Over-current protection circuit of insulated gate bipolar transistor

Abstract

An embodiment of the invention discloses an over-current protection circuit of an insulated gate bipolar transistor. According to the protection circuit, the input end of an over-current comparison unit is connected with the output end of the insulated gate bipolar transistor; the output end of the over-current comparison unit is connected with the first input end of a first driving unit through an isolation unit; the output end of the first driving unit is connected with the gate of the insulated gate bipolar transistor through a second driving unit; the over-current comparison unit is used for acquiring a current value of the output end of the insulated gate bipolar transistor, and generating an output comparison signal when it is judged that an over-current phenomenon occurs according to the current value; and the isolation unit outputs a preset voltage signal to the first driving unit according to the output comparison signal so as to trigger the first driving unit to generate a driving signal used for driving the second driving unit to turn off the insulated gate bipolar transistor. The protection circuit performs soft turn-off on the insulated gate bipolar transistor when theover-current phenomenon occurs, so that the reliability of the transistor is improved, and over-voltage damage is avoided.

Description

technical field [0001] The present application relates to the field of circuit technology, in particular to an overcurrent protection circuit for an insulated gate bipolar transistor. Background technique [0002] At present, in some circuits that use high-power IGBTs (English full name: Insulated Gate Bipolar Transistor, Chinese name: Insulated Gate Bipolar Transistor), protection circuits are installed to protect high-power IGBTs when overcurrent occurs. [0003] However, due to the slow switching characteristics of high-power IGBTs, when there is an overcurrent phenomenon, especially the overcurrent phenomenon caused by the short circuit between the output phases, the current rises slowly and takes a long time. This makes the protection circuit hard turn off the IGBT by directly blocking the front-end PWM (English full name: Pulse Width Modulation, Chinese name: Pulse Width Modulation) driving signal. This hard turn-off of the IGBT will generate a very large voltage stre...

AI Technical Summary

Problems solved by technology

[0003] However, due to the slow switching characteristics of high-power IGBTs, when there is an overcurrent phenomenon, especially the overcurrent phenomenon caused by the short circuit between the output phases, the current rises slowly and takes a long time. Make the protection circuit hard turn off the IGBT by directly blocking the front-end PWM (English full name: Pulse Width Modulation, Chinese name: Pulse Width Modulation) drive signal

This hard turn-off of the IGBT will generate a very large voltage stress, which not only affects the reliability of the IGBT, but also greatly reduces the stress margin of the IGBT, and in severe cases will cause the IGBT to be damaged by overvoltage

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