JP2000261125A - Mounting structure of hybrid integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the desired characteristics of a temperature sensitive part to be maintained even if the temperature of a heat generating part rises and a hybrid integrated circuit to be miniaturized, by arranging a temperature sensitive part a heat generating part with a distance therebetween to satisfy a specified formula. SOLUTION: A hybrid integrated circuit is constituted of a temperature sensitive part 2, a heat generating part 3 and an electronic part 4 such as a capacitor and a resistance on a substrate of ceramic, glass epoxy resin, etc. The heat generating part 3 and the temperature sensitive part 2 are arranged so that a distance L1 between the heat generating part 3 and the temperature sensitive part 2 satisfies a formula. In the formula, (k) is heat transmission coefficient of the substrate 1, Th1 is heat generation temperature of the heat generating part 3 and β is an error range of heat transmission ratio of the substrate 1. The temperature of the temperature sensitive part 2 is the sum of the heat generation temperature Tb of itself, an ambient temperature Ta and temperature rise due to transmission heat whose heat generation source is a heat generation part. The temperature rise changes according to the distance L1 between the heat generating part 3 and the temperature sensitive part 2 and an absolute value of heat transmission coefficient increases in reverse proportion to the square of the distance L1 and does not exceed a control temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure of a hybrid integrated circuit in which a component having a limited use temperature and a component (element) that generates heat when energized are mixed.

[0002]

2. Description of the Related Art In recent years, there has been a trend for hybrid integrated circuits to be miniaturized while incorporating power components that consume large amounts of power. There is a hybrid integrated circuit in which a part or an element having a restriction on the use temperature (hereinafter, referred to as a temperature-constrained part) and a part or element which generates heat during operation (when energized) (hereinafter, referred to as a heat-generating part) are mixed. In this circuit,
Even if a temperature rise due to heat generation of the heat-generating component occurs, it is necessary to keep the temperature-constrained component at or below a predetermined temperature (a temperature at which desired component characteristics can be obtained). The heat generated in the hybrid integrated circuit is efficiently radiated by enlarging the substrate or by providing a heat radiation fin on the substrate.

[0003]

However, the enlargement of the substrate size and the provision of the heat radiation fins cause a problem that the size of the hybrid integrated circuit is increased, which is inconsistent with the aforementioned miniaturization of the hybrid integrated circuit. Further, in order to obtain the heat radiation effect, there is a problem that the number of parts is increased or the number of processing steps is increased, thereby increasing the cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has a temperature-limited component having desired characteristics even when a temperature rise occurs due to heat generation of a heat-generating component, and the mounting of a hybrid integrated circuit capable of reducing the size of the hybrid integrated circuit. The purpose is to provide a structure.

[0005]

In order to solve the above problem, according to the first aspect of the present invention, the distance between the temperature limiting component (2) and the first heat generating component (3, 3a) is increased. L
1. The ambient temperature around the temperature constrained component (2) is Ta, the temperature rise due to the heat generation of the temperature constrained component (2) is Tb, the heat generation temperature of the first heat generated components (3, 3a) is Th1, and the temperature constrained component is Th1. Is the constrained temperature of Tc, the heat transfer coefficient of the board (1) between the temperature constrained component (2) and the first heat generating component (3, 3a) is k, and the vicinity of the first heat generating component (3, 3a). Is an error range in the heat transfer coefficient of the first heat generating component (3, 3).
When the error range in the heat transfer coefficient in the distance of a) is β, the temperature-constrained component (2) and the first heat-generating components (3, 3a) are arranged so as to satisfy Equation (1). And

As described above, the temperature constraining component (2) and the heat generating components (3, 3a) are arranged so that the distance between the temperature constraining component (2) and the heat generating components (3, 3a) satisfies the distance L1. Thus, even if the temperature constrained component (2) and the heat generating components (3, 3a) are arranged at a short interval of the distance L1, the temperature constrained component (2) does not exceed the constrained temperature. Therefore,
The desired characteristics of the temperature constrained component (2) can be obtained, and the size of the hybrid integrated circuit can be reduced.

According to the second aspect of the present invention, there is provided a second heat generating component (3b) which generates heat during operation, and a distance between the second heat generating component (3b) and the temperature restricting component (2). Is L2, the heat generation temperature of the second heat-generating component (3b) is Th2, and the temperature rise of the temperature-constrained component (2) due to the heat generation of the first heat-generating component (3, 3a) is Te1. The temperature constraint part (2) and the second heat generation part (3
b) are arranged.

[0008] As described above, the plurality of power generation components are connected to the substrate (1).
In the case where the heat-generating components (3a, 3b) are arranged above, a plurality of heat-generating components (3a, 3b) are arranged by setting a predetermined distance between the temperature-constrained component (2) and each of the heat-generating components (3a, 3b). Also in this case, the same effect as in claim 1 can be obtained. The heat transfer coefficient of the substrate (1) has a relationship that is inversely proportional to the square of the distance that heat travels through the substrate (1).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 shows a mounting structure of a hybrid integrated circuit to which one embodiment of the present invention is applied. Hereinafter, the mounting structure of the hybrid integrated circuit will be described with reference to FIG. As shown in FIG. 1, the hybrid integrated circuit has a configuration in which a plurality of components are provided on a substrate 1 made of ceramic, glass epoxy resin, or the like. Each of the plurality of components includes a temperature constraint component 2, a heating component 3, and electronic components 4 such as a capacitor and a resistor. Here, the temperature-constrained component 2 is generally a semiconductor element having a junction temperature (Tj) of 150 ° C., a component connected by solder that softens from about 170 ° C., or an operating temperature based on temperature characteristics. Indicates a restricted resistor or capacitor. The heat-generating components 3 are all heat-generating components such as power MOS transistors and other high-power semiconductor elements, resistors, and coils.

The heat-generating component 3 and the temperature-constrained component 2 are arranged so that the distance L1 between the heat-generating component 3 and the temperature-constrained component 2 satisfies Equation 3.

[0011]

(Equation 3)

Here, Ta: ambient temperature, Tb: heat generation temperature of the temperature-constrained component 2 itself, k: heat transfer coefficient of the substrate 1, T:
c: limited temperature of temperature-limited component 2 (temperature at which desired characteristics can be obtained) Th1; heat-generating temperature of heat-generating component 3, α, β;
Is the error range for the heat transfer coefficient of Equation 3 will be described.

First, considering the temperature of the temperature constrained component 2, the temperature of the temperature constrained component 2 is determined by the heat generation temperature Tb of the temperature constrained component 2, the ambient temperature of the temperature constrained component 2, and the heat generation of the heat generated component 3. Expressed as the sum of the temperature rise due to the heat transferred as the source. Of these, the heating component 3
Rises due to the heat transmitted using the heat source as a heat source, the temperature rise depends on the distance L1 between the heat-generating component 3 and the temperature-constrained component 2, so that the sum does not exceed the constrained temperature of the temperature-constrained component 2. Need to be set.

Therefore, the heat-generating component 3 and the temperature-constrained component 2
And the heat transfer coefficient of the substrate 1 between them.
When the relationship was examined, the characteristics shown in FIG. 2 were obtained. This
As shown in the figure, the absolute value of the heat transfer coefficient is the distance L
Inversely proportional to the square of 1 (1 / L1 ^Two) To make it bigger
Change. Therefore, the heat transmitted from the heat-generating component 3
Temperature rise is (k / L1^Two+ Β) × Th.
Then, the temperature of the temperature constrained part 2 is equal to or lower than the constrained temperature Tc.
It is necessary that the temperature
Temperature, ie, the constraint temperature Tc is as shown in Equation 4.
Can be represented by

[0015]

(Equation 4)

When this equation (4) is converted into an equation for the distance L1, equation (1) is derived. Thereby, the distance L1 between the heat generating component and the temperature constrained component 2 is set to such an extent that the temperature of the temperature constrained component 2 does not exceed the constrained temperature with respect to various assumed temperatures. This distance L1 is a relatively small value because ceramic or resin used as the substrate 1 is a material that is inferior in heat conductivity to a metal or the like and generates a relatively large temperature gradient. Therefore, the distance L1
Is a value that satisfies Equation 1 above, the distance L1 between the heat generating component 3 and the temperature constrained component 2 can be the shortest distance that allows the temperature of the temperature constrained component 2 to be equal to or less than the constrained temperature. Components can be connected with the shortest distance.
Therefore, not only can the temperature of the temperature constrained component 2 not exceed the constrained temperature, but also the size of the hybrid integrated circuit can be reduced.

Furthermore, since the connection can be made at the shortest distance, the effect of reducing the wiring resistance can be obtained. Further, thereby, heat generation due to a large current flowing through the wiring can be suppressed, and a synergistic effect that a temperature rise of the temperature constrained component 2 can be suppressed can be obtained. Although not shown, the conductor pattern density between the temperature restricting component 2 and the heat generating component 3 is made as small as possible. This allows
The absolute value of the thermal conductivity coefficient of the substrate 1 can be increased,
The effect that the distance L1 can be further reduced is obtained, and higher integration can be achieved.

Further, by disposing the heat generating component 3 in the vicinity of an object electrically or structurally connected to the hybrid integrated circuit, for example, a clip or a connector, the heat generated by the heat generating component 3 is radiated through these objects. It is also possible.
Further, in the present embodiment, although the board dimensions are not particularly described, the heat transfer coefficient greatly depends on the board dimensions, and the larger the board size, the larger the absolute value of the heat transfer coefficient becomes. It has been found that transmission to the temperature-constrained component 2 becomes difficult. For this reason, by increasing the board size, the space between the heat-generating component 3 and the temperature-constraining component 2 can be reduced in the board 1, increasing the space for arranging other components in the board 1, It is also possible to improve the degree of freedom in arranging the components.

(Second Embodiment) FIG. 3 shows a mounting structure of a hybrid integrated circuit according to a second embodiment of the present invention. Hereinafter, the configuration of the hybrid integrated circuit according to the present embodiment will be described with reference to FIG. However, in FIG. 3, the description of the same configuration as in FIG. 1 is omitted. In the present embodiment, a case where a plurality of temperature-constrained components 2 and heat-generating components 3 are arranged on the substrate 1 will be described. However, in the present embodiment, a case where two heat-generating components 3a and 3b are arranged for one temperature-constrained component 2 will be described for convenience.

As shown in FIG. 3, a heat-generating component 3a is disposed at a distance L1 from the temperature-constrained component 2, and a heat-generating component 3b is disposed at a position at a distance L2. In such a case, since the temperature of the temperature constrained component 2 rises due to heat generation in both the heat generating component 3a and the heat generating component 3b, the distance temperatures L1 and L2 are set in consideration of the heat generated by both.

More specifically, first, the temperature rise Te1 which the temperature constrained component 2 receives due to the heat generated by the heat generating component 3a is expressed by the following equation (5).
Is required.

[0022]

## EQU5 ## Te1 = (k / L1 ² + β) Th1 where Th1 is the heat generation temperature of the heat generating component 3a. The temperature of the temperature-constrained component 2 includes the original temperature Tb of the temperature-constrained component 2, the ambient temperature of the temperature-constrained component 2, and a temperature rise due to heat transmitted using the heat-generating components 3 a and 3 b as a heat source. , The distance L2 between the temperature constraining component 2 and the heat generating component 3b is expressed as in Equation 6.

[0023]

(Equation 6)

Here, Th2 is a heat generation temperature of the heat generation component 3a. For this reason, the distances L1 and L2 are arbitrarily set based on Equations 5 and 6 so that the temperature of the temperature-constrained component 2 is equal to or lower than the constrained temperature. 3b, it is possible to prevent the temperature of the temperature constrained component 2 from becoming equal to or higher than the constrained temperature.

In the case where there are a plurality of temperature-constrained components 2 and a plurality of heat-generating components, similarly to this embodiment, the temperature rise caused by the heat generation of each heat-conducting component for each of the temperature-constrained components 2 is also determined. By studying, it is possible to prevent the temperature of each temperature constrained component 2 from exceeding the respective constrained temperature.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a mounting structure of a hybrid integrated circuit according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between 1 / (square of distance) and a heat transfer coefficient.

FIG. 3 is a diagram illustrating a mounting structure of a hybrid integrated circuit according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... temperature constraint parts, 3, 3a, 3b ... heat generation parts, 4 ... electronic parts.

Claims (3)

[Claims] 1. A temperature constrained component (2) composed of a component or an element having a restriction on a use temperature and a first heat generating component (3, 3a) composed of a component or an element generating heat during operation on a substrate (1). ), The distance between the temperature constrained component (2) and the first heat generating component is L1, and the ambient temperature around the temperature constrained component (2) is Ta, Tb indicates a temperature rise due to heat generation of the temperature constrained component (2) itself, Th1 indicates a heat generation temperature of the first heat generating components (3, 3a), and T1 indicates a constrained temperature of the temperature constrained component (2).
c, the heat transfer coefficient of the substrate (1) between the temperature constraining component (2) and the first heat generating component (3, 3a) is k, in the vicinity of the first heat generating component (3, 3a). Α is the error range in the heat transfer coefficient of the first heat generating component (3,
Assuming that the error range in the distant heat transfer coefficient in 3a) is β, Wherein the temperature constraining component (2) and the first heat generating component (3, 3a) are arranged so as to satisfy the following. And a second heat generating component (3b) that generates heat during operation, wherein a distance between the second heat generating component (3b) and the temperature constraining component (2) is L2, When the heat generation temperature of the heat-generating component (3b) is Th2 and the temperature rise of the temperature-constrained component (2) due to the heat generation of the first heat-generating component (3, 3a) is Te1, The mounting structure of the hybrid integrated circuit according to claim 1, wherein the temperature constraining component (2) and the second heat generating component (3b) are arranged so as to satisfy the following. 3. The substrate according to claim 1, wherein a heat transfer coefficient of the substrate has a relationship inversely proportional to a square of a distance of the substrate in a planar direction. Mounting structure of hybrid integrated circuit.