Switching power supply device

Abstract

In this switching power supply device (1000), a main substrate (10) includes a wiring pattern (11a). A transformer (20) has a core (21) and a conductor film (22) that is wound around the core (21), and converts power. The transformer (20) is disposed on a main surface of the main substrate (10). On the main surface of the main substrate (10), a slit (12a) that penetrates the main substrate (10) is formed in a region that faces the transformer (20). The wiring pattern (11a) is connected to a stable potential. A part of the wiring pattern (11a) is formed in the slit (12a). A connection member (13a) is disposed inside the slit (12a) and electrically connects the conductor film (22) and the wiring pattern (11a) to each other.

Description

Switching Power Supply

[0001] The present invention relates to a switching power supply device.

[0002] A switching power supply is a device that converts power from DC to DC or from AC to DC. A switching power supply is equipped with a switching transformer. From the viewpoint of eliminating the need for skilled work in the process of mounting a shield plate, a proposal has been made as shown in Japanese Patent Laid-Open Publication No. 9-7858 (Patent Document 1).

[0003] Japanese Patent Application Publication No. 9-7858

[0004] In JP-A-9-7858, a U-shaped shield plate is placed over the transformer, and the wiring pattern of the board on which the transformer is mounted is connected to the edge of the shield plate to form a closed circuit. However, JP-A-9-7858 does not mention joining boards and components other than the transformer to the main board at the same time as the transformer. From this perspective, the proposal in JP-A-9-7858 leaves room for improvement in terms of improving productivity.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a switching power supply device that can achieve a shielding effect in a switching transformer through a simple mounting process.

[0006] A switching power supply device according to the present disclosure includes a main substrate, a switching transformer, and a connecting member. The main substrate has a main surface and includes a wiring pattern. The switching transformer has a core and a conductive film wound around the core, and converts power. The switching transformer is disposed on the main surface of the main substrate. A slit is formed in the main surface of the main substrate, penetrating the main substrate. The wiring pattern is connected to a stable potential. A portion of the wiring pattern is formed within the slit. The connecting member is disposed inside the slit, and electrically connects the conductive film and the wiring pattern.

[0007] According to the present disclosure, the conductive film and the wiring pattern are connected to a stable potential, thereby providing a shielding effect for the switching transformer. Such a configuration can be provided through a simple mounting process.

[0008] 7 is a schematic diagram of a switching power supply device according to a first embodiment. It is a circuit block diagram of a switching power supply device according to the first embodiment. It is a schematic cross-sectional view of a portion taken along line III-III in FIG. 1. It is a simplified diagram showing the distance relationship between the core and each substrate in a comparative example and the present embodiment when the transformer core is a floating conductor. It is a schematic diagram of a switching power supply device according to the first embodiment, in which the winding direction of the core and the conductive film is changed from that in FIG. 1. It is a schematic diagram of a switching power supply device according to the first embodiment, in which the positional relationship between the core and the conductive film and the main substrate is changed from that in FIG. 1. It is a schematic diagram of a switching power supply device according to a second embodiment. It is a circuit block diagram of a switching power supply device according to the second embodiment. It is a schematic cross-sectional view of a portion taken along line IX-IX in FIG. 7. It is a simplified diagram showing an aspect in which the distance between the first substrate and the second substrate is minimized when the conductive film in the second embodiment is connected to a ground potential. It is a schematic cross-sectional view corresponding to FIG. 3 in the third embodiment. It is a schematic cross-sectional view corresponding to FIG. 3 in the fourth embodiment. It is a schematic cross-sectional view corresponding to FIG. 3 in the fifth embodiment. It is a schematic cross-sectional view corresponding to FIG. 3 in the sixth embodiment.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For convenience of explanation, the X, Y, and Z directions are defined.

[0010] First Embodiment <Basic Configuration> Fig. 1 is a schematic diagram of a switching power supply device according to the first embodiment. Fig. 2 is a circuit block diagram of the switching power supply device according to the first embodiment.

[0011] The power supply device 1000, which serves as a switching power supply device according to the present embodiment, converts power received from an external source and transmits the converted power to the outside. The power supply device 1000 converts power, for example, from DC to DC or from AC to DC. As shown in FIGS. 1 and 2 , the power supply device 1000 mainly comprises a main board 10, an input connector IC, an output connector OC, a filter 30, and a module 300. As shown in FIG. 2 , the power supply device 1000 is arranged in the following order from the power input side to the power output side: the input connector IC, the filter 30, the module 300, and the output connector OC.

[0012] The main substrate 10 has a pair of main surfaces. The pair of main surfaces face the Z direction in FIG. 1. The Z direction corresponds to the height direction or vertical direction. The planar shape of the pair of main surfaces is, for example, rectangular.

[0013] The input connector IC receives power from outside the power supply device 1000. The input connector IC is installed on one of the main surfaces of the main board 10. The one main surface is the main surface on the upper side in the Z direction of the main board 10. The input connector IC may be arranged on the main surface of the main board 10, for example, at the end on the negative side in the Y direction. However, the position where the input connector IC is arranged is not limited to this.

[0014] The output connector OC transmits power to the outside of the power supply device 1000. The output connector OC is installed on one of the main surfaces of the main board 10. The output connector OC may be located, for example, at the end of the main surface of the main board 10 on the negative side in the Y direction, and may be arranged adjacent to the input connector IC with a gap in the X direction. However, the location of the output connector OC is not limited to this. In FIG. 1, the output connector OC is shown smaller than the input connector IC. However, this is not limited to this. For example, the output connector OC may be larger than the input connector IC, or the two may be the same size. The X direction and the Y direction correspond to the horizontal direction. The X direction and the Y direction are perpendicular to each other on a horizontal plane.

[0015] The filter 30 is a noise filter. The filter 30 includes a coil-connecting capacitor 31, a choke coil 32, and a module-connecting capacitor 33. The coil-connecting capacitor 31 has a first capacitor 31a and a second capacitor 31b. The first capacitor 31a is connected to the input connector IC. The choke coil 32 has one end and the other end. The one end is connected to the first capacitor 31a. The other end opposite the one end is connected to the second capacitor 31b. The module-connecting capacitor 33 includes a pair of third capacitors 33a and 33b. The third capacitors 33a and 33b are connected in parallel with the second capacitor 21b.

[0016] In other words, the input connector IC has at least three terminals not shown in FIGS. 1 and 2 . Two of the three or more terminals of the input connector IC receive power from outside the power supply device 1000. These two terminals are connected to one end and the other end of the first capacitor 31a, respectively. One end and the other end of the first capacitor 31a connected to the two terminals are connected to one end of the choke coil 32. One end of the choke coil 32 is connected to the first capacitor 31a, and the other end is connected to the second capacitor 31b. The third capacitors 33a and 33b are connected in series. The series-connected third capacitors 33a and 33b, i.e., one and the other end of the entire module connection capacitor 33, are connected to one and the other end of the second capacitor 31b, respectively. One and the other end of the entire module connection capacitor 33 are also connected to the module 300. Of the three or more terminals of the input connector IC, one other than the above two terminals is connected to a stable potential, the ground potential 40. The ground potential 40 is also connected to a portion connecting the third capacitor 33a and the third capacitor 33b.

[0017] The module 300 is a switching power supply module. The module 300 mainly includes a first substrate 100, a transformer 20, and a second substrate 200. The first substrate 100, which serves as the primary substrate of the transformer 20, can receive power from the outside. The first substrate 100 receives power from an input connector IC via a filter 30 and forms a switching waveform (high-frequency pulse wave). The transformer 20 is a so-called switching transformer. The transformer 20 is sandwiched between the first substrate 100 and the second substrate 200. The transformer 20 has an insulating function. In other words, the transformer 20 provides insulation between the first substrate 100 and the second substrate 200. The second substrate 200, which serves as the secondary substrate of the transformer 20, can transmit power to the outside. The second substrate 200 adjusts the power transmitted to the outside. For example, the circuit formed on the second substrate 200 rectifies and smoothes the energy transferred from the first substrate 100 via the transformer 20 and outputs it to the outside as direct current.

[0018] Module 300 of power supply device 1000 performs power conversion, such as DC to DC and AC to DC, via transformer 20, which serves as an insulating component. Transformer 20 electrically insulates input terminal IN from output terminal OUT. This provides increased safety compared to power supply devices that use, for example, non-insulated transformers.

[0019] 1 , in module 300, first substrate 100, transformer 20, and second substrate 200 are arranged in this order, spaced apart from one another in the X direction. Module 300 is adjacent to filter 30, spaced apart from one another in the Y direction. However, the configuration of module 300 is not limited to this arrangement.

[0020] In the transformer 20, a coil N on the first substrate 100 side and a coil N on the second substrate 200 side are wound around a portion of the core 21 while being insulated from each other. In the transformer 20, the current flowing through the coil N on the first substrate 100 side and the voltage of the coil N change relative to the current flowing through the coil N on the second substrate 200 side. This allows the power supply device 1000 to output any predetermined voltage and current. The choke coil 32 of the filter 30 is connected to the input side of the first substrate 100. The choke coil 32 is a so-called common mode choke coil. In other words, the choke coil 32 is a coil that passes direct current or low-frequency current. Therefore, the current input to the first substrate 100 is direct current or low-frequency alternating current.

[0021] One end and the other end of capacitor 4a are connected to the first board 100. One end and the other end of capacitor 4b are connected to the second board 200. Capacitors 4a and 4b are so-called bulk capacitors. The negative end of capacitor 4a is connected to a first reference potential 41 as a stable potential. The negative end of capacitor 4b is connected to a second reference potential 42 as a stable potential. Both the positive and negative ends of capacitor 4b are connected to the output connector OC.

[0022] FIG. 3 is a schematic cross-sectional view of a portion taken along line III-III in FIG. 1. As shown in FIG. 3, 1, and 2, the transformer 20 mainly includes a core 21, a conductor film 22, and a coil N. The core 21 is a component disposed as a core around which the coil N is wound. For this reason, the core 21 is preferably formed of a commonly known magnetic material such as ferrite. Although not shown, a core portion of the core 21 is disposed inside the coil N in FIG. 1. The coil N is wound around the core portion of the core 21. In addition to the core portion, the core 21 has an outer portion disposed outside the coil N. The outer portion of the core 21 surrounds the coil N in a manner that forms four of the six faces of a rectangular parallelepiped.

[0023] A conductive film 22 is wound around the outer surface of the outer portion of the core 21. The conductive film 22 may be, for example, a thin metal foil. In this case, the thickness of the metal foil is 1 mm or less. Alternatively, the conductive film 22 is not limited to metal, and may be a sheet-like member having electrical conductivity.

[0024] Two of the four outer surfaces of the core 21 face the main surface of the main substrate 10 so as to be aligned with the main surface. The other two of the four outer surfaces of the core 21 intersect with the main surface of the main substrate 10, for example, are substantially perpendicular to the main surface.

[0025] Of the four surfaces of the outer part of the core 21, two surfaces that extend along the main surface of the main substrate 10 are connected to the other two surfaces at their ends in the X direction. The conductive film 22 extends along the X direction or the Z direction and is wrapped around the four surfaces of the outer part of the core 21. The conductive film 22 has a width in the Y direction that is approximately the same as that of the outer part of the core 21.

[0026] Circuits (not shown) are formed on the main surfaces of the first substrate 100 and the second substrate 200. Terminals (not shown) are formed on the first substrate 100 and the second substrate 200. The first substrate 100 and the second substrate 200 are connected to the main substrate 10 via these terminals.

[0027] As shown in Fig. 3, wiring pattern 11a is formed on main substrate 10. Wiring pattern 11a is formed on a pair of main surfaces of main substrate 10. Wiring pattern 11a is a thin film of a conductor such as metal. Wiring pattern 11a is electrically connected to conductor film 22 of transformer 20. Filter 30, capacitor 4a, and the like are electrically connected by wiring patterns on the main surfaces of main substrate 10, which are not shown in Fig. 1. As a result, the circuit shown in Fig. 2 is configured on main substrate 10.

[0028] A slit 12a is formed in the main substrate 10. The slit 12a penetrates the main substrate 10 from one main surface to the other main surface. The other main surface is the main surface on the lower side in the Z direction of the main substrate 10.

[0029] Transformer 20 is disposed on one main surface of main substrate 10. Slit 12a is formed in a region of one main surface of main substrate 10 facing transformer 20. That is, transformer 20 is disposed above the main surface of main substrate 10 so as to cover the region where slit 12a is formed. As a result, conductive film 22 is disposed above wiring pattern 11a on the main surface of main substrate 10 so as to cover at least a portion of slit 12a. In particular, in FIG. 3 , transformer 20 including conductive film 22 is mounted on wiring pattern 11a so that conductive film 22 is in contact with wiring pattern 11a.

[0030] Wiring patterns 11b to 11d are formed on the main substrate 10. The wiring patterns 11b to 11d are formed on a pair of main surfaces of the main substrate 10. The wiring patterns 11b to 11d are thin films of a conductor such as metal. Slits 12b to 12d are formed on the main substrate 10. The slits 12b to 12d penetrate the main substrate 10 from one main surface to the other main surface.

[0031] The slits 12b and 12c are spaced apart from the slit 12a in the X direction. The slits 12b and 12c are formed so as to sandwich the slit 12a in the X direction. The first substrate 100 is inserted into the slit 12b. The second substrate 200 is inserted into the slit 12c. The main surface of the first substrate 100 intersects with the main surface of the main substrate 10. As shown in FIG. 3, the main surface of the first substrate may be substantially perpendicular to the main surface of the main substrate 10. Similarly, the main surface of the second substrate 200 intersects with the main surface of the main substrate 10. The main surface of the second substrate 200 may be substantially perpendicular to the main surface of the main substrate 100. As described above, the first substrate 100 and the second substrate 200 are connected to the main substrate 10 so as to sandwich the transformer 20 in the X direction. As shown in FIG. 3, the transformer 20 may be positioned closer to the first substrate 100 than the second substrate 200 in the X direction, for example. However, the arrangement of the transformer 20 is not limited to this. For example, the transformer 20 may be arranged closer to the second substrate 200 than to the first substrate 100. Alternatively, the transformer 20 may be arranged at an equal distance from both the first substrate 100 and the second substrate 200.

[0032] A part of the wiring pattern 11a is formed inside the slit 12a. The wiring pattern 11a is formed so as to extend from inside the slit 12a onto one and the other main surfaces of the main substrate 10 adjacent to the slit 12a.

[0033] Similarly, a portion of wiring pattern 11b is formed in slit 12b. A portion of wiring pattern 11c is formed in slit 12c. A portion of wiring pattern 11d is formed in slit 12d. Similarly, wiring patterns 11b, 11c, and 11d are formed so as to extend from within slits 12b, 12c, and 12d onto the main surface of main substrate 10 adjacent to each slit, respectively.

[0034] The power supply device 1000 further includes a connection member 13a. The connection member 13a is a conductive member. The connection member 13a is disposed inside the slit 12a. The connection member 13a electrically connects the wiring pattern 11a inside the slit 12a to the conductive film 22 above the slit 12a. This is because the connection member 13a inside the slit 12a contacts both the wiring pattern 11a inside the slit 12a and the conductive film 22 located directly above the top of the slit 12a. The connection member 13a also mechanically connects the wiring pattern 11a to the conductive film 22.

[0035] Connecting member 13b is disposed inside slit 12b. A first wiring pattern 101 is formed on the main surface of first substrate 100. First wiring pattern 101 is electrically connected to components on first substrate 100. Connecting member 13b electrically and mechanically connects wiring pattern 11b in slit 12b to first wiring pattern 101 of first substrate 100 inserted into slit 12b.

[0036] Connecting member 13c is disposed inside slit 12c. Second wiring pattern 201 is formed on the main surface of second substrate 200. Second wiring pattern 201 is electrically connected to components on second substrate 200. Connecting member 13c electrically and mechanically connects wiring pattern 11c inside slit 12c to second wiring pattern 201 of second substrate 200 inserted into slit 12c.

[0037] The connecting member 13d is disposed inside the slit 12d. The capacitor 4b is provided with a terminal 4bb. The connecting member 13d electrically and mechanically connects the wiring pattern 11d in the slit 12c to the terminal 4bb inserted into the slit 12d.

[0038] The connection members 13b and 13c are made of the same material as the connection member 13a. For example, if the connection member 13a is solder, the connection members 13b and 13c are also made of the same solder as the connection member 13a. The first substrate 100 is connected to the main substrate 10 by the connection member 13b as a substrate connecting member. The second substrate 200 is connected to the main substrate 10 by the connection member 13c as a substrate connecting member. Furthermore, the connection member 13d is made of the same material as the connection member 13a and the connection members 13b and 13c. Note that silver paste may be used for the connection members 13a to 13d instead of solder.

[0039] As shown in Figures 2 and 3, in this embodiment, the wiring pattern 11a is connected to a stable potential. As an example of a stable potential, in Figures 2 and 3, the wiring pattern 11a electrically connected to the conductor film 22 is connected to a first reference potential 41. The first reference potential 41 is a so-called primary ground potential. The first wiring pattern 101 of the first substrate 100 also has a stable potential. The stable potential of the first wiring pattern 101 may be the first reference potential 41. Furthermore, the second wiring pattern 201 of the second substrate 200 also has a stable potential. The stable potential of the second wiring pattern 201 may be a second reference potential 42. The second reference potential 42 is a so-called secondary ground potential or a so-called signal ground potential.

[0040] The first reference potential 41 oscillates at a relatively low frequency, between 100 Hz and 360 Hz, which is an integer multiple of the commercial frequency of 50 Hz or 60 Hz, for example, between two and six times the commercial frequency, relative to the ground potential. The first reference potential 41 is sufficiently stable, i.e., has little fluctuation, compared to the potential at the driving frequency of the switching power supply, which is between 1 kHz and 1 MHz. Here, a stable potential is defined as a potential that fluctuates little compared to the driving frequency of the switching power supply, which is between 1 kHz and 1 MHz. In other words, a stable potential is defined to include a potential that fluctuates slightly at the relatively low frequency. A stable potential is also defined to include a potential that fluctuates even less than the above definition. Therefore, the second reference potential 42, described below, is also included in the stable potential.

[0041] The second reference potential 42 is a potential close to the ground potential, and is even more stable with less fluctuation in potential than the first reference potential 41. The second reference potential 42 may be a potential that is substantially fixed at a certain value.

[0042] Note that Fig. 3 is an example for ease of understanding. Therefore, the portions of the first substrate 100 and the second substrate 200 that are considered to have a stable potential may be located at positions different from those shown in the cross-sectional view of Fig. 3. In other words, the connecting members 13b and 13c do not necessarily have a stable potential. Furthermore, the stable potential may be a stable potential with very little fluctuation as described above as a reference value.

[0043] 3 shows the first reference potential 41 and the second reference potential 42 as an example, but a gap is provided between the wiring pattern 11a and the wiring patterns 11b and 11c. This indicates that the potential of the wiring pattern 11a may differ from the potential of the wiring patterns 11b and 11c. The wiring patterns 11b and 11c are separate wiring patterns from the wiring pattern 11a. The first wiring pattern 101 is electrically connected to the wiring pattern 11b, which is another wiring pattern, by a connecting member 13b. The second wiring pattern 201 is electrically connected to the wiring pattern 11c, which is another wiring pattern, by a connecting member 13c.

[0044] <Effects> The power supply device 1000 according to this embodiment includes a main substrate 10, a transformer 20, and a connecting member 13a. The main substrate 10 has a main surface and includes a wiring pattern 11a. The transformer 20 has a core 21 and a conductive film 22 wrapped around the core 21, and converts power. The transformer 20 is disposed on the main surface of the main substrate 10. A slit 12a is formed in the main surface of the main substrate 10, penetrating the main substrate 10. The wiring pattern 11a is connected to a stable potential. A portion of the wiring pattern 11a is formed within the slit 12a. The connecting member 13a is disposed inside the slit 12a, and electrically connects the conductive film 22 and the wiring pattern 11a.

[0045] Since the conductive film 22 and the wiring pattern 11a are electrically connected, the conductive film 22 is connected to a stable potential. A stable potential is a stable potential with very little fluctuation. Therefore, the conductive film 22 wound around the core 21 suppresses noise leakage from within the transformer 20. This is due to the shielding effect of the conductive film 22.

[0046] Consider a case where a stable potential is supplied by, for example, the first substrate 100. In this case, it is preferable that the first substrate 100 be connected to the main substrate 10. A capacitor may also be connected to the main substrate 10. In this case, a substrate connecting member (connecting member 13b) is used to connect the first substrate 100 to the main substrate 10. A capacitor connecting member is used to connect the capacitor to the main substrate 10. Furthermore, a connecting member 13a is used to connect the transformer 20 to the main substrate 10. In this case, the substrate connecting member (connecting member 13b), the capacitor connecting member, and the connecting member 13a may all be supplied simultaneously. This allows the transformer 20, the first substrate 100, and the like to be connected to the main substrate 10 simultaneously. In other words, a configuration that provides a shielding effect at the transformer 20 by connecting the conductive film 22 to a stable potential can be provided through a simple mounting process. Here, a simple process means that the time required for the process is reduced by simultaneously connecting the transformer 20, the first substrate, and the capacitor to the main substrate 10.

[0047] As described above, according to this embodiment, a configuration that provides a shielding effect in the transformer 20 can be provided through a simple mounting process.

[0048] In this embodiment, the connecting member 13 a is disposed inside the slit 12 a. If the connecting member 13 a is made of solder, this configuration can be realized by a flow soldering process. By using the flow soldering process, the above-described simple mounting process can be easily realized.

[0049] Additionally, in this embodiment, the connection between the module 300 including the transformer 20 and the main board 10 is strengthened because the connecting member 13a electrically and mechanically connects the conductive film 22 and the wiring pattern 11a, thereby improving the vibration resistance of the power supply device 1000.

[0050] Furthermore, the heat generated in the transformer 20 can be transferred to the main board 10 with high efficiency, thereby reducing the temperature of the transformer 20. This is also an effect obtained by the connecting member 13a that connects the conductive film 22 and the wiring pattern 11a.

[0051] In the power supply device 1000 of this embodiment, the wiring pattern 11a is formed so as to extend from within the slit 12a onto the main surface of the main substrate 10 adjacent to the slit 12a. The conductor film 22 is disposed on the wiring pattern 11a on the main surface so as to cover at least a portion of the slit 12a. As a result, the conductor film 22 and the wiring pattern 11a come into contact with each other. This makes it possible to more reliably establish an electrical connection between the conductor film 22 and the wiring pattern 11a. This makes it possible to more reliably apply a stable potential to the conductor film 22.

[0052] The power supply device 1000 of this embodiment further includes a first board 100 and a second board 200. The first board 100 is capable of receiving power from the outside. The second board 200 is capable of transmitting power to the outside. The first board 100 and the second board 200 are connected to the main board 10 so as to sandwich the transformer 20. As a result, if the first board 100 and the second board 200 have a stable potential, for example, the first board 100 and the second board 200 can provide a shielding effect that suppresses noise leakage from the transformer 20. The shielding effect is obtained by electrostatic shielding provided by the first board 100, etc., which are connected to a stable potential.

[0053] In the power supply device 1000 of this embodiment, the first substrate 100 includes a first wiring pattern 101 having a first reference potential 41 as a stable potential. The second substrate 200 includes a second wiring pattern 201 having a second reference potential 42 as a stable potential. The main substrate 10 includes wiring patterns 11b and 11c as other wiring patterns arranged at a distance from the wiring pattern 11a. At least one of the first wiring pattern 101 and the second wiring pattern 201 is electrically connected to the wiring patterns 11b and 11c. In this manner, for the same reasons as described above, the first substrate 100 and the second substrate 200 provide a shielding effect that suppresses noise leakage from the transformer 20.

[0054] In the power supply device 1000 of this embodiment, the first wiring pattern 101 is electrically connected to another wiring pattern, wiring pattern 11b. The transformer 20 is disposed closer to the first substrate 100 than the second substrate 200. This allows the module 300 to be made smaller, as will be described below with reference to FIG. 4.

[0055] FIG. 4 is a simplified diagram showing the distance relationship between the core and each substrate in a comparative example in which the transformer core is a floating conductor and in this embodiment. Specifically, FIG. 4A shows the distance relationship between the core 21 and the first and second substrates 100 and 200 in an example in which the transformer core is a floating conductor, as a comparative example different from this embodiment. In FIG. 4A, the core 21 of the transformer 20 is at a floating potential. The first substrate 100 is connected to a first reference potential 41, which is a stable potential. The second substrate 200 is connected to a second reference potential 42, which is also a stable potential. Here, the distance between the core 21 and the first substrate 100 is defined as distance L1, and the distance between the core 21 and the second substrate 200 is defined as distance L2. The sum of distance L1 and distance L2 must be equal to or greater than the required insulation distance between the first substrate 100 and the second substrate 200. This is because the core 21 is considered a conductor.

[0056] 4B is a simplified diagram showing the distance relationship between the core 21 and each substrate when the core is connected to the first reference potential as a comparative example different from the present embodiment. As shown in FIG. 4B, consider the case where both the core 21 and the first substrate 100 are connected to the first reference potential 41. The reason for connecting the core 21 to the first reference potential 41 is to obtain the shielding effect of the conductor film 22 as described above. Note that the second substrate 200 is connected to the second reference potential 42, as in FIG. 4A.

[0057] In this case, as in (a), it is assumed that the distance between the core 21 and the first substrate 100 is distance L1. In this case, the distance between the core 21 and the second substrate 200 needs to be equal to or greater than (L1 + L2). This is for the following reason. That is, in FIG. 4 (b), the core 21 and the first substrate 100 are both connected to the first reference potential 41. Therefore, in the configuration of (b), in order to ensure the insulation distance between the first substrate 100 and the second substrate 200 similar to that in (a), the distance between the core 21 and the second substrate 200 needs to be equal to or greater than (L1 + L2) as described above. As a result, the total distance in the X direction between the first substrate 100 and the second substrate 200 excluding the core 21 is (L1 + L1 + L2). This means that the size of the module 300 is larger than in (a).

[0058] FIG. 4C is a simplified diagram showing the distance relationship between the core 21 and each substrate when the core 21 is connected to the first reference potential 41 in this embodiment. The potentials of each component in FIG. 4C are the same as those in FIG. 4B. As shown in FIG. 4C, the core 21 and the first substrate 100 are both connected to the first reference potential 41. Therefore, the core 21 and the first substrate 100 may be closer to each other than in FIG. 4B. In this case, the core 21 and the first substrate 100 may be in contact with each other. This allows the transformer 20 to be positioned closer to the first substrate 100 than to the second substrate 200. In this way, the sum of the distances in the X direction between the first substrate 100 and the second substrate 200, excluding the core 21, is shorter than the sum of the distances in FIG. 4B. Therefore, the module 300 can be made smaller in FIG. 4C than in FIG. 4B.

[0059] In the power supply device 1000 of this embodiment, the first board 100 and the second board 200 are connected to the main board 10 by connecting members 13b and 13c, which serve as board connecting members made of the same material as the connecting member 13a. Such a configuration is preferable.

[0060] This provides the following advantageous effects. Specifically, connecting member 13a is used to connect transformer 20 to main board 10. Connecting member 13b is used as a board connecting member to connect first board 100 to main board 10. Connecting member 13c is used as a board connecting member to connect second board 200 to main board 10. If connecting members 13a to 13c are all made of the same material, they can all be connected at the same time. A flow soldering process, for example, can be used for the connection. This allows module 300 to be provided through a simple mounting process.

[0061] In the power supply device 1000, the conductive film 22 contacts the wiring pattern 11a, thereby enabling electrical connection between the conductive film 22 and the wiring pattern 11a with a simple configuration.

[0062] The power supply device 1000 of this embodiment includes an input connector IC and a filter 30. The input connector IC is installed on the main board 10 and receives power from an external source. The filter 30 includes a first capacitor 31a, a choke coil 32, a second capacitor 31b, and a third capacitor 33b. The first capacitor 31a is connected to the input connector IC. The choke coil 32 is connected to the first capacitor 31a. The second capacitor 31b is connected to the choke coil 32 on the side opposite to the first capacitor 31a. The third capacitor 33b is connected in parallel with the second capacitor 31b. The filter 30 can suppress noise from the power supply device 1000.

[0063] <Modifications> In this embodiment, the following modifications may be applied.

[0064] First, although the input connector IC has three or more terminals in the above description, in this embodiment, the input connector IC may be configured with two terminals. In other words, the input connector IC in FIG. 2 does not need to have the ground potential 40.

[0065] Second, the conductive film 22 may be a metal tape having an adhesive layer on one main surface of a metal foil. When a metal foil is used as the conductive film 22, the metal is copper or tin, which has good compatibility with solder. However, instead of the above, a lightweight metal material such as aluminum may be used as the metal. A material with a high shielding effect, such as iron, may also be used as the metal. For example, the conductive film 22 is wrapped around the core 21 so that the adhesive layer contacts the core 21. This allows the conductive film 22 to be fixed to the surface of the core 21. This simplifies the manufacturing process. Furthermore, if the adhesive layer is a thin insulating layer, an insulating effect can be expected between the core 21 and the conductive film 22 in that area.

[0066] Third, the winding direction of the core 21 and the conductive film 22 is not limited to the direction shown in FIG. 1 . FIG. 5 is a schematic diagram of a switching power supply device according to the first embodiment, in which the winding direction of the core and the conductive film is changed from that shown in FIG. 1 . FIG. 5 is the same as FIG. 1 except for the following points. Therefore, the same parts as those in FIG. 1 will not be described again here. As shown in FIG. 5 , two of the four outer surfaces of the core 21 face along the main surface of the main substrate 10. The other two of the four surfaces intersect with the main surface of the main substrate 10. The two of the four outer surfaces of the core 21 facing the main surface of the main substrate 10 are connected to the other two surfaces at their ends in the Y direction. The conductive film 22 extends along the Y direction or the Z direction and is wound around the four outer surfaces of the core 21. The conductive film 22 has a width in the X direction that is approximately the same as the width of the outer portion of the core 21. Such a configuration may be used. Although not shown, the transformer 20 may have both the core 21 and the conductive film 22 oriented as shown in FIG. 1 and the core 21 and the conductive film 22 oriented as shown in FIG.

[0067] Fourth, the core 21 and the conductive film 22 do not have to face the main surface of the main substrate 10. Figure 6 is a schematic diagram of a switching power supply device in accordance with the first embodiment, in which the relative positions of the core and the conductive film and the main substrate are changed from those in Figure 1. Figure 6 is the same as Figure 1 except for the following points. Therefore, the same parts as those in Figure 1 will not be described again here.

[0068] As shown in Fig. 6, similarly to Fig. 1, two of the four surfaces of the outer part of core 21 that extend along the X and Z directions are connected to the other two surfaces at their ends in the X direction. However, in Fig. 6, all four surfaces of core 21 intersect, for example, are perpendicular to the main surface of main board 10. In other words, none of the four surfaces of core 21 face the main surface of main board 10. In this case, the other two surfaces of the four surfaces of core 21 are connected to the other two surfaces at their ends in the Y direction. The transformer 20 of this embodiment may be configured in this manner.

[0069] 3 are fixed to the main board 10 by being inserted into the slits 12b, 12c. Instead of this configuration, connectors may be mounted on the first board 100, the second board 200, and the main board 10, respectively, and the boards may be fixed to each other by fitting the connectors together.

[0070] Sixth, the overall thickness of the wiring pattern 11a may be increased by forming a copper film, for example, by plating, on a thin film of a conductor such as copper. This allows heat generated in the transformer 20 to be efficiently dissipated from the wiring pattern 11a downward, thereby cooling the transformer 20. Furthermore, it is preferable to form the wiring pattern 11a on the main board 10 over as large an area as possible on the main surface of the main board 10. This improves the heat dissipation from the main board 10 to the surroundings of the power supply device 1000 via the wiring pattern 11a. This therefore further cools the transformer 20.

[0071] The conductive thin film of the wiring pattern 11a is, for example, 18 μm or more and 175 μm or less. The thickness of the plating film of the wiring pattern 11a may be, for example, 10 μm or more. Alternatively, the thickness of the plating film may be 15 μm or more, or 25 μm or more. The thickness of the plating film may even exceed 25 μm. The total thickness of the wiring pattern 11a is preferably 30 μm or more and 200 μm or less.

[0072] Seventh, through holes or thermal vias may be formed in the wiring pattern 11a, which increases the thermal conductivity from the core 21 to the main board 10. As a result, the transformer 20 can be cooled more efficiently.

[0073] As described above, the transformer 20 is coupled to the main board 10 with low thermal resistance, which facilitates thermal management of the transformer 20.

[0074] Second Embodiment. <Basic Configuration> FIG. 7 is a schematic diagram of a switching power supply device according to the second embodiment. FIG. 8 is a circuit block diagram of the switching power supply device according to the second embodiment. FIG. 9 is a schematic cross-sectional view of a portion taken along line IX-IX in FIG. 7. In FIGS. 7, 8, and 9, portions exhibiting the same features as those of power supply device 1000 according to the first embodiment will not be described repeatedly. As shown in FIGS. 7, 8, and 9, transformer 20 according to the present embodiment basically has the same configuration as power supply device 1000 according to the first embodiment. However, transformer 20 according to the present embodiment differs from that according to the first embodiment in the members wound on the surface of core 21. Specifically, first insulating member 23a, conductive film 22, and second insulating member 23b are arranged on the surface of core 21. First insulating member 23a, conductive film 22, and second insulating member 23b are wound in this order, starting from the side closest to the surface of core 21. Therefore, the first insulating member 23 a, the conductive film 22, and the second insulating member 23 b are wound in layers. The first insulating member 23 a and the second insulating member 23 b are made of a commonly known insulating material, such as a resin material.

[0075] The transformer 20 is placed on the wiring pattern 11a so that at least a portion of the outermost second insulating member 23b contacts the wiring pattern 11a. This is shown in FIG. 9. As shown in FIG. 9, the second insulating member 23b is missing in a portion facing the slit 12a. As a result, the second insulating member 23b has an opening in the portion facing the slit 12a. In the opening where the second insulating member 23b is missing, the conductive film 22 formed inside is exposed. In the opening, the exposed portion of the conductive film 22 is connected to the connecting member 13a. The conductive film 22 and the wiring pattern 11a are connected by the connecting member 13a.

[0076] The present embodiment differs from the first embodiment in the following respects regarding potential. As shown in Fig. 9, the wiring pattern 11a of the main substrate 10 has a ground potential 40 as a stable potential. The conductive film 22 in contact with the wiring pattern 11a is also connected to the ground potential 40.

[0077] The first wiring pattern 101 of the first substrate 100 has a first reference potential 41 as a stable potential, as in the first embodiment. The second wiring pattern 201 of the second substrate 200 has a second reference potential 42 as a stable potential, as in the first embodiment.

[0078] <Effects> In the power supply device 1000 according to this embodiment, the first insulating member 23a, the conductive film 22, and the second insulating member 23b are arranged on the surface of the core 21 in this order from the side closest to the surface of the core 21. An opening is formed in the second insulating member 23b in a portion facing the slit 12a. The portion of the conductive film 22 exposed in the opening is connected to the connecting member 13a. This configuration may be adopted.

[0079] The first insulating member 23a is in direct contact with the core 21. This allows the core 21 to be at a floating potential. Meanwhile, a stable potential is applied to the conductive film 22, as in the first embodiment. This allows the core 21 to be at a floating potential while still providing a shielding effect through the conductive film 22. The reason why it is preferable to keep the core 21 at a floating potential is as follows: An insulating distance must be provided between the core 21 and the inside of the core 21 (inside the transformer 20) of the transformer 20. If the core 21 were at the same potential as the ground potential, the insulating distance between the core 21 and the inside of the transformer 20 would need to be increased. Therefore, if the core 21 were at the same potential as the ground potential, the overall size of the transformer 20 would increase. To avoid this, it is preferable to keep the core 21 at a floating potential.

[0080] The second insulating member 23b is disposed outside the first insulating member 23a via the conductive film 22. The second insulating member 23b ensures insulation for the conductive film 22 of the transformer 20. This will be described in more detail below.

[0081] In the first embodiment, a first reference potential 41 serving as a stable potential is applied to the conductive film 22. However, in the present embodiment, unlike the first embodiment, a ground potential 40 serving as a stable potential is applied to the conductive film 22. In other words, the conductive film 22 is connected to the ground potential 40, which is even less fluctuating and more stable than the first reference potential 41 in the first embodiment, which allows for slight fluctuations. The ground potential 40 is the reference potential for all devices. Therefore, in the present embodiment, a higher shielding effect of the conductive film 22 can be obtained than in the first embodiment.

[0082] It is usually preferable to ensure a large insulation distance between the ground potential 40 and the first reference potential 41 on the primary circuit side. By providing the second insulating member 23b, it is possible to significantly increase the creepage distance between the first substrate 100 having the first reference potential 41 and the conductive film 22 having the ground potential 40 wound inside the second insulating member 23b. This makes it possible to sufficiently increase the insulation distance between the ground potential 40 and the first reference potential 41.

[0083] In this embodiment, the second insulating member 23b may reliably ensure insulation between the first substrate 100 and the conductive film 22 and core 21 inside the second insulating member 23b. In this case, the distance between the first substrate 100 and the second substrate 200 and the core 21 around which the second insulating member 23b is wound can be reduced. FIG. 10 is a simplified diagram showing an example in which the distance between the first substrate 100 and the second substrate 200 is minimized when the conductive film in embodiment 2 is connected to a ground potential. As shown in FIG. 10 , consider a case in which the second insulating member 23b covers almost the entire surface of the conductive film 22 inside the conductive film 22. Covering almost the entire surface of the conductive film 22 basically means that the entire surface of the conductive film 22 is covered by the second insulating member 23b. However, covering almost the entire surface of the conductive film 22 also includes a case in which the entire conductive film 22 is covered by the second insulating member 23b except for a minimally exposed area for connecting the terminal for ground potential 40.

[0084] In the case of FIG. 10 , the distance (L1 + L2) between the first substrate 100 and the second substrate 200 can be reduced. Specifically, in the example of FIG. 10 , the wiring pattern 11a (see FIG. 9 ) of the main substrate 10 has a ground potential 40 as a stable potential. The first substrate 100 includes a first wiring pattern 101 (see FIG. 9 ) having a first reference potential 41 as a stable potential. The second substrate 200 includes a second wiring pattern 201 (see FIG. 9 ) having a second reference potential 42 as a stable potential. The conductor film 22 is connected to the ground potential 40. The distance between the ground potential 40 and the second reference potential 42 is shorter than the distance between the ground potential 40 and the first reference potential 41. Therefore, in this embodiment, as shown in FIG. 9 , the transformer 20 may be positioned closer to the second substrate 200 than to the first substrate 100, but this is not limited to this. That is, in FIG. 10 , the distance between the first substrate 100 and the second substrate 200 is (L1 + L2).

[0085] The distance between the portion of the conductive film 22 connected to the ground potential 40 (the portion connected to the connecting member 13a in FIG. 9) and the second substrate 200 having the second reference potential 42 is shorter than the distance between the portion of the conductive film 22 connected to the ground potential 40 and the first substrate 100 having the first reference potential 41. Therefore, between the first reference potential 41 and the second reference potential 42, the portion of the conductive film 22 connected to the ground potential 40 is positioned closer to the second reference potential 42 than to the first reference potential 41. This means that the size of the module in FIG. 10 is reduced compared to examples such as those in FIGS. 4(b) and 4(c).

[0086] 9, as in Fig. 3, the portions of the first substrate 100 and the second substrate 200 that are at a stable potential may be located at positions different from those on the cross-sectional view shown in Fig. 9. In other words, the connecting members 13b and 13c do not necessarily have to have a stable potential.

[0087] <Modifications> All of the above-described modifications of the first embodiment can also be applied to the present embodiment. In addition, in the present embodiment, first, the conductor film 22 may be connected to a second reference potential 42 provided on the main substrate 10. In this case, as in the other embodiments, the core 21 of the transformer 20 is disposed between the first substrate 100 and the second substrate 200. In this modification, the core 21 is disposed closer to the second substrate 200 than to the first substrate 100. This allows the power supply device 1000 to be made smaller.

[0088] Second, in this embodiment, the conductive film 22 may be connected to the positive terminal of the capacitor 4a or the capacitor 4b shown in Fig. 8. The positive terminal of the capacitor 4a or the capacitor 4b has a fixed stable potential that is different from the first reference potential 41 and the second reference potential 42, but is also fixed stable together with these potentials. When the conductive film 22 is installed, a shielding effect is obtained due to the stable potential.

[0089] Thirdly, the first insulating member 23a and the second insulating member 23b may be made of a resin material used in molding.

[0090] Fourth, insulating tape may be used for the first insulating member 23a and the second insulating member 23b. That is, both the first insulating member 23a and the second insulating member 23b may be insulating tape having an adhesive layer on one main surface of a thin insulating layer. This adhesive layer is similar to the adhesive layer provided on one main surface of the metal foil of the conductive film 22 in embodiment 1. In this manner, the insulating tape has adhesive properties. As a result, as shown in FIG. 9 , the first insulating member 23a can be fixed on the surface of the core 21, and the second insulating member 23b can be fixed on the surface of the conductive film 22. The adhesive layer of the conductive film 22 allows the conductive film 22 to be fixed on the first insulating member 23a. Using tape having an adhesive layer in this manner improves the workability of the module 300.

[0091] Embodiment 3. <Basic Configuration> Fig. 11 is a schematic cross-sectional view of embodiment 3, corresponding to Fig. 3. That is, Fig. 11 shows a cross-sectional view of the present embodiment taken along line III-III in Fig. 1. In Fig. 11, the same aspects as Fig. 3 of embodiment 1 will not be described again. Furthermore, except for the following differences, this embodiment basically has the same features as Figs. 1 and 2 of embodiment 1. The same aspects of this embodiment as Figs. 1 and 2 will not be described again.

[0092] As shown in FIG. 11 , the transformer 20 of this embodiment is disposed on the wiring pattern 11a on the main surface of the main substrate 10. This point is the same as in the first embodiment. However, in FIG. 11 , the connection member 13a extends from within the slit 12a to the region between the wiring pattern 11a and the conductor film 22 on the main surface of the main substrate 10. On the main surface of the main substrate 10, the connection member 13a contacts both the wiring pattern 11a and the conductor film 22 directly above it. The connection member 13a is also disposed within the slit 12a. Therefore, the connection member 13a contacts all of the wiring pattern 11a within the slit 12a, the wiring pattern 11a on the main surface of the main substrate 10, and the conductor film 22. In FIG. 11 , unlike FIG. 3 , the conductor film 22 does not contact the wiring pattern 11a located on the main surface of the main substrate 10. This is because the connection member 13a is sandwiched between the wiring pattern 11a and the conductor film 22.

[0093] <Effects> In the power supply device 1000 according to this embodiment, the connecting member 13a extends from within the slit 12a to the region between the wiring pattern 11a and the conductive film 22. This configuration may be adopted. This reduces the thermal contact resistance, particularly between the wiring pattern 11a on the main surface of the main board 10 and the conductive film 22. Therefore, the connecting member 13a can conduct heat from the transformer 20 to the wiring pattern 11a located on the main surface of the main board 10. This allows the heat generated in the transformer 20 to be dissipated more efficiently to the underside of the main board 10. This allows the transformer 20 to be cooled. Furthermore, thermal management of the transformer 20 becomes easier.

[0094] According to this embodiment, the so-called pin-in-paste method can be used when mounting each component on the main board 10. In the pin-in-paste method, cream solder as a connecting material is first pushed out of the slit, and then is sucked up into the slit by capillary action as it passes through a reflow furnace. This suction allows soldering to be performed at the desired location. With the pin-in-paste method, the reflow soldering process can supply the connecting material 13a to both the inside of the slit 12a and the area between the conductive film 22 and the wiring pattern 11a. This eliminates the need for a flow soldering process. Note that if the main board 10 does not have a slit, each component can be mounted on the main board 10 using the reflow soldering process.

[0095] <Modification> Through holes or thermal vias may be formed in the wiring pattern 11a of the main board 10. Solder may be supplied into these holes, and the holes may be filled with solder as a connecting member by a reflow soldering process. This further increases the thermal conductivity from the transformer 20 to the connecting member 13a. As a result, the transformer 20 can be cooled more efficiently.

[0096] Embodiment 4. Figure 12 is a schematic cross-sectional view of embodiment 4, corresponding to Figure 3. That is, Figure 12 shows a cross-sectional view of the present embodiment taken along line III-III in Figure 1. In Figure 12, the same aspects as those in Figure 3 of embodiment 1 will not be described again. Furthermore, except for the following differences, this embodiment basically has the same features as Figures 1 and 2 of embodiment 1. The same aspects of this embodiment as those in Figures 1 and 2 will not be described again.

[0097] In this embodiment, in the cross section shown in Fig. 12, the conductor film 22 of the transformer 20 includes one end 22E and the other end 22F. The cross section shown in Fig. 12 is a plane along the Z-axis and the X-axis. In the cross section of Fig. 12, the conductor film 22 is wound around the core 21, so that the one end 22E and the other end 22F are adjacent to each other and spaced apart in the X-direction. The other end 22F is located on the opposite side to the one end 22E in the direction in which the conductor film 22 is wound around the core 21.

[0098] Both one end 22E and the other end 22F are disposed at positions overlapping with the inside of slit 12a in a plan view from the Z direction. In other words, both one end 22E and the other end 22F are disposed at positions facing slit 12a in the Z direction. Both one end 22E and the other end 22F are disposed directly above slit 12a in the Z direction.

[0099] One end 22E and the other end 22F are connected to a connecting member 13a disposed inside the slit 12a. In Fig. 12, one end 22E and the other end 22F are covered by the connecting member 13a. In other words, the connecting member 13a is disposed so as to extend from inside the slit 12a onto the surface of the conductor film 22, including the one end 22E and the other end 22F directly above the slit 12a. The connecting member 13a is disposed so as to fill at least a portion of both the inside of the slit 12a and the area directly above it, sandwiched between the one end 22E and the other end 22F.

[0100] The connecting member 13a electrically and mechanically connects the one end 22E, the other end 22F, and the wiring pattern 11a. Note that it is sufficient that at least a portion of the one end 22E and at least a portion of the other end 22F are electrically connected to the connecting member 13a. The entire surfaces of the one end 22E and the other end 22F may be covered by the connecting member 13a, or only a portion of the entire surfaces may be covered by the connecting member 13a.

[0101] <Effects> In the power supply device 1000 according to this embodiment, the conductive film 22 includes one end 22E and the other end 22F. The other end 22F is located on the opposite side of the conductive film 22 from the one end 22E, and is arranged adjacent to the one end 22E with a gap therebetween by winding the conductive film 22 around the core 21. The one end 22E and the other end 22F are arranged in positions facing the slit 12a. The one end 22E and the other end 22F are connected to the connecting member 13a.

[0102] One end 22E and the other end 22F are electrically connected by the connecting member 13a. This allows a circuit loop to be formed by the conductive film 22 wound around the outer periphery of the core 21. A current flows through the circuit loop so as to cancel out generated noise. This is expected to further enhance the shielding effect of the conductive film 22.

[0103] Note that a circuit loop is also formed by the conductive film 22 that does not have one end 22E and the other end 22F and that wraps around the outer surface of the core 21, as in the first embodiment, and a loop current flows through it. However, when actually manufacturing the embodiment 1, a seam is inevitably formed in the conductive film 22. That is, one end 22E and the other end 22F are formed with a small gap between them. This point is not particularly mentioned in the description of the first embodiment. In order to form a circuit loop when a seam is formed in the conductive film 22 in the first embodiment, the seam may be soldered at a completely different location away from the slit 12a, for example. Alternatively, the circuit loop may be formed by electrically connecting the one end 22E and the other end 22F together.

[0104] Next, with the configuration of this embodiment, a so-called flow soldering process can be used when mounting each component on the main substrate 10. That is, connecting members 13a to 13d, such as solder, are filled into the slits 12a to 12d of the main substrate 10. In this way, each component is mounted on the main substrate 10. At this time, connecting member 13a, which connects one end 22E and the other end 22F of the conductor film 22, is supplied simultaneously with the supply of connecting members 13b to 13d. This allows the soldering process to be performed with high efficiency.

[0105] Fifth Embodiment. Figure 13 is a schematic cross-sectional view of the fifth embodiment, corresponding to Figure 3. That is, Figure 13 shows a cross-sectional view of the present embodiment taken along line III-III in Figure 1. In Figure 13, the same aspects as those in Figure 3 of the first embodiment will not be described again. Furthermore, except for the following differences, this embodiment basically has the same features as those in Figures 1 and 2 of the first embodiment. The same aspects of this embodiment as those in Figures 1 and 2 will not be described again.

[0106] In this embodiment, in the cross section shown in Fig. 13, the conductor film 22 of the transformer 20 includes one end 22E and the other end 22F. The cross section shown in Fig. 13 is a plane along the Z-axis and the X-axis. In the cross section of Fig. 13, the conductor film 22 is wound around the core 21, so that the one end 22E and the other end 22F are adjacent to each other with a gap between them. The other end 22F is located on the opposite side of the one end 22E in the direction in which the conductor film 22 is wound around the core 21. This point is common to the fourth embodiment.

[0107] However, in FIG. 13 , the other end 22F is arranged to overlap with the one end 22E in a plan view from the Z direction. In FIG. 13 , the one end 22E is arranged higher in the Z direction than the other end 22F. However, conversely, the other end 22F may be arranged higher in the Z direction than the one end 22E. In FIG. 13 , the region adjacent to the one end 22E is linear, while the region adjacent to the other end 22F has a bent portion. This may also be reversed. In other words, the region adjacent to the other end 22F may be linear, and the region adjacent to the one end 22E may have a bent portion. This is true regardless of whether the one end 22E or the other end 22F is arranged higher in the Z direction.

[0108] Hereinafter, one end 22E and the region adjacent to one end 22E may be collectively referred to as one end 22E. Also, hereinafter, the other end 22F and the region adjacent to the other end 22F may be collectively referred to as the other end 22F. The portion where one end 22E and the other end 22F overlap in a plan view from the Z direction is referred to as an overlapping portion 22EF. Herein, the overlapping portion 22EF refers to both one end 22E and the other end 22F themselves at the overlapping portion where one end 22E and the other end 22F overlap, as well as the region therebetween.

[0109] At least a portion of the overlapping portion 22EF is disposed within the slit 12a. In Fig. 13, the entire other end 22F and the region therebetween are disposed within the slit 12a.

[0110] The overlapping portion 22EF is connected to a connecting member 13a disposed inside the slit 12a. Furthermore, within the slit 12a, a region adjacent to one end 22E and a region adjacent to the other end 22F may be covered by the connecting member 13a and connected to the connecting member 13a. A configuration in which a portion of the overlapping portion 22EF is not connected to the connecting member 13a is also possible. Furthermore, if a portion of the overlapping portion 22EF protrudes outside the slit 12a, the connecting member 13a may protrude from inside the slit 12a to outside the slit 12a and be connected to the overlapping portion 22EF. The connecting member 13a electrically and mechanically connects the one end 22E, the other end 22F, and the wiring pattern 11a.

[0111] In this embodiment, as in the above-described embodiments, it is preferable that an adhesive layer be provided on one main surface of the conductive film 22. As in the other embodiments, the adhesive layer may be a thin insulating layer. In this way, the conductive film 22 is fixed to the surface of the core 21, which facilitates the manufacturing process. In addition, an insulating effect can be expected between the core 21 and the conductive film 22 in this portion.

[0112] <Effects> In the power supply device 1000 according to this embodiment, the conductive film 22 includes one end 22E and the other end 22F. The other end 22F is located on the opposite side of the conductive film 22 from the one end 22E, and is arranged to overlap with the one end 22E by winding the conductive film 22 around the core 21. At least a portion of the overlapping portion 22EF, which is the portion where the one end 22E and the other end 22F overlap, is arranged within the slit 12a. The overlapping portion 22EF is connected to the connecting member 13a.

[0113] As a result, similar to the fourth embodiment, it is expected that the current flowing in the circuit loop formed by the conductive film 22 will further enhance the shielding effect of the conductive film 22. Also, similar to the fourth embodiment, the use of a flow soldering process can increase the efficiency of the soldering process.

[0114] Furthermore, because at least a portion of the overlapping portion 22EF is disposed within the slit 12a, even if the conductive film 22 is further overlapped thereon, an increase in the height of the transformer 20 on the main substrate 10 in the Z direction can be suppressed. This allows the module 300 to be miniaturized. As a result, the entire power supply device 1000 can be miniaturized.

[0115] Sixth Embodiment Fig. 14 is a schematic cross-sectional view of the sixth embodiment, corresponding to Fig. 3. That is, Fig. 14 shows a cross-sectional view of the present embodiment taken along line III-III in Fig. 1. In Fig. 14, the same aspects as those in Fig. 3 of the first embodiment will not be described again. Furthermore, except for the following differences, this embodiment basically has the same features as Figs. 1 and 2 of the first embodiment. The same aspects of this embodiment as those in Figs. 1 and 2 will not be described again.

[0116] In this embodiment, in the cross section shown in Fig. 14, the slit 12e is formed in a region other than the region facing the transformer 20. Here, facing means that the slit 12e faces the transformer 20 in the Z direction in the cross section along the XZ plane as shown in Fig. 14. In the cross section of Fig. 14, the slit 12e is not disposed directly below the transformer 20 in the Z direction. Therefore, the slit 12e does not face the transformer 20.

[0117] Therefore, the slits 12e are formed in an area of ​​the main substrate 10 other than the area facing the conductive film 22 wrapped around the core 21 of the transformer 20. In other words, the slits 12e do not face the conductive film 22 of the transformer 20 in the Z direction. In other words, the slits 12e are arranged so as not to overlap with the conductive film 22 in the Z direction. In this respect, the present embodiment differs in configuration from the above-described embodiments in which the slits are arranged so as to overlap with the transformer 20 and the conductive film 22 in the Z direction.

[0118] As shown in FIG. 14 , the connection member 13e is disposed inside the slit 12e. The connection member 13e is made of the same material as the connection member 13a. The connection member 13e extends from inside the slit 12e to the surface of the conductive film 22 outside the slit 12e. The surface of the conductive film 22 refers to the surface of the portion of the conductive film 22 that is wrapped around the side surface of the core 21 extending along the Z direction. In other words, the connection member 13e extends from inside the slit 12e to the conductive film 22 on the side surface of the core 21. The connection member 13e is attached to the conductive film 22 on the side surface of the core 21 on which the slit 12e exists. In FIG. 14 , the side on which the slit 12e exists is the right side of the core 21 (positive side in the X direction). In other words, the connection member 13e is attached to the surface of the conductive film 22 on the right side surface of the core 21. As a result, the connecting member 13e is disposed both within the slit 12e and directly above it in the Z direction.

[0119] 14 can be formed by moving the main board 10 to the right in the X direction relative to a stationary solder bath during a flow soldering process. Alternatively, the embodiment shown in FIG. 14 may be achieved by wetting and spreading the connecting member 13e without moving the main board 10 relative to a stationary solder bath.

[0120] The slit 12e may be present on the left side (negative side in the X direction) of the core 21. In this case, for example, in a flow soldering process, the slit 12e can be formed by moving the main board 10 to the left in the X direction relative to a stationary solder bath.

[0121] In the module 300 formed as described above, the conductor film 22 and the wiring pattern 11a are electrically and mechanically connected by the connection member 13e. The wiring pattern 11a is arranged directly below the transformer 20 in the Z direction. The wiring pattern 11a is formed on the main surface of the main substrate 10. The wiring pattern 11a is formed from above the main surface of the main substrate 10 into the slit 12e. The connection member 13e is arranged so as to contact both the wiring pattern 11a in the slit 12e and the conductor film 22 directly above it in the Z direction. This electrically and mechanically connects the conductor film 22 and the wiring pattern 11a via the connection member 13e.

[0122] <Effects> In the power supply device 1000 according to the present embodiment, the slits 12e are formed in an area of ​​the main substrate 10 other than the area facing the conductive film 22. The connecting members 13e extend continuously from within the slits 12e to the surface of the conductive film 22 outside the slits 12e.

[0123] This allows the conductive film 22 and the wiring pattern 11a to be more firmly connected, thereby improving the vibration resistance of the power supply device 1000. Furthermore, the connecting member 13e improves heat dissipation from the transformer 20 and the conductive film 22 to the surroundings of the power supply device 1000, such as the lower part of the main board 10. This allows the transformer 20 to be cooled more efficiently.

[0124] The features described in each of the above-described embodiments (each example included therein) may be applied in an appropriate combination within the scope of technical compatibility.

[0125] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0126] (Supplementary Note) Various aspects of the present disclosure will be summarized below as supplementary notes.

[0127] (Supplementary Note 1) A switching power supply device comprising: a main substrate having a main surface and including a wiring pattern; a switching transformer having a core and a conductive film wound around the core and converting power; and a connecting member, wherein the switching transformer is disposed on the main surface of the main substrate, a slit penetrating the main substrate is formed in the main surface of the main substrate, the wiring pattern is connected to a stable potential, a portion of the wiring pattern is formed within the slit, and the connecting member is disposed inside the slit and electrically connects the conductive film and the wiring pattern.

[0128] (Supplementary Note 2) The switching power supply device according to Supplementary Note 1, wherein the wiring pattern is formed so as to extend from within the slit onto the main surface of the main substrate adjacent to the slit, and the conductive film is disposed on the wiring pattern on the main surface so as to cover at least a portion of the slit.

[0129] (Supplementary Note 3) The switching power supply device according to Supplementary Note 1 or 2, further comprising: a first board capable of receiving power from the outside; and a second board capable of transmitting power to the outside, wherein the first board and the second board are connected to the main board so as to sandwich the switching transformer.

[0130] (Appendix 4) A switching power supply device according to Appendix 3, wherein the first substrate includes a first wiring pattern having a first reference potential as the stable potential, the second substrate includes a second wiring pattern having a second reference potential as the stable potential, the main substrate includes another wiring pattern arranged at a distance from the wiring pattern, and at least one of the first wiring pattern and the second wiring pattern is electrically connected to the other wiring pattern.

[0131] (Supplementary Note 5) The switching power supply device according to Supplementary Note 4, wherein the first wiring pattern is electrically connected to the other wiring pattern, and the switching transformer is disposed at a position closer to the first substrate than to the second substrate.

[0132] (Supplementary Note 6) The switching power supply device according to any one of Supplementary Notes 3 to 5, wherein the first substrate and the second substrate are connected to the main substrate by a substrate connecting member made of the same material as the connecting member.

[0133] (Supplementary Note 7) A switching power supply device according to Supplementary Note 3, wherein a first insulating member, the conductive film, and a second insulating member are arranged on the surface of the core in this order from the side closest to the surface of the core, an opening is formed in the second insulating member at a portion facing the slit, and the portion of the conductive film exposed at the opening is connected to the connecting member.

[0134] (Appendix 8) A switching power supply device according to Appendix 7, wherein the main substrate has a ground potential as the stable potential, the first substrate includes a first wiring pattern having a first reference potential as the stable potential, the second substrate includes a second wiring pattern having a second reference potential as the stable potential, the conductor film is connected to the ground potential, and a distance between the ground potential and the second reference potential is shorter than a distance between the ground potential and the first reference potential.

[0135] (Supplementary Note 9) The switching power supply device according to any one of Supplementary Notes 1 to 8, wherein the connection member extends from within the slit to a region between the wiring pattern and the conductive film.

[0136] (Supplementary Note 10) The switching power supply device according to any one of Supplementary Notes 1 to 8, wherein the conductive film is in contact with the wiring pattern.

[0137] (Supplementary Note 11) The switching power supply device according to any one of Supplementary Notes 1 to 10, wherein the conductor film includes one end and a second end that is located on the opposite side of the conductor film from the one end and that is arranged adjacent to the one end with a gap therebetween by winding the conductor film around the core, the one end and the second end being arranged in a position facing the slit, and the one end and the second end being connected to the connecting member.

[0138] (Supplementary Note 12) The switching power supply device according to any one of Supplementary Notes 1 to 10, wherein the conductor film includes one end and another end that is located on the opposite side of the conductor film from the one end and that is arranged to overlap with the one end by wrapping the conductor film around the core, at least a part of the overlapping portion of the one end and the other end is arranged within the slit, and the overlapping portion of the one end and the other end is connected to the connecting member.

[0139] (Supplementary Note 13) The switching power supply device according to any one of Supplementary Notes 1 to 12, comprising: an input connector that is installed on the main board and that receives power from an external source; and a noise filter, wherein the noise filter includes: a first capacitor connected to the input connector; a choke coil connected to the first capacitor; a second capacitor connected to the choke coil on the side opposite to the first capacitor; and a third capacitor connected in parallel with the second capacitor.

[0140] (Appendix 14) The switching power supply device according to Appendix 1, wherein the slit is formed in an area of ​​the main substrate other than an area facing the conductive film, and the connecting member extends continuously from within the slit onto a surface of the conductive film adjacent to the slit.

[0141] 4a, 4b capacitor, 4bb terminal, 10 main board, 11a, 11b, 11c, 11d wiring pattern, 12a, 12b, 12c, 12d, 12e slit, 13a, 13b, 13c, 13d, 13e connecting member, 20 switching transformer, 21 core, 22 conductive film, 22E one end, 22EF superimposed portion, 22F other end, 23a first insulating member, 23b second insulating member, 30 filter, 31 coil connection capacitor, 31a first capacitor, 31b second capacitor, 32 choke coil, 33 module connection capacitor, 40 ground potential, 41 first reference potential, 42 second reference potential, 100 first board, 101 first wiring pattern, 200 second board, 201 second wiring pattern, 300 module, 1000 power supply device, IC input connector, N Coil, OC output connector.

Claims

1. A switching power supply comprising: a main substrate having a main surface and including a wiring pattern; a switching transformer having a core and a conductive film wrapped around the core and converting power; and a connecting member, wherein the switching transformer is disposed on the main surface of the main substrate; a slit is formed on the main surface of the main substrate that penetrates the main substrate; the wiring pattern is connected to a stable potential; a portion of the wiring pattern is formed within the slit; and the connecting member is disposed inside the slit and electrically connects the conductive film and the wiring pattern.

2. The switching power supply device according to claim 1, wherein the wiring pattern is formed so as to extend from within the slit onto the main surface of the main substrate adjacent to the slit, and the conductive film is disposed on the wiring pattern on the main surface so as to cover at least a portion of the slit.

3. A switching power supply device as described in claim 1 or 2, further comprising a first board capable of receiving power from the outside and a second board capable of transmitting power to the outside, the first board and the second board being connected to the main board so as to sandwich the switching transformer.

4. The switching power supply device according to claim 3, wherein the first substrate includes a first wiring pattern having a first reference potential as the stable potential, the second substrate includes a second wiring pattern having a second reference potential as the stable potential, the main substrate includes another wiring pattern arranged at a distance from the wiring pattern, and at least one of the first wiring pattern and the second wiring pattern is electrically connected to the other wiring pattern.

5. The switching power supply device according to claim 4, wherein the first wiring pattern is electrically connected to the other wiring pattern, and the switching transformer is disposed closer to the first substrate than to the second substrate.

6. The switching power supply device according to claim 3, wherein the first and second substrates are connected to the main substrate by a substrate connecting member made of the same material as the connecting member.

7. A switching power supply device as described in claim 3, wherein a first insulating member, the conductive film, and a second insulating member are arranged on the surface of the core in this order from the side closest to the surface of the core, an opening is formed in the second insulating member at a portion facing the slit, and the portion of the conductive film exposed at the opening is connected to the connecting member.

8. A switching power supply device as described in claim 7, wherein the main substrate has a ground potential as the stable potential, the first substrate includes a first wiring pattern having a first reference potential as the stable potential, the second substrate includes a second wiring pattern having a second reference potential as the stable potential, the conductor film is connected to the ground potential, and the distance between the ground potential and the second reference potential is shorter than the distance between the ground potential and the first reference potential.

9. The switching power supply device according to claim 1 or 2, wherein the connecting member extends from within the slit to the region between the wiring pattern and the conductive film.

10. The switching power supply device according to claim 1 or 2, wherein the conductive film is in contact with the wiring pattern.

11. A switching power supply device as described in claim 1 or 2, wherein the conductor film includes one end and another end that is located on the opposite side of the conductor film from the one end and that is arranged adjacent to the one end with a gap between them as a result of the conductor film being wound around the core, the one end and the other end being arranged in a position facing the slit, and the one end and the other end being connected to the connecting member.

12. A switching power supply device as described in claim 1 or 2, wherein the conductor film includes one end and another end that is located on the opposite side of the conductor film from the one end and that is arranged to overlap the one end by wrapping the conductor film around the core, at least a part of the overlapping portion of the one end and the other end is arranged within the slit, and the overlapping portion of the one end and the other end is connected to the connecting member.

13. A switching power supply device as claimed in claim 1 or 2, comprising: an input connector mounted on the main board for receiving power from an external source; and a noise filter, the noise filter including: a first capacitor connected to the input connector; a choke coil connected to the first capacitor; a second capacitor connected to the choke coil on the side opposite to the first capacitor; and a third capacitor connected in parallel with the second capacitor.

14. A switching power supply device as described in claim 1, wherein the slit is formed in an area of ​​the main substrate other than an area facing the conductive film, and the connecting member extends continuously from within the slit to the surface of the conductive film outside the slit.

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