JP6556114B2 - Switching power supply - Google Patents

Description

  The present invention relates to a switching power supply apparatus in which input and output are insulated by a transformer, and an output winding and a rectifier circuit are connected by a metal bus bar.

  Conventionally, as disclosed in Patent Document 1, a transformer provided with a primary winding (input winding) and a secondary winding (output winding) and a rectifier circuit that rectifies the voltage of the secondary winding are provided. A plurality of printed circuit boards mounted, and a conductor frame (bus bar) connecting the secondary winding, the rectifier circuit and the smoothing circuit, and the plurality of printed circuit boards are arranged so as to face each other around the magnetic core of the transformer, There was a switching power supply device in which each printed circuit board was connected to the secondary winding. According to the structure of this switching power supply device, the high frequency current loop formed in the secondary winding of the transformer is reduced, so that the parasitic inductance component viewed from the primary winding side of the transformer is reduced, and the high frequency current and the parasitic inductance component are reduced. The loss due to can be reduced. Further, since the path through which a large current flows is connected by a conductor frame having a low resistance value, loss due to wiring resistance can be reduced. The high frequency current loop and the loss due to the high frequency current and the parasitic inductance component are described in detail in Patent Document 1.

JP 2013-99086 A

  The structure of the switching power supply device disclosed in Patent Document 1 can reduce the parasitic inductance component seen from the primary winding side of the transformer to some extent, but has other problems such as being compact and easy to assemble and ensuring sufficient insulation. However, it was still difficult to obtain sufficient performance.

  The present invention has been made in view of the above-described background art, and an object thereof is to provide a switching power supply device that is compact and easy to assemble and can significantly reduce unnecessary parasitic inductance components on the transformer and output winding side. .

The present invention relates to a transformer having an input winding and an output winding, and a circuit connected to both ends of the output winding, the rectifying circuit having a rectifying element for rectifying an AC voltage generated in the output winding. And a smoothing circuit connected to an output end of the rectifier circuit and smoothing a rectified voltage output from the rectifier circuit, and having an output capacitor for generating an output voltage at both ends, and the output winding The switching power supply device in which the rectifier circuit and the smoothing circuit are connected by a metal bus bar,
The output winding is provided by a plurality of coils formed on each conductive layer of a plurality of first substrates arranged in directions facing each other, and the rectifying element is provided on each of the coils on the first substrate. Each of the bus bars is mounted at a nearby position, and the bus bar is connected to each conductive layer of the plurality of first substrates, an output unit to which an external load is connected, the connection unit, and the output And a plurality of substrate receiving portions formed of slits or through holes formed in the plate-like connecting portion, the plurality of substrate receiving portions being provided in the plate-like connecting portion, The first substrate is arranged in a direction intersecting with the connection portion of the bus bar, each end portion of the first substrate is individually inserted into the plurality of substrate receiving portions, and each conductive layer is formed in the substrate receiving portion. Switching power supply connected via solder It is the location.

  The smoothing circuit has an output inductor, and the output inductor is provided by attaching a magnetic core to the peripheral surface of the connecting portion of the bus bar.

  The bus bar includes a first bus bar that outputs a positive potential of an output voltage and a second bus bar that outputs a negative potential, and the first and second bus bars respectively include the connection portion, The output part and the connecting part are integrally formed. In this case, it is preferable that the first bus bar and the second bus bar are fixedly connected to each other at a specific portion of each connecting portion by a connecting member made of resin.

  The output capacitor is mounted on a second substrate different from the first substrate, and the second substrate is provided with a pair of through holes that allow external connection of the positive side and the negative side of the output capacitor. The first and second bus bars are arranged such that specific portions of the connecting portions are flush with each other, and a pair of connection terminals stand up from the specific portions, and the second board has the through holes. The through-hole and the connection terminal can be connected to each other via solder in a state where the connection terminal is inserted through and positioned at the specific location. In this case, the connection terminal can be provided by cutting up a part of the connecting portion. Or the said connection terminal can be provided by joining a metal pin to the said connection part.

  Since the switching power supply device of the present invention has a structure in which the output winding of the transformer is configured by the coil formed in the conductive layer of the first substrate and the rectifying element is mounted in the vicinity of the coil on the first substrate, The connected high frequency current loop can be made smaller than before, and the loss due to the high frequency current and the parasitic inductance component can be greatly reduced. In addition, since the output winding, the rectifier circuit, the smoothing circuit, and the output section to which the external load is connected are directly connected by a metal bus bar having a low resistance value, the resistance value of the path through which a large current flows can be kept low, Loss due to wiring resistance is small.

  The connection portion between the output winding and the rectifying element and the bus bar has a unique structure in which a slit-like substrate receiving portion is provided in the bus bar, and the end portion of the first substrate is inserted into the substrate receiving portion and soldered. Therefore, it is very compact and easy to assemble, and sufficient connection strength can be obtained.

It is a perspective view which shows the external appearance of one Embodiment of the switching power supply device of this invention. It is the perspective view which looked at the output side circuit unit from the 1st and 2nd bus-bar side. It is the perspective view which looked at the output side circuit unit from the transformer side. It is a circuit diagram of an output side circuit unit. A perspective view showing the assembled transformer (a), a perspective view showing the input coil constituting the input winding, a perspective view showing the first substrate provided with the output coil and the rectifying element constituting the output winding. (C), The perspective view (d) which shows the magnetic core of a transformer, and the perspective view (e) which shows insulating paper. They are a perspective view (a), a front view (b), a right side view (c), and a plan view (d) showing the first and second bus bars. It is a perspective view which shows the magnetic core and gap material for forming an output inductor. It is a perspective view which shows two 2nd board | substrates in which the output capacitor was mounted. It is the perspective view (a) which shows the 1st modification of a 1st and 2nd bus bar, a front view (b), a right view (c), and a top view (d). It is the perspective view (a) which shows the 2nd modification of a 1st and 2nd bus bar, a front view (b), a right view (c), and a top view (d).

  Hereinafter, an embodiment of a switching power supply device of the present invention will be described with reference to FIGS. As shown in FIG. 1, the switching power supply device 10 of this embodiment is housed in a substantially rectangular parallelepiped metal casing 12, and an input side wiring portion 14 to which an external input power source is connected to one side surface of the metal casing 12. An output side wiring section 16 to which an external load is connected is disposed. The circuit of the switching power supply device 10 includes an input side circuit and an output side circuit that are insulated from each other by a transformer. For example, the chopper type stable converter (converter whose on-time ratio of the main switching element changes) and the full-bridge type non-stable converter (the on-time ratio of the main switching element are fixed to about 50% for the input side circuit. The output side circuit is a circuit on the output side of the astable converter.

  A portion indicated by a broken line in FIG. 1 is an output side circuit unit 18 constituting an output side circuit (including a transformer of an unstable converter). As shown in FIGS. 2 and 3, the output side circuit unit 18 is a structure integrally formed by a plurality of members, and output portions 54 and 60 of first and second bus bars 32 and 34 described later are made of metal. It protrudes to the outside of the housing 12 and becomes the output side wiring portion 16. Hereinafter, the output side circuit unit 18 will be described in detail.

  As shown in the circuit diagram of FIG. 4, the output side circuit unit 18 is connected to a transformer 24 having an input winding 20 and an output winding 22, and both ends of the output winding 22, and an alternating current generated in the output winding 22. A rectifier circuit 28 having a rectifier element 26 that rectifies the voltage, and a smoothing circuit 30 that is connected to the output terminal of the rectifier circuit 28 and smoothes the rectified voltage output from the rectifier circuit 28, an output winding 22, and a rectifier circuit 28 and the smoothing circuit 30 are connected by metal first and second bus bars 32 and 34.

  Next, the configuration of each member of the output side circuit unit 18 will be described individually. The transformer 24 and the rectifying element 26 are integrally provided as shown in FIG. The input winding 20 of the transformer 24 is obtained by connecting two input coils 20 (1) and 20 (2) in parallel. As shown in FIG. 5 (b), the input coil 20 (1) is an air-core coil in which two layers of plane coils wound in a spiral shape are coaxially continuous, and the input coil 20 (1) having the same structure ( 2) are arranged in the thickness direction, and the end portions are connected to form an input winding 20 having a four-layer structure. The diameter of the central through hole 21 is slightly larger than the diameter of a middle leg portion 44 a of the magnetic core 44 described later, and the outer shape of each planar coil is a size that enters the inside of the magnetic core 44. As the electric wires used for the input coils 20 (1) and 20 (2), for example, a three-layer insulated wire (reinforced insulated wire) with a fusion coating is suitable.

  The output winding 22 is composed of four sets of output coils 22 (1) to 22 (4). The output coils 22 (1) are a set of two, and are formed on the conductor layers on the front and back sides of the first substrate 36 (1) as shown in FIG. 5C. The first substrate 36 (1) is, for example, a glass epoxy substrate, for example, a conductor in which a copper plate having a predetermined thickness is soldered on the wiring pattern of the first substrate 36 (1) in order to reduce the resistance value of the coil. The output coil 22 (1) may be formed of layers. Similarly, the output coils 22 (2) to 22 (4) are also formed on the front and back conductor layers of the first substrates 36 (2) to 36 (4), respectively.

  The rectifying element 26 includes four sets of MOS type FETs 26 (1) to 26 (4). The MOS type FET 26 (1) is a set of two, and is soldered and mounted on the conductor layers on the front and back sides of the first substrate 36 (1) (wiring patterns in the vicinity of each output coil 22 (1)). Similarly, the MOS type FETs 26 (2) to 26 (4) are formed on the front and back conductor layers of the first substrates 36 (2) to 36 (4), respectively.

  The outer shape of the first substrate 36 (1) is sized to enter the inside of a magnetic core 44 described later. A through hole 38 (1) is provided inside the output coil 22 (1), and the diameter of the through hole 38 (1) is slightly larger than a middle leg portion 44a of a magnetic core 44 described later. A first end 40 (1) protruding in the opposite direction to the output coil 22 (1) is provided at the upper corner of the end close to the MOS type FET 26 (1), and two output coils 22 (1 ) Can be connected externally. Furthermore, a second end portion 42 (1) projecting in the opposite direction to the output coil 22 (1) is provided at the lower corner of the end portion close to the MOS type FET 26 (1), and two MOS type FETs 26 ( The connection point 1) can be connected externally. The first substrates 36 (2) to 36 (4) have substantially the same structure, and the through holes 38 (2) to 38 (4) corresponding to the through holes 38 (1) and the first end portion 40 (, respectively). First end portions 40 (2) to 40 (4) corresponding to 1) and second end portions 42 (2) to 42 (4) corresponding to the second end portion 42 (1) are provided. ing.

  Since the rectifier circuit 28 is a synchronous rectifier type rectifier circuit, it has a drive circuit (not shown) for driving the MOS type FETs 26 (1) to 26 (4). Since the MOS FETs 26 (1) to 26 (4) become a part of the above-described high frequency current loop, the output coils 22 (1) of the first substrates 36 (1) to 36 (4) are formed in order to reduce the high frequency current loop. Although it is necessary to mount in the vicinity of 1) to 22 (4), the drive circuit is not part of the high-frequency current loop, so it is mounted on a substrate other than the first substrate 36 (1) to 36 (4). Alternatively, it may be mounted on the first substrates 36 (1) to 36 (4).

  The transformer 24 has a magnetic core 44 made of a ferrite material or the like. As shown in FIG. 5D, the magnetic core 44 has, for example, a PQ type or EE type outer shape and includes a pair of outer leg portions 44b on both sides of the middle leg portion 44a.

  Furthermore, an insulating paper 46 for improving insulation is provided inside the transformer 24. As a material of the insulating paper 46, meta-aramid fiber excellent in insulation, workability, heat resistance and flame retardancy is suitable. The insulating paper 46 has eight surfaces overlapped in the thickness direction by punching a blank into a strip shape and then bending it into a zigzag shape. The eight surfaces are sized to cover the coils 22 (1) to 22 (4), respectively. At the center of each of the eight surfaces, a through hole 48 is provided so as to be arranged substantially coaxially. The diameter of the through hole 48 is slightly larger than the diameter of the middle leg portion 44 a of the magnetic core 44.

  The first and second bus bars 32 and 34 are integrally formed by subjecting a copper plate, a brass plate or the like to a plurality of processes (punching, bending, drilling, etc.), respectively. The first bus bar 32 is a bus bar for outputting a positive potential of the output voltage, and the second bus bar 34 is a bus bar for outputting a negative potential of the output voltage. As shown in (d), they are connected and fixed to each other via a connecting member 50 made of resin.

  The first bus bar 32 includes a connection portion 52 connected to each conductive layer of the first substrates 36 (1) to 36 (4), an output portion 54 to which an external load is connected, a connection portion 52 and an output portion 54. The connection portion 52 and the output portion 54 are bent upward and are raised from the substantially horizontal connection portion 56. At the upper end portion of the connecting portion 52, four substrate receiving portions 52a (1) to 52a (4) are provided which are formed by slits. The substrate receiving portions 52a (1) to 52a (4) can be inserted into the first end portions 40 (1) to 40 (4) of the first substrates 36 (1) to 36 (4), respectively. It has become. The output portion 54 is provided with an attachment hole for connecting an electric wire (relatively thick electric wire) for connecting an external load.

  The second bus bar 34 includes a connection part 58 connected to each conductive layer of the first substrates 36 (1) to 36 (4), an output part 60 to which an external load is connected, a connection part 58 and an output part 60. The connecting portion 58 and the output portion 54 are bent downward and stand up with respect to the substantially horizontal connecting portion 62. At the lower end portion of the connecting portion 58, four substrate receiving portions 58a (1) to 58a (4) formed by slits formed in slits are provided. The substrate receiving portions 58a (1) to 58a (4) have shapes into which the second end portions 42 (1) to 42 (4) of the first substrates 36 (1) to 36 (4) can be inserted, respectively. It has become. The output unit 60 is provided with an attachment hole for connecting an electric wire (relatively thick electric wire) for connecting an external load.

  The connecting member 50 is a member that connects the connecting portions 56 and 62 of the first and second bus bars 32 and 34, and is provided, for example, by insert molding a thermoplastic resin such as PBT (polybutylene terephthalate). ing. The connecting member 50 has a substantially rectangular thin plate shape, and is provided with groove portions 50a that are continuous with the four side circumferential surfaces at a substantially central portion in the thickness direction.

  The first and second bus bars 32, 34 are connected and fixed by the connecting member 50, and the upper and lower surfaces of the connecting portions 56, 62 are arranged flush with each other. Then, the connection terminal 56a and the connection terminal 62a stand upward and downward from the respective portions that are flush with each other. The connection terminal 56a is provided by inserting and joining (for example, caulking) a metal pin into a through-hole penetrating the first coupling portion 56 in the thickness direction, and the connection terminal 62a is similarly connected to the second terminal 56a. It is provided by inserting and joining a metal pin into a through-hole penetrating the connecting portion 62 in the thickness direction. The connection terminals 56a and 62a are used to connect the output capacitors 68 (1) and 68 (2), which are components of the smoothing circuit 30, to the first and second bus bars 32 and 34.

  The smoothing circuit 30 is a π-type filter circuit including an output inductor 64, four capacitors 66 (1) to 66 (4), and two output capacitors 68 (1) and 68 (2). The output inductor 64 is provided by attaching a magnetic core 69 to the peripheral surface of the connecting portion 62 of the second bus bar 34. For example, as shown in FIG. 7, the magnetic core 69 is suitably of a type in which a U-core 69a and an I-core 69b are abutted to form a square closed magnetic circuit. When using a ferrite material, the gap material 69c is sandwiched between the U core 69a and the I core 69b, and the inductance characteristics (DC superposition characteristics) may be adjusted.

  The π-type first-stage capacitors 66 (1) to 66 (4) are mounted on the first substrates 36 (1) to 36 (4), respectively (not shown in FIGS. 2, 3 and 5). ) As shown in FIG. 8, the second-stage output capacitors 68 (1) and 68 (2) are mounted on second substrates 70 (1) and 70 (2) such as glass epoxy substrates, respectively. The second substrate 70 (1) is provided with a pair of through holes 70a (1) that allow external connection of the positive side and the negative side of the output capacitor 68 (1). The same applies to the second substrate 70 (2). In addition, a pair of through holes 70a (2) are provided to allow external connection of the positive side and the negative side of the output capacitor 68 (2).

  Next, an example of an assembly method of the output side circuit unit 18 will be described. First, the first substrates 36 (1) to 36 (4) are prepared, the output coils 22 (1) to 22 (4) are provided, and the MOS FETs 26 (1) to 26 (4) are mounted. Also, second substrates 68 (1) and 68 (2) are prepared, and output capacitors 68 (1) and 68 (2) are mounted. Further, after winding the input coils 20 (1) and 20 (2) using a predetermined electric wire, an input winding 20 in which four layers of planar coils are coaxially connected is manufactured by combining them.

  Next, the first and second bus bars 32 and 34 connected and fixed by the connecting member 50 are prepared, and the operation of forming the output inductor 64 at the connecting portion 62 of the second bus bar 34 is performed. First, the U core 69a is inserted into the slightly narrowed portion 62b of the connecting portion 62, and one side surface of the I core 69b is butted against the tip of the leg portion of the U core 69a (if necessary, the gap material 69c is sandwiched). Fix them together with an adhesive. Thus, the magnetic core is mounted on the peripheral surface of the connecting portion 62, and the output inductor 64 is formed.

  Next, an operation of connecting the output capacitors 68 (1) and 68 (2) to the connecting portions 56 and 62 of the first and second bus bars 32 and 34 is performed. First, the back surface side (the side on which the output capacitor 68 (1) is not mounted) of the second substrate 70 (1) is brought into contact with the upper surfaces of the connecting portions 56 and 62, and connected to the pair of through holes 70a (1). The terminals 56a and 62a are inserted and soldered to fix them to each other. Similarly, the back surface side (the side on which the output capacitor 68 (2) is not mounted) of the second substrate 70 (2) is brought into contact with the lower surfaces of the connecting portions 56 and 62, and is placed in the pair of through holes 70a (2). The connection terminals 56a and 62a are inserted and soldered to fix them to each other. Since the connection part 56 and the connection part 62 have the same upper surface and lower surfaces, the second substrates 70 (1) and 70 (2) can be appropriately positioned.

  Next, an operation of connecting the output winding 22 of the transformer 24 and the rectifying element 26 to the connecting portions 52 and 58 of the first and second bus bars 32 and 34 is performed. First, the first substrate 36 (1) is arranged so as to intersect the two connection portions 52, 58 at a substantially right angle, the first end portion 40 (1) is inserted into the substrate receiving portion 52a (1), The second end portion 42 (2) is inserted into the board receiving portion 58a (1) and soldered to fix them to each other. As a result, the conductive layer of the first substrate 36 (1) and the connection portions 52, 58 are connected, and the first substrate 36 (1) is firmly fixed to the connection portions 52, 58. Thereafter, the same operation is performed for the first substrates 36 (2) to 36 (4). The four first substrates 36 (1) to 36 (4) are attached to the connecting portions 52 and 58 and face each other with a predetermined interval, and the through holes 38 (1) to 38 (4) are coaxial. Placed in.

  Next, an operation for assembling the transformer 24 is performed. First, the insulating paper 46 is attached to the four first substrates 36 (1) to 36 (4). Specifically, the insulating paper 46 is inserted so that the first substrates 36 (1) to 36 (4) fit in the gaps Sa (1) to Sa (4), and the through holes 48 are formed in the first substrate 36 ( 1) to 36 (4) are arranged so as to be coaxial with the through holes 38 (1) to 38 (4). Then, the input winding 20 is inserted so that the three planar coils are accommodated in the gaps Sb (1) to Sb (3) of the insulating paper 46, and the through holes 21 are formed in the first substrates 36 (1) to 36 (4). ) Through-holes 38 (1) to 38 (4). The magnetic core 44 is inserted from both sides so that the middle leg portion 44a communicates with each of the through holes 21, 38 (1) to 38 (4), 48, and is fixed integrally using an adhesive or tape. Thereafter, in order to further enhance the insulation inside the transformer 24, an operation of impregnating the entire transformer 24 into a varnish and drying it may be performed. Thus, the assembly of the output side circuit unit 18 is completed, and the state shown in FIGS. 2 and 3 is obtained.

  The output side circuit unit 18 is housed in the metal casing 12 together with other members, and is in the state of the switching power supply device 10 shown in FIG. The output side circuit unit 18 is fixed on the bottom plate of the metal housing 12, and the output portions 54 and 60 of the first and second bus bars 32 and 34 protrude outward from the opening 12 a of the metal housing 12. At this time, the peripheral edge portion of the opening 12a enters deeply into the groove portion 50a of the resin-made connecting member 50, and the output portions 54 and 60 are accurately positioned and fixed.

  As described above, the switching power supply apparatus 10 includes the output winding 22 of the transformer 24 by the output coils 22 (1) to 22 (4) of the first substrates 36 (1) to 36 (4), and the rectifying element. 26 (MOS type FET 26 (1) to 26 (4)) is mounted in the vicinity of the output coils 22 (1) to 22 (4) on the first substrates 36 (1) to 36 (4). The high frequency current loop connected to 22 can be made smaller than before, and the loss due to the high frequency current and the parasitic inductance component can be greatly reduced. Further, since the output winding 22, the rectifier circuit 28 and the smoothing circuit 30 are connected by metal bus bars 32 and 34 having a low resistance value, the resistance value of the path through which a large current flows can be suppressed low, and the loss due to the wiring resistance. Is also small.

  The connecting portions between the output winding 22 and the rectifying element 26 and the bus bars 32 and 34 are provided with slit-shaped substrate receiving portions 52a (1) to 52a (4) and 58a (1) to 58a (4) on the bus bars 32 and 34, respectively. Provided, and the end portions 40 (1) to 40 (4) and 42 (1) to 42 (4) of the first substrates 36 (1) to 36 (4) are inserted into the respective substrate receiving portions and are connected by soldering. It is a structure. This eliminates the need for screw tightening using a screwdriver, makes it very compact and easy to assemble, and provides sufficient connection strength.

  Further, the connection portion between the output capacitors 68 (1), 68 (2) and the bus bars 32, 34 is connected to the connection terminals 56a, 62a provided on the bus bars 32, 34 of the second substrates 70 (1), 70 (2). It has a unique structure in which it is inserted into the through holes 70a (1) and 70a (2) and soldered. The output inductor 64 also has a structure in which a magnetic core 69 (U core 69a, I core 69b, and gap material 69c) is mounted on the peripheral surface of the second bus bar 34. Therefore, it is possible to obtain a smooth circuit 30 that is very compact and easy to assemble.

  Next, a first modification of the first and second bus bars will be described with reference to FIG. Here, the same configurations as those of the first and second bus bars 32 and 34 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 9, the first bus bar 72 of the first modification has an output portion 54 and a connecting portion 56 similar to the first bus bar 32, but the structure of the connecting portion 76 is the above connecting portion. A little different from 52. The connecting portion 76 is bent upward with respect to the connecting portion 56, and has six substrate receiving portions 76a (1) to 76a (6) formed of through holes formed in a slit shape at the upper end portion thereof. It is characterized by being. The reason why the number of substrate receiving portions is increased from four to six is to connect six first substrates. The reason why the shape of the substrate receiving portion is changed from the notch to the through hole is to increase the area where the first substrate and the substrate receiving portion are soldered, and to lower the resistance value of the connecting portion. .

  Further, as shown in FIG. 9, the second bus bar 74 of this modification has an output part 60 and a connecting part 62 similar to those of the second bus bar 34, but the structure of the connection part 78 is the above connection. Part 58 is slightly different. The connecting portion 78 stands upward with respect to the connecting portion 62, and six substrate receiving portions 78 a (1) to 78 a (6) formed by notches formed in a slit shape are provided at the upper end portion thereof. There is a feature. The reason why the number of substrate receiving portions is increased from four to six is to connect six first substrates. Further, although the shape of the substrate receiving portion is cut here, it may be changed to a through hole in the same manner as described above.

  For example, when designing a power supply device having an output current larger than that of the switching power supply device 10, it is conceivable to increase the first substrate from four to six in order to reduce the overall resistance value of the output winding 22. In such a case, the first and second bus bars 72 and 74 may be used instead of the first and second bus bars 32 and 34 described above.

  Next, a second modification of the first and second bus bars will be described with reference to FIG. Here, the same configurations as those of the first and second bus bars 32 and 34 are denoted by the same reference numerals, and description thereof is omitted.

  The first bus bar 80 of the second modification is formed of a metal plate that is thinner than the first bus bar 32. Further, as shown in FIG. 10, the connection portion 52 and the connection portion 56 are the same as those of the first bus bar 32, but the structure of the output portion 84 is different from that of the output portion 54. The shape of the output portion 84 extends straight from the connecting portion 56 and bends downward in the middle, and is L-shaped when viewed from the front as indicated by a broken line in FIG. And the screw | thread which makes it easy to connect the electric wire (relatively thin electric wire) for connecting an external load to each of two L-shaped surfaces is attached.

  The connection terminal of the connection part 56 is provided by cutting up a part of the connection part 56 instead of joining the metal pin as described above. That is, the connection terminal 56a (1) for connecting the second substrate 70 (1) is provided by cutting and raising a part of the connecting portion 56 upward, and the connection terminal 56a (2 for connecting the second substrate 70 (2). ) Is provided by cutting and raising a part of the connecting portion 56 downward.

  The second bus bar 82 of this modification is formed of a metal plate that is thinner than the second bus bar 34. Further, as shown in FIG. 10, the connection portion 58 and the connection portion 62 are the same as those of the second bus bar 34, but the structure of the output portion 86 is different from that of the output portion 60. The output portion 86 extends straight from the connecting portion 62, bends downward in the middle, and has an L shape when viewed from the front. And the screw | thread which makes it easy to connect the electric wire (relatively thin electric wire) for connecting an external load to each of two L-shaped surfaces is attached.

  The connection terminal of the connecting part 62 is provided by cutting up a part of the connecting part 62 instead of joining the metal pins as described above. That is, the connection terminal 62a (1) for connecting the second substrate 70 (1) is provided by cutting and raising a part of the connecting portion 62 upward, and the connection terminal 62a (2) for connecting the second substrate 70 (2). ) Is provided by cutting and raising a part of the connecting portion 62 downward.

Further, the fixing member 88 for connecting and fixing the first and second bus bars 80 and 82 is formed in an inverted E shape in plan view as shown in FIG. 10 (d), and is output by three extending portions. 84 and 86 are separated. For example, when designing a model having a relatively small maximum output current of the switching power supply device 10 (for example, a model having the same output power and a high output voltage), the two bus bars 80 and 82 made of slightly thin metal plates are used. By using it, the cost can be reduced. Further, the connection terminals 56a (1), 56a (2), 62a (1), 62a (2) for connecting the second substrate can also be provided at low cost by cutting and raising. In addition, when the maximum output current is relatively small, a relatively thin wire is used for connecting the external load. Therefore, if the structure such as the output portions 84 and 86 is used, the user can easily wire the wire. Can be removed.

  The switching power supply device of the present invention is not limited to the above embodiment. For example, in the case of the switching power supply device 10 described above, the output capacitor is mounted on the second board and connected to the two bus bars via the second board, but connected to the two bus bars by other methods. Also good.

  Further, at least one bus bar is sufficient, and either the positive potential or the negative potential may be connected by a method other than the bus bar.

  The method of assembling the output side circuit unit 18 is not limited to the method described above, and can be changed as appropriate. In addition, the shape and size of each member constituting the output side circuit unit 18 can be freely changed within a range in which the above-described object of the present invention can be achieved. For example, when using the above assembling method, it is convenient that two bus bars are fixed to each other by a connecting member, but when using other assembling methods, the connecting member may be omitted as necessary. it can.

DESCRIPTION OF SYMBOLS 10 Switching power supply device 18 Output side circuit unit 20 Input winding 22 Output winding 22 (1) -22 (4) Output coil 24 Transformer 26 Rectifier 28 Rectifier circuit 30 Smoothing circuit 32, 72, 80 First bus bar 34, 74, 82 Second bus bars 36 (1) -36 (4) First substrates 40 (1) -40 (4) First ends 42 (1) -42 (4) Second ends 50, 88 Connecting members 52, 58, 76, 78 Connection portions 52a (1) to 52a (4), 58a (1) to 58a (4), 76a (1) to 76a (6), 78a (1) to 78a (6) Substrate receiving portions 54, 60, 84, 86 Output portions 56, 62 Connecting portions 56a, 56a (1), 56a (2), 62a, 62a (1), 62a (2) Connection terminal 64 Output inductor 68 (1), 68 (2) Output capacitor 69 Magnetic core 69a U core 69b I core 69c Gap material 70 (1), 70 (2) Second substrate 70a (1), 70a ( 2) Through hole

Claims (7)

A transformer having an input winding and an output winding; a circuit connected to both ends of the output winding, the rectifying circuit having a rectifying element for rectifying an alternating voltage generated in the output winding; and the rectification A circuit connected to the output terminal of the circuit for smoothing the rectified voltage output from the rectifier circuit, comprising a smoothing circuit having an output capacitor for generating the output voltage at both ends, the output winding, the rectifier circuit And in the switching power supply device in which the smoothing circuit is connected by a metal bus bar,
The output winding is provided by a plurality of coils formed on each conductive layer of a plurality of first substrates arranged in directions facing each other,
The rectifying elements are respectively mounted on the first substrate at positions near the coils,
The bus bar includes a plate-like connecting portion connected to the conductive layers of the plurality of first substrates, an output portion to which an external load is connected, and a connecting portion that connects the connecting portion and the output portion. Are formed integrally, and a plurality of substrate receiving portions formed of slits or through holes formed in the plate-like connection portion are provided,
The plurality of first substrates are arranged in a direction intersecting with the connection portion of the bus bar, each end portion of the first substrate is individually inserted into the plurality of substrate receiving portions, and each conductive layer is the substrate. A switching power supply device, wherein the switching power supply device is connected to a receiving portion via solder.   The switching power supply device according to claim 1, wherein the smoothing circuit includes an output inductor, and the output inductor is provided by mounting a magnetic core on a peripheral surface of the connecting portion of the bus bar.   The bus bar includes a first bus bar that outputs a positive potential of an output voltage and a second bus bar that outputs a negative potential, and the first and second bus bars respectively include the connection portion, 3. The switching power supply device according to claim 1, wherein the output part and the connecting part are integrally formed.   4. The switching power supply device according to claim 3, wherein the first and second bus bars are fixedly connected to each other at a specific portion of each connecting portion by a connecting member made of resin. The output capacitor is mounted on a second board different from the first board,
The second substrate is provided with a pair of through holes that allow external connection of the positive side and the negative side of the output capacitor,
The first and second bus bars are arranged such that specific portions of the respective connecting portions are flush with each other, and a pair of connection terminals stand up from the specific portions,
The said 2nd board | substrate has the said connection terminal penetrated to each said through hole, and the said through hole and the said connection terminal are mutually connected via the solder in the state positioned at the said specific location. 4. The switching power supply device according to 4.   The switching power supply device according to claim 5, wherein the connection terminal is provided by cutting and raising a part of the connecting portion.   The switching power supply device according to claim 5, wherein the connection terminal is provided by joining a metal pin to the connecting portion.

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