Switching power supply device, and power supply module

Abstract

To provide a switching power supply device capable of being reduced in size than conventional ones, while sufficiently securing insulation strength between a primary side circuit and a secondary side circuit; and to provide a power supply module thereof.SOLUTION: In a circuit board 34, a winding area MA and a secondary side area 2A are continuous with each other; an intermediate area TA and a primary side area 1A are continuous with one end of the secondary side area 2A in order; and the primary side area 1A is located on a side of the winding area MA via a main notch 58. A ferrite core 36 whose outer leg 42(1) is arranged in the main notch 58 is attached to the winding area MA to become one of secondary side components 28m. An insulation cap 46 attached to the primary side area 1A covers specific areas such as a front face and a rear face of the primary side area 1A, an end face on a main notch 58 side, and an end face on an opposite side of the main notch 58, and an end face continuous with the foregoing two end faces in such a manner that insulation strength between the ferrite core 36 and a conduction part on each of the front face and the rear face of the primary side area 1A becomes a specified value or more.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a switching power supply device in which a primary circuit and a secondary circuit are insulated via a transformer, and to a power supply module for constituting this switching power supply device. [Background technology]

[0002] Conventionally, as disclosed in Patent Document 1, for example, there has been an isolated AC-DC converter configured by connecting a power supply module to a main device. The main device includes a first printed wiring board to which the power supply module is connected. The power supply module includes a second printed wiring board that is a multilayer printed wiring board, a planar transformer formed by assembling a core to a primary coil and a secondary coil formed by the wiring pattern of the second printed wiring board, a primary member mounted on the second printed wiring board and connected to the primary coil, and a secondary member mounted on the second printed wiring board and connected to the secondary coil.

[0003] In the case of the embodiment shown in FIG. 6 to FIG. 8 of Patent Document 1, the second printed wiring board (33) has a first plate portion (34) on which a primary coil and a secondary coil are provided, a second plate portion (35) from which the primary coil is drawn, and a third plate portion (36) from which the secondary coil is drawn and on which a secondary member is mounted, and the second plate portion (35), the first plate portion (34), and the third plate portion (36) are arranged in a row in sequence. The core (65) is made of ferrite and has a width dimension that is approximately the same as the width dimensions of the second plate portion (35) and the third plate portion (36). When the core (65) is attached to the first plate portion (34), the second plate portion (35), the core (65), and the third plate portion (36) are arranged in a row in sequence in a plan view. The power supply module is incorporated into the main device by drawing out a specific conductive portion of the second printed wiring board (33) to one end of the external connection pin and connecting the other end of the external connection pin to the first printed wiring board (13), and the power supply module and the main device work together to perform power conversion operations. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-95937 A Summary of the Invention [Problem to be solved by the invention]

[0005] Power supplies that convert high voltages of several hundred volts, such as commercial AC voltage, to low voltages of several tens of volts or less, require high insulation strength between the primary and secondary circuits to prevent electric shock. For example, many international safety standards also stipulate minimum insulation distances (minimum creepage distances and clearance distances that must be maintained between the primary and secondary circuits) as indicators for ensuring sufficient insulation strength.

[0006] In the case of the AC-DC converter and power supply module of Patent Document 1, the conductive core (65) is treated as the primary member, and the primary side member closest to the secondary member is the core (65). Therefore, the secondary member mounted on the second plate portion (36) is arranged in an area W=4.8 to 6.9 mm or more away from the core, thereby ensuring the minimum insulation distance between the primary member and the secondary member. However, this insulation structure creates large areas (rectangular areas defined by the dimension W) on both the front and back sides where the primary and secondary members cannot be arranged, which is a major factor preventing the miniaturization of the external shape.

[0007] The present invention has been made in view of the above-mentioned background art, and has an object to provide a switching power supply device and a power supply module that can be made smaller in external size than conventional devices while ensuring sufficient insulation strength between a primary side circuit and a secondary side circuit. [Means for solving the problem]

[0008] The invention described in claim 1 is a power supply module for constituting a switching power supply device in which a primary side circuit and a secondary side circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, The transformer includes a circuit board having circuit components mounted on a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern, a ferrite core which is a component of the transformer and has a pair of flat plate portions connected to each other at a center leg portion and two outer legs when assembled, an insulating cap formed in a bottomed cylindrical shape, and an external connection terminal portion for drawing out a specific conductive portion of the circuit board to the outside, the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by a wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components that are part of the primary side circuit and their wiring patterns are arranged on the front side, the back side, or both; a secondary side area in which secondary side components that are part of the secondary side circuit and their wiring patterns are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the secondary side area are continuous, the intermediate area and the primary side area are continuous in order to one end of the secondary side area, and the primary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the middle leg portion is disposed in the middle leg hole of the winding area, one of the outer legs is disposed in the main cutout, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the secondary side components; The insulating cap is a power supply module that is attached to the primary side area of ​​the circuit board and covers all or part of the front and back sides of the primary side area, the end face on the main notch side, the end face opposite the main notch, and the end face continuous with the two end faces so that the insulation strength between the conductive parts on the front and back sides of the primary side area and the ferrite core is above a specified value.

[0009] The invention described in claim 2 is a power supply module for constituting a switching power supply device in which a primary side circuit and a secondary side circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, The transformer includes a circuit board having circuit components mounted on a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern, a ferrite core which is a component of the transformer and has a pair of flat plate portions connected to each other at a center leg portion and two outer legs when assembled, an insulating cap formed in a bottomed cylindrical shape, and an external connection terminal portion for drawing out a specific conductive portion of the circuit board to the outside, the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by the wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components that are part of the primary side circuit and their wiring patterns are arranged on the front side, the back side, or both; a secondary side area in which secondary side components that are part of the secondary side circuit and their wiring patterns are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the primary side area are continuous, the intermediate area and the secondary side area are continuous in order to one end of the primary side area, and the secondary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the center leg portion is disposed in the center leg hole of the winding area, one of the outer legs is disposed in the main cutout, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the primary side components; The insulating cap is a power supply module that is attached to the secondary area of ​​the circuit board and covers all or part of the front and back surfaces of the secondary area, the end face on the main notch side, the end face opposite the main notch, and the end face continuous with the two end faces so that the insulation strength between the conductive parts on the front and back surfaces of the secondary area and the ferrite core is above a specified value.

[0010] The external connection terminal portion can be formed by a land that is a part of the wiring pattern of the multilayer printed wiring board, or an end electrode formed so as to be continuous with the wiring pattern of the multilayer printed wiring board, or by both (invention as recited in claim 4). Alternatively, the external connection terminal portion can be a metal terminal having one end connected to the wiring pattern of the multilayer printed wiring board (invention as recited in claim 5).

[0011] The invention described in claim 6 is a switching power supply device comprising a power supply module described in claim 1 or 2 and a main body device having a terminal receiving portion for connecting the external connection terminal portion of the power supply module.

[0012] The invention described in claim 7 is a switching power supply device in which a primary side circuit and a secondary side circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, The transformer includes a circuit board having a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern and circuit components mounted thereon, a ferrite core which is a component of the transformer and has a pair of flat plate portions connected to each other at a middle leg portion and two outer legs when assembled, an insulating cap formed in a bottomed cylindrical shape, and an external connection terminal portion for drawing out a specific conductive portion of the multilayer printed wiring board to the outside, the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by a wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components and their wiring patterns which form the primary side circuit are arranged on the front side, the back side, or both; a secondary side area in which secondary side components and their wiring patterns which form the secondary side circuit are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the secondary side area are continuous, the intermediate area and the primary side area are continuous in order to one end of the secondary side area, and the primary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the middle leg portion is disposed in the middle leg hole of the winding area, one of the outer legs is disposed in the main cutout, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the secondary side components; The insulating cap is a switching power supply device that is attached to the primary side area of ​​the circuit board and covers all or part of the front and back sides of the primary side area, the end face on the main cut side, the end face opposite the main cut, and the end face continuous with the two end faces, so that the insulation strength between the conductive parts on the front and back sides of the primary side area and the ferrite core is above a specified value.

[0013] The invention described in claim 8 is a switching power supply device in which a primary side circuit and a secondary side circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, The transformer includes a circuit board having a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern and circuit components mounted thereon, a ferrite core which is a component of the transformer and has a pair of flat plate portions connected to each other at a middle leg portion and two outer legs when assembled, an insulating cap formed in a bottomed cylindrical shape, and an external connection terminal portion for drawing out a specific conductive portion of the multilayer printed wiring board to the outside, the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by a wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components and their wiring patterns which form the primary side circuit are arranged on the front side, the back side, or both; a secondary side area in which secondary side components and their wiring patterns which form the secondary side circuit are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the primary side area are continuous, the intermediate area and the secondary side area are continuous in order to one end of the primary side area, and the secondary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the center leg portion is disposed in the center leg hole of the winding area, one of the outer legs is disposed in the main cutout, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the primary side components; The insulating cap is a switching power supply device that is attached to the secondary area of ​​the circuit board and covers all or part of the front and back surfaces of the secondary area, the end face on the main cut side, the end face opposite the main cut, and the end face continuous with the two end faces, so that the insulation strength between the conductive parts on the front and back surfaces of the secondary area and the ferrite core is above a specified value.

[0014] The insulating cap is preferably an integrally molded product made of synthetic resin (inventions described in claims 3 and 9). Effect of the Invention

[0015] The power supply module according to claim 1 or 2 has a simple structure in which a ferrite core and an insulating cap are attached to a circuit board with a unique outer shape, and while ensuring sufficient insulation strength between the primary circuit and the secondary circuit, the wasted space (the area of ​​the intermediate area where no circuit components are arranged) generated on the circuit board can be reduced compared to conventional methods, making it easy to miniaturize the outer shape. The same effect can be obtained in the switching power supply device according to claim 7 or 8. The switching power supply device according to claim 6 can be easily manufactured by attaching the above-mentioned power supply module to the main device, and can obtain the same effect. [Brief description of the drawings]

[0016] [Figure 1] 1A, 1B, and 1C are a plan view, a front view, and a right side view, respectively, showing the appearance of a switching power supply device according to a first embodiment of the present invention. [Diagram 2] 2A and 2B are a front view and a rear view showing the external appearance of the power supply module (one embodiment of the power supply module of the present invention) in FIG. [Diagram 3] 3A is a plan view showing the assembled state of the ferrite core of the power supply module of FIG. 2, FIG. 3B is a front view showing the structure of the I-type core that constitutes the flight core, and FIG. 3C is a rear view showing the structure of the E-type core. [Figure 4] 3A, 3B, 3C, and 3D are a plan view, a front view, a bottom view, and a rear view, respectively, showing the structure of an insulating cap of the power supply module of FIG. 2. [Diagram 5] 3A is a front view showing the structure of a circuit board of the power supply module of FIG. 2, FIG. 3B is a rear view showing the structure of the circuit board of the power supply module of FIG. 2, and FIG. 3C is a vertical cross-sectional view showing the internal structure of the winding area. [Figure 6] 3A is a front view showing the appearance of a first modified example of the power supply module in FIG. 2, and FIG. 3B is a front view showing the structure of a circuit board. [Figure 7] 3A is a front view showing the appearance of a second modified example of the power supply module in FIG. 2, and FIG. 3B is a front view showing the structure of a circuit board. [Figure 8]5A, 5B, and 5C are a plan view, a bottom view, and a rear view, respectively, showing the external appearance of a switching power supply device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] <<Switching power supply device 10 and power supply module 14 of the first embodiment>> Hereinafter, a first embodiment of a switching power supply device of the present invention and an embodiment of a power supply module of the present invention will be described with reference to FIGS. 1 to 7. FIG. <Configuration of the Switching Power Supply Device 10 and the Power Supply Module 14> The switching power supply device 10 of this embodiment is an AC-DC converter or the like equipped with large components such as an aluminum electrolytic capacitor and a noise filter circuit, and is composed of a main device 12 and a power supply module 14 [one embodiment of the power supply module of the present invention], as shown in Fig. 1. The main device 12 is equipped with some of the large and small components described above, and the power supply module 14 is equipped with other small components. By attaching the power supply module 14 to the main device 12, one switching power supply device 10 is formed.

[0018] The switching power supply device 10 has a primary circuit 16 and a secondary circuit 18 that are insulated from each other. The primary circuit 16 is connected to a primary winding 22 of a transformer 20, and the secondary circuit 18 is connected to a secondary winding 24. Hereinafter, a portion of the primary circuit 16 that is mounted on the main device 12 is referred to as a primary circuit 16h, and the primary circuit 16h is assumed to be composed of primary components 26h and their wiring patterns. In addition, a portion of the primary circuit 16 that is mounted on the power supply module 14 is referred to as a primary circuit 16m, and the primary circuit 16m is assumed to be composed of primary components 26m and their wiring patterns. Similarly, a portion of the secondary circuit 18 that is mounted on the main device 12 is referred to as a secondary circuit 18h, and the secondary circuit 18h is assumed to be composed of secondary components 28h and their wiring patterns. Moreover, the portion of the secondary circuit 18 that is mounted on the power supply module 14 is referred to as a secondary circuit 18m, and the secondary circuit 18m is assumed to be composed of secondary components 28m and their wiring patterns.

[0019] As shown in Fig. 1, the main device 12 has a main circuit board 30 in which circuit components and the like are mounted on a main printed wiring board 30a. On the upper surface side of the main printed wiring board 30a, primary side components 26h, secondary side components 28h, and a power supply module 14 are mounted, and the conductive parts are each connected to a wiring pattern. The power supply module 14 has external connection terminals 44(1), 44(2) described later, and the external connection terminals 44(1), 44(2) are connected to terminal receiving parts (not shown) of the main printed wiring board 30a. On the lower surface side of the main printed wiring board 30a, the primary side components 26h and secondary side components 28h are mounted, and the conductive parts are each connected to a wiring pattern.

[0020] Additionally, a primary side external connection terminal portion 32(1) and a secondary side external connection terminal portion 32(2) made of metallic pin members are mounted on the underside of the main circuit board 30, and the base ends of the pin members are soldered to the wiring patterns. The external connection terminal portions 32(1) and (2) are input / output terminal portions of the switching power supply device 10, and are connected to the circuit board of the user device when the device is mounted on the user device.

[0021] The power supply module 14 is a module that is mounted vertically on the main circuit board 30, and is composed of a circuit board 34, a ferrite core 36, an insulating cap 46, and external connection terminals 44(1), 44(2) as shown in FIG. 2. The ferrite core 36 is one of the components of the transformer 20, and as shown in FIG. 3(a), in the assembled state, a pair of flat plate parts 38(1), 38(2) are connected to each other by a middle leg part 40 and two outer legs 42(1), 42(2). For example, it is formed by assembling an I-shaped core 36a shown in FIG. 3(b) and an E-shaped core 36b shown in FIG. 3(c). As shown in FIG. 4, the insulating cap 46 is structured such that one end of a square cylinder composed of four consecutive side plates 48(1) to 48(4) is closed by a top plate 50, and an opening 52 is provided on the opposite side. Also, the boundary portion (the end portion on the opening 52 side) between the side plates 48(3) and 48(4) is slightly cut away to provide a relief portion 54. The insulating cap 46 is preferably a one-piece molded product made of synthetic resin.

[0022] 5(a) and 5(b), the circuit board 34 is a member in which circuit components and the like are mounted on a multilayer printed wiring board 34a having multiple wiring layers, and includes a winding area MA, a primary side area 1A, a secondary side area 2A, and an intermediate area TA. The winding area MA is an area in which the primary winding 22 and the secondary winding 24 are formed by a wiring pattern, and is provided with a middle foot hole 56 through which the middle foot portion 40 of the ferrite core 36 is inserted, and the primary winding 22 and the secondary winding 24 are wound around the middle foot hole 56.

[0023] 5(c), multilayer printed wiring board 34a has eight wiring layers, in which secondary winding 24(1), primary windings 22(1)-22(4), secondary windings 24(2) and 24(3) are formed in this order from the surface layer on the front side, and secondary winding 24(1) on the surface layer on the front side is covered with solder resist 34b, which is an insulating film. Also, no windings are formed on the surface layer on the back side, and it is not covered with solder resist.

[0024] The connection method and use of each winding are not particularly limited, but for example, the primary windings 22(1) to 22(4) are connected to each other through via holes and used as the primary winding 22 for power transmission, and the secondary windings 24(1) to 24(3) are connected to each other through via holes and used as the secondary winding 24 for power transmission. Alternatively, some of the primary windings 22(1) to 22(4) may be used as the primary winding 22 for supplying power to the primary side circuit 16m or for outputting a trigger signal, and some of the secondary windings 24(1) to 24(3) may be used as the secondary winding 24 for supplying power to the secondary side circuit 18m or for outputting a trigger signal.

[0025] The primary windings 22(1)-22(4), via holes connecting the primary windings 22(1)-22(4), and the wiring pattern leading from the primary winding 22 to other areas are not exposed on the front and back surfaces of the winding area MA. This is to ensure sufficient insulation strength for the ferrite core 36 when assembled into the power supply module 14.

[0026] The primary side area 1A is an area where the primary side circuit 16m (primary side components 26m and their wiring patterns) are arranged on the front side, the back side, or both. The secondary side area 2A is an area where the secondary side circuit 18m (secondary side components 28m and their wiring patterns) are arranged on the front side, the back side, or both. The intermediate area TA is an area where the primary side circuit 16m and the secondary side circuit 18m are not arranged on the front side or the back side.

[0027] The circuit board 34 has a layout in which the winding area MA and the secondary side area 2A are continuous, and the intermediate area TA and the primary side area 1A are continuous in sequence with one end of the secondary side area 2A, and the primary side area 1A is positioned to the side of the winding area MA via a main cut 58 of a predetermined width.

[0028] In FIG. 5(b), the circuit component mounted across the intermediate area TA is a high-voltage capacitor element 60. The capacitor element 60 is an element that returns switching noise generated in the primary circuit 16 to the secondary circuit 18 so that it does not leak to an external input power source, and returns switching noise generated in the secondary circuit 18 to the primary circuit 16 so that it does not leak to an external load. The main body of the capacitor element 60 is firmly insulated, and one terminal (conductor part) is connected to the primary area 1A to become part of the primary circuit 16m, and the other terminal (conductor part) is connected to the secondary area 2A to become part of the secondary circuit 18m. In addition, when a signal transmission element such as a high-voltage photocoupler is mounted across the intermediate area TA, it is treated in the same way as the capacitor element 60.

[0029] The external connection terminals 44(1), 44(2) are terminals for drawing out specific conductive parts of the circuit board 34 to the outside, and are provided as part of the circuit board 34 here. The primary-side external connection terminal 44(1) is made up of multiple lands provided on the front and back surfaces of the lower end of the primary-side area 1A of the circuit board 34, and specific conductive parts of the primary-side circuit 16m are drawn out to these lands. The secondary-side external connection terminal 44(2) is made by protruding the lower end of the secondary area 2A of the circuit board 34 in an elongated shape, with lands provided on the front and back surfaces of the protruding parts, and the end faces and side end faces on the tip side of the protruding parts are covered with conductive plating, and specific conductive parts of the secondary-side circuit 18m are drawn out to the lands and conductive plating.

[0030] To explain an example of a method for assembling the power supply module 14, first, the ferrite core 36 is attached to the circuit board 34. Specifically, adhesive is applied to the inner surface of the flat portion 38(2) of the E-shaped core 36b, the middle leg 40 is inserted into the middle leg hole 56 from one side of the winding area MA, and the outer leg 42(1) is positioned in the main cut 54, and the inner surface of the flat portion 38(2) is adhesively fixed to the front surface of the winding area MA. Then, adhesive is thinly applied to the end faces of the middle leg 40 and the outer leg portions 42(1), 42(2) protruding from the back side of the winding area MA, and one side of the I-shaped core 36a is adhesively fixed.

[0031] When the ferrite core 36 is attached to the winding area MA, the center leg 40 is disposed in the center leg hole 56, the outer leg 42(1) is disposed in the main cutout 58, the outer leg 42(2) is disposed near the outside of the winding area MA, and the pair of flat plate portions 38(1), 38(2) are disposed on the front and back sides of the multilayer printed wiring board 34a. In this state, when the relationship between the ferrite core 36 and the primary winding 22 and the secondary winding 24 is examined, the insulation between the ferrite core 36 and the primary winding 22 is sufficient, but the flat plate portion 38(1) is adjacent to the secondary winding 24(1) with the solder resist 34b sandwiched therebetween. The solder resist 34b is a very thin insulating film and does not have a high insulating strength, so the ferrite core 36 needs to be treated as one of the secondary components 28m.

[0032] Next, the insulating cap 46 is attached to the primary side area 1A of the circuit board 34. First, an appropriate amount of adhesive is filled inside the insulating cap 46, and the insulating cap 46 is attached so as to cover the primary side area 1A of the circuit board 34. Then, the wide areas of the front and back surfaces of the primary side area 1A are covered with the side plates 48(1) and 48(3), the end face on the main cut 58 side is covered with the side plate 48(4), the wide area of ​​the end face opposite to the main cut 58 is covered with the side plate 48(2), and the end face continuous with the two end faces is covered with the top plate 50. Then, when the adhesive inside the insulating cap 46 is cured, the power supply module 14 is in the assembled state shown in Figures 2(a) and (b). It is preferable that the width of the main cut 58 is as narrow as possible while ensuring a width that allows the outer leg portion 42(1) of the ferrite core 36 and the side plate 48(4) of the insulating cap 46 to be inserted without difficulty.

[0033] If the insulating cap 46 is not attached to the power supply module 14, the outer surface of the outer leg 42(1) of the ferrite core 36 is closest to the primary circuit 16m (primary components 26m and wiring pattern) in the secondary circuit 18m (primary components 28m and wiring pattern), and the insulation strength between the primary circuit 16m and the secondary circuit 18m cannot be sufficiently ensured. However, by appropriately covering the primary circuit 16m with the insulating cap 46, it is possible to ensure sufficient insulation strength.

[0034] The insulating cap 46 does not need to cover the entire area of ​​the front and back surfaces of the primary side area 1A, the end face on the main cut 58 side, the end face opposite to the main cut 58, and the end face continuous with the two end faces, and may be structured to cover only the necessary area (only a part of the area). For example, as shown in FIG. 2(b), the insulating cap 46 has a recess 54 so as not to hit the main body of the capacitor element 60, and does not completely cover the primary side terminal (conductive part) of the capacitor element 60. However, since the primary side terminal (conductive part) of the capacitor element 60 is located at a certain distance from the ferrite core 36, the insulating strength can be ensured even if it is not completely covered by the insulating cap 46.

[0035] Also, when only considering the insulation strength, there is no need to cover the end face opposite the main cut 58 of the primary side area 1A with the insulating cap 46, and the side plate 48(2) makes almost no contribution to the insulation strength. However, the side plate 48(2) is provided in consideration of the shape stability of the insulating cap 46, ease of handling during installation, design, etc.

[0036] When mounting the power supply module 14 to the main device 12, the external connection terminals 44(1), 44(2) are set in terminal receptacles such as through holes provided on the main circuit board 30 and connected by soldering. This completes the assembled state of the switching power supply device 10, as shown in Figures 1(a) to 1(c).

[0037] <Effects of the switching power supply device 10 and the power supply module 14> As described above, the power supply module 14 has a simple structure in which a ferrite core 36 and an insulating cap 46 are attached to a circuit board 34 with a unique external shape, and while ensuring sufficient insulation strength between the primary circuit 16m and the secondary circuit 18m, it is possible to reduce the amount of wasted space (the area of ​​the intermediate area TA where no circuit components are placed) generated on the circuit board 34 to a smaller size than before, making it easy to reduce the external shape. Furthermore, the switching power supply device 10 can be easily manufactured by attaching the above-mentioned power supply module 14 to the main device 12, and the same effects can be obtained.

[0038] <Two Modifications of the Power Supply Module 14> Next, we will explain two modified examples of the power supply module 14. In the first modified example, the power supply module 14x, as shown in Fig. 6(a), the above-mentioned circuit board 34 is replaced with a circuit board 34x having a slightly different external shape, but the other configurations are the same as those of the power supply module 14.

[0039] As shown in FIG. 6(b), the circuit board 34x has a layout in which the end of the secondary side area 2A opposite the intermediate area TA is extended, and this extended portion is positioned to the side of the winding area MA via a cutout 62 of a predetermined width.

[0040] When the ferrite core 36 is attached to the winding area MA of the circuit board 34x, the middle leg 40 is disposed in the middle leg hole 56, the outer leg 42(1) is disposed in the main cutout 58, and the outer leg 42(2) is disposed in the cutout 62, and the pair of flat plate portions 38(1), 38(2) are disposed on the front and back sides of the multilayer printed wiring board 34a, respectively. Similarly to the circuit board 34, the insulating cap 46 is attached so as to cover the primary side area 1A of the circuit board 34x.

[0041] In the case of the power supply module 14x, the insulation between the ferrite core 36 and the primary circuit 16m (primary components 26m and wiring pattern) is similar to that of the power supply module 14. Also, although the extension portion of the secondary circuit 18m (secondary components 28m and wiring pattern) is close to the outer leg 42(2) of the ferrite core 36, since the ferrite core 36 is one of the secondary components 28m, the insulation strength does not become an issue.

[0042] According to the power supply module 14x, it is possible to obtain the same effects as the above-mentioned power supply module 14, and it is possible to further increase the mounting space for the secondary side circuit 18m.

[0043] As shown in FIG. 7(a), the second modified power supply module 14y has the circuit board 34x of the power supply module 14x replaced with a circuit board 34y having a slightly different outer shape, but the other configurations are the same as those of the power supply module 14x.

[0044] 7(b), the circuit board 34y is characterized in that the extended portion of the secondary side area 2A is further extended and continues to the opposite end of the winding area MA. In addition, in the circuit board 34y, the cutouts 62 of the circuit board 34x are changed to outer foot holes 64.

[0045] When the ferrite core 36 is attached to the winding area MA of the circuit board 34y, the middle leg 40 is disposed in the middle leg hole 56, the outer leg 42(1) is disposed in the main notch 58, and the outer leg 42(2) is disposed in the outer leg hole 64, and the pair of flat plate portions 38(1), 38(2) are disposed on the front and back sides of the multilayer printed wiring board 34a, respectively. The insulating cap 46 is attached so as to cover the primary side area 1A of the circuit board 34x, in the same manner as in the case of the circuit board 34x.

[0046] The power supply module 14y can provide the same effects as the above-mentioned power supply module 14x, and furthermore, the secondary winding 24 can be pulled out from the opening on the opposite side of the ferrite core 36 (the upper opening in FIG. 7(a)), thereby improving the freedom of pattern design.

[0047] <<Switching power supply device 66 of second embodiment>> Next, a second embodiment of the switching power supply device of the present invention will be described with reference to Fig. 8. A switching power supply device 66 of this embodiment has many similarities to the above-mentioned power supply module 14x (first modified example of the power supply module 14), so the same components are given the same reference numerals and their explanations are omitted, and the following description will focus on the differences in the components. <Configuration of Switching Power Supply Device 66> The switching power supply device 66 is a DC-DC converter or the like that does not have large circuit components such as an aluminum electrolytic capacitor or a noise filter circuit, and the primary side circuit 16 and the secondary side circuit 18 are all mounted on a circuit board 68, with no configuration corresponding to the above-mentioned main device 12. Therefore, in the following description, the primary side circuit 16 of the switching power supply device 66 will be referred to as the primary side circuit 16h (primary side components 26h and their wiring pattern), and the secondary side circuit 18 will be referred to as the secondary side circuit 18h (secondary side components 28h and their wiring pattern).

[0048] As shown in FIG. 8, the switching power supply device 66 is composed of a circuit board 68, a ferrite core 36, an insulating cap 46x, and external connection terminal portions 32(1), 32(2).

[0049] The circuit board 68 is a member in which circuit components and the like are mounted on a multilayer printed wiring board 68a having multiple wiring layers, and includes a winding area MA, a primary side area 1A, a secondary side area 2A, and an intermediate area TA, which are laid out in the same manner as the circuit board 34x shown in Fig. 6(b). However, the external connection terminal section of the circuit board 68 is provided with external connection terminal sections 32(1), 32(2) made of metal pin members whose base ends are connected to the wiring pattern, instead of the external connection terminal sections 44(1), 44(2) described above. The switching power supply device 66 is assumed to be mounted horizontally on the circuit board of the user device, and the tip end of each pin member is inserted into a terminal receiving section (through hole) of the main body board and connected by soldering.

[0050] The insulating cap 46x has almost the same structure as the insulating cap 46 described above, but differs in that a cutout 70 of a predetermined width is provided in the side plate 48(3) extending from the edge on the opening 52 side toward the top plate 50. Since the external connection terminal 32(1) is provided upright in the primary side area 1A of the circuit board 68, the cutout 70 serves to prevent the side plate 48(3) from hitting the external connection terminal 32(1) when the insulating cap 46 is attached to the primary side area 1A.

[0051] <Effects of the switching power supply unit 66> As described above, the switching power supply device 66 has a simple structure in which a ferrite core 36 and an insulating cap 46x are attached to a circuit board 68 with a unique external shape, and while sufficiently ensuring the insulation strength between the primary side circuit 16m and the secondary side circuit 18m, it is possible to reduce the amount of wasted space (the area of ​​the intermediate area TA where no circuit components are arranged) generated on the circuit board 68, and the external shape can be easily reduced in size.

[0052] <<Other embodiments and modifications>> The switching power supply device and the power supply module of the present invention are not limited to the above embodiment. For example, the above ferrite core 36 is a combination of an I-type core 36a and an E-type core 36b, but it may be formed by combining two E-type cores as long as it has a similar shape when assembled. Also, the insulating cap may be structured to be adhesively fixed to the circuit board, or may be structured to be engaged and fixed to an appropriate portion of the circuit board.

[0053] The multilayer printed wiring board used as the circuit board may have two or more wiring layers, and is not limited to eight, as in the case of the multilayer printed wiring board 34a described above. The shape of the external connection terminal portion is not limited to the shape of the external connection terminal portions 32(1), 32(2), 44(1), and 44(2) described above, and can be freely changed to match the shape of the mating terminal receiving portion. For example, if the mating terminal receiving portion is a male connector, the external connection terminal portion can be a female connector.

[0054] When a switching power supply device is composed of a main device and a power supply module, it is possible to freely set which parts of the primary side circuit and the secondary side circuit are to be mounted on the power supply module. For example, the device may be configured so that part of the wiring pattern of the primary side circuit (excluding primary side components) and part of the secondary side circuit are mounted on the power supply module, or the device may be configured so that part of the wiring pattern of the secondary side circuit (excluding secondary side components) and part of the primary side circuit are mounted on the power supply module.

[0055] In each of the above embodiments, the ferrite core is one of the secondary components, and the insulating cap is attached to the primary area of ​​the circuit board, but it is also possible to use a configuration in which the ferrite core is one of the primary components, and the insulating cap is attached to the secondary area of ​​the circuit board. In this case, the embodiment can be explained by replacing all instances of "primary" in the explanation of each of the above embodiments with "secondary" and all instances of "secondary" with "primary", and the same effect can be obtained. [Explanation of symbols]

[0056] 10,66 Switching power supply 12 Main Device 14,14x,14y Power Supply Module 16,16h,16m Primary circuit 18, 18h, 18m Secondary circuit 20. Transformer 22, 22(1)~22(4) Primary winding 24,24(1)~24(3) Secondary winding 26h,26m Primary side parts 28h,28m Secondary side parts 32(1), 32(2) External connection terminal section (switching power supply unit) 34,34x,68 Circuit Board 34a,68a Multilayer printed wiring board 36 Ferrite core 38(1),38(2) Flat plate part 40 Midfoot 42(1),42(2) External foot 44(1), 44(2) External connection terminal section (power supply module) 46,46x Insulating Cap 56 Metatarsal foramen 58 Main cut 1A Primary area (circuit board) 2A Secondary area (circuit board) MA Winding area (circuit board) TA Middle area (circuit board)

Claims

1. A power supply module for constituting a switching power supply device in which a primary side circuit and a secondary side circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, The transformer includes a circuit board having circuit components mounted on a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern, a ferrite core which is a component of the transformer and has a pair of flat plate portions connected to each other at a center leg portion and two outer legs when assembled, an insulating cap formed in a bottomed cylindrical shape, and an external connection terminal portion for drawing out a specific conductive portion of the circuit board to the outside, the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by a wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components that are part of the primary side circuit and their wiring patterns are arranged on the front side, the back side, or both; a secondary side area in which secondary side components that are part of the secondary side circuit and their wiring patterns are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the secondary side area are continuous, the intermediate area and the primary side area are continuous in order to one end of the secondary side area, and the primary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the center leg portion is disposed in the center leg hole of the winding area, one of the outer legs is disposed in the main cut, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the secondary side components; A power supply module characterized in that the insulating cap is attached to the primary side area of ​​the circuit board and covers all or part of the front and back sides of the primary side area, the end face on the main notch side, the end face opposite the main notch, and the end face continuous with the two end faces, so that the insulation strength between the conductive parts on the front and back sides of the primary side area and the ferrite core is above a specified value.

2. A power supply module for constituting a switching power supply device in which a primary side circuit and a secondary side circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, The transformer includes a circuit board having circuit components mounted on a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern, a ferrite core which is a component of the transformer and has a pair of flat plate portions connected to each other at a center leg portion and two outer legs when assembled, an insulating cap formed in a bottomed cylindrical shape, and an external connection terminal portion for drawing out a specific conductive portion of the circuit board to the outside, the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by the wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components that are part of the primary side circuit and their wiring patterns are arranged on the front side, the back side, or both; a secondary side area in which secondary side components that are part of the secondary side circuit and their wiring patterns are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the primary side area are continuous, the intermediate area and the secondary side area are continuous in order to one end of the primary side area, and the secondary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the center leg portion is disposed in the center leg hole of the winding area, one of the outer legs is disposed in the main cutout, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the primary side components; The insulating cap is attached to the secondary area of ​​the circuit board and covers all or part of the front and back surfaces of the secondary area, the end face on the main notch side, the end face opposite the main notch, and the end face continuous with the two end faces, so that the insulation strength between the conductive parts on the front and back surfaces of the secondary area and the ferrite core is above a specified value.

3. 3. The power supply module according to claim 1, wherein said insulating cap is a one-piece molded product made of synthetic resin.

4. 3. A power supply module as described in claim 1 or 2, wherein the external connection terminal portion is formed by a land which is part of the wiring pattern of the multilayer printed wiring board, or an end electrode formed so as to be continuous with the wiring pattern of the multilayer printed wiring board, or both.

5. 3. The power supply module according to claim 1, wherein said external connection terminal portion is a metal terminal having one end connected to a wiring pattern of said multilayer printed wiring board.

6. 3. A switching power supply device comprising: a power supply module according to claim 1; and a main body device having a terminal receiving portion for connecting the external connection terminal portion of the power supply module.

7. In a switching power supply device in which a primary circuit and a secondary circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, a circuit board in which circuit components are mounted on a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern; a ferrite core which is a component of the transformer and has a shape in which a pair of flat plate portions are connected to each other at a middle leg portion and two outer legs when assembled; an insulating cap formed in a bottomed cylindrical shape; and an external connection terminal portion for drawing out a specific conductive portion of the multilayer printed wiring board to the outside; the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by a wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components and their wiring patterns which form the primary side circuit are arranged on the front side, the back side, or both; a secondary side area in which secondary side components and their wiring patterns which form the secondary side circuit are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the secondary side area are continuous, the intermediate area and the primary side area are continuous in order to one end of the secondary side area, and the primary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the center leg portion is disposed in the center leg hole of the winding area, one of the outer legs is disposed in the main cut, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the secondary side components; a first insulating cap that is attached to the first area of ​​the circuit board and covers all or part of the first and second surfaces of the primary area, the end face on the main cut side, the end face opposite the main cut, and the end face continuous with the two end faces, so that the insulation strength between the conductive parts on the first and second surfaces of the primary area and the ferrite core is equal to or greater than a specified value.

8. In a switching power supply device in which a primary circuit and a secondary circuit, which are insulated from each other, are connected via a primary winding and a secondary winding of a transformer, a circuit board in which circuit components are mounted on a multilayer printed wiring board having a plurality of wiring layers for forming a wiring pattern; a ferrite core which is a component of the transformer and has a shape in which a pair of flat plate portions are connected to each other at a middle leg portion and two outer legs when assembled; an insulating cap formed in a bottomed cylindrical shape; and an external connection terminal portion for drawing out a specific conductive portion of the multilayer printed wiring board to the outside; the circuit board comprises: a winding area in which the primary winding and the secondary winding are formed by a wiring pattern, the winding area having a middle foot hole through which the middle foot portion of the ferrite core is inserted, and the primary winding and the secondary winding are wound around the middle foot hole; a primary side area in which primary side components and their wiring patterns which form the primary side circuit are arranged on the front side, the back side, or both; a secondary side area in which secondary side components and their wiring patterns which form the secondary side circuit are arranged on the front side, the back side, or both; and an intermediate area in which the primary side components, the secondary side components, and their wiring patterns are not arranged on the front side or the back side, the winding area and the primary side area are continuous, the intermediate area and the secondary side area are continuous in order to one end of the primary side area, and the secondary side area is located to the side of the winding area via a main cut of a predetermined width; the ferrite core is attached to the winding area of ​​the circuit board, the center leg portion is disposed in the center leg hole of the winding area, one of the outer legs is disposed in the main cutout, and the pair of flat plate portions are disposed on the front and back sides of the multilayer printed wiring board, respectively, to form one of the primary side components; a first end face on the side of the secondary side area of ​​the circuit board, the first end face being connected to the first end face of the secondary side area, the second end face being connected to the first end face, and the second end face being connected to the first end face;

9. 9. A switching power supply device according to claim 7, wherein the insulating cap is a one-piece molded product made of synthetic resin.

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