JPH11289143A - Electronic equipment - Google Patents

Abstract

(57) [Problem] To provide an electronic device in which another substrate can be newly and easily and reliably provided. SOLUTION: When a terminal block 24 is placed on a heat sink 2,
The lower end of the metal terminal 24d is pressed against the solder pad 4a provided on the ceramic substrate 4 to obtain an electrical connection between the metal terminal 24d and the ceramic substrate 4. When the printed board 22 is supported and fixed to the terminal block 24, the upper end of the metal terminal 24d is inserted into the insertion hole 22a of the printed board 22, and the printed board 22 and the metal terminal 24 are fixed.
d is electrically connected by soldering. With such a structure, electrical connection between the two substrates can be made extremely easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having a circuit board closely attached to an inner surface of a housing.

[0002]

2. Description of the Related Art Conventionally, as a mode of disposing a circuit board in a housing of an electronic device, a circuit board surface is brought into close contact with an inner surface of the housing (for example, a bottom surface inside the housing) and generated on the circuit board. In order to quickly dissipate heat to the outside of the housing, there is known a device using a part of the housing as a heat sink.

[0003]

However, if the number of required electronic components increases with the increase in the functions required of the electronic device, it is not easy to realize all the functions with one circuit board. . As the circuit board, a circuit board having a large area may be used. However, in general, the larger the circuit board, the higher the unit price of the circuit board, and the manufacturing cost when electronic components are mounted on the circuit board. There is a problem that the yield is reduced. In addition, the size of the electronic device itself may be increased, and the mounting place on an automobile or the like may be restricted.

Therefore, among the electronic components to be mounted, those having a small amount of heat are arranged on a separate circuit board which is not brought into close contact with the housing, and those having a large amount of heat are placed on the circuit board which is brought into close contact with the case. It is conceivable that signals are exchanged between both circuit boards via a signal line such as a flat wire. However, it is troublesome to connect flat wires etc. to both circuit boards by soldering for each signal line, and the circuit board adhered to the housing quickly releases heat, so the soldering itself is easy. Not. Thus, it was not easy to newly provide another circuit board.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to enable a new circuit board to be easily and reliably provided in an electronic device.

[0006]

Means for Solving the Problems and Effects of the Invention In order to solve the above-mentioned problems, an electronic device according to the present invention (Claim 1) has a second circuit board around a first circuit board on the surface of a heat sink. A support is provided, and a connection member for electrically connecting the first circuit board and the second circuit board is provided on the support.

[0007] Therefore, according to the electronic device of the first aspect, since the base is provided, a new circuit board can be easily and reliably arranged. Since the connection member is provided on the base, electrical connection with a newly provided circuit board can be easily achieved.

Various methods are conceivable for electrically connecting the connecting member to each of the two circuit boards. For example, when the base is provided on the surface of the radiator plate as described in claim 2, The connection member may be provided on the base so that the end of the connection member contacts the first circuit board. According to this configuration, it is possible to obtain the electrical connection between the connection member and the first circuit board very easily by simply providing the base for supporting the second circuit board around the first circuit board on the surface of the heat sink. Is preferred.

Here, it is difficult to bring the connecting member into contact with the first circuit board due to restrictions on the pattern of the electronic circuit formed on the first circuit board, or the contact resistance at the contact portion is reduced. There may be cases where it cannot be ignored. Therefore, when the base is provided on the surface of the heat sink, a step having a height substantially equal to the height from the surface of the heat sink to the components on the first circuit board is formed on the base. The connecting member may be provided on the base such that the end of the connecting member is exposed at the formed step. In this way, even when there is a restriction on the pattern of the electronic circuit, a component (for example, an electronic component or a metal component for connection) on the first circuit board is directly connected to the connection member by, for example, wire bonding. Can be electrically connected.

[0010] On the other hand, as for the connection between the connection member and the second circuit board, when the second circuit board is supported on a table, the end of the connection member connects the second circuit board. The connection member may be provided on the base so that the connection member penetrates. In this case, the connection member and the second circuit board are connected to each other by soldering at a portion where the end of the connection member penetrates the second circuit board. Can be easily obtained. In addition, the second circuit board can be more firmly installed on the table. In addition, it is preferable to use a conventionally known jet soldering bath for the soldering, since the electrical connection between the connection member and the second circuit board can be more easily obtained.

The transmission and reception of signals from the electronic apparatus to the outside is easy if the electronic apparatus is connected via a connector. Therefore, as described in claim 5, at least one of the first circuit board and the second circuit board is provided with a connector for transmitting and receiving signals to and from the outside, a table is provided on the surface of the heat sink, and the second circuit is further mounted on the table. When the substrate is supported, the connection member may be provided on the base such that the end of the connection member is close to the connector.
With this configuration, the wiring distance between the connection member and the connector can be shortened, so that the entire electronic device can be made compact, and a voltage drop or an induced noise that may occur between the connection member and the connector can be achieved. Can be suppressed.

According to a sixth aspect of the present invention, the first heat radiating plate is provided on the heat radiating plate.
If a convex portion having the same shape as the circuit board is formed, the first circuit board can be installed at an accurate position on the surface of the heat sink by adjusting the shape of the convex portion, and the thickness of the heat sink increases. This is preferable because heat generated on the first circuit board can be more effectively absorbed. Further, if a frame having the same shape as the convex portion and capable of fitting the convex portion is formed on the table, the table can be accurately provided on the surface of the heat sink. Further, in the case where a step is provided on the base and the end of the connecting member is exposed at the step, the height of the projection may be adjusted to adjust the end of the connecting member. It is preferable because the height difference between the part and the component on the first substrate can be adjusted to easily perform wire bonding.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing an overall configuration of an electronic control unit 1 (hereinafter, referred to as “ECU 1”) as an electronic device to which the present invention is applied, as a first embodiment.

The ECU 1 includes a radiator plate 2 provided with a ceramic substrate 4 as a first circuit board, a printed circuit board 22 as a second circuit board provided with a connector 20 for transmitting and receiving signals to and from the outside, and a printed circuit board. A terminal block 24 as a “table” for holding the ceramic substrate 4 and electrically connecting the ceramic substrate 4 and the printed circuit board 22;
Printed circuit board 22 and ceramic substrate 4 connected by
And a cover 26 for covering and protecting the cover.

The heat radiating plate 2 is made of aluminum having good heat conductivity and is formed in a substantially plate shape. On its upper surface, a convex portion 2a having the same shape as the ceramic substrate 4 is provided.
A ceramic substrate 4 is in close contact with the upper surface of the substrate via an adhesive 6 (FIG. 2). An electronic circuit (not shown) is formed on the printed circuit board 22, and operates together with the electronic circuit on the ceramic substrate 4 to exchange signals with the outside via the connector 20. The connector 20 is electrically and mechanically connected to the printed circuit board 22 by inserting a large number of signal lines 20a into holes of the printed circuit board 22 and soldering the inserted portions. The printed circuit board 22 has metal terminals 24 on a terminal block 24 to be described later.
d is inserted into the connector 2
In addition, a through hole 22b is formed near the zero signal line 20a and used to fix the printed board 22 to the terminal block 24 with screws.

The terminal block 24 is composed of two support portions 24a for supporting the vicinity of both ends of the printed circuit board 22, and a connection portion 24b for connecting the two support portions 24a. A frame 24c having the same shape as the convex portion 2a of the heat sink 2 is formed below the terminal block 24.
When placed on the top, the protrusion 2a is fitted into the frame 24c. In this embodiment, the support portion 24a and the connection portion 24
A frame 24c is formed by the lower part of b.

As shown in FIGS. 1 and 2, one of the support portions 24a is provided with a large number of metal terminals 24d as connection members. The metal terminal 24d is formed in a substantially L-shaped rod shape, and one end of the metal terminal 24d is provided on the upper portion of the support portion 24a (that is,
When the terminal block 24 supports the printed circuit board 22, it is inserted into an insertion hole 22 a provided in the printed circuit board 22.
One end of the metal terminal 24d thus inserted into the insertion hole 22a and the electronic circuit formed on the printed circuit board 22
It can be electrically connected by soldering. This soldering is preferably performed using a conventionally known jet soldering bath because it can be easily performed.

The other end of the metal terminal 24d is connected to a support portion 24a.
When the terminal block 24 is installed on the heat sink 2 so as to surround the ceramic substrate 4,
It comes into pressure contact with a solder pad 4 a provided on the ceramic substrate 4. As a result, the metal terminal 24d is electrically connected to the electronic circuit formed on the ceramic substrate 4.
Note that the support portion 24a is provided with a screw hole 24e for fixing the printed circuit board 22 with a screw.

According to the ECU 1 configured as described above,
When the terminal block 24 is placed on the heat sink 2, the metal terminals 24d
Is pressed against the solder pad 4a provided on the ceramic substrate 4 so that the electrical connection between them can be made extremely easily, and the two substrates (ie, the ceramic substrate 4 and the printed circuit board) in the ECU 1 can be connected. 22) can be easily and reliably connected.

Next, the printed circuit board 22 is
Is screwed into a screw hole 24e provided in the terminal block 24, thereby fixing the metal terminal 24d to the insertion hole 22a of the printed circuit board 22. Inserted. Then, the electronic circuit on the printed circuit board 22 and the metal terminal 24d are connected by soldering. Since the insertion hole 22a is provided near the connector and the path from the ceramic substrate to the connector is shortened, the ECU 1 can be made compact, and a high voltage and a large current can be transmitted from the ceramic substrate through the connector. This is preferable because it is possible to suppress a voltage drop and the generation of induced noise when outputting the signal.

The radiating plate 2 is provided with a convex portion 2a for mounting the ceramic substrate 4. For this reason, the heat generated in the ceramic substrate 4 is more quickly dissipated.
You can escape. By the way, conventionally, as shown in FIG. 4, the ceramic substrate 4 is provided at an accurate position by a plurality of protrusions 2 b provided on the heat radiating plate 2, but it becomes an obstacle when the terminal block 24 is provided. Therefore, in the present embodiment, by forming the ceramic substrate 4, the projection 2a, and the frame 24c in the same shape, the terminal block 24 can be accurately placed on the heat sink 2 together with the ceramic substrate 4. In general, the protrusion 2b is formed by cutting out the heat sink 2, but it is preferable to cut out the convex portion 2a as in this embodiment because it is easier.

Next, as a second embodiment, an ECU 1 to which the present invention is applied will be described. FIG. 3 shows E of the second embodiment.
FIG. 3 is a cross-sectional view of a heat sink 2 and a terminal block 24 placed on the heat sink 2 in the CU 1. The support portion 24a of the terminal block 24 includes
As in the first embodiment, a substantially L-shaped metal terminal 24d is buried, and one end of the metal terminal 24d projects from the upper portion of the support portion 24a. On the other hand, the other end of the metal terminal 24 d is
It is exposed upward in a step portion 24f formed near the lower portion of the substrate a, and is electrically connected to a component 28 provided on the ceramic substrate 4 by wire bonding. Except for the configuration of the terminal block 24, the configuration is the same as that of the first embodiment, and a description thereof will be omitted.

As described above, the metal terminal 24d of the terminal block 24
Even if the ceramic substrate 4 and the ceramic substrate 4 are connected by the bonding wires 30, the electrical connection between them can be easily and reliably obtained. As shown in FIG. 3, even when the component 28 includes a tall high-tall component 28a and a short low-tall component 28b, the height of the stepped portion 24f of the terminal block 24 from the heat sink 2 is increased. If the height (ie, the height of the lower end of the metal terminal 24d from the heat radiating plate 2) is substantially the same as the height of each component 28, the connection with the bonding wire 30 can be performed without any problem. It is preferable because it is possible.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can take various aspects. For example, in the electronic device of the above embodiment, the ceramic substrate 4 having good thermal conductivity and heat dissipation is used as the first circuit board mounted on the heat sink, and the description has been given, but the present invention is not limited to this. Instead, for example, a metal core substrate (having a metal piece such as aluminum embedded in a glass epoxy resin substrate) or another substrate having good heat conductivity may be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an overall configuration of an electronic device according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating an internal structure of the electronic device according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating an internal structure of an electronic device according to a second embodiment.

FIG. 4 is an explanatory view showing a projection for determining a position of a circuit board in a conventional heat sink.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electronic control unit (electronic device), 2 ... Heat sink, 4 ...
Ceramic substrate (first circuit board), 20 connectors, 2
2: Printed circuit board (second circuit board), 22a: Insertion hole,
Reference numeral 24: terminal block (stand), 24a: support portion, 24b: connection portion, 24c: frame, 24d: metal terminal (connection means), 24
f: step, 28: parts.

Claims (6)

[Claims] 1. An electronic device comprising a radiator plate and a first circuit board adhered to a surface of the radiator plate, wherein a second circuit board is supported around the first circuit board on the radiator plate surface. An electronic device, comprising: a base; and a connection member for electrically connecting the first circuit board and the second circuit board to the base. 2. The electronic device according to claim 1, wherein when the base is provided on the surface of the heat sink, the connection member is connected to the first circuit board such that an end of the connection member contacts the first circuit board. An electronic device, comprising: 3. The electronic device according to claim 1, wherein when the base is provided on the surface of the heat sink, the height is substantially the same as the height from the surface of the heat sink to the components on the first circuit board. A step is formed on the base, and when the base is placed on the surface of the heat sink, the connecting member is provided on the base such that an end of the connecting member is exposed at the step. Electronic device characterized by. 4. The electronic device according to claim 1, wherein when the base supports the second circuit board, an end of the connection member penetrates the second circuit board. An electronic device, wherein the connecting member is provided on the base. 5. The electronic device according to claim 1, wherein at least one of the first circuit board and the second circuit board is provided with a connector for transmitting and receiving signals to and from the outside. The connection member is provided on the base such that the end of the connection member is close to the connector when the second circuit board is supported by the base and provided on the surface of the heat sink. Electronic devices. 6. The electronic device according to claim 1, wherein a convex portion having the same shape as the first circuit board is formed on a surface of the heat sink, and the base has the same shape as the convex portion. An electronic device, comprising: a frame having a shape in which the convex portion can be inserted.