JPH11330321A - Overheating protective structure for circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the operational reliability of a circuit element, by preventing the occurrence of faults by heat in the element by making the detecting timing of the temperature fluctuation of the circuit element faster. SOLUTION: A circuit board 21 is constituted by laminating a metallic substrate 23 upon a radiator 23 and a heat spreader 27 upon the substrate 23 through an insulating layer 24, a wiring pattern layer 25, and a solder layer 26. On the heat spreader 27, a circuit element section 30 is constituted by laminating a circuit element 29 which generates heat upon the heat spreader 27 through another solder layer 28. On the heat spreader 27, in addition, a heat detecting element section 35 is also constituted by laminating an wiring pattern layer 32, a solder layer 33, and a thermistor 34 upon the heat spreader 27 in this order through an insulating layer 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overheat protection structure for a circuit element such as an integrated circuit element.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of a circuit board 1 according to the prior art. Hereinafter, the related art will be described with reference to FIG. In this conventional circuit board 1, a metal substrate 3 is laminated on a radiator 2, an insulating layer 4 made of an electrically insulating material, and a wiring pattern formed by printing copper or aluminum on the metal substrate 3. The layer 5, the solder layer 6, the heat spreader 7, the solder layer 8 and, for example, a circuit element 9 with heat generation such as an integrated circuit element are sequentially laminated, and a circuit element section 10 is formed.
Is composed.

On the metal substrate 3, a wiring pattern layer 11, a solder layer 12 and a thermistor 13 are laminated in this order via the insulating layer 4, and
Is composed.

[0004] In such a circuit board 1, heat generated in the circuit element 9 by energization is changed from the circuit element 9 to the solder layer 8 and the heat spreader 7 in the circuit element section 10 as shown by an arrow A 1 in FIG. 2. , Reaches the metal substrate 3 via the solder layer 6, the wiring pattern layer 5, and the insulating layer 4,
Conduction in the metal substrate 3 reaches the thermistor 13 via the insulating layer 4, the wiring pattern layer 11 and the solder layer 12 in the heat detecting element portion 14, and heat is detected by the thermistor 13. Is output as a temperature signal.

The temperature signal from the thermistor 13 is input to a control device (not shown). The control device compares the detected temperature of the circuit element 9 with a reference temperature, and when the circuit element 9 is in an overheated state, performs control to stop energization of the circuit element 9.

[0006]

In such prior art, the temperature detected by the thermistor 13 is such that the heat from the circuit element 9 is determined by the solder layer 8, the heat spreader 7, the solder layer 6, the wiring pattern layer 5, The insulating substrate 4 and the metal substrate 3 are heated, and the temperature is raised to a temperature-steady state.
Temperature. Therefore, there is a problem that the temperature of the circuit element 9 during the temperature rise cannot be detected in real time. Further, the phenomenon in which heat is radiated from the metal substrate 3 to the radiator 2 also increases the degree of the problem.

Therefore, if the current flowing through the circuit element 9 causes a rapid change in current and the temperature of the circuit element 9 rises rapidly, the above-described problem may cause the thermistor 13 to detect the heating state of the circuit element 9. There is a problem that the circuit element 9 may be thermally damaged and the operation reliability of the circuit element 9 is low.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to advance the timing of detecting a temperature change of a circuit element to prevent a failure caused by heat of the circuit element. Another object of the present invention is to provide a circuit element overheat protection structure that can improve the operational reliability of the circuit element.

[0009]

An overheat protection structure for a circuit element according to the present invention comprises a metal substrate, a heat spreader laminated on the metal substrate via an electric insulating film, and a heat spreader laminated on the heat spreader via an electric insulating film. And a heat detecting element laminated on the heat spreader with an electric insulating film interposed therebetween.

[0010]

According to the present invention, the heat from the circuit element is transmitted to the heat detecting element via the heat spreader before reaching the metal substrate having a relatively large heat capacity. As a result, the heat detecting element can detect the temperature change of the circuit element at a relatively early timing, and even when a rapid temperature change occurs in the circuit element, the heat detecting element can quickly detect the temperature change and detect the circuit element. Therefore, it is possible to take measures such as stopping power supply to the power supply and rapid cooling, thereby improving the operational reliability of the circuit element.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 shows an embodiment of the present invention. FIG. 1 is a sectional view of a circuit board 21 according to the present embodiment. Hereinafter, this embodiment will be described with reference to FIG. Circuit board 2 of the present embodiment
1, a metal substrate 23 is laminated on a radiator 22, an insulating layer 24 made of an electrically insulating material, a wiring pattern layer 25 formed by printing copper or aluminum, and a solder layer 26 on the metal substrate 23. Through the heat spreader 27
Are laminated. On the heat spreader 27, for example, a circuit element 29 that generates heat, such as an integrated circuit element, is laminated via a solder layer 28 to form a circuit element section 30.

Further, on the heat spreader 27,
The wiring pattern layer 32 and the solder layer 3 via the insulating layer 31
3 and the thermistor 34 are stacked in this order to form a heat detecting element section 35.

In such a circuit board 21, heat generated in the circuit element 29 by energization is, as shown by an arrow A 2 in FIG.
9 reaches the heat spreader 27 via the solder layer 28, conducts through the heat spreader 27, reaches the thermistor 34 via the insulating layer 31, the wiring pattern layer 32, and the solder layer 33 in the heat detecting element 34, and At 34, heat is detected, and the temperature of the circuit element 29 is output as a temperature signal.

The temperature signal from the thermistor 34 is input to a controller (not shown). The control device compares the detected temperature of the circuit element 29 with the reference temperature, and when the circuit element 29 is in an overheated state, stops the energization of the circuit element 29 or activates another cooling device to perform rapid cooling. Control.

As described above, in the circuit board 21 of this embodiment, the heat from the circuit element 29 has a relatively large heat capacity,
Further, the heat is transmitted to the thermistor 34 via the heat spreader 27 before reaching the metal substrate 23 which is in contact with the radiator 22 and transfers a large amount of heat to the radiator 22. Thereby, the thermistor 34 can detect the temperature change of the circuit element 29 at a relatively early timing, and even when a sudden temperature change occurs in the circuit element 29, the temperature change is quickly detected and the circuit element 29 is detected. Countermeasures such as stopping power supply to the element 29 and rapid cooling can be performed, and the operational reliability of the circuit element 29 can be improved.

The present invention is not limited to the above embodiment, but includes a wide variety of modifications without departing from the spirit of the present invention.

[0017]

As described above, according to the present invention, the heat from the circuit element is transmitted to the heat detecting element via the heat spreader before reaching the metal substrate having a relatively large heat capacity. . As a result, the heat detecting element can detect the temperature change of the circuit element at a relatively early timing, and even when a rapid temperature change occurs in the circuit element, the heat detecting element can quickly detect the temperature change and detect the circuit element. Therefore, it is possible to take measures such as stopping power supply to the power supply and rapid cooling, thereby improving the operational reliability of the circuit element.

[Brief description of the drawings]

FIG. 1 is a sectional view of a circuit board 21 according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional circuit board 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Circuit board 22 Heat radiator 23 Metal substrate 24, 31 Insulating layer 25, 32 Wiring pattern layer 26, 28, 33 Solder layer 27 Heat spreader 29 Circuit element 30 Circuit element part 34 Thermistor 35 Thermal detection element part

Claims (1)

[Claims] A metal substrate, a heat spreader laminated on the metal substrate via an electrical insulating film, a heat-generating circuit element laminated on the heat spreader via an electrical insulating film, and a heat spreader laminated on the heat spreader. An overheat protection structure for a circuit element including a heat detection element stacked with an electric insulating film interposed therebetween.