Semiconductor module and power conversion device

Abstract

A semiconductor module and a power conversion device capable of achieving sufficient temperature protection are obtained. The switching element (2a, 2b, 2c) has a gate pad (3). The output portion (5a, 5b, 5c) has an output pad (10) connected to the gate pad (3) of the switching element (2a, 2b, 2c) through a line (11), and a drive signal is output from the output pad (10) to the switching element (2a, 2b, 2c). The temperature protection circuit (6) detects the temperature and performs a protection action. The heat conductive pattern (13) is connected to the output pad (10), extends from the output pad (10) toward the temperature protection circuit (6), and conducts the heat generated by the switching element (2a, 2b, 2c) to the temperature protection circuit (6).

Description

Technical Field

[0001] The present invention relates to a semiconductor module and a power conversion device that detect temperature and perform a protective action. Background Art

[0002] In recent years, the LVIC (low-voltage integrated circuit) mounted on the inverter module has a temperature detection function for overheat protection. The heat generated inside the module is mainly generated by the IGBT chip. The heat generated by the IGBT chip reaches the temperature protection circuit of the LVIC via the metal frame and the molding resin for packaging (for example, refer to Patent Document 1). The temperature protection circuit has become an indispensable protection function for the phenomenon that the module temperature rises slowly when the motor is overloaded or the cooling fan fails.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2011-199150

[0004] However, during transient operations such as motor locking or short-circuiting, in which the junction temperature Tj of the IGBT chip rises sharply, a temperature deviation occurs between the temperature Tj and the temperature Tlvic of the temperature protection circuit, which results in insufficient temperature protection. Summary of the invention

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a semiconductor module and a power conversion device that can achieve sufficient temperature protection.

[0006] The semiconductor module involved in the present invention is characterized in that it comprises: a switching element having a gate pad; an output portion having an output pad connected to the gate pad of the switching element through a line, and the output portion outputs a driving signal from the output pad to the switching element; a temperature protection circuit that detects temperature and performs a protection action; and a heat conductive pattern that is connected to the output pad, extends from the output pad toward the temperature protection circuit, and conducts heat generated by the switching element to the temperature protection circuit.

[0007] Effects of the Invention

[0008] In the present invention, a heat conduction pattern extending from the output pad toward the temperature protection circuit is provided in order to conduct the heat generated by the switching element to the temperature protection circuit. As a result, the temperature of the temperature protection circuit follows the transient change of the temperature of the switching element, and thus the temperature protection circuit can accurately detect the rapid temperature rise of the switching element. Therefore, even in an operation mode in which the temperature of the switching element rises rapidly, such as a motor locking operation or a short circuit operation, sufficient temperature protection can be achieved to suppress the destruction of the semiconductor module. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a plan view showing the semiconductor module according to the first embodiment.

[0010] Figure 2 This is an enlarged plan view of the output pad and the temperature protection circuit according to the first embodiment.

[0011] Figure 3 1 is a cross-sectional view showing an output pad and a temperature protection circuit according to the first embodiment.

[0012] Figure 4 is a circuit diagram showing a temperature protection circuit.

[0013] Figure 5 This is a flow chart of the laser trimming operation.

[0014] Figure 6 It is a plan view showing Modification 1 of the heat transfer pattern according to the first embodiment.

[0015] Figure 7 It is a plan view showing a second modification of the heat transfer pattern according to the first embodiment.

[0016] Figure 8 It is a plan view showing a third modification of the heat transfer pattern according to the first embodiment.

[0017] Fig. 9 It is a plan view showing a semiconductor module according to the second embodiment.

[0018] Fig.10 It is a plan view showing a switching element and an output unit according to the third embodiment.

[0019] Fig.11 This is an enlarged plan view of the output pad and the temperature protection circuit according to the third embodiment.

[0020] Fig.12 It is a block diagram showing the structure of a power conversion device to which the semiconductor module according to the third embodiment is applied. DETAILED DESCRIPTION

[0021] The semiconductor module and the power conversion device according to the embodiment will be described with reference to the drawings. The same reference numerals are given to the same or corresponding components, and duplicate descriptions may be omitted.

[0022] Implementation method 1.

[0023] Figure 11 is a top view showing a semiconductor module according to Embodiment 1. The semiconductor module is an inverter module. LVIC 1 for low voltage side driving drives switching element 2a of U phase, switching element 2b of V phase, and switching element 2c of W phase. Switching elements 2a, 2b, 2c are, for example, IGBTs and have gate pads 3. LVIC 1 has an input section 4, output sections 5a, 5b, 5c, a temperature protection circuit 6, a power supply circuit 7, an overcurrent protection circuit 8, and a power supply drop protection circuit 9. U phase output section 5a, V phase output section 5b, and W phase output section 5c are provided for switching elements 2a, 2b, 2c of U phase, V phase, and W phase, respectively.

[0024] The input unit 4 transmits a control signal from the outside to the output units 5a, 5b, and 5c. The output units 5a, 5b, and 5c have output pads 10. The output pads 10 of the output units 5a, 5b, and 5c are connected to the gate pads 3 of the switching elements 2a, 2b, and 2c through wires 11, respectively. The wires 11 are metal wires such as Au, Ag, and Cu. The output units 5a, 5b, and 5c output drive signals from the output pads 10 to the switching elements 2a, 2b, and 2c.

[0025] The temperature protection circuit 6 detects the temperature and performs a protection action. The protection action includes OT protection and VOT protection. In OT protection, when the temperature of the temperature protection circuit 6 rises sharply, the operation of the output parts 5a, 5b, and 5c of each phase is stopped. In VOT protection, the LVIC 1 itself does not perform self-protection, but the external microcomputer senses the rise of the output voltage VOT of the temperature protection circuit 6 and cuts off the control input signal.

[0026] The power supply circuit 7 receives power supply voltage from the outside and transmits it to each circuit module in the LVIC 1. The overcurrent protection circuit 8 cuts off the switch elements 2a, 2b, and 2c when an overcurrent is detected by an externally connected shunt resistor. The power supply drop protection circuit 9 cuts off the switch elements 2a, 2b, and 2c when the power supply voltage drops.

[0027] Figure 2 This is an enlarged plan view of the output pad and the temperature protection circuit according to the first embodiment. Figure 31 is a cross-sectional view showing an output pad and a temperature protection circuit according to Embodiment 1. An output pad 10, a temperature protection circuit 6, and a thermal conductive pattern 13 are provided on a semiconductor substrate 12 of the LVIC 1. The thermal conductive pattern 13 is connected to the output pad 10, and the thermal conductive pattern 13 extends from the output pad 10 toward the temperature protection circuit 6 and overlaps the temperature protection circuit 6. An insulating film (not shown) is provided between the thermal conductive pattern 13 and the temperature protection circuit 6. Therefore, the thermal conductive pattern 13 is not electrically connected to the temperature protection circuit 6, but is thermally connected. The thermal conductive pattern 13 is formed by aluminum sputtering, but may also be formed by other metals.

[0028] Heat generated by the switching elements 2a, 2b, 2c is conducted to the output pad 10 via the wire 11, and the heat conduction pattern 13 conducts the heat to the temperature protection circuit 6. The wire 11 is not only electrically conductive but also thermally conductive, so the diameter of the wire 11 is preferably 200 to 500 μm.

[0029] Figure 4 : is a circuit diagram showing a temperature protection circuit. A constant current circuit CC and a temperature sensing diode D1 are connected in series between a DC power supply and a grounding point. The temperature sensing diode D1 may be one or multiple temperature sensing diodes D1 may be connected in series. The anode voltage OTVF of the temperature sensing diode D1 is input to the -input terminal of the operational amplifier OA via a resistor R1. A resistor R2 is connected between the output terminal and the -input terminal of the operational amplifier OA. A resistor Ra, a laser trimming circuit LT, and a resistor Rb are connected in series between a reference voltage VREGOT of a reference voltage circuit and a grounding point. The output voltage OTref of the laser trimming circuit LT is input to the +input terminal of the operational amplifier OA.

[0030] The operational amplifier OA inverts and amplifies the anode voltage OTVF of the temperature sensing diode D1 and outputs the output voltage VOT represented by equation (1) as an analog temperature signal.

[0031] VOT=OTref·(1+R2 / R1)-OTVF·R2 / R1…………(1)

[0032] If the temperature of the temperature protection circuit 6 rises, the forward voltage of the temperature sensing diode D1 decreases, and the output voltage VOT of the operational amplifier OA increases.

[0033] The anode voltage OTVF and the reference voltage VREGOT fluctuate due to element fluctuations, etc. Therefore, the laser trimming circuit LT corrects the fluctuations of the anode voltage OTVF and the reference voltage VREGOT as described below. Figure 5 This is a flow chart of the laser trimming operation.

[0034] First, the output voltage VOT and the reference voltage VREGOT are measured (step S1). It is confirmed whether VREGOT is within the fluctuation specification (step S2). If it is outside the specification, it is determined to be a test defective product. It is confirmed whether VOT is within the fluctuation specification (step S3). If it is outside the specification, it is determined to be a test defective product. It is confirmed whether VOT is a specified value (step S4). If it is a specified value, it is determined to be a test qualified product. In addition, the laser trimming circuit LT makes point A and point B respectively in a connected state.

[0035] OTref when the point A and the point B of the laser trimming circuit LT are connected is obtained by equation (2).

[0036] OTref=VREGOT·Rb / (Ra+Rb)…………(2)

[0037] Next, it is checked whether VOT is larger than a predetermined value (step S5). If it is larger, point A is cut off. In this case, OTref is obtained by equation (3). The variable resistor RLT that becomes the optimum VOT is determined by equations (1) and (3).

[0038] OTref=VREGOT·Rb / (Ra+RLT+Rb)…………(3)

[0039] When the VOT output voltage is less than a predetermined value, the point B is cut off. In this case, OTref is obtained by equation (4). The variable resistor RLT that becomes the optimum VOT is determined by equations (1) and (4).

[0040] OTref=VREGOT·(RLT+Rb) / (Ra+RLT+Rb)…………(4)

[0041] In this way, the resistance value of the variable resistor RLT at which VOT becomes the optimal value is calculated based on the measured value of VREGOT, and the trimming value of RLT is determined and trimming is performed.

[0042] As described above, in this embodiment, in order to conduct the heat generated by the switching elements 2a, 2b, and 2c to the temperature protection circuit 6, a heat conduction pattern 13 extending from the output pad 10 toward the temperature protection circuit 6 is provided. As a result, the temperature Tlvic of the temperature protection circuit 6 follows the transient change of the temperature Tj of the switching elements 2a, 2b, and 2c, and therefore, the temperature protection circuit 6 can accurately detect the rapid temperature rise of the switching elements 2a, 2b, and 2c. Therefore, even in an operation mode in which the temperature of the switching elements 2a, 2b, and 2c rises rapidly, such as a motor locking operation or a short circuit operation, sufficient temperature protection can be achieved to suppress the destruction of the semiconductor module.

[0043] In addition, when the semiconductor module according to the present embodiment is assembled into various products for civil or industrial use, the temperature protection setting in the customer-side system can be simplified. Furthermore, the present embodiment can be implemented by the existing inverter module structure, so the temperature detection accuracy of the LVIC mounted on the inverter module can be improved at a low cost.

[0044] Figure 6 1 is a top view showing a modification example 1 of the heat conduction pattern according to Embodiment 1. Two straight heat conduction patterns 13 overlap on the temperature protection circuit 6, and another two straight heat conduction patterns 13 are provided on the sides of the temperature protection circuit 6. In this way, by providing a plurality of heat conduction patterns 13, the thermal conductivity to the temperature protection circuit 6 is further improved.

[0045] Figure 7 1 is a top view showing a modification example 2 of the heat conduction pattern according to the first embodiment. The heat conduction pattern 13 surrounds the temperature protection circuit 6. The heat conduction pattern 13 is separated from the temperature protection circuit 6, and heat is conducted from the heat conduction pattern 13 to the temperature protection circuit 6 via the semiconductor substrate 12. In addition, the heat conduction pattern 13 may be in contact with the side surface of the temperature protection circuit 6 via an insulating film. Even with such a heat conduction pattern 13, the heat generated by the switching elements 2a, 2b, and 2c can be conducted to the temperature protection circuit 6.

[0046] Figure 8 1 is a plan view showing a modification 3 of the heat transfer pattern according to Embodiment 1. Two heat transfer patterns 13 surround the temperature protection circuit 6. Thus, by providing a plurality of heat transfer patterns 13, the heat transfer to the temperature protection circuit 6 is further improved.

[0047] In addition, the heat conduction pattern 13 is arranged close to the temperature protection circuit 6 as a whole. Figure 4 In the structure of the temperature protection circuit 6, the temperature sensing diode D1, the laser trimming circuit LT and the element temperatures and characteristic values ​​of the resistors Ra and Rb change with the temperature change of the module, and contribute to the output voltage VOT. Therefore, it is sufficient to provide the heat conductive pattern 13 close to these parts.

[0048] Implementation Method 2

[0049] Fig. 9 1 is a top view showing a semiconductor module according to Embodiment 2. The temperature protection circuit 6 is arranged near the output pad 10 of the output portion 5a, 5b, 5c, compared with other circuits such as the power drop protection circuit 9 included in the LVIC 1. As a result, the thermal conductivity to the temperature protection circuit 6 is further improved, so that a sharp rise in the temperature Tj of the switching elements 2a, 2b, 2c can be detected more accurately.

[0050] Implementation method 3.

[0051] Fig.10 1 is a plan view showing the switching elements and output units according to Embodiment 3. Dummy pads 14 are provided next to the output pads 10 of the output units 5a, 5b, 5c. Dummy pads 15 are provided next to the gate pads 3 of the switching elements 2a, 2b, 2c.

[0052] Output pads 10 of output parts 5a, 5b, 5c are connected to gate pads 3 of switching elements 2a, 2b, 2c via conductive wires 16. Dummy pads 14 of output parts 5a, 5b, 5c are connected to dummy pads 15 of switching elements 2a, 2b, 2c via thermal wires 17.

[0053] Fig.11 1 is an enlarged top view of the output pad and the temperature protection circuit involved in Embodiment 3. The heat conduction pattern 13 is connected to the dummy pad 14. The heat conduction pattern 13 extends from the dummy pad 14 toward the temperature protection circuit 6, and conducts the heat generated by the switching elements 2a, 2b, and 2c to the temperature protection circuit 6. The other structures are the same as those of Embodiments 1 and 2.

[0054] In the structure of this embodiment, as in the first and second embodiments, the temperature Tlvic of the temperature protection circuit 6 follows the transient change of the temperature Tj of the switching elements 2a, 2b, 2c, so the temperature protection circuit 6 can accurately detect the rapid temperature rise of the switching elements 2a, 2b, 2c. Therefore, even in the operation mode where the temperature of the switching elements 2a, 2b, 2c rises rapidly, such as the motor locking operation or the short circuit operation, sufficient temperature protection can be achieved to suppress the destruction of the semiconductor module.

[0055] In order to conduct heat efficiently, the diameter of the heat-conducting wire 17 is preferably thicker than the diameter of the conductive wire 16, for example, 200 to 500 μm. The heat-conducting wire 17 and the conductive wire 16 are metal wires such as Au, Ag, and Cu. However, the material of the heat-conducting wire 17 can also be a non-conductive component such as a high thermal conductivity fine ceramic represented by AlN. In addition, in order to conduct heat more efficiently, it is preferred that the heat-conducting pattern 13 is connected not only to the dummy pad 14 but also to the output pad 10.

[0056] Implementation method 4.

[0057] This embodiment applies the semiconductor modules according to the above-mentioned Embodiments 1 to 3 to a power conversion device. The present invention is not limited to a specific power conversion device, but the case where the present invention is applied to a three-phase inverter will be described below.

[0058] Fig.12 It is a block diagram showing the structure of a power conversion device to which the semiconductor module according to the third embodiment is applied.

[0059] The power conversion device includes a power supply 100, a semiconductor module 101 for power conversion, an inductive load 102, a control circuit 103, and a heat sink 104. The power supply 100 is a DC power supply, and supplies DC power to the semiconductor module 101. The power supply 100 can be composed of various power supplies, for example, it can be composed of a DC system, a solar cell, a storage battery, or a rectifier circuit or an AC / DC converter connected to an AC system. In addition, the power supply 100 can also be composed of a DC / DC converter that converts the DC power output from the DC system into a predetermined power.

[0060] The semiconductor module 101 is a three-phase inverter connected between the power source 100 and the inductive load 102 , converts DC power supplied from the power source 100 into AC power, and supplies the AC power to the inductive load 102 .

[0061] The inductive load 102 is a three-phase motor driven by AC power supplied from the power conversion semiconductor module. In addition, the inductive load 102 is not limited to a specific use, and is a motor mounted on various electrical equipment, for example, used as a motor for hybrid vehicles, electric vehicles, railway vehicles, elevators or air conditioning equipment.

[0062] The details of the semiconductor module 101 are described below. The semiconductor module 101 has a switching element, a freewheeling diode, and an IC for controlling them. By turning the switching element on and off, the DC power supplied from the power supply 100 is converted into AC power and supplied to the inductive load 102. There are various structures for the specific circuit structure of the semiconductor module 101, but the semiconductor module 101 involved in this embodiment is a 2-level three-phase full-bridge circuit, which can be composed of 6 switching elements and 6 freewheeling diodes connected in reverse parallel to each switching element. The 6 switching elements are connected in series two by two to form upper and lower bridge arms, and each upper and lower bridge arm constitutes each phase (U / V / W phase) of the full-bridge circuit. In addition, the output terminals of each upper and lower bridge arm, that is, the three output terminals of the semiconductor module 101, are connected to the inductive load 102. In addition, the semiconductor module involved in the above-mentioned embodiments 1 to 3 is applied to the semiconductor module 101.

[0063] The control IC built into the semiconductor module 101 generates a drive signal for driving the switch element also built into the semiconductor module 101. Specifically, according to the control signal from the control circuit 103 described later, a drive signal for setting the switch element to the on state and a drive signal for setting the switch element to the off state are output to the control electrode of each switch element. When the switch element is maintained in the on state, the drive signal is a voltage signal (on signal) greater than or equal to the threshold voltage of the switch element, and when the switch element is maintained in the off state, the drive signal becomes a voltage signal (off signal) less than or equal to the threshold voltage of the switch element.

[0064] The control circuit 103 controls the switching elements of the semiconductor module 101 to supply the desired power to the inductive load 102. Specifically, based on the power to be supplied to the inductive load 102, the time (on time) at which each switching element of the semiconductor module 101 should be in the on state is calculated. For example, the semiconductor module 101 can be controlled by PWM control that modulates the on time of the switching element corresponding to the voltage to be output. In addition, a control instruction (control signal) is output to the control IC built into the semiconductor module 101 to output an on signal to the switching element that should be in the on state and an off signal to the switching element that should be in the off state at each moment. The control IC outputs the on signal or the off signal as a drive signal to the control electrode of each switching element according to the control signal.

[0065] The heat dissipation fins 104 dissipate the heat generated by the driving of the semiconductor module 101 to the outside. Specifically, a bonding grease is applied between the heat dissipation fins 104 and the semiconductor module 101, and the heat generated by the semiconductor module 101 is dissipated to the outside by heat conduction of the heat dissipation fins 104 and the bonding grease. In addition, the heat dissipation fins 104 can be installed only on one side of the semiconductor module for power conversion, or can be installed on both sides.

[0066] In the power conversion device according to the present embodiment, since the semiconductor modules according to Embodiments 1 to 3 are used as the semiconductor modules 101 , it is possible to improve the accuracy of the temperature protection function of the power conversion device.

[0067] In this embodiment, an example of applying the present invention to a 2-level three-phase inverter is described, but it is not limited to this and can be applied to various power conversion devices. In this embodiment, a 2-level power conversion device is used, but a 3-level or multi-level power conversion device can also be used. In the case of supplying power to a single-phase load, the present invention can also be applied to a single-phase inverter. In addition, in the case of supplying power to a DC load, etc., the present invention can also be applied to a DC / DC converter or an AC / DC converter.

[0068] In addition, the power conversion device to which the present invention is applied is not limited to the case where the above-mentioned load is an electric motor. For example, it can also be used as a power supply device for an electric discharge machine, a laser processing machine, an induction heating cooker or a contactless power supply system, and can also be used as a power conditioner for a solar power generation system and a power storage system.

[0069] Description of the label

[0070] 2a, 2b, 2c switching elements, 3 gate pads, 5a, 5b, 5c output parts, 6 temperature protection circuit, 10 output pads, 11 wires, 13 thermal conductive patterns, 14, 15 dummy pads, 16 conductive wires, 17 thermal conductive wires.

Claims

1. A semiconductor module, characterized in that: have: a switching element having a gate pad; an output unit having an output pad connected to the gate pad of the switching element through a line, the output unit outputting a driving signal from the output pad to the switching element; A temperature protection circuit detects the temperature and performs a protective action; as well as The heat conductive pattern is connected to the output pad and extends from the output pad toward the temperature protection circuit to conduct the heat generated by the switch element to the temperature protection circuit.

2. The semiconductor module according to claim 1, characterized in that The heat conductive pattern overlaps the temperature protection circuit.

3. The semiconductor module according to claim 1, characterized in that The heat conductive pattern surrounds the temperature protection circuit.

4. The semiconductor module according to any one of claims 1 to 3, characterized in that A plurality of the heat conducting patterns are provided.

5. The semiconductor module according to any one of claims 1 to 4, characterized in that The temperature protection circuit is disposed closer to the output pad than other circuits.

6. The semiconductor module according to any one of claims 1 to 5, characterized in that The diameter of the wire is 200-500 μm.

7. A semiconductor module, characterized in that: have: A switch element having a gate pad and a first dummy pad disposed next to the gate pad; an output unit having an output pad connected to the gate pad of the switching element through a conductive line and a second dummy pad provided next to the output pad and connected to the first dummy pad of the switching element through a thermally conductive line, wherein the output unit outputs a driving signal from the output pad to the switching element; A temperature protection circuit that detects temperature and performs protection actions; and The heat conduction pattern is connected to the second dummy pad, extends from the second dummy pad toward the temperature protection circuit, and conducts heat generated by the switching element to the temperature protection circuit.

8. The semiconductor module according to claim 7, characterized in that The heat conductive wire has a diameter larger than that of the electrical conductive wire.

9. The semiconductor module according to claim 7 or 8, characterized in that The material of the heat conducting wire is a non-conductive component.

10. The semiconductor module according to any one of claims 7 to 9, characterized in that The thermal conductive pattern is also connected to the output pad.

11. The semiconductor module according to any one of claims 1 to 10, characterized in that The heat conductive pattern is made of metal and is not electrically connected to the temperature protection circuit.

12. A power conversion device, characterized in that: have: The semiconductor module according to any one of claims 1 to 11, which converts input power and outputs it; and A control circuit outputs a control signal for controlling the semiconductor module to the semiconductor module.

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