Active miller clamping protection circuit

Abstract

The invention relates to an active miller clamping protection circuit. The active miller clamping protection circuit comprises a hysteresis comparator circuit, a grid voltage sampling enabling circuit, a positive-voltage crosstalk clamping action circuit and a negative-voltage crosstalk clamping action circuit; the positive input end of the hysteresis comparator circuit samples voltage at the output end of the grid voltage sampling enabling circuit; the sampled grid voltage is superposed onto the positive input end of the hysteresis comparator circuit, and compared with the reference voltage of the negative input end; when the sampled grid voltage is greater than the reference voltage, the hysteresis comparator circuit outputs saturated positive voltage; when the sampled grid voltage is less than the reference voltage, the hysteresis comparator circuit outputs saturated negative voltage; hysteresis output on the sampled grid voltage is formed; normal on / off of an insulated gate devicecannot be influenced; when the grid has very high positive-voltage pulse interference, due to clamping of the positive-voltage crosstalk clamping action circuit, at this time, the grid voltage is clamped at the tube voltage drop of a diode; and, when the grid has negative-voltage pulse interference, due to clamping of the negative-voltage crosstalk clamping action circuit, at this time, the grid voltage is clamped around a negative-voltage power supply.

Description

technical field [0001] The invention relates to a protection circuit of an insulating gate device. In particular, it relates to a circuit for suppressing the crosstalk of IGBT in the bridge arm circuit. Background technique [0002] Insulated gate bipolar transistor (IGBT) has become a mainstream power semiconductor device. IGBT has a series of excellent characteristics such as voltage type drive, high input impedance, fast switching speed, small switching power loss, and small on-state voltage drop. , making it an ideal power switching device for medium and high power switching power supplies, frequency converters, inverters, induction heating, active filters, household appliances and other occasions that require power conversion. [0003] The IGBT needs a protection circuit to protect and control it during operation, so as to prevent the abnormal state of its own drive system or the power electronic circuit where the operating voltage or current of the IGBT exceeds the sa...

AI Technical Summary

Problems solved by technology

Although this method can suppress the parasitic conduction caused by crosstalk to a certain extent, it will increase the complexity of triode driving. The biggest disadvantage is that this active clamp can only suppress the positive voltage interference caused by crosstalk. The negative voltage interference brought about has no effect, and the negative voltage drive that the IGBT gate can withstand also has a certain limit value. When the negative voltage exceeds a certain limit value, the IGBT will be damaged to a certain extent and affect the working characteristics of the IGBT.

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