of the plate-like secondary winding 102O.

  The plate-like secondary winding 102O has a winding part 121O and terminal lead parts 122Oa and 122Ob. The terminal lead part 122Oa has a connection part 123O, a heat dissipation part 124O, and a terminal part 125Oa, and the terminal lead part 122Ob has a connection part 123O (not shown), a heat dissipation part 124O, and a terminal part 125Ob. Have. The terminal lead-out portion 122Oa extends on the bottom surface side of the one magnetic core 103A and is drawn out of the one magnetic core 103A. As described above, the terminal lead portion 122Na of the plate-shaped secondary winding 102N extends on the bottom surface side of the bobbin 104B and the bottom surface side of the terminal lead portion 122Ob of the plate-shaped secondary winding 102O. It is laminated on the part 122Ob and connected to the terminal lead part 122Ob.

  The plate-like secondary winding 102P has a winding part 121P and terminal lead parts 122Pa and 122Pb. The terminal lead part 122Pa has a connection part 123P, a heat dissipation part 124P, and a terminal part 125Pa, and the terminal lead part 122Pb has a connection part 123P (not shown), a heat dissipation part 124P, and a terminal part 125Pb. Have. The terminal lead portion 122Pa extends from the bottom surface side of the bobbin 104C, the plate-like secondary winding 102Q, and the other magnetic core 103B, and is drawn to the outside of the other magnetic core 103B. The terminal lead portion 122Pb extends from the bottom surface side of the terminal lead portion 122Na of the bobbin 104A and the plate-like secondary winding 102N, is stacked on the terminal lead portion 122Na, and is connected to the terminal lead portion 122Na.

  The plate-like secondary winding 102Q has a winding part 121Q and terminal lead parts 122Qa and 122Qb. The terminal lead part 122Qa has a connection part 123Q, a heat dissipation part 124Q, and a terminal part 125Qa, and the terminal lead part 122Qb has a connection part 123Q, a heat dissipation part 124Q, and a terminal part 125Qb. The terminal lead-out portion 122Qa extends from the bottom surface side of the terminal lead-out portion 122Pb of the bobbin 104C, the plate-like secondary winding 102P, and the plate-like secondary winding 102P, and is laminated on the terminal lead-out portion 122Pb to the terminal lead-out portion 122Pb. It is connected. The terminal lead portion 122Qb extends on the bottom surface side of the other magnetic core 103B and is drawn to the outside of the other magnetic core 103B.

The terminal portions 125Na, 125Ob, 125Pb, and 125Qa are stacked and constitute one terminal portion as a center tap terminal.
Terminal portions 125Oa, 125Na and 125Ob, 125Nb, 125Pa, 125Pb and 125Qa, 125Qb correspond to terminals w1, w2, w3, w4, w5, and w6 in FIG. 20, respectively. The terminal portions 125Oa (w1) and 125Pa (w4) and the terminal portions 125Nb (w3) and 125Qb (w6) are connected by a wiring pattern formed on the bus bar (not shown) or the low voltage rectifier circuit board 310A, respectively. The
Other configurations in the ninth embodiment are the same as those in the first embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

The transformer 100H of the ninth embodiment also has the same effect as that of the first embodiment.
In particular, in the ninth embodiment, a first secondary winding constituted by plate-like secondary windings 102N and 102O and a second secondary winding constituted by plate-like secondary windings 102P and 102Q are arranged in parallel. Since they are connected, the current flowing through each winding part 121N, 121O, 121P, 121Q can be reduced, and the heat generated from each winding part 121N, 121O, 121P, 121Q can be reduced. Further, since the winding start side is divided into the heat radiating parts 124O and 124P and the winding end side is divided into the heat radiating parts 124N and 124Q, in addition to the effect of heat generation dispersion, the heat radiating parts can be divided and arranged. The area of the heat radiating part thermally coupled to the member 20 can be increased. For this reason, the heat dissipation of the transformer 100H can be made more efficient.

--Embodiment 10--
21 is an exploded perspective view of the transformer 100I according to the tenth embodiment of the present invention, and FIG. 22 is a configuration diagram of a power conversion circuit unit of the DC-DC converter 10 to which the transformer 100I illustrated in FIG. 21 is applied. It is an example.
The difference between the transformer 100I of the tenth embodiment and the transformer 100H of the ninth embodiment is that the transformer 100I is connected to the low voltage rectifier circuit 330 without connecting each terminal of the divided secondary winding. .

  As shown in FIG. 22, the secondary winding of the transformer 100I (T) is divided into two, and one of the secondary windings includes two rectifying phases composed of MOSFETs S11 and S21. , MOSFETs S31 and S41 and an active clamp capacitor Cc1 is connected to a first low voltage rectifier circuit unit 330a including an active clamp circuit. The other secondary winding is a second low-voltage rectifier circuit including two rectifying phases composed of MOSFETs S12 and S22 and an active clamp circuit composed of MOSFETs S32 and S42 and an active clamping capacitor Cc2. Connected to the unit 330b.

  The first low-voltage rectifier circuit unit 330a includes a smoothing circuit including a choke coil LO connected to the center tap terminal of the transformer 100I (T) and a smoothing capacitor CO. The first low voltage rectifier circuit unit 330a includes a smoothing circuit including a filter coil L1 and a filter capacitor C1.

The first low voltage rectifier circuit unit 330a and the second low voltage rectifier circuit unit 330b are connected in parallel, and the center tap terminal of the other secondary winding is connected to the first low voltage via the filter coil L1. It is connected to the smoothing circuit of the rectifier circuit unit 330a. That is, in the transformer 100I of the tenth embodiment, the center tap terminal of the split core is connected at the subsequent stage of the choke coil LO, and the divided secondary windings of the transformer 100I (T) are respectively connected to the rectifying phase and the active coil. The first and second low-voltage rectifier circuit units 330a and 330b having a clamp circuit are connected.
Therefore, the secondary winding of the transformer 100I (T) includes six terminals w1 to w6 as illustrated in FIG.

21, the transformer 100I is different from the transformer 100H illustrated in FIG. 19 as the ninth embodiment in that the plate-like secondary windings 102P and 102Q in the ninth embodiment are respectively plate-like secondary windings 102R. , 102S.
Therefore, in the following description regarding FIG. 21, only matters related to the plate-like secondary windings 102R and 102S will be described.

  The plate-like secondary winding 102R includes a winding part 121R and terminal lead parts 122Ra and 122Rb. The terminal lead-out portion 122Ra has a connection portion 123R, a heat dissipation portion 124R, and a terminal portion 125Ra, and the terminal lead-out portion 122Rb has a connection portion 123R, a heat dissipation portion 124R, and a terminal portion 125Rb. The terminal lead-out portion 122Ra extends on the bottom surface side of the bobbin 104C, the plate-like secondary winding 102S, and the other magnetic core 103B, and is drawn out of the one magnetic core 103B. The terminal lead portion 122Rb extends to the bottom surface side of the bobbin 104C and the plate-like secondary winding 102S.

  The plate-like secondary winding 102S includes a winding part 121S and terminal lead parts 122Sa and 122Sb. The terminal lead part 122Sa has a connection part 123S, a heat dissipation part 124S, and a terminal part 125Sa, and the terminal lead part 122Sb has a connection part 123S, a heat dissipation part 124S, and a terminal part 125Sb. The terminal lead portion 122Sb extends on the bottom surface side of the other magnetic core 103B and is drawn to the outside of the magnetic core 103B. As described above, the terminal lead portion 122Rb of the plate-like secondary winding 102R extends on the lower surface of the terminal lead portion 122Sa, and the terminal lead portion 122Sa and the terminal lead portion 122Rb are stacked and connected. Yes. The terminal lead-out portion 122Sb and the terminal lead-out portion 122R are stacked and extend on the bottom surface side of the other magnetic core 103B and are pulled out to the outside of the magnetic core 103B.

The terminal portion 125Na and the terminal portion 125Ob are stacked to form one terminal portion serving as a center tap terminal, and the terminal portion 125Rb and the terminal portion 125Sa are stacked to configure one terminal portion serving as a center tap terminal. To do.
Terminal portions 125Oa, 125Na and 125Ob, 125Nb, 125Ra, 125Rb and 125Sa, 125Sb correspond to terminals w1 to w6 in FIG. 22, respectively.
Other configurations in the tenth embodiment are the same as those in the ninth embodiment, and the corresponding components are denoted by the same reference numerals and description thereof is omitted.

The transformer 100I of the tenth embodiment also has the same effect as that of the ninth embodiment.
In particular, since the terminal portions 125Na and 125Ob, 125Rb and 125Sa, which are the center tap terminals w2 and w5, are formed separately, the current flowing through the terminal lead portions 122Na and 122Ob or the terminal lead portions 122Rb and 122Sa is reduced. In addition, the heat dissipation of the transformer 100I can be performed more efficiently than in the case of the ninth embodiment.

  In the ninth and tenth embodiments, the transformers 100H and 100I in which a larger number of plate-like secondary windings 102 are installed can be used. Further, as illustrated in FIG. 16, each of the plate-like secondary windings 102N to 102S of the transformers 100H and 100I may be connected by a connecting portion 128.

In the above embodiment, the base member 20 is made of metal, but may be made of resin or a member in which metal and resin are integrally formed.
The base member 20 is exemplified as a flat plate member, but may be a case member. Moreover, it is good also as a case member which has a cooling flow path into which cooling media, such as cooling water, flow inside.
The control circuit board 400A is exemplified as a structure in which the control circuit unit 400 and the high voltage side circuit unit 200 are configured. However, the board constituting the high voltage side circuit unit 200 may be another board.

  In the above embodiment, the winding portions 121A to 121S of the plate-like secondary windings 102A to 102S of the transformers 100A to 100I are not limited to one turn but may be wound a plurality of turns.

In addition, the transformers 100 </ b> A to 100 </ b> I shown in the above embodiment may be partially combined, or a part of the shape may be changed.
In short, a transformer having a primary winding and a plate-like secondary winding, the winding axis direction is arranged on one surface of the base member, parallel to the in-plane direction of the one surface, It has a connecting part, a heat radiating part, and a terminal part. The connecting part extends from the winding part of the plate-like secondary winding toward the base member, and the heat radiating part is thermally coupled to the base member so as to conduct heat. Any structure may be used.

DESCRIPTION OF SYMBOLS 10 DC-DC converter 20 Base member 21 One side 100, 100A-100H Transformer 102A-102S Plate-like secondary winding 103A Magnetic body core 103B Magnetic body core 104, 104A, 104B Bobbin 104a, 104b Winding frame part 121A-121S Winding Line part 122Aa, 122Ab-122L Terminal lead-out part 123A-123S Connection part 124A-124S Heat radiation part 125Aa, 125Ab-125Sa, 125Sb Terminal part 128 Connection part H1-H4 MOSFET
S1-S4 MOSFET
XX Winding axis direction

Claims (10)

On both sides in the winding axis direction of the primary winding and the plate-like secondary winding across the primary winding, the plate-like secondary winding, and the primary winding and the plate-like secondary winding A transformer having a pair of magnetic cores disposed;
A base member that has one surface thermally coupled to the transformer and radiates heat generated from the transformer;
The transformer is disposed on the base member such that the winding axis direction is substantially parallel to the in-plane direction of the one surface of the base member,
The plate-like secondary winding has a winding part and a pair of terminal lead parts extended from at least both ends of the winding part,
The terminal lead part has a connection part, a heat dissipation part, and a terminal part connected to another circuit,
The connection part of the terminal lead part extends from the end of the winding part toward the base member, and the heat dissipation part is substantially parallel to the one surface of the base member from the connection part. A DC-DC converter that is bent and thermally coupled to the one surface of the base member so as to conduct heat. The DC-DC converter according to claim 1, wherein
The transformer includes a DC-DC converter including at least one plate-like secondary winding disposed between the primary winding and only one of the pair of magnetic cores. The DC-DC converter according to claim 1, wherein
The transformer includes at least one first plate-like secondary winding disposed between one of the pair of magnetic cores and the primary winding, the other of the pair of magnetic cores, A DC-DC converter comprising at least one second plate-like secondary winding disposed between the primary winding. The DC-DC converter according to claim 3,
Each of the first plate-like secondary winding and the second plate-like secondary winding has the terminal lead portion having a terminal portion laminated on each other, and the terminals laminated on each other The unit is a DC-DC converter that is a center tap terminal. The DC-DC converter according to claim 1, wherein
The plate-like secondary winding is connected at a connecting portion, and includes a plurality of the winding portions wound at least one turn, respectively, and the plurality of winding portions are connected at end portions of the respective winding portions. DC-DC converters interconnected by each other. The DC-DC converter according to claim 5,
The coupling portion is a DC-DC converter having a heat radiating portion thermally coupled to the one surface of the base member and a terminal portion connected to another circuit. The DC-DC converter according to any one of claims 1 to 6,
The terminal portion is a DC-DC converter that is thermally coupled to the one surface of the base member so as to conduct heat. The DC-DC converter according to any one of claims 1 to 6,
The magnetic core has a substantially rectangular shape having a side surface on the long side and a side surface on the short side, and the transformer has one of the side surfaces on the long side facing the one surface of the base member. A DC-DC converter disposed on the member. The DC-DC converter according to claim 1, wherein
The transformer includes first and second plate-like secondary windings that are insulated from each other between one of the pair of magnetic cores and the primary winding, and the pair of magnetic cores. And the third and fourth plate-like secondary windings arranged to be insulated from each other between the other of the body cores and the primary winding, and the first to the fourth A DC-DC converter in which a plate secondary winding is provided with the terminal lead portions having the terminal portions stacked on each other, and the terminal portions stacked on each other serve as center tap terminals. . The DC-DC converter according to claim 1, wherein
The transformer includes first and second plate-like secondary windings that are insulated from each other between one of the pair of magnetic cores and the primary winding, and the pair of magnetic cores. A third and fourth plate-like secondary windings arranged insulated from each other between the other of the body core and the primary winding, and the first plate-like secondary winding Each of the winding and the second plate-like secondary winding has the terminal lead portion having terminal portions stacked on each other, and the terminal portions stacked on each other serve as center tap terminals. The third plate-like secondary winding and the fourth plate-like secondary winding each have the terminal lead-out portion having a terminal portion laminated on each other, and are laminated on each other. The terminal part is a DC-DC converter, which is a center tap terminal.

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