JPH05275822A - Electronic circuit mounting unit - Google Patents

Abstract

PURPOSE:To effect size and cost reduction by providing a means for electrically connecting together a metal substrate on which circuit components are mounted and a resin substrate on which circuit components are mounted. CONSTITUTION:Electronic components 302, 307 and 308 mounted on a metal substrate 1 are soldered to a pad 102 using solder 4, thereby constituting a circuit via a pattern 101. In the meantime, electronic components 301, 303, 304, 305, 306 and 309 mounted on a resin substrate 5 are soldered to the pad 102 and a land 6, thereby constituting a circuit via the pattern 101. The transmission of signals and electric power is carried out between both substrates by way of an aluminum wire 7. Heat built up by electronic components having a high heat release value on the metal substrate 1, such as the resistor 302, the power MOSFET 307 and the diode 308, is transmitted to a cooling fin, because the substrate 1 is made of aluminum 104 which is superior in heat conduction. On the other hand, electronic components on the resin substrate 5 are thermally isolated from the substrate 1 and the cooling fin 2, and fixed on a structured body 8, whereby they are maintained at a low temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an electronic circuit in which an electronic component which requires heat radiation using a cooling fin and generates a large amount of heat and an electronic component which does not require heat radiation using a cooling fin are mounted together. To be done. Specifically, it contributes to downsizing and cost reduction of the field of power electronics, for example, switching power supplies, inverters, servo amplifiers, UPSs and the like.

[0002]

2. Description of the Related Art An example of mounting a switching power supply using a conventional metal substrate is shown in FIG. In the figure, 1 is a metal substrate, 2
Are cooling fins thermally and mechanically fixed to the metal substrate 1, and 301 to 309 are electronic components mounted on the metal substrate 1. 301 is a transformer, 302 is a resistor, 303
Is an IC, 304 is a tantalum capacitor, 305 is a ceramic capacitor, 306 is an electrolytic capacitor, 307 is a power MOSFET, 308 is a diode, and 309 is a terminal block. Further, 101 is a pattern for forming a circuit on the metal substrate 1, 102 is a pad, 103 is an insulating layer, 1
04 is aluminum. Further, 4 is solder.

Next, the operation will be described. The electronic components 301 to 309 mounted on the metal substrate 1 are soldered to the pads 102 with the solder 4 to form a circuit via the pattern 101, and the circuit performs a desired operation. On the other hand, electronic components that generate a large amount of heat, such as a resistor 302 and a power MOSFET
Since the metal substrate 1 of the 07, the diode 308 and the like is made of aluminum 104 having good heat conduction, heat is transferred to the cooling fin 2. On the other hand, since the cooling fins 2 radiate heat to the surrounding air, the temperature rise of the cooling fins 2 is suppressed, and the heat-generating components on the metal substrate 1 are cooled.

[0004]

The conventional mounting method of the metal substrate 1 has the following problems.

First of all, if the metal substrate 1 is used, the pattern can be passed only on one side of the substrate, and the component can be mounted on only one side, so that miniaturization cannot be pursued.

Secondly, when the metal substrate 1 is used, bare chips can be mounted or only electronic components for surface mounting can be mounted. However, not all the parts to be mounted are commercially available in the form of bare chips or surface mounting, and it is necessary to develop new special products, making availability difficult. Moreover, both development costs and product costs are disadvantageous. To give a specific example, transformer 3
01, an electrolytic capacitor 306, and a terminal block 309.

The third problem is the problem of heat treatment. That is, the electronic components that generate a large amount of heat on the metal substrate 1 and require heat dissipation by the cooling fins 2 are the resistor 302, the power MOSFET 307, and the diode 308 as described above.
Is. Conversely, the IC 303, the tantalum capacitor 304,
The ceramic capacitor 305 and the electrolytic capacitor 306 generate relatively little heat, and in terms of thermal reliability, it is preferable to keep the temperature low. That is, while the heating element is mounted on the metal substrate, electronic components that generate a small amount of heat and are weak to heat are also mounted, so that reliability is reduced. In order to ensure reliability, the heating element needs to be cooled more than necessary, and the cooling fin becomes large in size, resulting in an increase in cost.

The fourth problem is that the cost of the metal substrate is high. The modern metal substrate 1 is more than double the price of the widely used resin substrate. However, as mentioned in the third problem, the electronic components that originally generate a small amount of heat and do not need to be mounted on the metal substrate 1 are also mounted, and the pattern that only one side can pass through is electronic components. However, due to the fact that only one side can be mounted, the area of the metal substrate becomes larger than necessary (compared to the resin substrate), which is a factor of cost increase.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to obtain an electronic component mounting apparatus which can be miniaturized and which is inexpensive.

[0010]

An electronic circuit mounting apparatus according to the present invention has means for electrically connecting a metal substrate on which circuit components are mounted, a resin substrate on which circuit components are mounted, and both substrates. It is a thing.

[0011]

The metal substrate on which the circuit component according to the present invention is mounted mainly carries out the electronic circuit operation of the electronic component serving as a heating element. On the other hand, the resin substrate is an electronic component that generates little heat, and it is preferable that the electronic component should not be mounted on the metal substrate in terms of reliability for circuit operation. Transmission of signals and electric power between the two is performed by electrical connection means.

[0012]

EXAMPLES Example 1. An embodiment of the invention will be described below. In FIG. 1, 1 is a metal substrate, 2 is a cooling fin that is thermally and mechanically fixed to the metal substrate 1, 302,
Reference numerals 307 and 308 are electronic components mounted on the metal substrate 1. Also, 301, 303, 304, 305, 306,
Reference numeral 309 is an electronic component mounted on the resin substrate 5. Three
01 is a transformer, 302 is a resistor, 303 is an IC, 304
Is a tantalum capacitor, 305 is a ceramic capacitor, 306 is an electrolytic capacitor, and 307 is a power MOSF.
ET, 308 are diodes, and 309 is a terminal block. Further, 101 is a pattern for forming a circuit on the metal substrate 1, 102 is a pad, 103 is an insulating layer, and 104 is aluminum. Further, 4 is solder. 6 is a land. Further, 7 is an aluminum wire. Reference numeral 8 is a structure fixed to the cooling fin.

Next, the operation will be described. The electronic components 302, 307, 308 mounted on the metal substrate 1 are soldered to the pads 102 with the solder 4, form a circuit via the pattern 101, and the circuit performs a desired operation. On the other hand, the electronic components 301, 303, 30 mounted on the resin substrate 5
4, 305, 306 and 309 are the pad 102 and the land 6
Is soldered to form a circuit through the pattern 101 and performs a desired operation. Signal and power transmission between both boards is
It is performed through the aluminum wire 7. Here, the electronic components with large heat generation on the metal substrate 1, the resistor 302, the power MOSF
Since the metal substrate 1 of the ET 307, the diode 308, and the like is made of aluminum 104 having good heat conduction, heat is applied to the cooling fins 2. On the other hand, since the cooling fins 2 radiate heat to the surrounding air, the temperature rise of the cooling fins 2 is suppressed, and the heat-generating components on the metal substrate 1 are cooled. On the other hand, the electronic components on the resin substrate 5 are thermally isolated from the metal substrate 1 and the cooling fins 2 and fixed to the structure 8, so that the temperature is kept low and the reliability is secured.

Example 2. Further, as shown in FIG. 2, if the cooling fins 2 are made of aluminum die-cast and also serve as the structure 8, the assembling property is improved and the price can be reduced. Further, as shown in FIG. 3, the resin substrate is double-sided mounted, and the aluminum die cast in this portion is recessed, which is advantageous because the resin substrate 5 can be further downsized.

As the electrical connection between the metal substrate 1 and the resin substrate 5, the aluminum wire 7 is used in the present embodiment, but a gold wire or a metal piece may be soldered,
It may be a connector.

In this embodiment, the switching power supply is taken as an example, but it goes without saying that it can be applied to various power electronics devices. For example, general-purpose inverter, servo amplifier, uninterruptible power supply,
Its applications are endless, including inverters for air conditioners, inverter welders, and inverter fluorescent lights.

[0017]

As described above, according to the present invention, since the electronic component is divided into the metal substrate and the resin substrate, the size of the expensive metal substrate can be minimized and the cost can be reduced. Can be miniaturized. Further, since lead parts can be used as needed, availability is good, development costs can be suppressed, and product unit price can be suppressed. If both sides of the resin substrate are mounted, further miniaturization can be promoted.

[Brief description of drawings]

FIG. 1 is a diagram showing an electronic circuit mounting apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a conventional electronic circuit mounting apparatus.

[Explanation of symbols]

 1 Metal Substrate 2 Cooling Fin 5 Resin Substrate 7 Aluminum Wire 8 Structures 301-309 Electronic Components

Claims (1)

[Claims] 1. An electronic circuit mounting apparatus comprising: a metal substrate on which circuit components are mounted; a resin substrate on which circuit components are mounted; and means for electrically connecting the two substrates.