A Gate Open-Circuit Failure Detection Method of SiC MOSFETs Based on Internal Gate State Extraction

Gate open-circuit failure caused by cracking and liftoff of gate bond wires has been demonstrated to be a new failure mode of SiC MOSFETs, which can cause serious consequences such as shoot-through fault and gate-oxide breakdown. To enhance the reliability and robustness of SiC MOSFETs, a fast and accurate detection scheme for such failure is required. This article proposes a gate open-circuit failure detection method based on the extraction of the internal gate state. Although this state is unavailable externally, it can be extracted from gate current pulses. The gate open-circuit failures are then detected by checking the inconsistency between the drive signal and the internal gate state. Experimental results validate that the proposed method can accurately detect all types of gate open-circuit failures within 55ns.