Short circuit protection circuit and method for an insulated gate bipolar transistor

Abstract

The application provides a short circuit protection circuit and method of an insulated gate bipolar transistor, which comprises: an insulated gate bipolar transistor; a voltage detection sub-circuit for sampling a voltage drop between a collector and an emitter of the insulated gate bipolar transistor, so as to determine a voltage detection level based on a first sampling voltage; a temperature detection sub-circuit for sampling a voltage of a temperature sensor, so as to determine a temperature detection level based on a second sampling voltage; a current detection sub-circuit connected with the emitter of the insulated gate bipolar transistor through a current sensor, and the current detection sub-circuit is used for sampling a voltage of the current sensor, so as to determine a current detection level based on a third sampling voltage; and a logic selection protection sub-circuit for controlling the insulated gate bipolar transistor to be turned off when the insulated gate bipolar transistor is short-circuited.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor applications, and in particular to a short-circuit protection circuit and method for an insulated gate bipolar transistor. BACKGROUND

[0002] With the continuous depletion of chemical energy and the aggravation of environmental pollution, the market share of electric vehicles has been increasing year by year. The motor controller, as the core component of the electric vehicle, provides driving force for the whole vehicle. As the core component of the control part, the insulated gate bipolar transistor (IGBT) plays an important role. In practical applications, short-circuit protection needs to be considered. In practical applications, it is necessary to ensure that the IGBT works below its maximum allowable collector current. Once a short circuit occurs, the short-circuit current of the IGBT will generate extremely high heat, causing the IGBT to exceed its temperature limit and fail, and even cause the IGBT to burst and be damaged. Therefore, in the application of IGBT, the function of rapid short-circuit detection and protection becomes particularly important.

[0003] The prior art (CN115663763A) discloses a SiC MOSFET high-precision short-circuit protection circuit, which comprises an external interface circuit, a clock generating circuit, a voltage following detection circuit, a comprehensive control logic circuit, a voltage detection circuit, an output driving circuit, a detection resistor Rd1, a detection resistor Rd2 and a detection capacitor Cd1. The voltage detection circuit is used for detecting the desaturation input signal Vdes generated by the detection resistor Rd1, the detection resistor Rd2 and the detection capacitor Cd1 through the detection of the Desat signal, and outputs the desaturation sampling signal Vdesin under the control of the desaturation control clock. The voltage following detection circuit outputs the desaturation quantization signal Ddes to the comprehensive control logic circuit according to the desaturation sampling signal Vdesin. The comprehensive control logic circuit is used for generating a power switch driving signal Dout, an error signal Error and a control signal. The present application can dynamically monitor all abnormal changes of VDS by detecting the change slope of drain-source voltage (VDS) to determine whether the state of VDS voltage is in the safe interval, which greatly improves the protection accuracy of the short-circuit protection circuit. The patent only uses a single voltage detection method for short-circuit detection.

[0004] The commonly used short-circuit detection methods at present mainly include current detection, saturation voltage drop detection, di / dt detection and gate charge characteristic detection. Relying on such a single detection means, the short-circuit protection threshold of the IGBT needs to be greatly improved, which will produce a large delay time and cannot realize rapid short-circuit protection and reduce the false triggering probability of short-circuit protection. SUMMARY

[0005] In view of the above prior art problems, the application provides a short-circuit protection circuit and method for an insulated gate bipolar transistor, mainly solving the problem that the existing short-circuit protection is prone to false triggering and affects normal function operation.

[0006] To achieve the above object and other objects, the application adopts the technical scheme as follows.

[0007] The application provides a short-circuit protection circuit for an insulated gate bipolar transistor, comprising:

[0008] an insulated gate bipolar transistor;

[0009] a voltage detection sub-circuit, configured to sample a voltage drop between a collector and an emitter of the insulated gate bipolar transistor to obtain a first sampling voltage, and determine a voltage detection level based on the first sampling voltage;

[0010] a temperature detection sub-circuit, configured to collect a temperature of the insulated gate bipolar transistor by a temperature sensor, and sample a voltage of the temperature sensor to obtain a second sampling voltage, and determine a temperature detection level based on the second sampling voltage;

[0011] a current detection sub-circuit, configured to be connected to the emitter of the insulated gate bipolar transistor by a current sensor, sample a voltage of the current sensor to obtain a third sampling voltage, and determine a current detection level based on the third sampling voltage;

[0012] a logic selection protection sub-circuit, configured to determine whether the insulated gate bipolar transistor is short-circuited according to at least two of the voltage detection level, the temperature detection level and the current detection level, and control the insulated gate bipolar transistor to be turned off when the insulated gate bipolar transistor is short-circuited.

[0013] In an embodiment of the application, the voltage detection sub-circuit comprises a first diode, a second diode, a third diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first capacitor, a first comparator and a first triode.

[0014] The negative end of the first diode is connected with the collector of the insulated gate bipolar transistor, and the positive end is connected with one end of the first resistor; the other end of the first resistor is connected with one end of the second resistor and one end of the third resistor respectively; the other end of the third resistor is connected with one end of the first capacitor, the negative end of the second diode and the positive input end of the first comparator respectively; the positive end of the second diode is connected with the positive end of the third diode; one end of the fourth resistor, the power supply pin of the first comparator, one end of the sixth resistor and one end of the ninth resistor are connected with a preset reference voltage respectively, and the other end of the fourth resistor is connected with the negative input end of the first comparator and one end of the fifth resistor respectively; the other end of the sixth resistor is connected with the output end of the first comparator and one end of the seventh resistor respectively; the other end of the seventh resistor is connected with the gate of the first triode and one end of the eighth resistor respectively; the other end of the ninth resistor is connected with the collector of the first triode and one end of the tenth resistor respectively; the other end of the tenth resistor is used for outputting the voltage detection level; the emitter of the insulated gate bipolar transistor, the other end of the second resistor, the other end of the first capacitor, the negative end of the third diode, the other end of the fifth resistor, the ground pin of the first comparator, the other end of the eighth resistor and the emitter of the first triode are grounded respectively.

[0015] In an embodiment of the present application, the temperature detection sub-circuit comprises a fourth diode, a fifth diode, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a second capacitor, a second comparator, and a second triode; one end of the temperature sensor is connected to one end of the eleventh resistor and one end of the twelfth resistor respectively; the other end of the twelfth resistor is connected to one end of the second capacitor, a negative terminal of the fourth diode, and a positive input terminal of the second comparator respectively; a positive terminal of the fourth diode is connected to a positive terminal of the fifth diode; the other end of the temperature sensor, one end of the thirteenth resistor, a power supply pin of the second comparator, one end of the fifteenth resistor, and one end of the eighteenth resistor are connected to the preset reference voltage respectively; the other end of the thirteenth resistor is connected to a negative input terminal of the second comparator and one end of the fourteenth resistor respectively; the other end of the fifteenth resistor is connected to an output terminal of the second comparator and one end of the sixteenth resistor respectively; the other end of the sixteenth resistor is connected to a gate of the second triode and one end of the seventeenth resistor respectively; the other end of the eighteenth resistor is connected to a collector of the second triode and one end of the nineteenth resistor respectively; the other end of the nineteenth resistor is used for outputting the temperature detection level; the other end of the eleventh resistor, the other end of the second capacitor, a negative terminal of the fifth diode, the other end of the fourteenth resistor, a ground pin of the second comparator, the other end of the seventeenth resistor, and an emitter of the second triode are grounded respectively.

[0016] In an embodiment of the present application, the current detection sub-circuit comprises a sixth diode, a seventh diode, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a twenty-eighth resistor, a third capacitor, a third comparator, and a third NPN transistor; the twentieth resistor is connected in parallel with the current sensor, and one end of the twentieth resistor is connected with one end of the twenty-first resistor; the other end of the twenty-first resistor is connected with one end of the third capacitor, the negative end of the sixth diode, and the positive input end of the third comparator, respectively; the positive end of the sixth diode is connected with the positive end of the seventh diode; one end of the twenty-second resistor, the power supply pin of the third comparator, one end of the twenty-fourth resistor, and one end of the twenty-seventh resistor are connected with the preset reference voltage, respectively; the other end of the twenty-second resistor is connected with one end of the twenty-third resistor and the negative input end of the third comparator, respectively; the other end of the twenty-fourth resistor is connected with the output end of the third comparator and one end of the twenty-fifth resistor, respectively; the other end of the twenty-fifth resistor is connected with one end of the twenty-sixth resistor and the gate of the third NPN transistor, respectively; the other end of the twenty-seventh resistor is connected with the collector of the third NPN transistor and one end of the twenty-eighth resistor, respectively; the other end of the twenty-eighth resistor is used for outputting the current detection level; the other end of the twentieth resistor, the other end of the third capacitor, the negative end of the seventh diode, the other end of the twenty-third resistor, the ground pin of the third comparator, the other end of the twenty-sixth resistor, and the emitter of the third NPN transistor are connected with the ground, respectively.

[0017] In an embodiment of the present application, the logic selection protection sub-circuit comprises a decoder, a first AND gate, a first NAND gate, a second NAND gate, and a second AND gate; the decoder takes the voltage detection level, the temperature detection level, and the current detection level as inputs, and obtains four-way outputs through decoding, and takes the four-way outputs as inputs of the first AND gate; the output end of the first AND gate is connected with the first input end of the first NAND gate; the second input end of the first NAND gate is connected with the output end of the second NAND gate; the output end of the first NAND gate is used for outputting an alarm signal; the first input end of the second NAND gate is connected with the output end of the first NAND gate; the second input end of the second NAND gate is connected with a reset signal; the first input end of the second AND gate is connected with the output end of the second NAND gate; the second input end of the second AND gate is connected with a driving signal; and the output end of the second AND gate is connected with the gate of the insulated gate bipolar transistor.

[0018] The application further provides a short circuit protection method for an insulated gate bipolar transistor, comprising: providing an insulated gate bipolar transistor; sampling a voltage drop between a collector and an emitter of the insulated gate bipolar transistor to obtain a first sampling voltage, and determining a voltage detection level based on the first sampling voltage; collecting a temperature of the insulated gate bipolar transistor by a temperature sensor, and sampling a voltage of the temperature sensor to obtain a second sampling voltage, and determining a temperature detection level based on the second sampling voltage; connecting a current sensor to the emitter of the insulated gate bipolar transistor, sampling a voltage of the current sensor to obtain a third sampling voltage, and determining a current detection level based on the third sampling voltage; determining whether the insulated gate bipolar transistor is short-circuited according to at least two of the voltage detection level, the temperature detection level and the current detection level, and turning off the insulated gate bipolar transistor when the insulated gate bipolar transistor is short-circuited.

[0019] In an embodiment of the application, the voltage detection level is determined based on the first sampling voltage, comprising: if the first sampling voltage is greater than a preset first reference voltage, the voltage detection level is a low level; and if the first sampling voltage is less than or equal to the first reference voltage, the voltage detection level is a high level.

[0020] In an embodiment of the application, the temperature detection level is determined based on the second sampling voltage, comprising: if the second sampling voltage is greater than a preset second reference voltage, the temperature detection level is a low level; and if the second sampling voltage is less than or equal to the second reference voltage, the temperature detection level is a high level.

[0021] In an embodiment of the application, the current detection level is determined based on the third sampling voltage, comprising: if the third sampling voltage is greater than a preset third reference voltage, the current detection level is a low level; and if the third sampling voltage is less than or equal to the third reference voltage, the current detection level is a high level.

[0022] In an embodiment of the application, whether the insulated gate bipolar transistor is short-circuited is determined according to at least two of the voltage detection level, the temperature detection level and the current detection level, comprising: decoding the voltage detection level, the temperature detection level and the current detection level to obtain a multiplexed decoding output; if all of the voltage detection level, the temperature detection level and the current detection level are high levels or only one of them is a high level, the multiplexed decoding output is all high levels, and at this time the insulated gate bipolar transistor is not short-circuited; and if at least two of the voltage detection level, the temperature detection level and the current detection level are low levels, one of the multiplexed decoding outputs is pulled down to a low level, and at this time the insulated gate bipolar transistor is short-circuited.

[0023] As described above, the short-circuit protection circuit and method of the insulated gate bipolar transistor provided by the present application have the following beneficial effects.

[0024] The present application obtains corresponding detection levels by detecting the voltage, temperature and current of the IGBT respectively, and judges whether the IGBT has a short circuit by voting based on the three detection levels, and then performs short-circuit protection when a short circuit occurs. Compared with the existing single short-circuit protection detection means, the short-circuit protection threshold does not need to be improved to avoid short-circuit protection false triggering. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 FIG. 1 is a structural schematic diagram of a short-circuit protection circuit of an insulated gate bipolar transistor according to an embodiment of the present application.

[0026] Figure 2 FIG. 2 is a circuit structural schematic diagram of a temperature detection sub-circuit according to an embodiment of the present application.

[0027] Figure 3 FIG. 2 is a circuit structural schematic diagram of a temperature detection sub-circuit according to an embodiment of the present application.

[0028] Figure 4 FIG. 3 is a circuit structural schematic diagram of a current detection sub-circuit according to an embodiment of the present application.

[0029] Figure 5 FIG. 4 is a circuit structural schematic diagram of a logic selection protection sub-circuit according to an embodiment of the present application.

[0030] Figure 6 FIG. 5 is a truth table of a decoder according to an embodiment of the present application.

[0031] Figure 7 FIG. 6 is a flowchart of a short-circuit protection method of an insulated gate bipolar transistor according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] The embodiments of the present application will be described in detail hereinafter with specific reference to the drawings. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the present specification. The present application can also be implemented or applied by different specific embodiments, and the details in the present specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0033] It is to be noted that the drawings provided in the following embodiments only schematically illustrate the basic concepts of the present application, and only the components related to the present application are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The shapes, number and proportions of the components in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complex.

[0034] Referring to Figure 1 The present application provides a short-circuit protection circuit of an insulated gate bipolar transistor, which comprises an insulated gate bipolar transistor, a voltage detection sub-circuit, a temperature detection sub-circuit, a current detection sub-circuit and a logic selection protection sub-circuit. The voltage detection sub-circuit is used for sampling the voltage drop between the collector and the emitter of the insulated gate bipolar transistor to obtain a first sampling voltage, and determining a voltage detection level based on the first sampling voltage; the temperature detection sub-circuit collects the temperature of the insulated gate bipolar transistor through a temperature sensor, and is used for sampling the voltage of the temperature sensor to obtain a second sampling voltage, and determining a temperature detection level based on the second sampling voltage; the current detection sub-circuit is connected with the emitter of the insulated gate bipolar transistor through a current sensor, and is used for sampling the voltage of the current sensor to obtain a third sampling voltage, and determining a current detection level based on the third sampling voltage; and the logic selection protection sub-circuit is used for judging whether the insulated gate bipolar transistor is short-circuited according to at least two of the voltage detection level, the temperature detection level and the current detection level, and controlling the insulated gate bipolar transistor to be turned off when the insulated gate bipolar transistor is short-circuited. The voltage detection sub-circuit of the IGBT detects the saturation voltage drop between the collector and the emitter of the IGBT in real time, the current detection sub-circuit of the IGBT detects the emitter current of the IGBT in real time, and the temperature detection sub-circuit of the IGBT detects the temperature of the IGBT chip in real time. Once the insulated gate bipolar transistor is short-circuited, the saturation voltage drop of the insulated gate bipolar transistor, the emitter current and the temperature of the IGBT chip will exceed the protection threshold, and the short-circuit protection circuit of the IGBT will execute short-circuit protection and output an alarm signal.

[0035] Referring to Figure 2 , Figure 2As shown in FIG. 1, the temperature detection sub-circuit in an embodiment of the present application includes a first diode DZ, a second diode Z1, a third diode Z2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor C1, a first comparator A1, and a first triode Q1. The negative terminal of the first diode DZ is connected to the collector of the insulated gate bipolar transistor, and the positive terminal is connected to one end of the first resistor R1. The other end of the first resistor R1 is connected to one end of the second resistor R2 and one end of the third resistor R3, respectively. The other end of the third resistor R3 is connected to one end of the first capacitor C1, the negative terminal of the second diode, and the positive input terminal of the first comparator, respectively. The positive terminal of the second diode Z1 is connected to the positive terminal of the third diode Z2. One end of the fourth resistor R4, the power supply pin of the first comparator A1, one end of the sixth resistor R6, and one end of the ninth resistor R9 are connected to a preset reference voltage VCC1, respectively. The other end of the fourth resistor R4 is connected to the negative input terminal of the first comparator A1 and one end of the fifth resistor R5, respectively. The other end of the sixth resistor R6 is connected to the output terminal of the first comparator A1 and one end of the seventh resistor R7, respectively. The other end of the seventh resistor R7 is connected to the gate of the first triode Q1 and one end of the eighth resistor R8, respectively. The other end of the ninth resistor R9 is connected to the collector of the first triode Q1 and one end of the tenth resistor R10, respectively. The other end of the tenth resistor R10 is used to output the voltage detection level DY_Signal. The emitter of the insulated gate bipolar transistor, the other end of the second resistor R2, the other end of the first capacitor C1, the negative terminal of the third diode Z2, the other end of the fifth resistor R5, the ground pin of the first comparator A1, the other end of the eighth resistor R8, and the emitter of the first triode Q1 are connected to the ground, respectively.

[0036] The saturation voltage drop between the collector and the emitter of the IGBT is sampled by the first diode DZ through the voltage division of the series connection of resistor R1 and resistor R2 (the sampling voltage can be adjusted by reasonably selecting the resistance values of R1 and R2), filtered by resistor R3 and capacitor C1, and then input to the first comparator A1 after being stabilized by the voltage stabilizing diodes Z1 and Z2. The reference voltage is sampled by the series connection of resistor R4 and resistor R5, and then input to the first comparator A1 (the reference voltage value can be adjusted by reasonably selecting the resistance values of R4 and R5). The output of the first comparator A1 is input to the gate of the first triode Q1 through resistors R6, R7 and R8, and the overvoltage signal (i.e. the voltage detection level) DY_Signal is output from the collector of the first triode Q1 through resistors R9 and R10. Under normal circumstances, the value of the saturation voltage drop of the IGBT is very small, the first diode DZ is in an off state, the sampling voltage value is 0, and the overvoltage signal DY_Signal outputs a high level. When the IGBT is short-circuited, the saturation voltage drop of the IGBT rises sharply, the first diode DZ is reversely broken down, the sampling voltage value is greater than the reference voltage value, the first comparator A1 is flipped, the first triode Q1 is turned on, and the overvoltage signal DY_Signal outputs a low level.

[0037] Please refer to Figure 3 , Figure 3A circuit structure schematic diagram of a temperature detection sub-circuit in an embodiment of the present application. The temperature detection sub-circuit comprises a fourth diode Z3, a fifth diode Z4, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a second capacitor C2, a second comparator A2, and a second triode Q2. One end of the temperature sensor NTC is connected to one end of the eleventh resistor R11 and one end of the twelfth resistor R12. The other end of the twelfth resistor R12 is connected to one end of the second capacitor C2, a negative end of the fourth diode Z3, and a positive input end of the second comparator A2. A positive end of the fourth diode Z3 is connected to a positive end of the fifth diode Z4. The other end of the temperature sensor NTC, one end of the thirteenth resistor R13, a power supply pin of the second comparator A2, one end of the fifteenth resistor R15, and one end of the eighteenth resistor R18 are connected to the preset reference voltage VCC1. The other end of the thirteenth resistor R13 is connected to a negative input end of the second comparator A2 and one end of the fourteenth resistor R14. The other end of the fifteenth resistor R15 is connected to an output end of the second comparator A2 and one end of the sixteenth resistor R16. The other end of the sixteenth resistor R16 is connected to a gate of the second triode Q2 and one end of the seventeenth resistor R17. The other end of the eighteenth resistor R18 is connected to a collector of the second triode Q2 and one end of the nineteenth resistor R19. The other end of the nineteenth resistor R19 is used to output the temperature detection level WD_Signal. The other end of the eleventh resistor R11, the other end of the second capacitor C2, a negative end of the fifth diode Z4, the other end of the fourteenth resistor R14, a ground pin of the second comparator A2, the other end of the seventeenth resistor R17, and an emitter of the second triode Q2 are grounded.

[0038] The NTC temperature sensor of the IGBT and the resistor R11 sample voltage by series voltage division (the sampling voltage can be adjusted by reasonably selecting the resistance value of R11), and then the voltage is filtered by the resistor R12 and the capacitor C2, and then is input to the comparator A2 after being stabilized by the voltage stabilizing diodes Z3 and Z4; the resistor R13 and the resistor R14 sample reference voltage by voltage division, and then the voltage is input to the second comparator A2 (the reference voltage value can be adjusted by reasonably selecting the resistance value of R13 and R14). The output of the second comparator A2 is input to the gate of the second triode Q2 through the resistors R15, R16 and R17, and the over-temperature signal (i.e. the temperature detection level) WD_Signal is output from the collector of the second triode Q2 through the resistors R18 and R19. Under normal circumstances, the temperature of the IGBT chip is low, the NTC resistance is large, and the sampling voltage value is almost 0, so the over-temperature signal WD_Signal outputs a high level; when the IGBT is short-circuited, the temperature of the IGBT chip rises sharply, the NTC resistance decreases, and when the sampling voltage value is greater than the reference voltage value, the comparator A2 flips, the triode Q2 is turned on, and the over-temperature signal WD_Signal outputs a low level.

[0039] Please refer to Figure 4 , Figure 4A circuit structure schematic diagram of a current detection sub-circuit in an embodiment of the present application. The current detection sub-circuit comprises a sixth diode Z5, a seventh diode Z6, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-eighth resistor R28, a third capacitor C3, a third comparator A3, and a third triode Q3. The twentieth resistor R20 is connected in parallel with the current sensor, and one end of the twentieth resistor R20 is connected to one end of the twenty-first resistor R21. The other end of the twenty-first resistor R21 is connected to one end of the third capacitor C3, the negative end of the sixth diode Z5, and the positive input end of the third comparator A3, respectively. The positive end of the sixth diode Z5 is connected to the positive end of the seventh diode Z6. One end of the twenty-second resistor R22, the power supply pin of the third comparator A3, one end of the twenty-fourth resistor R24, and one end of the twenty-seventh resistor R27 are connected to the preset reference voltage VCC1, respectively. The other end of the twenty-second resistor R22 is connected to one end of the twenty-third resistor R23 and the negative input end of the third comparator A3, respectively. The other end of the twenty-fourth resistor R24 is connected to the output end of the third comparator A3 and one end of the twenty-fifth resistor R25, respectively. The other end of the twenty-fifth resistor R25 is connected to one end of the twenty-sixth resistor R26 and the gate of the third triode Q3, respectively. The other end of the twenty-seventh resistor R27 is connected to the collector of the third triode Q3 and one end of the twenty-eighth resistor R28, respectively. The other end of the twenty-eighth resistor R28 is used to output the current detection level DL_Signal. The other end of the twentieth resistor R20, the other end of the third capacitor C3, the negative end of the seventh diode Z6, the other end of the twenty-third resistor R23, the ground pin of the third comparator A3, the other end of the twenty-sixth resistor R26, and the emitter of the third triode Q3 are connected to the ground, respectively.

[0040] The current sensor of the IGBT samples voltage through resistance R20 (the sampling voltage can be adjusted by reasonably selecting the resistance value of R20), and then is filtered through resistance R21 and capacitor C3, and is input to the third comparator A3 after being stabilized by voltage stabilizing diodes Z5 and Z6. Resistance R22 and resistance R23 sample reference voltage by voltage division, and then are input to the third comparator A3 (the reference voltage value can be adjusted by reasonably selecting the resistance value of R22 and R23). The output of the third comparator A3 is input to the gate of the third triode Q3 through resistance R24, R25 and R26, and the collector of the third triode Q3 outputs the overcurrent signal (i.e. the current detection level) DL_Signal through resistance R27 and R28. Under normal circumstances, the current of the IGBT is small, and the sampling voltage value is almost 0, and the overcurrent signal DL_Signal outputs high level. When the IGBT is short-circuited, the current of the IGBT chip rises sharply, and when the sampling voltage value is greater than the reference voltage value, the third comparator A3 flips, the third triode Q3 is turned on, and the overcurrent signal DL_Signal outputs low level.

[0041] Please refer to Figure 5 , Figure 5 The figure is a circuit structure diagram of a logic selection protection sub-circuit in an embodiment of the application. The logic selection protection sub-circuit comprises a decoder, a first AND gate U1:A, a first NAND gate U2:A, a second NAND gate U2:B and a second AND gate U3:A. The decoder takes the voltage detection level, the temperature detection level and the current detection level as input, and obtains four-way output through decoding, and takes the four-way output as the input of the first AND gate U1:A. The output terminal of the first AND gate U1:A is connected with the first input terminal of the first NAND gate U2:A. The second input terminal of the first NAND gate U2:A is connected with the output terminal of the second NAND gate U2:B. The output terminal of the first NAND gate U2:A is used for outputting an alarm signal. The first input terminal of the second NAND gate U2:B is connected with the output terminal of the first NAND gate U2:A. The second input terminal of the second NAND gate U2:B is connected with a reset signal. The first input terminal of the second AND gate U3:A is connected with the output terminal of the second NAND gate U2:B. The second input terminal of the second AND gate U3:A is connected with a driving signal. The output terminal of the second AND gate U3:A is connected with the gate of the insulated gate bipolar transistor.

[0042] Specifically, the decoder can adopt a 3-8 decoder 74LS138, the overvoltage signal DY_Signal, the overtemperature signal WD_signal and the overcurrent signal DL_Signal are connected to input pins A0, A1 and A2 of the 3-8 decoder 74LS138 respectively, the output pins Y0, Y1, Y2 and Y4 of the 3-8 decoder are connected to the input end of the four-input AND gate U1:A, the alarm signal is output through the NAND gate U2:A, and then the short-circuit protection signal is latched and output through the NAND gate U2:B, the short-circuit alarm signal and the driving signal are input to the input end of the AND gate U3:A, and the output end of U3:A is connected to the gate of the IGBT to control the opening and closing of the IGBT.

[0043] Please refer to Figure 6 , Figure 6 The truth table of the decoder in an embodiment of the present application is intended. Normally, the overvoltage signal DY_Signal, the overtemperature signal WD_signal and the overcurrent signal DL_Signal in the IGBT system loop are simultaneously output as high level, the 3-8 decoder Y0, Y1, Y2, Y4 is simultaneously output as high level, and the long high level is latched and output through the AND gate U1:A, the NAND gate U2:A and U2:B, and is simultaneously input to the AND gate U3:A with the driving signal to normally control the opening and closing of the gate of the IGBT; when at least two of the overvoltage signal DY_Signal, the overtemperature signal WD_signal and the overcurrent signal DL_Signal in the IGBT system loop are triggered, it is determined that the IGBT has a short circuit, at this time one of the output ends Y0, Y1, Y2, Y4 of the 3-8 decoder will be pulled down to low level, the long low level is latched and output through the AND gate U1:A, the NAND gate U2:A and U2:B, and is simultaneously input to the AND gate U3:A with the driving signal, the AND gate U3:A outputs long low level, and the IGBT always maintains the off state; when the short-circuit fault disappears, the overvoltage signal DY_Signal, the overtemperature signal WD_signal and the overcurrent signal DL_Signal in the IGBT system loop are simultaneously output as high level, the 3-8 decoder Y0, Y1, Y2, Y4 is simultaneously output as high level, the long low level is latched and output through the AND gate U1:A, the NAND gate U2:A and U2:B, at this time the reset switch is pressed, the reset signal FW_Signal is pulled down to low level, the long high level is latched and output through the NAND gate U2:B, and the driving signal normally controls the opening and closing of the gate of the IGBT.

[0044] Based on the above circuit of the embodiment of the present application, the IGBT state can be detected simultaneously through the voltage detection sub-circuit, the current detection sub-circuit and the chip temperature detection sub-circuit, and the short-circuit protection of the IGBT can be realized through the three-person hand-raising voting circuit. Compared with the existing single short-circuit protection detection means, it is not necessary to increase the short-circuit protection threshold to avoid the false triggering of the short-circuit protection, the IGBT short-circuit protection can be quickly realized, and the false triggering of the short-circuit protection can be avoided.

[0045] Referring to Figure 7 , Figure 7 FIG. 7 is a flowchart of a short-circuit protection method for an IGBT according to an embodiment of the present application. The short-circuit protection method is used to implement the short-circuit protection circuit described above. The method includes the following steps:

[0046] In step S700, an IGBT is provided.

[0047] In step S710, a voltage drop between a collector and an emitter of the IGBT is sampled to obtain a first sampling voltage. A voltage detection level is determined based on the first sampling voltage.

[0048] In step S720, a temperature of the IGBT is collected by a temperature sensor, and a voltage of the temperature sensor is sampled to obtain a second sampling voltage. A temperature detection level is determined based on the second sampling voltage.

[0049] In step S730, a voltage of a current sensor connected to the emitter of the IGBT is sampled to obtain a third sampling voltage. A current detection level is determined based on the third sampling voltage.

[0050] In step S740, whether the IGBT is short-circuited is determined according to at least two of the voltage detection level, the temperature detection level, and the current detection level. The IGBT is turned off when the IGBT is short-circuited.

[0051] In an embodiment, the voltage detection level is determined based on the first sampling voltage, including: if the first sampling voltage is greater than a first reference voltage, the voltage detection level is a low level; and if the first sampling voltage is less than or equal to the first reference voltage, the voltage detection level is a high level.

[0052] In an embodiment, the temperature detection level is determined based on the second sampling voltage, including: if the second sampling voltage is greater than a second reference voltage, the temperature detection level is a low level; and if the second sampling voltage is less than or equal to the second reference voltage, the temperature detection level is a high level.

[0053] In an embodiment, the current detection level is determined based on the third sampling voltage, including: if the third sampling voltage is greater than a third reference voltage, the current detection level is a low level; and if the third sampling voltage is less than or equal to the third reference voltage, the current detection level is a high level.

[0054] In one embodiment, determining whether the IGBT is short-circuited according to at least two of the voltage detection level, the temperature detection level and the current detection level comprises: decoding the voltage detection level, the temperature detection level and the current detection level to obtain a plurality of decoded outputs; if the voltage detection level, the temperature detection level and the current detection level are all high or only one is high, then all of the decoded outputs are high, and at this time the IGBT is not short-circuited; if at least two of the voltage detection level, the temperature detection level and the current detection level are low, then one of the decoded outputs is pulled down to low, and at this time the IGBT is short-circuited.

[0055] The above embodiments are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A short-circuit protection circuit for an insulated-gate bipolar transistor, characterized in that, include: Insulated-gate bipolar transistor; A voltage detection sub-circuit is used to sample the voltage drop between the collector and emitter of the insulated gate bipolar transistor to obtain a first sampling voltage, so as to determine the voltage detection level based on the first sampling voltage; A temperature detection sub-circuit is provided, which acquires the temperature of the insulated gate bipolar transistor through a temperature sensor. The temperature detection sub-circuit is used to sample the voltage of the temperature sensor to obtain a second sampling voltage, and to determine the temperature detection level based on the second sampling voltage. A current detection sub-circuit is connected to the emitter of the insulated gate bipolar transistor via a current sensor. The current detection sub-circuit is used to sample the voltage of the current sensor to obtain a third sampling voltage, and to determine the current detection level based on the third sampling voltage. A logic selection protection sub-circuit is used to determine whether the insulated gate bipolar transistor (IGBT) is short-circuited based on at least two of the voltage detection level, temperature detection level, and current detection level, and to control the IGBT to turn off when the IGBT is short-circuited.

2. The short-circuit protection circuit for an insulated gate bipolar transistor according to claim 1, characterized by The voltage detection sub-circuit includes a first diode, a second diode, a third diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first capacitor, a first comparator, and a first transistor. The negative terminal of the first diode is connected to the collector of the insulated-gate bipolar transistor, and the positive terminal is connected to one end of the first resistor; the other end of the first resistor is connected to one end of the second resistor and one end of the third resistor; the other end of the third resistor is connected to one end of the first capacitor, the negative terminal of the second diode, and the positive input terminal of the first comparator; the positive terminal of the second diode is connected to the positive terminal of the third diode; one end of the fourth resistor, the power supply pin of the first comparator, one end of the sixth resistor, and one end of the ninth resistor are respectively connected to a preset reference voltage; the other end of the fourth resistor is connected to the negative input terminal of the first comparator and the fifth resistor. One end of the resistor; the other end of the sixth resistor is connected to the output terminal of the first comparator and one end of the seventh resistor; the other end of the seventh resistor is connected to the gate of the first transistor and one end of the eighth resistor; the other end of the ninth resistor is connected to the collector of the first transistor and one end of the tenth resistor; the other end of the tenth resistor is used to output the voltage detection level; the emitter of the insulated gate bipolar transistor, the other end of the second resistor, the other end of the first capacitor, the negative terminal of the third diode, the other end of the fifth resistor, the ground pin of the first comparator, the other end of the eighth resistor, and the emitter of the first transistor are all grounded.

3. The short-circuit protection circuit for an insulated gate bipolar transistor according to claim 2, characterized by The temperature detection sub-circuit comprises a fourth diode, a fifth diode, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a second capacitor, a second comparator, and a second triode; One end of the temperature sensor is connected to one end of the eleventh resistor and one end of the twelfth resistor; the other end of the twelfth resistor is connected to one end of the second capacitor, a negative end of the fourth diode, and a positive input end of the second comparator; a positive end of the fourth diode is connected to a positive end of the fifth diode; the other end of the temperature sensor, one end of the thirteenth resistor, a power supply pin of the second comparator, one end of the fifteenth resistor, and one end of the eighteenth resistor are connected to the preset reference voltage; the other end of the thirteenth resistor is connected to a negative input end of the second comparator and one end of the fourteenth resistor; the other end of the fifteenth resistor is connected to an output end of the second comparator and one end of the sixteenth resistor; the other end of the sixteenth resistor is connected to a gate of the second triode and one end of the seventeenth resistor; the other end of the eighteenth resistor is connected to a collector of the second triode and one end of the nineteenth resistor; the other end of the nineteenth resistor is used for outputting the temperature detection level; the other end of the eleventh resistor, the other end of the second capacitor, a negative end of the fifth diode, the other end of the fourteenth resistor, a ground pin of the second comparator, the other end of the seventeenth resistor, and an emitter of the second triode are grounded.

4. The short-circuit protection circuit for an insulated gate bipolar transistor according to claim 2, characterized by The current detection sub-circuit comprises a sixth diode, a seventh diode, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor, a twenty-sixth resistor, a twenty-seventh resistor, a twenty-eighth resistor, a third capacitor, a third comparator, and a third triode; The twentieth resistor is connected in parallel with the current sensor, and one end of the twentieth resistor is connected to one end of the twenty-first resistor; the other end of the twenty-first resistor is connected to one end of the third capacitor, a negative end of the sixth diode, and a positive input end of the third comparator; a positive end of the sixth diode is connected to a positive end of the seventh diode; one end of the twenty-second resistor, a power supply pin of the third comparator, one end of the twenty-fourth resistor, and one end of the twenty-seventh resistor are connected to the preset reference voltage; The other end of the twenty-second resistor is connected to one end of the twenty-third resistor and a negative input end of the third comparator; the other end of the twenty-fourth resistor is connected to an output end of the third comparator and one end of the twenty-fifth resistor; the other end of the twenty-fifth resistor is connected to one end of the twenty-sixth resistor and a gate of the third triode; An other end of the twenty-seventh resistor is connected to a collector of the third transistor and an one end of the twenty-eighth resistor respectively; an other end of the twenty-eighth resistor is used for outputting the current detection level; an other end of the second resistor, an other end of the third capacitor, a negative end of the seventh diode, an other end of the twenty-third resistor, a ground pin of the third comparator, an other end of the twenty-sixth resistor and an emitter of the third transistor are grounded respectively.

5. The short-circuit protection circuit for an insulated gate bipolar transistor according to Claim 1, characterized by The logic selection protection sub-circuit comprises a decoder, a first AND gate, a first NAND gate, a second NAND gate and a second AND gate. The decoder takes the voltage detection level, the temperature detection level and the current detection level as inputs, and obtains four-way outputs through decoding, and takes the four-way outputs as inputs of the first AND gate; an output end of the first AND gate is connected with a first input end of the first NAND gate; a second input end of the first NAND gate is connected with an output end of the second NAND gate; an output end of the first NAND gate is used for outputting an alarm signal; a first input end of the second NAND gate is connected with the output end of the first NAND gate; a second input end of the second NAND gate is connected with a reset signal; a first input end of the second AND gate is connected with the output end of the second NAND gate; a second input end of the second AND gate is connected with a driving signal; and an output end of the second AND gate is connected with a gate of the insulated gate bipolar transistor.

6. A short-circuit protection method for an insulated gate bipolar transistor, characterized by, comprising: providing an insulated gate bipolar transistor; sampling a voltage drop between a collector and an emitter of the insulated gate bipolar transistor to obtain a first sampling voltage, to determine a voltage detection level based on the first sampling voltage; acquiring a temperature of the insulated gate bipolar transistor through a temperature sensor, and sampling a voltage of the temperature sensor to obtain a second sampling voltage, to determine a temperature detection level based on the second sampling voltage; connecting a current sensor with the emitter of the insulated gate bipolar transistor, and sampling a voltage of the current sensor to obtain a third sampling voltage, to determine a current detection level based on the third sampling voltage; determining whether the insulated gate bipolar transistor is short-circuited according to at least two of the voltage detection level, the temperature detection level and the current detection level, and controlling the insulated gate bipolar transistor to be turned off when the insulated gate bipolar transistor is short-circuited.

7. The short-circuit protection method for an insulated gate bipolar transistor according to claim 6, characterized by, determining a voltage detection level based on the first sampling voltage, comprising: if the first sampling voltage is greater than a preset first reference voltage, the voltage detection level is a low level; if the first sampling voltage is less than or equal to the first reference voltage, the voltage detection level is a high level.

8. The short-circuit protection method for an insulated gate bipolar transistor according to claim 7, characterized by, determining a temperature detection level based on the second sampling voltage, comprising: if the second sampling voltage is greater than a preset second reference voltage, the temperature detection level is a low level; if the second sampling voltage is less than or equal to the second reference voltage, the temperature detection level is a high level.

9. The short-circuit protection method for an insulated gate bipolar transistor according to claim 8, characterized by, determining a current detection level based on the third sampling voltage, comprising: if the third sampling voltage is greater than a preset third reference voltage, the current detection level is a low level; If the third sampling voltage is less than or equal to the third reference voltage, the current detection level is high.

10. The short-circuit protection method for an insulated gate bipolar transistor according to claim 9, characterized by, determining whether the insulated gate bipolar transistor is short-circuited according to at least two of the voltage detection level, the temperature detection level and the current detection level, comprising: decoding the voltage detection level, the temperature detection level and the current detection level to obtain a plurality of decoding outputs; if the voltage detection level, the temperature detection level and the current detection level are all high or only one of them is high, the plurality of decoding outputs are all high, and at this time the insulated gate bipolar transistor is not short-circuited; if at least two of the voltage detection level, the temperature detection level and the current detection level are low, one of the plurality of decoding outputs is pulled down to low, and at this time the insulated gate bipolar transistor is short-circuited.

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