JP2016025690A - Electronic module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic module which enables reduction of an entire height compared to a conventional electronic module.SOLUTION: An electronic module 2 includes: a circuit board 4; and a transformer 6A mounted on the circuit board 4. A cutout 22 formed as a space extending from a surface, on which the transformer 6A is mounted, to the inner side of the circuit board 4 is provided on the circuit board 4. At least a part of the transformer 6A is positioned in the cutout 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic module, and more particularly to an electronic module in which an electronic component is mounted on a thick copper multilayer substrate.

  A DC-DC converter is known as a kind of electronic module formed by mounting various electronic components on a substrate. In a general DC-DC converter, an electronic component such as a transformer is surface-mounted on a substrate. In such a DC-DC converter, since a large current flows in the circuit, a large current substrate that can cope with the large current is used as the circuit substrate. As a wiring member incorporated in such a large current substrate, not a general copper foil but a copper plate material thicker than the copper foil, a so-called thick copper plate is used. The thick copper plate has low electrical resistance and excellent heat dissipation. As a large current substrate formed using such a thick copper plate, for example, a substrate disclosed in Patent Document 1 is known.

JP-A-8-222838

  Many large current substrates are also used. Since the thick copper multilayer substrate, which is a multilayered large current substrate, has a thick copper plate in each layer, the overall thickness is thicker than a circuit substrate used for general purposes. When various electronic components are surface-mounted on such a thick copper multilayer substrate, the overall height of the obtained electronic module such as a DC-DC converter becomes relatively high.

  In recent years, downsizing of the product itself in which the electronic module is incorporated has been promoted, and thus downsizing of the electronic module is also desired. Therefore, as one of the measures for reducing the size of the electronic module, the height of the entire electronic module is reduced by using electronic components that are as low as possible. Here, for example, in the case of a DC-DC converter, since the transformer is the highest electronic component among the electronic components to be mounted, it is necessary to use a transformer with the lowest possible height.

  However, since the transformer is an electronic component that requires a certain height due to the number of turns of the coil, there is a limit to reducing the height of the transformer itself. For this reason, it is difficult to reduce the overall height of the electronic module in which the transformer is surface-mounted.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide an electronic module capable of lowering the overall height as compared with the prior art.

  In order to achieve the above object, according to the present invention, a circuit board and a transformer mounted on the circuit board are provided, and the circuit board includes an inner side of the circuit board from a surface on which the transformer is mounted. There is provided an electronic module in which a space is provided, and at least a part of the transformer is positioned in the space.

  Preferably, the space is a notch provided in a side portion of the circuit board.

  The space is preferably a through hole penetrating the circuit board.

  An electronic module according to the present invention includes a circuit board and a transformer mounted on the circuit board. The circuit board described above is provided with a space extending from the surface on which the transformer is mounted to the inside of the circuit board. At least a part of the above-described transformer is positioned in the above-described space. For this reason, the height of the transformer protruding on the circuit board can be reduced, and as a result, the height of the entire electronic module can be made lower than before. Therefore, the electronic module according to the present invention contributes to miniaturization of a device in which the electronic module itself is incorporated.

It is the perspective view which showed the electronic module which concerns on the 1st Embodiment of this invention. It is a front view of a transformer It is a perspective view of a transformer. It is the perspective view which showed the assembly procedure of the electronic module which concerns on 1st Embodiment. It is the side view which expanded and showed the transformer mounted in the circuit board. It is the perspective view which showed the electronic module which concerns on the 2nd Embodiment of this invention. It is the side view which expanded and showed the transformer contained in the electronic module which concerns on the 3rd Embodiment of this invention.

[First Embodiment]
A form of a DC-DC converter (hereinafter referred to as a converter) 2 as an electronic module to which the present invention is applied will be described below with reference to the drawings.

  As shown in FIG. 1, the converter 2 includes a circuit board 4 and an electronic component 6 mounted on the circuit board 4.

  In addition to the transformer 6A, the electronic component 6 mounted on the circuit board 4 includes various electronic functional components (such as LSI) 6B having functions necessary for configuring the converter 2.

  Here, as shown in FIGS. 2 and 3, the transformer 6 </ b> A includes a rectangular parallelepiped transformer body 8 in which a coil and the like are incorporated, and a plurality of electrode terminals 10 protruding from the transformer body 8.

  As is apparent from FIG. 2, the electrode terminal 10 is located on one of the left and right side surfaces 12 and 14 of the transformer body 8 that is biased toward one end side in the vertical direction of the transformer body 8 (lower side in FIG. 2). From the side surfaces 12 and 14. Here, in the transformer main body 8, an end portion on the side where the electrode terminal 10 exists is a terminal side end portion 16, and an end portion opposite to the terminal side end portion 16 is a head portion 18. These electrode terminals 10 are bent in a crank shape, and a total of six electrode terminals 10 are provided on each side of the transformer body 8. Thus, the transformer 6A in which the electrode terminal 10 is bent is a surface-mounting transformer. The transformer 6A is a component having the largest dimension in the height direction among the electronic components 6 included in the converter 2.

  Next, the circuit board 4 is a multilayer board in which a large number of wiring layers are laminated via an insulating layer, and has a substantially rectangular shape as a whole.

  A wiring layer consists of a predetermined-shaped wiring pattern formed of a thick copper plate that is thicker than a normal copper foil. Here, as the thick copper plate, a copper plate having a thickness of 36 to 2000 μm is usually used. The wiring layer includes an outer layer circuit pattern positioned on the surface of the circuit board and a plurality of inner layer circuit patterns positioned inside the circuit board. An insulating layer is interposed between the outer layer circuit pattern and the inner layer circuit pattern and between the inner layer circuit patterns, and the surface of the circuit board is covered with a solder resist. In addition, the outer layer circuit pattern and the inner layer circuit pattern are electrically connected to each other through via holes. The number of inner layer circuit patterns is not particularly limited. Therefore, the number of layers of the multilayer substrate is not particularly limited.

  In the above-described solder resist, predetermined portions on the outer layer circuit pattern are peeled off, and the outer layer circuit pattern is partially exposed. This exposed portion becomes a land 20 to which the electrode terminal of the electronic component to be mounted is soldered. That is, the electrode terminal of the electronic component 6 is electrically connected to the land 20, and the electronic component 6 is mounted on the circuit board 4.

Here, a mode in which the transformer 6A is mounted on the circuit board 4 will be described in detail.
First, in the circuit board 4, a notch 22 is provided as a space extending from the surface on which the transformer 6 </ b> A is mounted to the inside of the circuit board 4. In the present invention, the surface of the circuit board on which the transformer is mounted refers to the surface on which lands to which the electrode terminals of the transformer are connected are provided.

  As shown in FIG. 4, the notch 22 described above extends from one surface 26 of the circuit board 4 to the other surface 28 in the side portion 24 of the circuit board 4, and has a rectangular shape in plan view. The size of the notch 22 is such that the portion of the transformer main body 8 of the transformer 6A can be accommodated with a margin and the electrode terminal 10 of the transformer 6A is locked by the peripheral edge 30 of the notch 22. Is set.

  Further, as is apparent from FIG. 4, a land 20 connected to the electrode terminal 10 of the transformer 6 </ b> A is formed on the peripheral edge 30 of the notch 22.

  The transformer 6A is positioned in the notch 22 as described above. Specifically, with respect to the transformer 6A, the transformer main body 8 is inserted into the notch 22 from the head 18 side with the terminal side end 16 facing upward and the head 18 facing downward. Then, the corresponding lands 20 and the electrode terminals 10 are brought into contact with each other and then soldered. Thereby, as shown in FIG. 1, the converter 2 according to the present invention is obtained in which the transformer 6 </ b> A is mounted on the circuit board 4 with the transformer body 8 positioned in the notch 22.

  In this way, the transformer 6A is housed and mounted in the notch 22 of the circuit board 4 (see FIG. 5), so that the converter 2 can be compared with the case where the transformer 6A is mounted on the circuit board 4 as in the prior art. The overall height can be kept low. In the present invention, the surface mount transformer 6A can be used as it is simply by reversing the head 18 and the terminal-side end 16 in the opposite direction, so that the entire converter 2 can be maintained while maintaining the versatility of the electronic component. As a result, a low profile can be realized.

[Second Embodiment]
When compared with the converter 2 according to the first embodiment, the converter 32 according to the second embodiment is different in the form of the space provided in the circuit board 4, and other parts are the same as in the first embodiment. This is the same as the converter 2 in FIG. Therefore, in describing the converter 32 according to the second embodiment, members and parts that perform the same functions as those of the converter 2 of the first embodiment already described are given the same reference numerals, and these Will be omitted, and only the differences will be described.

  As shown in FIG. 6, the converter 32 includes a through hole 34 as a space provided in the circuit board 4. Specifically, the through hole 34 is formed from one surface 26 to the other surface 28 along the thickness direction of the circuit board 4 in a portion other than the side portion 24 of the circuit board 4. The through hole 34 has a rectangular shape in plan view. The size of the through hole 34 is large enough to accommodate the portion of the transformer main body 8 of the transformer 6A with a margin, and the electrode terminal 10 of the transformer 6A is locked by the peripheral portion 36 of the through hole 34. Is set.

  Such a through hole 34 can be formed at an arbitrary location such as the center of the circuit board 4, and the degree of freedom in designing the converter 32 can be increased.

[Third Embodiment]
The converter 38 according to the third embodiment is different from the converter 2 according to the first embodiment in the form of the transformer, and the other portions are the same as the converter 2 in the first embodiment. . Therefore, in describing the converter 38 according to the third embodiment, members and parts that perform the same functions as those of the converter 2 of the first embodiment already described are denoted by the same reference numerals, and these Will be omitted, and only the differences will be described.

  The transformer 6C used in the converter 38 includes a straight type electrode terminal 42 that does not have a bent portion as shown in FIG. That is, since the transformer 6C does not have the bent portion of the electrode terminal 10 as in the case of the transformer 6A, the space in the notch 22 can be used more effectively. Therefore, the volume of the transformer main body 44 can be expanded by the amount of space used for accommodating the bent portion, and a larger transformer 6C can be accommodated.

  The present invention is not limited to the first to third embodiments described above, and various modifications can be made. For example, the space provided in the circuit board according to the present invention is not limited to the notch 22 or the through hole 34 as long as the transformer can be positioned therein, and is a bottomed hole that does not penetrate. May be.

2 Converter 4 Circuit board 6 Electronic component 6A Transformer 6B Electronic functional component 6C Transformer 8 Transformer main body 10 Electrode terminal 16 Terminal side end 18 Head 22 Land 22 Notch 34 Through hole

Claims (3)

A circuit board;
A transformer mounted on the circuit board,
The circuit board is provided with a space extending from the surface on which the transformer is mounted to the inside of the circuit board,
The transformer is an electronic module, at least a part of which is positioned in the space.   The electronic module according to claim 1, wherein the space is a notch provided in a side portion of the circuit board.   The electronic module according to claim 1, wherein the space is a through-hole penetrating the circuit board.

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