Electronic device

Abstract

To provide an electronic device such as a power converter capable of satisfactorily reducing wiring loss.SOLUTION: An electronic device (1) includes an output wire (113) and a ground wire (114) which are a pair of wires, and a base plate (102) made of a conductor. The output wiring and the ground wiring are formed on the printed circuit board (101). The output wiring is disposed between the ground wiring and the base plate so that a ground current path (115) is formed in the base plate. Specifically, a gap (G) between the output wiring provided on the printed circuit board and the base plate is set such that a current path for grounding is formed in the base plate.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to electronic devices such as power converters. [Background technology]

[0002] Patent Document 1 discloses a power conversion device provided with a transformer having a primary winding and a secondary winding. In this transformer, the primary winding is composed of three winding layers, and the secondary winding is composed of two winding layers. The winding layers constituting the primary winding and the winding layers constituting the secondary winding are alternately stacked.

[0003] When current flows through two windings that are close to each other, the magnetic field generated around one of the windings causes a Lorentz force to act on the electrons flowing through the other winding, resulting in a phenomenon known as the proximity effect, which causes a bias in the current flowing through the windings.When the proximity effect occurs, the resistance of the windings increases, and winding loss (i.e. copper loss) increases.

[0004] In this regard, in Patent Document 1, the winding layers constituting the primary winding and the winding layers constituting the secondary winding are arranged alternately. In other words, the current flowing through a certain winding flows in the opposite direction to the current flowing through the windings on either side of that certain winding. This cancels out the influence of the magnetic field acting on that certain winding, and the current distribution within the winding is made uniform. This reduces winding loss. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-13055 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, power converters for electric vehicles, such as DC / DC converters for charging auxiliary batteries, in which a large current flows on the low-voltage side of the transformer, have become widely used. In such power converters in which a large current flows, there is a concern that wiring loss will increase.

[0007] The present invention has been made in view of the above-mentioned circumstances, etc. That is, the present invention provides an electronic device such as a power converter that can effectively reduce wiring loss. [Means for solving the problem]

[0008] The electronic device (1) according to claim 1 comprises: a pair of wiring, an output wiring (113) and a ground wiring (114); a conductive base plate (102); Equipped with The output wiring is disposed between the ground wiring and the base plate so that a ground current path (115) is formed in the base plate.

[0009] In addition, in each section of the application documents, each element may be given a reference symbol in parentheses. However, such reference symbol merely indicates an example of the correspondence between the element and the specific means described in the embodiment described below. Therefore, the present invention is not limited in any way by the above-mentioned reference symbols. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a schematic circuit configuration of an electronic device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing a schematic configuration of the electronic device shown in FIG. [Figure 3] 3 is an enlarged cross-sectional view of a portion of the electronic device shown in FIG. 2. FIG. [Figure 4] 2 is an enlarged cross-sectional view showing an embodiment of a main configuration of the electronic device shown in FIG. 1. FIG. [Figure 5] 10A and 10B are diagrams illustrating the results of electromagnetic field analysis in a wiring structure according to a comparative example. [Figure 6] 10A and 10B are diagrams illustrating electromagnetic field analysis results for a wiring structure according to an embodiment. [Figure 7] 3 is a schematic circuit diagram showing a current path around the center tap terminal shown in FIG. 2. FIG. [Figure 8] FIG. 10 is an enlarged cross-sectional view showing a main configuration of an electronic device according to another embodiment. [Figure 9] FIG. 10 is an enlarged cross-sectional view showing a main configuration of an electronic device according to yet another embodiment. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing a main configuration of an electronic device according to yet another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Embodiment) Hereinafter, exemplary embodiments and specific examples of the present invention will be described with reference to the drawings as appropriate. Note that the following embodiments and their modifications, as well as the descriptions in the drawings, are schematic or simplified for the purpose of concisely explaining the contents of the present invention, and are not intended to limit the contents of the present invention in any way. Therefore, it goes without saying that the descriptions in the drawings do not necessarily coincide with the actual device configuration. In other words, unless expressly limited by the applicant in the prosecution history of this application, it goes without saying that the present invention should not be interpreted as being limited by the descriptions in the drawings and the device configuration, functions, or operations described below corresponding thereto.

[0012] (Circuit configuration) 1, electronic device 1 is configured as a power converter with a transformer 4 provided between a high-voltage side circuit 2 and a low-voltage side circuit 3. Specifically, electronic device 1 is configured to convert the voltage of power input to high-voltage side circuit 2 and output the converted voltage between output section 5, i.e., first output terminal 5a and second output terminal 5b, provided in low-voltage side circuit 3. Electronic device 1 according to one embodiment of the present invention is a so-called DC / DC converter and can be used, for example, to charge an auxiliary battery in a hybrid vehicle.

[0013] The high-voltage side circuit 2 includes a bridge circuit (for example, a full-bridge circuit) having a plurality of switching elements (not shown), and is configured to convert an input DC voltage into an AC voltage and output it. The switching elements provided in the high-voltage side circuit 2 operate under the control of the control device 6.

[0014] The low-voltage side circuit 3 has a rectifier circuit 3a and a smoothing circuit 3b. The rectifier circuit 3a has a rectifier element 31. The rectifier element 31 is a switching element that operates under the control of the control device 6, and each rectifier element 31 is provided so as to be connected to the ungrounded side of the secondary winding 42 of the transformer 4. The smoothing circuit 3b has a choke coil 32 and a smoothing capacitor 33. The choke coil 32 is provided on the side of the first output terminal 5a, which is the ungrounded output terminal. The smoothing capacitor 33 is provided between the output line 34, which is the ungrounded wiring, and the ground line 35, which is the grounded wiring.

[0015] The transformer 4 has a primary winding 41, a secondary winding 42, and a core 43. The primary winding 41 is connected to the high-voltage side circuit 2. The secondary winding 42 is connected to the low-voltage side circuit 3. In this embodiment, a center tap 44 is provided between the pair of secondary windings 42. The basic circuit configuration of the electronic device 1 as described above was already publicly known or well-known at the time of filing of this application (see, for example, Japanese Patent Application Laid-Open No. 2023-184134). Therefore, further detailed description of the circuit configuration shown in FIG. 1 will be omitted.

[0016] (Device configuration) 2, electronic device 1 has a configuration in which printed circuit board 101 and base plate 102 are fastened together with a plurality of board fastening screws 103. Printed circuit board 101 is provided with high-voltage side circuit 2 and low-voltage side circuit 3 shown in FIG. 1. Base plate 102 is a plate-shaped member made of a good conductor of metal so as to be electrically grounded.

[0017] The electrical connection between the base plate 102 and the transformer 4, i.e., the grounding of the transformer 4, is formed using a plurality of transformer fastening screws 104 made of conductive metal. One of the plurality of transformer fastening screws 104 fastens a center tap terminal 105 provided on the transformer 4. That is, the electronic device 1 is provided with a center tap fastening portion 106, which is the fastening point between the transformer fastening screw 104 and the center tap terminal 105, and a board fastening portion 107, which is the other fastening point by the transformer fastening screw 104.

[0018] 3 corresponds to a cross-sectional view taken along the dashed dotted line in FIG. 2, enlarging the area around the center tap fastening portion 106 and the board fastening portions 107 on both sides of it. As shown in FIG. 3, a cylindrical protrusion 108 that penetrates the printed circuit board 101 and protrudes upward is provided on the base plate 102 at a position corresponding to the center tap fastening portion 106. Then, with the cylindrical protrusion 108 and the center tap terminal 105 placed one above the other while in contact with each other, an electrical connection is formed between the base plate 102 and the center tap terminal 105 by fastening a transformer fastening screw 104 to the cylindrical protrusion 108.

[0019] The printed circuit board 101 has a board insulating layer 111 and a board wiring layer 112, which is a conductor layer. The board insulating layer 111 is provided between a pair of board wiring layers 112 arranged in the thickness direction of the printed circuit board 101. Hereinafter, the thickness direction of the printed circuit board 101 will be referred to as the "board thickness direction." In contrast, the direction perpendicular to the board thickness direction, i.e., the direction along the surface of the printed circuit board 101, will be referred to as the "in-plane direction." Of the board wiring layers 112, the one that constitutes the ground wire 35 in FIG. 1 is electrically connected to the base plate 102 at the board fastening portion 107 via a well-known so-called via hole connection through the transformer fastening screw 104.

[0020] (First embodiment) Fig. 4 shows a schematic configuration corresponding to the first embodiment of the present invention. Specifically, Fig. 4 corresponds to an enlarged conceptual diagram of the lower end portion of printed circuit board 101 in the board thickness direction, i.e., the portion facing base plate 102, extracted from Fig. 3. Referring to Fig. 4, output wiring 113 and ground wiring 114 are formed on printed circuit board 101. Output wiring 113 and ground wiring 114 are provided in low-voltage side circuit 3 shown in Fig. 1.

[0021] The output wiring 113 is a board wiring layer 112 provided at the lower end of the printed circuit board 101 in the board thickness direction, and is disposed opposite the base plate 102 across a gap G. In other words, the output wiring 113 constitutes the output line 34 in FIG.

[0022] The grounding wiring 114 forms a pair of wiring together with the output wiring 113, and is provided at a position corresponding to the output wiring 113 in the in-plane direction. The grounding wiring 114 constitutes the ground line 35 in FIG. 1. The grounding wiring 114 is insulated and separated from the output wiring 113 by the substrate insulating layer 111. The output wiring 113 and the grounding wiring 114 are provided so that currents flow in opposite directions to each other. The base plate 102 and the grounding wiring 114 are electrically connected at the substrate fastening portion 107 by fastening the transformer fastening screw 104.

[0023] In this embodiment, the output wiring 113 is arranged between the base plate 102 and the ground wiring 114 so that a base plate current path 115, which is a current path for grounding, is formed in the base plate 102. Specifically, the distance between the output wiring 113 and the base plate 102 is set so that the base plate current path 115 is formed in the base plate 102 by bringing the output wiring 113 and the base plate 102 closer to each other. A current flows through the base plate current path 115 in the same direction as the ground wiring 114. In this embodiment, the electronic device 1 is configured so that the size of the gap G is approximately the same as the thickness of the substrate insulating layer 111, so that the magnitude of the current through the ground wiring 114 and the base plate current path 115 is approximately the same.

[0024] 2 and 3, the board fastening portion 107 is provided on both sides of the center tap fastening portion 106. Correspondingly, the electronic device 1 is configured so that the current flowing through the base plate 102 branches at the board fastening portion 107 and flows to the grounding wiring 114.

[0025] (effect) The effects achieved by the configuration of this embodiment will be described below.

[0026] Fig. 5 shows, as a comparative example, the results of electromagnetic field analysis when output wiring 113 and ground wiring 114, a pair of wiring through which currents flow in opposite directions, are arranged in the thickness direction of the substrate, i.e., when there is no base plate current path 115. In contrast, Fig. 6 shows, as an example, the results of electromagnetic field analysis when output wiring 113 is arranged between ground wiring 114 and base plate current path 115. Figs. 5 and 6 show the magnitude of current in the in-plane direction in contour diagrams.

[0027] 5, the proximity effect is pronounced in the comparative example configuration without the base plate current path 115. In contrast, the proximity effect is effectively suppressed in the example configuration with the base plate current path 115. The wiring loss in the example configuration was also reduced to about half that of the comparative example configuration.

[0028] 7 schematically shows the current path in the ground wire 35 leading to the center tap 44. As shown in FIG. 7, the current flowing through the base plate 102 branches at the board fastening portion 107 and flows to the grounding wiring 114. That is, two ground current paths are generated: one that passes only through the base plate 102 to the center tap 44, and another that branches at the board fastening portion 107, passes through the grounding wiring 114 on the printed circuit board 101 side, and flows to the center tap 44.

[0029] In this embodiment, the base plate 102 that supports and fixes the printed circuit board 101 is used as a ground current path, so that the ground current and the output current that flow in opposite directions are alternately stacked. This effectively suppresses the proximity effect, thereby effectively reducing wiring loss.

[0030] The size of gap G can be set according to the ratio of the magnitude of the current between ground wiring 114 and base plate current path 115. Specifically, for example, by making the size of gap G larger than the thickness of substrate insulating layer 111 between output wiring 113 and ground wiring 114, it becomes possible to allow a larger current to flow through base plate current path 115 than through ground wiring 114. In other words, when the distance between output wiring 113 and ground wiring 114 is A and the distance between output wiring 113 and base plate 102 is B, it becomes possible to set the current ratio between ground wiring 114 and base plate current path 115 to A:B.

[0031] Second Embodiment FIG. 8 shows a schematic configuration corresponding to a second embodiment of the present invention. In the following description of the second embodiment, differences from the first embodiment will be mainly described. In addition, identical or equivalent parts in the first and second embodiments are designated by the same reference numerals. Therefore, in the following description of the second embodiment, the description of the first embodiment may be appropriately applied to components having the same reference numerals as those in the first embodiment, unless there is a technical contradiction or a special additional explanation. The same applies to the third and subsequent embodiments and modified examples described below.

[0032] 8, in this embodiment, the base plate current path 115 is formed by a protrusion 116 provided on the base plate 102 so as to protrude toward the printed circuit board 101. The protrusion 116 is provided in the same in-plane pattern as the wiring pattern of the output wiring 113. With this configuration, the in-plane spread of the base plate current path 115 on the base plate 102 can be effectively suppressed, thereby more effectively suppressing the proximity effect.

[0033] (Third embodiment) FIG. 9 shows a schematic configuration corresponding to a third embodiment of the present invention. As shown in FIG. 9, in this embodiment, the base plate current path 115 is formed by a conductor layer 117 made of a highly conductive material provided on the base plate 102. The highly conductive material constituting the conductor layer 117 is gold, silver, copper, or an alloy containing one of these as a main component. That is, the conductor layer 117 may be provided as a conductor pattern formed on the surface of the planar base plate 102. This configuration can also achieve the same effects as the second embodiment.

[0034] (Fourth embodiment) Fig. 10 shows a schematic configuration corresponding to a third embodiment of the present invention. As shown in Fig. 10, in this embodiment, a heat transfer layer 118 is sandwiched between the output wiring 113 and the base plate 102. That is, the gap G is filled with the heat transfer layer 118.

[0035] The heat transfer layer 118 is made of an insulating, heat-conducting material. Examples of the insulating, heat-conducting material that can be used for the heat transfer layer 118 include well-known materials such as an insulating, heat-conducting resin such as silicon resin, a ceramic material such as AlN, and a synthetic resin containing such a ceramic material as a filler.

[0036] The heat transfer layer 118 is not limited to the configuration having the protrusions 116 as shown in Fig. 10, but can also be applied to a configuration without the protrusions 116 as shown in Fig. 4 or 9. With such a configuration, in addition to the effects achieved by the above-described embodiments, heat dissipation from the printed circuit board 101 to the base plate 102 is improved.

[0037] (Variation) The present invention is not limited to the above-described embodiments and specific examples. Therefore, the above-described embodiments and the like can be modified as appropriate. Representative modifications will be described below. In the following description of the modifications, differences from the above-described embodiments and the like will be mainly described. Furthermore, the same reference numerals are used for parts that are identical or equivalent to each other in the above-described embodiments and the following modifications. Therefore, in the following description of the modifications, the explanations in the above-described embodiments and the like can be used as appropriate for components that have the same reference numerals as the above-described embodiments and the like, unless there is a technical contradiction or special additional explanation.

[0038] The application of the present invention is not limited to DC / DC converters for charging auxiliary batteries in hybrid vehicles. That is, the present invention can be applied to a wide range of applications from the viewpoint of reducing wiring loss when a relatively large current flows through a pair of wiring. The basic circuit configuration and device configuration are also not limited to those disclosed in Figures 1 and 2.

[0039] It goes without saying that the elements constituting the above-described embodiments are not necessarily essential unless they are particularly clearly stated as essential or are considered to be clearly essential in principle. Furthermore, when numerical values ​​such as the number, value, amount, range, etc. of components are mentioned, the present invention is not limited to those specific numbers unless they are particularly clearly stated as essential or are clearly limited to specific numbers in principle. Similarly, when the shape, direction, positional relationship, etc. of components are mentioned, the present invention is not limited to those shapes, directions, positional relationship, etc. unless they are particularly clearly stated as essential or are clearly limited to specific shapes, directions, positional relationship, etc. in principle.

[0040] The modified examples are not limited to the above examples. For example, all or part of one of the multiple embodiments or specific examples may be combined with all or part of another embodiment, provided that there is no technical inconsistency. There is no particular limit to the number of combinations. Similarly, all or part of one of the multiple modified examples may be combined with all or part of another embodiment, provided that there is no technical inconsistency. Furthermore, all or part of the above specific example and all or part of the above modified example may be combined with each other, provided that there is no technical inconsistency. [Explanation of symbols]

[0041] 1 Electronic equipment 101 Printed Circuit Board 102 base plate 109 Gap 113 Output wiring 114 Grounding wiring 115 Baseplate current path 116 Protrusion 117 Conductor layer 118 Heat Transfer Layer

Claims

1. An electronic device (1), A pair of wirings, an output wiring (113) and a ground wiring (114), a conductive base plate (102); Equipped with the output wiring is disposed between the grounding wiring and the base plate so that a grounding current path (115) is formed in the base plate; electronic equipment.

2. Further provided is a fastening portion (107) that electrically connects the base plate and the grounding wiring, The current flowing through the base plate is branched at the fastening portion and flows into the grounding wiring. The electronic device of claim 1 .

3. The output wiring and the ground wiring are formed on a printed circuit board (101).

3. The electronic device of claim 2.

4. a gap (G) between the output wiring and the base plate is set so that the current path is formed in the base plate; The electronic device of claim 3 .

5. the spacing is set in accordance with the ratio of the magnitude of the current in the grounding wiring to the magnitude of the current in the current path in the base plate; 5. The electronic device of claim 4.

6. The current path is formed by a protrusion (116) provided on the base plate. The electronic device according to any one of claims 1 to 5.

7. The current path is formed by a conductor layer (117) made of a highly conductive material provided on the base plate. The electronic device according to any one of claims 1 to 5.

8. The highly conductive material is gold, silver, copper, or an alloy containing one of these as a main component.

8. The electronic device of claim 7.

9. The power supply further includes a heat transfer layer (118) sandwiched between the output wiring and the base plate. The electronic device according to any one of claims 1 to 5.

10. The power converter is configured to include a transformer (4) between a high-voltage side circuit (2) and a low-voltage side circuit (3), The output wiring and the ground wiring are provided in the low-voltage side circuit. The electronic device according to any one of claims 1 to 5.

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