IGBT short circuit protection circuit and method, IGBT driver and IGBT circuit

Abstract

The invention provides an IGBT short circuit protection circuit and method, an IGBT driver and an IGBT circuit. The IGBT short circuit protection circuit comprises a drive current detection unit, used for detecting the drive current flowing through an IGBT gate; a comparison unit, used for comparing the drive current with reference current and outputting a comparison result; and a protection unit, used for determining whether to start short circuit protection of the IGBT according to the comparison result. According to the technical scheme, the drive current flowing through the IGBT is detected to control the self locking of the IGBT drive circuit, so as to improve the reliability of the short circuit protection of the IGBT.

Description

technical field [0001] The invention relates to the technical field of circuits, in particular to an IGBT short-circuit protection circuit and method, an IGBT driver and an IGBT circuit. Background technique [0002] IGBT (Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor) is composed of MOSFET and bipolar transistor. Due to the advantages of large capacity of the type device, it has been more and more widely used in the current power electronics technology. However, whether the various protection functions of the IGBT driver are feasible and perfect, and whether the IGBT can be turned off in time under abnormal conditions, determines the service life of the IGBT to a certain extent. [0003] The short-circuit protection of the conventional IGBT driver detects the voltage of the collector CE terminal of the IGBT when it is turned on, that is, detects the gate voltage Vce(sat). When working normally, the value of Vce(sat) is about 2V, which cannot reach t...

AI Technical Summary

Problems solved by technology

[0004] However, in this method, since the external characteristic curve of the IGBT is qualitative and not quantitative when the working current is greater than 2 times the rated current, there may be some abnormal conditions that cause the short-circuit protection threshold to not reach the short-circuit protection threshold when the short-circuit current is extremely large, and the protection No action, that is, the short circuit protection fails, thus damaging the IGBT

Furthermore, when the inductance of the short-circuit loop is too large, the rate of change of the current becomes very low. At this time, it is not a short-circuit, but an over-current. In this case, the short-circuit protection will also lose its effect.

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