Semiconductor device and its overcurrent protection function

Abstract

To provide a semiconductor device and an over-current protection function of them, in which a switching element protective function is achieved with high accuracy.SOLUTION: A semiconductor device comprises: a chip temperature detection diode 8 of a switching element 2; a control circuit temperature detection diode 3 arranged at a control circuit controlling the switching element 2; and an over-current reference voltage collection circuit 4 that corrects an over-current reference voltage generated in an over-current reference voltage circuit 5 by comparing both detection potentials of them, and outputs the over-current reference voltage after the correction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power semiconductor device, and more particularly to a protection function in a module having a control circuit and a switching element such as an IGBT. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a configuration in which power switching elements such as transistors, IGBTs (Insulated Gate Bipolar Transistors), and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are modularized (hereinafter referred to as a switching element module).

[0003] These switching element modules are provided with various protection functions, one of which is an overcurrent protection function.

[0004] The overcurrent protection function is composed of a diode for detecting chip temperature that is attached to the switching element and an IC that performs the protection operation. The diode for detecting chip temperature may be integrated with the switching element (see, for example, Patent Document 1), or may be separated from the switching element and installed on the same circuit board, or may be installed in the same resin case as the switching element (see, for example, the second example of Patent Document 2, which is shown in Figure 24 of this document). Here, the circuit board is an insulating board that has a predetermined circuit pattern and on which electronic components are mounted.

[0005] FIG. 18 is a diagram showing an example of the internal configuration of a conventional IPM (Intelligent Power Module), which is a type of switching element module.

[0006] The IPM300 shown in FIG. 18 constitutes an inverter that outputs a three-phase AC voltage. Therefore, the IPM300 has a positive power supply terminal P, a negative power supply terminal N, and output terminals U, V, and W, and contains six IGBTs 301 to 306. The IGBTs 301 to 306 are connected in anti-parallel by protective diodes 311 to 316 mounted on the same circuit pattern. Between the positive power supply terminal P and the negative power supply terminal N, the IGBTs 301 and 302, the IGBTs 303 and 304, and the IGBTs 305 and 306 are connected in series to form three sets of arms. In addition, intermediate connections of the arms of the U, V, and W phases are connected to the output terminals U, V, and W, respectively (Patent Document 1).

[0007] A temperature detection diode having a PN junction is formed via an insulating layer at the center of the surface (emitter terminal) of each of the IGBTs 301 to 306. This makes it possible for the IGBTs 301 to 306 to observe the chip temperature close to the junction temperature by monitoring the temperature-dependent forward voltage of the temperature detection diode.

[0008] The gate terminals and temperature detection diodes of the IGBTs 301 to 306 are also connected to the control ICs 321 to 326. The control ICs 321 to 326 control the switching of the IGBTs 301 to 306, and detect an overheated state of the IGBTs 301 to 306 by passing a constant current through the temperature detection diodes.

[0009] 19 to 24 show a semiconductor element module, which is a type of switching element module, and a module unit in which a plurality of such modules are combined. Fig. 19 is a bird's-eye view of the internal structure of a semiconductor element module 500. An emitter pattern 404 and a collector pattern 405 are disposed on an insulating substrate 403 disposed on a bottom metal substrate 409, and an IGBT 401 and a diode element 402 are disposed on top of these, with the IGBT electrically connected to a gate pattern 406 and a control emitter pattern 408 by metal wires 407. The gate pattern 406 and the control emitter pattern 408 are provided with gate terminals413 and control emitter terminal 414 are connected. FIG. 20 is a view of the semiconductor element module 500 seen from above, and FIG. 21 is a view of FIG. 20 seen from the arrow A. In FIGS. 20 and 21, the internal structure shown in FIG. 19 is molded in a resin case 410, and a main emitter terminal 411, a main collector terminal 412, etc. are provided on an emitter pattern 404 and a collector pattern 405, respectively. FIG. 22 shows a module unit in which eight semiconductor element modules 500 are combined, and FIG. 23 shows FIG. 22 seen from the arrow A. There are IGBTs 401, semiconductor element modules 500 including the IGBTs, and a control board 420, but the control board 420 is mounted outside the semiconductor element module 500. 501 and 502 are unit frames. FIG. 24 shows a second embodiment, in which a thermistor 435 for detecting the temperature inside the semiconductor element module 600 is provided on a relay insulating board 431 and covered with a resin case (Patent Document 2).

[0010] In the following drawings, the same or similar parts are denoted by the same or similar reference numerals. The maximum and minimum operating temperatures assumed in a power semiconductor device are denoted as TH and TL, respectively.

[0011] 13 shows an example of a conventional power semiconductor device. It has a control circuit 1, a switching element 2, and a switching element temperature detection diode 8. The control circuit 1 has an overcurrent reference voltage circuit 5a, an overcurrent detection comparator 6, a sense voltage detection resistor 7, an overheat detection comparator 9, an overheat reference voltage circuit 10, and a filter 13.

[0012] 13, the control circuit 1 is connected to the switching element 2. That is, the control circuit 1 includes an output terminal OUT for outputting a gate voltage, an overcurrent detection terminal OC, and an overheat detection terminal OH.

[0013] The output terminal OUT is connected to the gate terminal of the switching element 2, and the overcurrent detection terminal OC is connected to the current sense emitter terminal of the switching element 2. The emitter terminal of the switching element 2 is connected to the ground potential.

[0014] In the control circuit 1, the overheat detection terminal OH is connected to a constant current source 11 and an inverting input terminal of an overheat detection comparator 9, and a non-inverting input terminal of the overheat detection comparator 9 is connected to an overheat reference voltage circuit 10. The overheat detection terminal OH is connected to an anode terminal of a switching element temperature detection diode 8, and a cathode terminal of the switching element temperature detection diode 8 is connected to the ground potential.

[0015] A constant current from a constant current source 11 is constantly applied to the switching element temperature detection diode 8, and a forward voltage corresponding to the chip temperature of the switching element 2 is applied to the inverting input terminal of the overheat detection comparator 9. Here, it is assumed that the temperature characteristic of the switching element temperature detection diode 8 has a negative temperature characteristic, and the overheat reference voltage circuit 10 outputs an overheat reference voltage VOH1 corresponding to a temperature of TH. As a result, when the chip temperature is below TH, the overheat detection comparator 9 outputs a low-level protection operation signal, and when the chip temperature becomes high and equal to or higher than TH, it outputs a high-level protection operation signal. When this high-level protection operation signal is output, the control circuit 1 outputs an alarm signal from the alarm output circuit and simultaneously controls to turn off the switching element 2.

[0016] In the control circuit 1, the overcurrent detection terminal OC is connected to a sense voltage detection resistor 7 and an inverting input terminal of an overcurrent detection comparator 6. Overcurrent detection comparator 6 The non-inverting input terminal of this is connected to the overcurrent reference voltage circuit 5a. Overcurrent detection comparator 6 The output of is connected to the input of a filter 13, which removes all voltages except the voltage proportional to the collector current.

[0017] A commonly known method for detecting overcurrent is to use the switching element 2 to shunt the emitter current to about 1 / 10,000, and then pass this current through a sense voltage detection resistor 7 to obtain a voltage (sense voltage). This voltage is then compared with the overcurrent reference voltage VOC generated by the overcurrent reference voltage circuit 5a of the overcurrent detection comparator 6 to detect the current. The magnitude of the sense voltage is then used to determine whether the current is large or small, and an alarm is then output or the gate is shut off by a protection operation transmission logic circuit.

[0018] The process of overcurrent detection and judgment is shown in Figure 15. The relationship between the collector current and the sense voltage is as shown by line 201, in which the higher the collector current, the higher the sense voltage, and the sense voltage is compared with a predetermined reference voltage value VB. If the sense voltage exceeds this, it is deemed to have exceeded the collector current value IC at the intersection of the two, and an overcurrent is detected.

[0019] The higher the temperature of the switching element 2, the higher the sense voltage becomes, and the higher the temperature of the control circuit, the higher the current detection voltage becomes.

[0020] 16 shows the overcurrent protection operation in a conventional power semiconductor device. 202 is the sense voltage when the temperature is TH, and 204 is the sense voltage when the temperature is TL. VBH is the reference voltage when the temperature is TH, and VBL is the reference voltage when the temperature is TL.

[0021] Usually, the temperature of the switching element and the control circuit are almost the same, or the temperature of the switching element is slightly higher.

[0022] 16, when both temperatures are TH, the sense voltage is represented by line 202, and the reference voltage is VBH, so the overcurrent protection value is the intersection 203 of the two, and the collector current ICTH or higher is in the overcurrent protection range. Similarly, when both temperatures are TL, the sense voltage is represented by line 204, and the reference voltage is VBL, so the overcurrent protection value is the intersection 205 of the two, and the collector current ICTL or higher is in the overcurrent protection range. [Prior art documents] [Patent documents]

[0023] [Patent Document 1] WO2016 / 039342 publication [Patent Document 2] Patent Publication No. 2002-184940 Summary of the Invention [Problem to be solved by the invention]

[0024] There may be cases where the temperature of the switching element and the temperature of the control circuit are extremely different. This may occur particularly when the control circuit is installed outside the switching element, as described in Patent Document 2, because heat from one side is not sufficiently transmitted to the other side.

[0025] When the temperature of the switching element is much higher than the temperature of the control circuit, the overcurrent protection value calculated by the conventional technology will be a value lower than what is actually required, resulting in excessive protection.

[0026] For example, when the switching element is at temperature TH and the control circuit is at temperature TL, the intersection 206 of the sense voltage 202 and reference voltage VBL is set to the overcurrent value, and collector currents ICmin and above are in the overcurrent protection range. However, when the switching element temperature is taken into consideration, the overcurrent protection range should actually be ICTH and above, and unnecessary protection is being performed when the collector current is between ICmin and ICTH.

[0027] Therefore, in the conventional technology, the overcurrent protection range has a redundant region as shown at 207.

[0028] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a semiconductor device having an improved switching element protection function and the protection function thereof. [Means for solving the problem]

[0029] In order to solve the above problems, the present invention provides a switching element, a control circuit with an overcurrent protection function that controls the switching element, and temperature detection means for each of the switching element and the control circuit, and corrects the overcurrent detection standard based on two detection values ​​detected by both temperature detection means.

[0030] The switching element may have a predetermined circuit pattern and may be mounted on a circuit board formed of an insulating substrate on which electronic components are mounted, and the control circuit may have a predetermined circuit pattern and may be mounted on a circuit board formed of an insulating substrate on which electronic components are mounted. The switching element and the control circuit may be mounted on the same circuit board.

[0031] The switching element may be covered by a resin case, and the control circuit may be covered by a resin case. The switching element and the control circuit may be mounted in the same resin case.

[0032] The temperature measuring means for the switching element is a device capable of measuring the temperature of the switching element within the same element, on a circuit board on which the switching element is mounted, or within a resin case in which the switching element is housed, or in the vicinity thereof. position will be installed.

[0033] The temperature measuring means for the control circuit is installed within the same control circuit, on the circuit board on which the control circuit is mounted, or in the resin case in which the control circuit is housed, or in the vicinity thereof, so that the control circuit temperature can be measured.

[0034] A MOSFET or an IGBT may be used as the switching element, and a diode may be used as the temperature detection means.

[0035] When using a temperature detection means having negative temperature characteristics, such as a diode, as a circuit for correcting the overcurrent detection standard, the detection voltage obtained by the temperature detection means of the switching element may be divided into multiple stages, and the converted voltage may be set into the same number of stages and converted into an output voltage with the magnitude relationship reversed relative to the detection voltage. A value calculated based on the sum of this and the detection voltage obtained by the temperature detection means of the control circuit may be output as the overcurrent detection reference value.

[0036] Alternatively, when a means having a positive temperature characteristic is used as the temperature detection means as a circuit for correcting the overcurrent detection standard, the detection voltage obtained by the temperature detection means of the control circuit may be divided into multiple stages, and the converted voltage may be set into the same number of multiple stages and converted into an output voltage with the magnitude relationship reversed relative to the detection voltage, and a value calculated based on the sum of this and the detection voltage obtained by the temperature detection means of the switching element may be output as the overcurrent detection reference value.

[0037] Alternatively, when using a means having negative temperature characteristics for the temperature detection means of the switching element and the control circuit as a circuit for correcting the overcurrent detection standard, the detection voltage obtained by the temperature detection means of the switching element may be converted into an output voltage with the magnitude relationship reversed, and a value calculated based on the sum of this and the detection voltage obtained by the temperature detection means of the control circuit may be output as the overcurrent detection standard value.

[0038] Alternatively, when using a means having a positive temperature characteristic for the temperature detection means of the switching element and the control circuit as a circuit for correcting the overcurrent detection standard, the detection voltage obtained by the temperature detection means of the control circuit may be converted into an output voltage with the magnitude relationship reversed, and a value calculated based on the sum of this and the detection voltage obtained by the temperature detection means of the switching element may be output as the overcurrent detection standard value.

[0039] Alternatively, when using a means having a positive temperature characteristic for the temperature detection means of the switching element and a means having a negative temperature characteristic for the temperature detection means of the control circuit as a circuit for correcting the overcurrent detection standard, a value calculated based on the sum of the detection voltages obtained by both temperature detection means may be output as the overcurrent detection standard value. Effect of the Invention

[0040] According to the present invention, by correcting the overcurrent protection detection level, the redundant range of the overcurrent protection current can be reduced, and the accuracy of the overcurrent protection function can be improved. [Brief description of the drawings]

[0041] [Figure 1] 1 is a block diagram showing a first embodiment of a power semiconductor device according to the present invention. [Diagram 2] 1 is a circuit diagram showing a first example of an overcurrent reference voltage correction circuit of the present invention. [Diagram 3] FIG. 2 is a diagram showing an example of the relationship between T1, T2, inputs VF1, VF2, and a correction value VOCa in the first example of the overcurrent reference voltage correction circuit of the present invention. [Figure 4] FIG. 2 is a diagram showing an example of the relationship between T1, T2 and the inputs VF1, VF2, the reference voltage VOCo before correction, and the output VOC in the first example of the overcurrent reference voltage correction circuit of the present invention. [Diagram 5] FIG. 4 is a circuit diagram showing a second example of an overcurrent reference voltage correction circuit of the present invention. [Figure 6] FIG. 11 is a circuit diagram showing a third example of an overcurrent reference voltage correction circuit of the present invention. [Figure 7] FIG. 11 is a diagram showing an example of the relationship between T1, T2, inputs VF1, VF2, and the correction value VOCa in the third example of the overcurrent reference voltage correction circuit of the present invention. [Figure 8] FIG. 11 is a diagram showing an example of the relationship between T1, T2, inputs VF1, VF2, pre-correction reference voltage VOCo, and output VOC in the third example of the overcurrent reference voltage correction circuit of the present invention. [Figure 9] FIG. 11 is a circuit diagram showing a fourth example of an overcurrent reference voltage correction circuit of the present invention. [Figure 10] FIG. 11 is a circuit diagram showing a fifth example of an overcurrent reference voltage correction circuit of the present invention. [Figure 11] FIG. 4 is an expanded view of the output of the diagram (FIG. 3) showing an example of the relationship between T1, T2, inputs VF1, VF2, and correction value VOCa in the first example of the overcurrent reference voltage correction circuit of the present invention, covering the range of T2>T1. [Figure 12] This is an expanded view of the output of a diagram (FIG. 4) showing an example of the relationship between T1, T2, the input VF1, VF2, the reference voltage VOCo before correction, and the output VOC in the first example of the overcurrent reference voltage correction circuit of the present invention, up to the range of T2>T1. [Figure 13] FIG. 1 is a block diagram showing an example of a conventional power semiconductor device. [Figure 14] FIG. 2 is a block diagram showing a second embodiment of a power semiconductor device according to the present invention. [Figure 15] FIG. 2 is a diagram showing an operating region of overcurrent protection in a power semiconductor device. [Figure 16] FIG. 1 is a diagram showing a redundant region for overcurrent protection operation in a conventional power semiconductor device. [Figure 17] 1 is a diagram showing a redundant region for an overcurrent protection operation in a power semiconductor device according to an embodiment of the present invention; [Figure 18] FIG. 1 is a diagram showing an example of an internal structure of a conventional switching element module (IPM). [Figure 19] FIG. 1 is a diagram showing an example of a conventional internal structure of a semiconductor element module in which a semiconductor element and a control circuit are separated from each other. [Figure 20] FIG. 1 is a diagram showing an example of a conventional internal structure of a semiconductor element module in which a semiconductor element and a control circuit are separated from each other. [Figure 21] FIG. 1 is a diagram showing an example of a conventional internal structure of a semiconductor element module in which a semiconductor element and a control circuit are separated from each other. [Figure 22] FIG. 1 is a diagram showing an example of a conventional module unit in which a semiconductor element and a control circuit are separated. [Figure 23] FIG. 1 is a diagram showing an example of a conventional module unit in which a semiconductor element and a control circuit are separated. [Figure 24] FIG. 1 is a diagram showing an example of a conventional internal structure of a semiconductor element module in which a semiconductor element and a control circuit are separated and a temperature detection means is provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] As shown in FIG. 1, the first embodiment of the power semiconductor device according to the present invention includes a control circuit 1, a switching element 2, and a switching element temperature detection diode 8. In this embodiment, an IGBT is used as the switching element 2. The switching element temperature detection diode 8 may be built into the switching element 2. When the switching element 2 is an IGBT, it is formed of polysilicon via an insulating film at the center of the surface (emitter terminal). The switching element temperature detection diode 8 may be disposed away from the switching element 2 at a position where the temperature of the switching element 2 can be measured. For example, it may be mounted on a circuit board on which the switching element 2 is mounted, or may be disposed in the same resin case as the switching element 2, or may be disposed near the resin case in which the switching element 2 is molded. Here, the circuit board is an insulating board having a predetermined circuit pattern.

[0043] The control circuit 1 has a temperature detection diode 3 of the control circuit, an overcurrent reference voltage correction circuit 4, an overcurrent reference voltage circuit 5, an overcurrent detection comparator 6, a sense voltage detection resistor 7, an overheat detection comparator 9, an overheat reference voltage circuit 10, constant current sources 11 and 12, and a filter 13. The control circuit 1 and the temperature detection diode 3 of the control circuit may be integrated in the same semiconductor substrate. For example, the diode 13 may be formed of polysilicon on the surface of the semiconductor substrate via an insulating film. The temperature detection diode 13 may be disposed away from the control circuit 1 at a position where the temperature of the control circuit 1 can be measured. For example, the diode 13 may be mounted on a circuit board on which the control circuit 1 is mounted, or may be disposed in the same resin case as the control circuit 1, or may be disposed near the resin case in which the control circuit 1 is molded.

[0044] As shown in Fig. 1, the control circuit 1 is connected to the switching element 2. The switching element 2 also incorporates a current sensing element in parallel with the IGBT through which the main current flows. The control circuit 1 is equipped with an output terminal OUT which outputs a gate voltage, an overcurrent detection terminal OC, and an overheat detection terminal OH. Furthermore, the control circuit 1 and the switching element 2, including the control circuit temperature detection diode 3 and the switching element temperature detection diode 8, may be installed on the same circuit board, installed in the same resin case, or molded separately.

[0045] The output terminal OUT is connected to the gate terminal of the switching element 2 , and the overcurrent detection terminal OC is connected to the current sensing terminal of the current sensing element of the switching element 2 . The emitter terminal of switching element 2 is , is connected to the ground potential.

[0046] In the control circuit 1, the overheat detection terminal OH is connected to a constant current source 11, an inverting input terminal of an overheat detection comparator 9, and an overcurrent reference voltage correction circuit 4, and a non-inverting input terminal of the overheat detection comparator 9 is connected to an overheat reference voltage circuit 10. The overheat detection terminal OH is connected to an anode terminal of a switching element temperature detection diode 8, and a cathode terminal of the switching element temperature detection diode 8 is connected to the ground potential of the control circuit 1.

[0047] A constant current from a constant current source 11 is constantly applied to the switching element temperature detection diode 8, and a forward voltage corresponding to the chip temperature of the switching element 2 is applied to the inverting input terminal of the overheat detection comparator 9. Here, it is assumed that the temperature characteristic of the switching element temperature detection diode 8 has a negative temperature characteristic, and the overheat reference voltage circuit 10 outputs an overheat reference voltage VOH1 corresponding to a temperature of TH. As a result, when the chip temperature is below TH, the overheat detection comparator 9 outputs a low-level protection operation signal, and when the chip temperature becomes high and equal to or higher than TH, it outputs a high-level protection operation signal. When this high-level protection operation signal is output, the control circuit 1 outputs an alarm signal from the alarm output circuit and simultaneously controls to turn off the switching element 2.

[0048] In the control circuit 1, the overcurrent detection terminal OC is connected to a sense voltage detection resistor 7 and an inverting input terminal of an overcurrent detection comparator 6, and the non-inverting input terminal of an overheat detection comparator 9 is connected to an overcurrent reference voltage correction circuit 4. The output portion of the overheat detection comparator 9 is connected to the input portion of a filter 13, which removes voltages other than those proportional to the collector current.

[0049] A constant current from a constant current source 12 always flows through the temperature detection diode 3 of the control circuit, and a forward voltage corresponding to the temperature of the control circuit 1 is applied to the overcurrent reference voltage correction circuit 4 as VF2.

[0050] The overcurrent reference voltage correction circuit 4 calculates a correction value VOCa for correcting the overcurrent reference voltage VOCo output from the overcurrent reference voltage circuit 5 based on the signal VF1 obtained from the switching element temperature detection diode 8 and the signal VF2 acquired from the temperature detection diode 3 of the control circuit, and outputs the corrected overcurrent reference voltage VOC to the non-inverting input of the comparator 6. Terminals Send to.

[0051] The overcurrent detection comparator 6 shunts the emitter current of the switching element 2 to a current that is approximately 1 / 10,000th of the current, and passes this current through a sense voltage detection resistor 7. The overcurrent detection comparator 6 compares the sense voltage obtained by this current with an overcurrent reference voltage VOC and transmits a protection operation signal.

[0052] As shown in FIG. 14, the second embodiment of the power semiconductor device according to the present invention includes a control circuit 1, a switching element 2a, and a switching element temperature detection diode 8. In this embodiment, a MOSFET is used as the switching element 2a. The switching element 2a and the switching element temperature detection diode 8 may be integrally formed as a single chip, or may be disposed in the same circuit board, in the same resin case, or in a position where the switching element temperature can be measured near the resin case in which the switching element 2a is molded. Here, the circuit board has a predetermined circuit pattern and is an insulating board on which electronic components are mounted.

[0053] The control circuit 1 has a control circuit temperature detection diode 3, an overcurrent reference voltage correction circuit 4, an overcurrent reference voltage circuit 5, an overcurrent detection comparator 6, a sense voltage detection resistor 7, an overheat detection comparator 9, an overheat reference voltage circuit 10, constant current sources 11 and 12, and a filter 13. The control circuit 1 and the control circuit temperature detection diode 3 may be integrally formed as a single chip, or may be disposed in the same circuit board or in the same resin case, or in a position near the resin case in which the control circuit 1 is molded, where the control circuit temperature can be measured.

[0054] As shown in FIG. 14, the control circuit 1 is connected to the switching element 2a. The switching element 2 also incorporates a current sensing element in parallel with the MOSFET through which the main current flows. The control circuit 1 has an output terminal OUT which outputs a gate voltage, an overcurrent detection terminal OC, and an overheat detection terminal OH. The drain terminal of the switching element 2a is connected to the ground potential. The control circuit 1 and the switching element 2a, including the temperature detection diode 3 of the control circuit and the switching element temperature detection diode 8, may be formed in the same resin case or may be formed separately.

[0055] The output terminal OUT is connected to the gate terminal of the switching element 2a, and the overcurrent detection terminal OC is connected to the source terminal of the switching element 2a.

[0056] In the control circuit 1, the overheat detection terminal OH is connected to a constant current source 11, an inverting input terminal of an overheat detection comparator 9, and an overcurrent reference voltage correction circuit 4, and a non-inverting input terminal of the overheat detection comparator 9 is connected to an overheat reference voltage circuit 10. The overheat detection terminal OH is also connected to an anode terminal of a switching element temperature detection diode 8 of the switching element 2a, and a cathode terminal of the switching element temperature detection diode 8 is connected to the ground potential of the control circuit 1.

[0057] A constant current from a constant current source 11 is constantly applied to the switching element temperature detection diode 8, and a forward voltage corresponding to the chip temperature of the switching element 2a is applied to the inverting input terminal of the overheat detection comparator 9. Here, it is assumed that the temperature characteristic of the switching element temperature detection diode 8 has a negative temperature characteristic, and the overheat reference voltage circuit 10 outputs an overheat reference voltage VOH1 corresponding to a temperature of TH. As a result, when the chip temperature is below TH, the overheat detection comparator 9 outputs a low-level protection operation signal, and when the chip temperature becomes high and equal to or higher than TH, it outputs a high-level protection operation signal. When this high-level protection operation signal is output, the control circuit 1 outputs an alarm signal from the alarm output circuit and simultaneously controls to turn off the switching element 2a.

[0058] In the control circuit 1, the overcurrent detection terminal OC is connected to a sense voltage detection resistor 7 and an inverting input terminal of an overcurrent detection comparator 6, and the non-inverting input terminal of an overheat detection comparator 9 is connected to an overcurrent reference voltage correction circuit 4. The output portion of the overheat detection comparator 9 is connected to the input portion of a filter 13, which removes voltages other than those proportional to the collector current.

[0059] A constant current from a constant current source 12 always flows through the temperature detection diode 3 of the control circuit, and a forward voltage corresponding to the temperature of the control circuit 1 is applied to the overcurrent reference voltage correction circuit 4 as VF2.

[0060] The overcurrent reference voltage correction circuit 4 calculates a correction value VOCa for correcting the overcurrent reference voltage VOCo output from the overcurrent reference voltage circuit 5 based on the signal VF1 obtained from the switching element temperature detection diode 8 and the signal VF2 acquired from the temperature detection diode 3 of the control circuit, and outputs the corrected overcurrent reference voltage VOC to the non-inverting input of the comparator 6. Terminals Send to.

[0061] The overcurrent detection comparator 6 compares the source voltage of the switching element 2a with an overcurrent reference voltage VOC, and transmits a protection operation signal.

[0062] 2 shows a first example of the overcurrent reference voltage correction circuit 4 of the present invention. It is composed of two-stage differential amplifier circuits 121 and 131. The first differential amplifier circuit 121 is composed of a comparator 122 and resistors 123-126, has VF2 as an inverting input and VF1 as a non-inverting input, and outputs a correction value VOCa for correcting the overcurrent reference voltage VOCo. The second differential amplifier circuit 131 is composed of a comparator 132 and resistors 133-136, has VOCa as an inverting input and the overcurrent reference voltage VOCo before correction as a non-inverting input, and outputs a corrected overcurrent reference voltage VOC.

[0063] Since a diode has a negative temperature characteristic, the lower the temperature of the switching element, the higher VF1 and VF2 become.

[0064] The first differential amplifier circuit 121 calculates VF1-VF2 as a correction value VOCa, and the second differential amplifier circuit 131 outputs VOCo-VOCa=VOCo+VF2-VF1 as a corrected overcurrent reference voltage VOC.

[0065] The overcurrent reference voltage VOCo before correction of the control circuit has a positive temperature characteristic, and is higher as the temperature of the control circuit is higher and is lower as the temperature is lower.

[0066] Fig. 3 shows an example of the relationship between the switching elements, the control circuit, and the output values ​​of VF1, VF2, and VOCa in a first example of the overcurrent reference voltage correction circuit 4, and Fig. 4 shows an example of the relationship between these and VOCo and VOC. Note that the numerical values ​​in these figures are assumed to be in degrees Celsius for T1 and T2, VF1, VF2, VOCa, VOCo, and VOC in V, the resistance values ​​of resistors 122 and 123 are equal, VF1=(150-T1)×10, VF2=(150-T2)×10, the voltage of power supply 124 is 750V, VCC=1500V, VF0=1500V, and VOCo=T1×8, but this is merely an example. In this diagram, the correction value VOCa = 0 when T1 = T2, but if it deviates from this and T1 is higher than T2, VOCa will output a negative value with a larger absolute value, and if VOCa is subtracted from VOCo, which has been reduced by the effect of the low temperature T2 of the control device, the overcurrent reference voltage VOC will be a value that depends almost exclusively on the switching element temperature.

[0067] 5 shows a second example of the overcurrent reference voltage correction circuit 4 of the present invention. Assuming that the temperature detection means has a positive temperature characteristic, the inputs of VF1 and VF2 are reversed with respect to the first differential amplifier circuit 121 of the first example.

[0068] The first differential amplifier circuit 121 calculates VF2-VF1 as the correction value VOCa, and the second differential amplifier circuit 131 outputs VOCo-VOCa=VOCo+VF1-VF2 as the corrected overcurrent reference voltage VOC. The longer T1 is higher than T2, the greater the absolute negative value of the correction value VOCa is, and the overcurrent reference voltage VOC becomes a value that depends almost exclusively on the switching element.

[0069] FIG. 6 shows a third example of the overcurrent reference voltage correction circuit 4 of the present invention. Non A digitizing circuit 101 is inserted on the inverting input side, and the digitizing circuit 101 performs multiple stages of digitization processing on the input value and outputs it, and the digital circuit 101 in Fig. 6 is for performing three stages of digitization. Note that the number of stages of digitization is not limited to three.

[0070] Digital circuit 101 comprises two comparators 102, 103, each of which receives a signal from VF1 as its inverting input and has two types of reference potentials as its non-inverting input, two switches 104, 105 for three types of potentials, three resistors 106-108 on the upstream side and four resistors 109-112 on the downstream side, and outputs potential VF1a obtained from resistors 109-112.

[0071] VF1 is input to the inverting input terminals of comparators 102 and 103 of digitizing circuit 101. Resistors 106, 107, and 108 are connected in series in this order to potential VCC, and one end of resistor 108 that is not connected to resistor 107 is connected to ground. The non-inverting input terminal of comparator 102 is connected between resistors 106 and 107, and the non-inverting input terminal of comparator 103 is connected between resistors 107 and 108.

[0072] The resistors 109, 110, 111, and 112 are connected in series in this order to a potential VCC, and the end of the resistor 112 that is not connected to the resistor 111 is connected to ground.

[0073] A switch 104 is connected between resistors 110 and 111, and the switch 104 is turned on / off depending on whether the output signal of comparator 102 is true or false. A switch 105 is connected between resistors 111 and 112, and the switch 105 is turned on / off depending on whether the output signal of comparator 103 is true or false.

[0074] The remaining ends of the switches 104 and 105 are connected to the resistors 109 and 110, and a voltage VF1a is output to the first differential amplifier circuit 121.

[0075] In the comparators 102 and 103, VF1 is compared with an overcurrent reference voltage generated by resistors 106 to 108, and a switch 104 is turned on / off depending on whether the comparator 102 is true or false, and a switch 105 is turned on / off depending on whether the comparator 103 is true or false.

[0076] When the temperature of the switching element is within the standard range, VF1 becomes a high value, false values ​​are output from all of the comparators 102 and 103, the switches 104 and 105 are turned off, and in the series connection of the resistors 109 to 112, the high potential obtained between the resistors 109 and 110 is output as VF1a.

[0077] However, if the temperature of the switching element is slightly higher than the standard range, comparator 102 outputs a true value and comparator 103 outputs a false value, switch 104 turns on, and in the series connection of resistors 109, 111, and 112, a slightly high potential obtained between resistors 109 and 111 is output as VF1a.

[0078] Furthermore, when the temperature of the switching element is higher than the standard range, VF1 becomes a low value, all of the comparators 102, 103 output true values, the switches 104, 105 turn on, and in the series connection of the resistors 109 and 112, the higher potential obtained between the resistors 109 and 112 is output as VF1a.

[0079] The first differential amplifier circuit 121 calculates VF1a-VF2 as a correction value VOCa, and the second differential amplifier circuit 131 outputs VOCo-VOCa=VOCo+VF2-VF1a as a corrected overcurrent reference voltage VOC.

[0080] FIG. 7 shows an example of the relationship between the switching elements, the control circuit, and the output values ​​of VF1, VF2, VF1a, and VOCa in the third example of overcurrent reference voltage correction circuit 4, and FIG. 8 shows an example of the relationship between these and VOCo and VOC. In these figures, it is assumed that the units for T1 and T2 are Celsius degrees, and the units for VF1, VF2, VF1a, VOCa, VOCo, and VOC are V. The resistance values ​​R106 to R112 of resistors 106 to 112 are R106=R107=R108, R123=R124=R125=R126, R133=R134=R135=R136, R109:R110:R111:R112=1:4:20:5, and the relationships VF1=(150-T1)×10, VF2=(150-T2)×10, VCC=1500V, VF0=1500V, and VOCo=T1×8 are only one example. In this diagram, T1 is in three stages: less than 50°C, between 50°C and 100°C, and above 100°C; in other words, VF1a = 250W, 750W, and 1250W are output for the three stages where VF1 exceeds 1000V, between 500V and 1000V, and below 500V. The correction value VOCa of the overcurrent reference voltage VOCo is close to 0 when T1 is close to T2, but the more it deviates from this and T1 is higher than T2, the more negative a value VOCa outputs will become with an absolute value that is large; and when VOCa is subtracted from VOCo, which has been reduced due to the influence of the low temperature T2 of the control device, the overcurrent reference voltage VOC becomes a value that depends almost exclusively on the switching element temperature.

[0081] Whereas the first and second forms treat VF1 and VF2 as continuous analog values, the third form treats the inverting input VF1a of the first differential amplifier circuit 121 as a discrete numerical value in three or multiple stages: standard, slightly high, and high, and therefore the outputs, the overcurrent reference voltage correction value VOCa and the overcurrent reference voltage VOC, are also slightly discrete values.

[0082] The digitizing circuit 101 may be connected to the non-inverting input side of the first differential amplifier circuit 121, or to the output side of the second differential amplifier circuit 131, or may be a combination of these. Similarly, when the temperature detection means of the switching element and the control circuit have a positive temperature characteristic, a similar connection may be made.

[0083] 9 shows a fourth example of the overcurrent reference voltage correction circuit 4, in which the digitizing circuit 101 is inserted on the non-inverting input side of the differential amplifier circuit 121. In this embodiment, the digitizing circuit 101 receives VF2 as an input value and outputs VF2a, which is a digitized value of the VF2, as an output value. Non VF1 on the inverting input side, Inverting input side Enter VF2a.

[0084] FIG. 10 shows a fifth example of the overcurrent reference voltage correction circuit 4. Second Differential Amplifier Circuit 131 In the fifth example, the digitizing circuit 101 is inserted on the output side of the second differential amplifier circuit. 131 The output value VOCb is the input value, and the digitized value is the output value VOC.

[0085] All of these overcurrent reference voltage correction circuits 4 are capable of narrowing the range of overcurrent protection deficiencies even in situations where the temperature of the control circuit is extremely higher than the temperature of the switching element, i.e., where the overcurrent protection value in the conventional technology is higher than what is actually required and protection is not provided in the current range where protection is required, i.e., where a so-called overcurrent protection deficiency range occurs.

[0086] Figures 11 and 12 show the relationship between temperatures T1, T2, VOCa, and VOC in the case where the temperature detection means of the switching element and control circuit have negative temperature characteristics, i.e., in the first example of the overcurrent reference voltage correction circuit 4. These are diagrams in which the display range of Figures 3 and 4 is expanded to the range T2>T1, and the definitions of each value are the same as those of the first embodiment of the circuit. As shown in these figures, even in a situation where the control circuit temperature is higher than the switching element temperature, the VOC output by the circuit is a value that depends almost only on the switching element temperature.

[0087] 17 shows an operating region of overcurrent protection in a power semiconductor device according to a first example of the overcurrent reference voltage correction circuit 4 of the present invention. Note that the maximum value of the operating temperature assumed in the power semiconductor device is denoted as TH and the minimum value as TL.

[0088] For example, when the temperature of the switching element is TH and the temperature of the control circuit is TL, the intersection 203 of the sense voltage 202 and the overcurrent reference voltage VBH, ie, the collector current ICTH, becomes the overcurrent value, and the redundant range becomes narrower as shown by 208. [Explanation of symbols]

[0089] 1...Control circuit 2...Switching element 2a...Switching element 3. Temperature detection diode for control circuit 4. Overcurrent reference voltage correction circuit 5. Overcurrent reference voltage circuit 5a...Overcurrent reference voltage circuit in the prior art 6…Overcurrent detection comparator 7…Sense voltage detection resistor 8...Diode for detecting switching element temperature 9…Overheat detection comparator 10…Overheating reference voltage circuit 11, 12...constant current source 13…Filter 101...Digital circuit (3 stages) 101a…Digitalization circuit (4 stages) 102~103, 102a, 103a...Comparator 104, 105, 104a, 105a... Switch 106~112, 123~126, 133~136, 106a, 110a...Resistance 121, 131...Differential amplifier circuit 201... Sense voltage for collector current 202...Sense voltage when switching element temperature is TH 203...Overcurrent protection value when the temperature of both the switching element and the control circuit is TH 204…Sense voltage when switching element temperature is TL 205...Overcurrent protection value when the temperature of both the switching element and the control circuit is TL 206...Overcurrent protection value when switching element temperature is TH and control circuit temperature is TL in conventional design 207…Redundant range of overcurrent protection in conventional design 208...Redundant range of overcurrent protection in the power semiconductor device according to the embodiment of the present invention 301~306…IGBT 311~316…Protection diodes 321~326…Control circuit 401...IGBT element 402...Diode element 403...Insulating substrate 404…Emitter pattern 405…Collector pattern 406…Gate pattern 407…Metal wire 408…Controlled emitter pattern 409…Bottom metal board 410…Resin case 411…Main emitter terminal 412…Main collector terminal 413 …Gate terminal 414 …Control emitter terminal 420…Control board 431...Relay insulating board 435…Thermistor 500, 600...Semiconductor device module 501, 502...Unit slots

Claims

1. A switching element; a control circuit for controlling the switching element, the control circuit including an overcurrent detection circuit for the switching element; a first temperature detection means for detecting the temperature of the switching element; a second temperature detection means for detecting the temperature of the control circuit; Equipped with the control circuit includes a reference correction circuit that corrects an overcurrent reference value of the overcurrent detection circuit based on a first detection value and a second detection value detected by the first temperature detection means and the second temperature detection means, and outputs the corrected overcurrent reference value; the reference correction circuit has a first differential amplifier circuit that receives as input the first detection value and the second detection value, and a second differential amplifier circuit that receives as input an output value of the first differential amplifier circuit and an overcurrent reference value of the overcurrent detection circuit.

2. 2. The semiconductor device according to claim 1, wherein the reference correction circuit corrects the overcurrent reference value based on the first detection value when it determines, based on the first detection value and the second detection value, that a difference between the temperature of the switching element and the temperature of the control circuit is greater than or equal to a predetermined value.

3. 3. The semiconductor device according to claim 1, wherein said switching element is mounted on a first circuit board having a predetermined circuit pattern and formed of an insulating substrate on which electronic components are mounted.

4. 4. The semiconductor device according to claim 1, wherein the control circuit is mounted on a second circuit board having a predetermined circuit pattern and formed of an insulating substrate on which electronic components are mounted.

5. 3. The semiconductor device according to claim 1, wherein said switching elements and said control circuit are mounted on a third circuit board having a predetermined circuit pattern and formed of an insulating substrate on which electronic components are mounted.

6. The semiconductor device according to claim 1 , further comprising a first resin case molded to cover the switching element.

7. The semiconductor device according to claim 1 , further comprising a second resin case molded to cover the control circuit.

8. The semiconductor device according to claim 1 , further comprising a third resin case molded to cover said switching element and said control circuit.

9. 9. The semiconductor device according to claim 1, wherein the first temperature detection means provided in the switching element is installed in a location within the same element as the switching element where the temperature of the switching element can be measured.

10. 4. The semiconductor device according to claim 3, wherein the first temperature detection means provided in the switching element is disposed at a location on the first circuit board where the temperature of the switching element can be measured.

11. 6. The semiconductor device according to claim 5, wherein the first temperature detection means provided in the switching element is disposed on the third circuit board at a location where the temperature of the switching element can be measured.

12. 7. The semiconductor device according to claim 6, wherein the first temperature detection means provided in the switching element is installed in the first resin case or in the vicinity of the first resin case at a location where the temperature of the switching element can be measured.

13. 9. The semiconductor device according to claim 8, wherein the first temperature detection means provided in the switching element is installed in a location within the third resin case or in the vicinity of the third resin case where the temperature of the switching element can be measured.

14. 10. The semiconductor device according to claim 1, wherein the second temperature detection means provided in the control circuit is installed in a location within the same element as the control circuit where the temperature of the control circuit can be measured.

15. 5. The semiconductor device according to claim 4, wherein said second temperature detection means provided in said control circuit is disposed at a position on said second circuit board where the temperature of said control circuit can be measured.

16. 6. The semiconductor device according to claim 5, wherein the second temperature detection means provided in the control circuit is installed on the third circuit board at a location where the temperature of the control circuit can be measured.

17. 8. The semiconductor device according to claim 7, wherein the second temperature detection means provided in the control circuit is installed in a location within the second resin case or in the vicinity of the second resin case where the temperature of the control circuit can be measured.

18. 9. The semiconductor device according to claim 8, wherein the second temperature detection means provided in the control circuit is installed in a location within the third resin case or in the vicinity of the third resin case where the temperature of the control circuit can be measured.

19. 19. The semiconductor device according to claim 1, wherein an IGBT is used as the switching element.

20. 19. The semiconductor device according to claim 1, wherein a MOSFET is used as the switching element.

21. 21. The semiconductor device according to claim 1, wherein the first and second temperature detection means have negative temperature characteristics.

22. 21. The semiconductor device according to claim 1, wherein the first and second temperature detection means have a positive temperature characteristic.

23. The semiconductor device according to claim 1 , wherein the reference correction circuit is connected to a digitization circuit.

24. 24. The semiconductor device according to claim 23, wherein said reference correction circuit inputs the output signal of said digitizing circuit as an inverted input signal of said first differential amplifier circuit.

25. 25. The semiconductor device according to claim 23, wherein the reference correction circuit inputs an output signal of the digitizing circuit as a non-inverting input signal of the first differential amplifier circuit.

26. 26. The semiconductor device according to claim 23, wherein the reference correction circuit connects an output side of the reference correction circuit to an input side of the digitizing circuit.

27. 27. The semiconductor device according to claim 1, wherein the overcurrent detection circuit has a function of comparing a current detection value based on the passing current of the switching element and the corrected overcurrent reference value as inputs, and a function of outputting a signal based on the comparison result.

28. detecting a first detection value by a first temperature detection means for detecting the temperature of the switching element; detecting a second detection value by a second temperature detection means for detecting a temperature of a control circuit having an overcurrent detection circuit for the switching element, the control circuit controlling the switching element; a reference correction circuit provided in the control circuit corrects an overcurrent reference value of the overcurrent detection circuit based on the first detection value and the second detection value, and outputs the corrected overcurrent reference value; The reference correction circuit is an overcurrent protection circuit for a semiconductor device, the overcurrent protection circuit having a first differential amplifier circuit that receives as input the first detection value and the second detection value, and a second differential amplifier circuit that receives as input the output value of the first differential amplifier circuit and the overcurrent reference value.

29. The first and second temperature detection means have negative temperature characteristics, 29. The overcurrent protection circuit of a semiconductor device as described in claim 28, wherein the reference correction circuit calculates an overcurrent reference correction value by taking the difference between the first detection value and the second detection value, and further calculates the corrected overcurrent reference value by taking the difference between the overcurrent reference correction value and the overcurrent reference value.

30. The first and second temperature detection means have a positive temperature characteristic, 29. The overcurrent protection circuit of a semiconductor device as described in claim 28, wherein the reference correction circuit calculates an overcurrent reference correction value by taking the difference between the first detection value and the second detection value, and further calculates the corrected overcurrent reference value by taking the difference between the overcurrent reference correction value and the overcurrent reference value.

31. 31. The overcurrent protection circuit of a semiconductor device according to claim 28, wherein the reference correction circuit has a digitization circuit that digitizes an input value into multiple stages according to its magnitude and outputs the digitized value, and digitizes and processes either the first detection value, the second detection value, or the corrected overcurrent reference value, or multiple values ​​thereof.

32. 32. An overcurrent protection circuit for a semiconductor device as claimed in any one of claims 28 to 31, which compares a current detection value based on the passing current of the switching element with the overcurrent reference value, and detects the occurrence of an overcurrent when the current detection value exceeds the overcurrent reference value.

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