Electronic devices

Abstract

An electronic device according to one embodiment of the present disclosure is capable of continuously ensuring heat conduction by a heat conductive connection body and comprises: a semiconductor element; a heat dissipation member; a heat conductive connection body for connecting the semiconductor element and the heat dissipation member to each other in a heat conductive manner; a power detection unit for detecting power consumption of the semiconductor element; an element temperature detection unit for detecting the temperature of the semiconductor element; an ambient temperature detection unit for detecting the ambient temperature of the heat dissipation member; and a heat resistance calculation unit for calculating heat resistance of the heat conductive connection body on the basis of a detection value of the power detection unit, a detection value of the element temperature detection unit, and a detection value of the ambient temperature detection unit.

Description

[Technical Field]

[0001] The present invention relates to electronic devices. [Background technology]

[0002] In electronic devices including semiconductor elements such as power semiconductors and CPUs, where heat generation can be a problem, a configuration is widely adopted in which a heat sink or other heat dissipation member is connected to the semiconductor element via a heat transfer connector such as a thermally conductive sheet, thereby dissipating the heat from the semiconductor element into the atmosphere. In such a configuration, the heat transfer connector is required to be easily deformed in order to increase the contact area with the semiconductor element or heat sink, and therefore it is not as easy to reduce the thermal resistance as compared to the semiconductor element or heat sink. To evaluate the performance of a heat transfer connector, the thermal resistance of the heat transfer connector is sometimes measured when the semiconductor element and heat dissipation member are actually connected by the heat transfer connector (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-121051 Summary of the Invention [Problem to be solved by the invention]

[0004] Because heat transfer connectors are formed to be deformable to ensure adhesion, their physical properties tend to be unstable compared to semiconductor elements or heat sinks. Therefore, heat transfer connectors may deteriorate during use, resulting in increased thermal resistance. For example, in electronic devices used in machine tools, cutting fluid seeping into the electronic device may accelerate the deterioration of the heat transfer connector. Insufficient thermal conduction due to deterioration of the heat transfer connector can lead to reduced performance of the electronic device, malfunction due to thermal runaway of the semiconductor element, or even burnout of the semiconductor element. Therefore, a technology that can continuously ensure the thermal conduction of heat transfer connectors used in electronic devices is desired. [Means for solving the problem]

[0005] An electronic device according to one aspect of the present disclosure includes a semiconductor element, a heat dissipation member, a heat transfer connector that connects the semiconductor element and the heat dissipation member in a heat transferable manner, a power detection unit that detects the power consumption of the semiconductor element, an element temperature detection unit that detects the temperature of the semiconductor element, an ambient temperature detection unit that detects the ambient temperature of the heat dissipation member, and a thermal resistance calculation unit that calculates the thermal resistance of the heat transfer connector based on the detection value of the power detection unit, the detection value of the element temperature detection unit, and the detection value of the ambient temperature detection unit. [Effects of the Invention]

[0006] According to the present disclosure, an electronic device can be provided that can continuously ensure heat conduction through a heat transfer connector. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of an electronic device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram showing the configuration of an electronic device 1 according to an embodiment of the present disclosure.

[0009] The electronic device 1 in FIG. 1 includes a semiconductor element 11, a heat dissipation member 12, a heat transfer connector 13, a fan 14, a power detection unit 15, an element temperature detection unit 16, an ambient temperature detection unit 17, a thermal resistance calculation unit 18, a deterioration determination unit 19, an element setting unit 20, a fan setting unit 21, a calculation execution control unit 22, and a notification unit 23.

[0010] The semiconductor element 11 is any type of element that is adopted depending on the function of the electronic device 1, and the effects of the configuration according to the present disclosure become significant when heat generation from the element can be a problem. Specific examples of the semiconductor element 11 include, but are not limited to, power semiconductors such as FETs and IGBTs, and computing elements such as CPUs and MPUs. Furthermore, the semiconductor element 11 may be a composite element in which multiple semiconductors are housed in a single package.

[0011] The heat dissipation member 12, also called a heat sink, dissipates heat into the atmosphere. The heat dissipation member 12 is made of a material with high thermal conductivity, such as copper or aluminum, and may have fins, protrusions, etc. that increase the contact area with the atmosphere.

[0012] The heat transfer connector 13 connects the semiconductor element 11 and the heat dissipation member 12 in a manner that allows heat transfer. A thermally conductive sheet formed into a sheet in advance, a thermally conductive paste grease that is spread in layers, or the like can be used as the heat transfer connector 13. The heat transfer connector 13 may be anisotropic, exhibiting particularly high thermal conductivity in its thickness direction, i.e., in the direction in which the semiconductor element 11 and the heat dissipation member 12 face each other.

[0013] The fan 14 forcibly ventilates the atmosphere around the heat dissipation member 12. The fan 14 is preferably disposed so as to generate an airflow that promotes heat exchange between the heat dissipation member 12 and the atmosphere, for example, an airflow in a direction along the fins or the like of the heat dissipation member 12.

[0014] It is preferable that the fan 14 is driven by a motor whose rotation speed can be controlled. Note that the rotation speed control of the fan 14 is not limited to a method that can set the rotation speed of the fan 14 to at least two rotation speeds other than zero (stop), and may be a method that can set the rotation speed roughly, such as multi-stage voltage control, without being limited to a method that can set the frequency precisely, such as frequency control.

[0015] The power detection unit 15 detects the power consumption of the semiconductor element 11. The power detection unit 15 may be built into the semiconductor element 11. For example, if the semiconductor element 11 is a computing element or the like, it generally has a configuration for detecting power consumption, and therefore the function of the semiconductor element 11 may be used as the power detection unit 15. In other words, the power detection unit 15 may be included in the semiconductor element 11.

[0016] The element temperature detection unit 16 detects the temperature of the semiconductor element 11. The element temperature detection unit 16 preferably detects the temperature of an area inside the semiconductor element 11 that generates a large amount of heat, typically the junction temperature. The element temperature detection unit 16 may also be built into the semiconductor element 11, and can utilize functions that are generally possessed by a computing element or the like.

[0017] Ambient temperature detection unit 17 detects the ambient temperature of heat dissipation member 12. The ambient temperature of heat dissipation member 12 may be the temperature of the air supplied to the periphery of heat dissipation member 12 by fan 14, or may be the temperature of the air immediately after it has moved from the periphery of heat dissipation member 12. The temperature of the air rises due to heat exchange with heat dissipation member 12, but as long as the temperature detection position of ambient temperature detection unit 17 is constant, this does not become a major error factor and can be corrected in thermal resistance calculation unit 18.

[0018] The thermal resistance calculation unit 18 calculates the thermal resistance of the heat transfer connector 13 based on the detection values ​​of the power detection unit 15, the element temperature detection unit 16, and the ambient temperature detection unit 17. If the rotation speed of the fan 14 is controlled, it is preferable that the thermal resistance calculation unit 18 calculates the thermal resistance of the heat transfer connector 13 taking the rotation speed of the fan 14 into consideration.

[0019] When the semiconductor element 11 is a computing element, the thermal resistance calculation unit 18 may be realized by causing the semiconductor element 11 to execute an appropriate program, or may be realized by causing a computing element provided separately from the semiconductor element 11 to execute an appropriate program. Also, the thermal resistance calculation unit 18 may be configured partly or entirely by a physical circuit.

[0020] Let the power consumption detected by the power detection unit 15 be Q [W], the temperature of the semiconductor element 11 detected by the element temperature detection unit 16 be Tj [°C], the ambient temperature detected by the ambient temperature detection unit 17 be Ta [°C], the thermal resistance inside the semiconductor element 11 (from the pn junction which is the heat generation point to the package surface) be Re [K / W], the thermal resistance of the heat dissipation member 12 be Rh [K / W], the thermal resistance of the heat transfer connector 13 be Rs [K / W], and the total thermal resistance of the semiconductor element 11, the heat transfer connector 13, and the heat dissipation member 12 be Rt [K / W]. Then, the relationships Rt = Re + Rs + Rh and Rt = (Tj - Ta) / Q hold.

[0021] Furthermore, when the rotation speed of the fan 14 is controlled, where the rotation speed of the fan 14 is M [rpm], the thermal resistance Rh of the heat dissipation member 12 can be expressed as a function F(M) of the rotation speed M of the fan 14. The function F(M) may be expressed as a mathematical formula or as a look-up table that associates the rotation speed M of the fan 14 with the thermal resistance Rh of the heat dissipation member 12. Depending on the definition of the function F(M), the rotation speed M of the fan 14 may be a value having different dimensions, such as the voltage, current, or power consumption of the motor of the fan 14. Meanwhile, the thermal resistance Re of the semiconductor element 11 may be considered to be constant.

[0022] From the above, the thermal resistance Rs of the heat transfer connector 13 can be calculated as Rs = Rt - (Re + Rh) = (Tj - Ta) / Q - {Re + F(M)}. In particular, even when the rotation speed of the fan 14 is controlled, the thermal resistance Rs of the heat transfer connector 13 can be estimated relatively accurately by calculating the thermal resistance Rh of the heat dissipation member 12 taking into account the rotation speed M of the fan 14.

[0023] The deterioration determination unit 19 determines the deterioration of the heat transfer connector 13 by comparing the thermal resistance Rs of the heat transfer connector 13 calculated by the thermal resistance calculation unit 18 with a pre-stored reference value. The deterioration determination unit 19 may be realized by other arithmetic elements that are the same as or similar to the thermal resistance calculation unit 18, or may be configured in part or entirely by physical circuits. Furthermore, the deterioration determination unit 19 does not have to be clearly distinguishable from the thermal resistance calculation unit 18 in terms of physical structure and program structure.

[0024] The deterioration determination unit 19 may store a number of reference values ​​for dividing the degree of deterioration of the heat transfer connections 13 into a number of categories, and determine the degree of deterioration of the heat transfer connections 13 based on the category to which the thermal resistance Rs of the heat transfer connections 13 calculated by the thermal resistance calculation unit 18 belongs. The deterioration determination unit 19 may also predict the time until the thermal resistance Rs of the heat transfer connections 13 reaches a predetermined reference value, based on the change over time in the thermal resistance Rs of the heat transfer connections 13 calculated by the thermal resistance calculation unit 18.

[0025] The element setting unit 20 maintains the power consumption of the semiconductor element 11 at a preset value. In other words, the element setting unit 20 operates in a measurement mode in which the heat generation amount of the semiconductor element 11 is fixed at a predetermined value, thereby creating a steady state of heat flux and enabling the thermal resistance calculation unit 18 to more accurately calculate the thermal resistance Rs of the heat transfer connector 13. The element setting unit 20 may be realized by other arithmetic elements that are the same as or similar to the thermal resistance calculation unit 18 and the deterioration determination unit 19, or may be configured in part or entirely by physical circuits, and need not be clearly distinguishable in terms of physical structure and program structure.

[0026] The fan setting unit 21 maintains the rotation speed of the fan 14 at a preset set rotation speed. The fan setting unit 21 may be realized by other arithmetic elements that are the same as or similar to the thermal resistance calculation unit 18, the deterioration determination unit 19, and the element setting unit 20, or may be configured in part or entirely by physical circuits, and may not be clearly distinguishable in terms of physical structure and program structure.

[0027] When the fan setting unit 21 maintains the rotation speed of the fan 14 at a preset set rotation speed, it is preferable that the thermal resistance calculation unit 18 calculates the thermal resistance Rs after the detection value of the element temperature detection unit 16 or the ambient temperature detection unit 17 has stabilized after the fan setting unit 21 has maintained the rotation speed of the fan 14 at the set rotation speed. This allows the thermal resistance Rh of the heat dissipation member 12 to be calculated accurately, and therefore the thermal resistance Rs of the heat transfer connecting body 13 to be estimated more accurately.

[0028] The fan setting unit 21 may sequentially hold the rotation speed of the fan 14 at a plurality of set rotation speeds. In this case, it is preferable that the thermal resistance calculation unit 18 calculates the thermal resistance Rs of the heat transfer connector 13 by taking into account the detection values ​​of the element temperature detection unit 16 and the ambient temperature detection unit 17 at the plurality of set rotation speeds. In other words, by having the thermal resistance calculation unit 18 calculate the thermal resistance Rs of the heat transfer connector 13 under a plurality of conditions with different rotation speeds of the fan 14, the thermal resistance Rs of the heat transfer connector 13 can be estimated more accurately.

[0029] The calculation execution control unit 22 causes the thermal resistance calculation unit 18 to calculate the thermal resistance when the electronic device 1 is not operating. The calculation execution control unit 22 may be realized by other arithmetic elements that are the same as or similar to the thermal resistance calculation unit 18, the deterioration determination unit 19, the element setting unit 20, and the fan setting unit 21, or may be configured in part or entirely by physical circuits, and may not be clearly distinguishable in terms of physical structure and program structure.

[0030] For example, the calculation execution control unit 22 may cause the thermal resistance calculation unit 18 to calculate the thermal resistance Rs of the heat transfer connector 13 as part of the process of shutting down the electronic device 1. This allows the thermal resistance Rs of the heat transfer connector 13 to be accurately calculated without fluctuations in the power consumption of the semiconductor element 11 due to operation of the electronic device 1.

[0031] To calculate the thermal resistance Rs more accurately, the calculation execution control unit 22 causes the element setting unit 20 to set the power consumption of the semiconductor element 11 and the fan setting unit 21 to set the rotation speed of the fan 14 in preparation for the thermal resistance calculation unit 18 to calculate the thermal resistance. The thermal resistance calculation unit 18 then calculates the thermal resistance Rs of the heat transfer connection 13 based on the detected values ​​of the power detection unit 15 and the element temperature detection unit 16 after a steady state is reached, thereby accurately estimating the thermal resistance Rs of the heat transfer connection 13. This allows the deterioration determination unit 19 to accurately identify the deterioration state of the heat transfer connection 13. In other words, the electronic device 1 can continuously ensure the thermal conduction of the heat transfer connection 13, i.e., the heat transfer from the semiconductor element 11 to the heat dissipation member 12. This allows the electronic device 1 to avoid unexpected thermal runaway or burnout of the semiconductor element 11 due to poor heat dissipation.

[0032] The notification unit 23 notifies the result of the determination by the deterioration determination unit 19. The notification unit 23 may be realized by other arithmetic elements that are the same as or similar to the thermal resistance calculation unit 18, the deterioration determination unit 19, the element setting unit 20, the fan setting unit 21, and the calculation execution control unit 22, or may be configured in part or entirely by physical circuits, and may not be clearly distinguishable in terms of physical structure and program structure.

[0033] The notification by the notification unit 23 may directly notify the user of the determination result by a visual signal, an auditory signal, etc., or may output a signal indicating the determination result to another device. The notification by the notification unit 23 may be made only when the determination result by the deterioration determination unit 19 is a predetermined result, for example, when it is determined that the degree of deterioration is equal to or greater than a certain level.

[0034] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the above-described embodiments.

[0035] For example, in the electronic device according to the present invention, the fan, the deterioration determining unit, the element setting unit, the fan setting unit, the calculation execution control unit, and the notification unit may be omitted. [Explanation of symbols]

[0036] 1 Electronic equipment 11 Semiconductor elements 12 Heat dissipation material 13 Heat transfer connector 14 Fan 15 Power detection section 16 Element temperature detection section 17 Ambient temperature detection section 18 Thermal resistance calculation section 19 Deterioration determination section 20 Element setting section 21 Fan Settings 22 Calculation execution control unit 23 Information Department

Claims

1. A semiconductor element; A heat dissipation member; a heat transfer connector that connects the semiconductor element and the heat dissipation member so as to be able to transfer heat; a power detection unit that detects the power consumption of the semiconductor element; an element temperature detection unit that detects the temperature of the semiconductor element; an ambient temperature detection unit that detects the ambient temperature of the heat dissipation member; a thermal resistance calculation unit that calculates the thermal resistance of the heat transfer connector based on the detection value of the power detection unit, the detection value of the element temperature detection unit, and the detection value of the ambient temperature detection unit; a deterioration determination unit that predicts the time until the thermal resistance of the heat transfer connector reaches a predetermined reference value based on the change over time in the thermal resistance of the heat transfer connector calculated by the thermal resistance calculation unit; a fan for forcibly ventilating the atmosphere of the heat dissipation member; Equipped with The thermal resistance calculation unit calculates the thermal resistance in consideration of the rotation speed of the fan.

2. 2. The electronic device according to claim 1, wherein the deterioration determining section further determines deterioration of the heat transfer connector by comparing the thermal resistance calculated by the thermal resistance calculating section with the reference value.

3. The electronic device according to claim 1 , further comprising an element setting unit that holds the power consumption of the semiconductor element at a preset value.

4. a fan setting unit that maintains the rotation speed of the fan at a preset rotation speed; 4. The electronic device according to claim 1, wherein the thermal resistance calculation unit calculates the thermal resistance after the detection value of the element temperature detection unit or the ambient temperature detection unit has stabilized after the fan setting unit has maintained the rotation speed at the set rotation speed.

5. the fan setting unit holds the rotation speed of the fan at a plurality of the set rotation speeds in sequence; The electronic device according to claim 4 , wherein the thermal resistance calculation section calculates the thermal resistance in consideration of detection values ​​of the element temperature detection section and the ambient temperature detection section at the plurality of set rotational speeds.

6. The electronic device according to claim 1 , further comprising a calculation execution control unit that causes the thermal resistance calculation unit to calculate the thermal resistance when the electronic device is not in operation.

Images