JPH0360196A - Power transistor mounter - Google Patents

Abstract

PURPOSE:To simultaneously attain reduction in size of an apparatus and improvement in heat dissipation from a power transistor by adhering circuit boards made of ceramics for mounting the transistors to both upper and lower surfaces of a housing body secured to a base. CONSTITUTION:Circuit boards 40 are adhered to the upper and lower surfaces of a mount 11, and semiconductor chips 41 containing power transistors are die bonded thereto. Bonding pads of the chips 41, circuit components on the boards 40 and the bonding pads on a terminal strips 21 are connected thereamong via bonding wires 42. Since the boards 40 on which the power transistors are mounted are adhered to both upper and lower surfaces of the mount 11, mounting density is enhanced to reduce size the whole device. Since the mount 11 is integrated with attachment 12 to form a housing body 10, the boards 40 are formed of ceramics and the mount 11 is formed of aluminum, heat dissipation can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power transistor mounting device in which a power transistor is mounted on a heat dissipating body.

[Conventional technology]

In general, power transistors generate heat when they operate, so
When this is installed, a heat dissipation design is applied. In automobile igniters, power is supplied to the ignition coil that generates high voltage for ignition through a power transistor, but this power transistor is combined with peripheral circuits into a single device (power transistor). installed in the vehicle.

On the other hand, in an ignition control system for an automobile that does not have a destroyer, a power transistor for an igniter and a peripheral circuit are required for each cylinder of the engine.

For this reason, devices equipped with power transistors
Coupled with the need for heat dissipation design, there is a trend towards larger sizes.

[Problems to be solved by the invention]

However, as a device equipped with a power transistor becomes larger, it becomes difficult to set this device near the engine in, for example, the above-mentioned ignition control system. Furthermore, if the packaging density of power transistors is increased in order to achieve miniaturization, it becomes difficult to dissipate heat efficiently.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a device equipped with a power transistor that can perform sufficient heat dissipation and can be made smaller as a whole.

[Means to solve the problem]

The power transistor mounting device according to the present invention includes a heat dissipating housing main body whose middle part is plate-shaped and which is attached to a base using attachment parts on both sides, and a housing main body in which the power transistor is mounted and which is attached to the top and bottom of the plate-shaped part of the housing main body. It is characterized by comprising at least two circuit boards attached to both sides, and a coupler attached to the housing body so that each terminal is electrically connected to each terminal of the circuit board.

[Effect]

According to the present invention, the circuit board on which the power transistor is mounted is attached to both the upper and lower surfaces of the housing body, so that miniaturization and improved heat dissipation can be achieved at the same time.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the structure of the embodiment; FIG. 1(a) is a partially cutaway plan view of the top cover, FIG. 1(b) is a side view showing a section along line B-B, and FIG. (c) is a front view showing a part of the cross section along CC line. As shown in the figure, the housing main body 10 made of aluminum has a plate-shaped intermediate mount portion 11, and mounting portions 12 extend on both sides thereof, and an opening 13 for bolt insertion is formed in the mounting portion 12. Also, no＼
The housing body 10 is formed into a wall-shaped housing part 14 that surrounds the mount part 11 between the mount part 11 and the attachment part 12. The coupler 20 is attached to the housing body 10 from a direction perpendicular to the direction in which the attachment portion 12 extends.

This coupler 20 consists of a terminal board 21 and a resin cover 2 surrounding it.
Wiring 23 is formed on the upper and lower surfaces of the terminal board 21 and is connected to a terminal 24 for external connection.

Note that this coupler 20 is fixed to the housing body 10 with screws 31 via a presser l1230.

A circuit board 40 made of, for example, ceramics is attached to the upper and lower surfaces of the mount section 11, respectively, and a semiconductor chip 41 including a power transistor is die-bonded to the circuit board 40. and,
The bonding pads of the chip 41, each circuit component (not shown) on the circuit board 40, and each bonding pad on the terminal board 21 are connected by bonding wires 42. Note that the wire 42 is shown only in FIG. A top M51 and a bottom M52 are fixed to the upper and lower sides of the housing portion 14 of the housing body 10, thereby sealing the inside. Note that the inside may be filled with silicone oil or the like as a gel-like substance.

According to the above configuration, the circuit board 40 on which the power transistors and the like are mounted is attached to both the upper and lower surfaces of the mount portion 11, so that the packaging density can be increased and the overall device size can be reduced. Moreover, the mount part 11 is attached to the mounting part 12.
Since the circuit board 40 is made of ceramics and the mount part 11 is made of aluminum or the like, heat dissipation can be improved.

This heat dissipation effect can be further enhanced by making the mount portion 11 thicker or by providing heat dissipation fins or the like on the outside of the housing portion 14. Note that the coupler 20 may be insert-molded in the housing body 10 in advance.

〔Effect of the invention〕

According to the present invention, the circuit board made of ceramics or the like on which the power transistor is mounted is attached to both the upper and lower surfaces of the housing body fixed to the base, thereby reducing the size of the device and improving heat dissipation from the power transistor. It has the effect of achieving improvements at the same time.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a power transistor mounting device according to an embodiment of the present invention. 10...Housing body, 11...Mount part, 1
2... Mounting part, 13... Opening, 14... Housing part, 20... Coupler, 21... Terminal board, 22...
・Resin cover 23... Wiring, 30... Holding plate, 40
...Circuit board, 41...Chip, 42...Wire, 51...Top cover, 52...Bottom cover.

Claims (2)

[Claims] 1. A housing main body for heat dissipation that has a plate-like middle part and is attached to a base using attachment parts on both sides thereof, and at least two boards each having a power transistor mounted thereon and affixed to both upper and lower surfaces of the plate-like part of the housing main body. A power transistor mounting device comprising: a circuit board; and a coupler attached to the housing body and having each terminal electrically connected to each terminal of the circuit board. 2. 2. The power transistor mounting device according to claim 1, wherein the housing body is made of a metal material, and the circuit board is made of a ceramic material.