Rapid high-power SiC MOSFET short-circuit fault detection circuit and detection method

Abstract

The invention discloses a rapid high-power SiC MOSFET short-circuit fault detection circuit and detection method. The detection circuit comprises a gate voltage change rate detection unit, a gate charge detection unit, a drain voltage detection unit and a logic control unit. According to the detection method, the logic control unit is used for detecting whether the SiC MOSFET has a short-circuit fault or not, and the detection method is divided into two stages of an open transient state and an open steady state; in a turn-on transient stage, a Miller platform is identified based on a gate voltage change rate detection unit and a gate charge detection unit, and the drain voltage detection unit is multiplexed to realize hard switch short circuit fault HSF detection; and in the open steady-state stage, desaturation detection of the short-circuit fault is realized based on the drain voltage detection unit. The reliability of HSF short-circuit fault detection is improved through a double Miller platform recognition mode and a wider Qref value range, meanwhile, the problem that desaturation detection action is not timely due to the fact that the avoiding time tblank is set is solved, and the rapidness of short-circuit fault detection is improved.

Description

technical field [0001] The invention relates to a fast high-power SiC MOSFET short-circuit fault detection circuit and a detection method, belonging to the field of SiC MOSFET short-circuit fault detection. Background technique [0002] Compared with traditional Si-based IGBTs, SiC MOSFETs have the characteristics of wide bandgap, high temperature resistance, and low switching loss. Therefore, SiC MOSFETs have broad application prospects in high-frequency, high-temperature, and high-power-density high-power applications. For high-power SiC MOSFETs Short-circuit protection technology has also become a research hotspot for SiC MOSFET applications. [0003] The larger short-circuit current and smaller chip size of SiC MOSFET lead to shorter short-circuit withstand time, which puts forward higher requirements for the rapidity of short-circuit protection. At present, most of the short-circuit detection methods of SiC MOSFETs are borrowed from IGBTs, including desaturation detect...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide a fast high-power SiC MOSFET short-circuit fault detection circuit and detection method, which overcomes the shortcomings of existing desaturation detection and gate charge detection

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