JPS625697A - Power module - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to heat dissipation of power circuits and conversion transformers, and particularly relates to a power module that improves heat dissipation of a conversion transformer in the power circuit portion of a switching power supply. .

BACKGROUND OF THE INVENTION In recent years, there has been a demand for smaller electronic devices, and significant progress has been made in reducing the size and weight of low-power systems. However, there has not been as much progress in high power systems, especially power circuits, as in low power systems.

In other words, the reality is that mounting techniques and methods for low-power systems are of little use in high-power systems.

This is due to the problem of heat dissipation from high power devices and the fact that high power devices must be placed nearby.

Therefore, currently, the relationship between primary and secondary circuit separation and heat radiation is
Since a large heat sink is attached to each side of the power semiconductor, each element is composed of discrete elements.

For example, thermal design is described in pages 172-177 of Switching Regulator Design Method and How to Use Power Devices published by Seibundo Shinkosha. Further, as an example of a switching regulator configured with discrete components, there is a description in P175-P2S5 published by Nikkei Electronics on June 9, 1980.

Problems to be Solved by the Invention In the above configuration, there are problems in mounting the power semiconductor on the heat sink, separating the primary and secondary circuits, and spatially mutually arranging the heat dissipation reservoirs. Moreover, this kind of thing must be designed for each power supply, which greatly affects the assembly process. Furthermore, in a switching power supply, the length of wiring between each element is related to noise. For this reason, it is desirable to arrange the power elements of the primary and secondary circuits and the conversion transformer close to each other, but this is difficult due to the above-mentioned spatial mutual arrangement problem.

In view of the above problems, the present invention provides a power module that enables more effective heat dissipation from a transformer with the primary and secondary circuits separated.

Means for Solving the Problems In order to solve the above problems, the power module of the present invention consolidates the power sections of the primary and secondary circuits on a single board, and includes heat radiation fins to enhance the heat radiation effect. A conversion transformer with an attached converter is placed nearby, and these are connected with an electrically insulating material with good thermal conductivity to form an integrated module.

Effects The present invention has the above-mentioned configuration, and by modularizing the primary and secondary power circuits and connecting this board and a transformer equipped with radiation fins for enhancing the heat radiation effect using an electrically insulating material with good thermal conductivity, Not only does this improve the heat dissipation effect of the transformer, but it also equalizes the heat generated within the power module, allowing for effective heat dissipation from the entire module. Molding also improves the insulation properties of the entire module, and also improves its strength against vibration and shock. Furthermore, the thermal design of the entire module is easy, which greatly contributes to miniaturization.

Embodiment Before describing the features of the present invention, FIG. 2 shows an example of a power supply circuit to which this module can be applied. Figure 2 is I)C-I)C
This is a converter type flyback switching power supply circuit, which is already well known. In FIG. 2, 6 is a DC power supply, 6 is a control circuit that controls on/off of the switching transistor 7 in order to stabilize the output voltage of the output load 13, and 8.10 is a snubber circuit added to the switching transistor 7 and the rectifier diode 11. .

3 is a conversion transformer. Since the flyback type switching power supply configured with these is already well known, the explanation of its operation will be omitted. .

Among the components shown in FIG. 2, the parts that generate heat on the primary side are the parts group shown by M, and the parts that generate heat on the secondary side are the parts group shown by B. Further, from the viewpoint of noise, it is desirable that the wiring between the component group B and the conversion transformer 3 be as short as possible.

Furthermore, due to insulation problems, it is necessary to separate the circuits between parts group and B.

FIGS. 1a and 1b show the power supply circuit configured with the power module of the present invention. In Figure 1,
1 is a primary side module board that has been modularized from the parts group B in Figure 2, and 2 is a modular board that has been modularized from parts group B in Figure 2.
In the next module board, 3 is a conversion transformer, and 4 is a resin used to connect the circuit components. During this period, an electrically insulating material with good thermal conductivity such as polyester or epoxy containing an inorganic filler is used. Here, the module boards 1 and 2 are arranged so that the element surfaces on which the elements 19.20g are attached face each other, and further between the module boards,
A transformer is installed with heat dissipation fins to improve the heat dissipation effect. As described above, the heat dissipation fins are directly attached to the conversion transformer, which is the heating element, and the module board and the conversion transformer are connected to the heat exchanger so that the fins are in contact with the outside air and can radiate heat to the surroundings. By molding with conductive resin, the heat dissipation effect of the conversion transformer itself, which is a heating element, becomes even higher. At the same time, by molding with a resin that has good thermal conductivity, the heat generated from the entire module can be made uniform, and the heat can be effectively radiated to the outside air through the entire resin. FIG. 3 shows the case where heat dissipation fins are attached to the top of the conversion transformer, and FIG. 4 is attached to the two sides of the conversion transformer. However, it goes without saying that the shape of the heat dissipation fins and the location where they are attached to the conversion transformer are not limited to those shown in the embodiments, but may vary depending on the situation.

In this example, the primary side module board and the secondary side module board are placed so that the surfaces on which the elements are attached face each other, and the conversion transformer is placed between the module power plates. The mutual positional relationship of the transformers is not limited to this, and may be the positional relationship described below. The first is a configuration in which the module boards are arranged so that the element surfaces of the primary module board and the secondary module board face each other, and the module board and the conversion transformer are arranged parallel and adjacent to each other. Otherwise, the module board is arranged so that the primary module board and the secondary module board are aligned in a straight line and the element surfaces are in the same direction, and the conversion transformer is located on the element surface side of the module board. It is.

Finally, although the present embodiment has been explained using a flyback type switching power supply, it is of course possible to use not only the flyback type but also other types of switching power supplies and other stabilized power supplies. Furthermore, although only the power circuit portion is shown mounted on the module board, a control circuit may also be included therein, and conversely, a snubber circuit for the power circuit portion may be mounted externally. It is also naturally possible to incorporate an auxiliary power circuit portion used in the power supply circuit into the power module of the present invention.

Effects of the Invention As described above, according to the present invention, the primary and secondary power circuits are modularized, and this substrate and the transformer equipped with heat dissipation fins for enhancing the heat dissipation effect are made of electrically insulating material with good thermal conductivity. By coupling them together, not only does the heat dissipation effect of the transformer increase, but it also equalizes the heat generated within the power module, making it possible to effectively dissipate heat from the entire module.

Molding also improves the insulation properties of the entire module, and also improves its strength against vibration and shock. Furthermore, the thermal design of the module as a whole becomes easier, which greatly contributes to miniaturization.

[Brief explanation of the drawing]

1A and 1B are a three-dimensional view and a plan view of a power module according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a power supply circuit to which the power module of the present invention can be applied. FIGS. 3 and 4 are three-dimensional views of other embodiments of the present invention. 1... Primary side module board, 2...
Secondary side module board, 3... Conversion transformer,
4... Electrical insulating material with good thermal conductivity, 17...
...Radiation fin for transformer installation, 18...
- Connection terminal, 19.20...Element on the module board. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
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Claims (1)

[Claims] A primary side module board that integrates a part of the primary side circuit in the power supply device, and a second module board that integrates a part of the secondary side circuit in the power supply device.
A power module characterized in that a next-side module board and a transformer partially or entirely fitted with heat dissipation fins to enhance the heat dissipation effect are combined and integrated using an electrically insulating material with good thermal conductivity.