This work presents a fast, online gate-source leakage detection method for SiC MOSFETs, utilizing the forward voltage drop across a diode placed in the gate loop. The presence of the diode has negligible impact on the switching operation of the SiC MOSFETs. During the on-state, the diode produces a noticeable voltage drop in the hundreds of millivolts, which makes detection via an amplifier feasible. The detection circuit is simple, can be easily integrated with existing gate drivers. Tests on a 1.2 kV SiC device show that the proposed method can detect sub-mA gate leakage current of 500 µA with a minimum detection time of 12 µs. This method offers a practical solution for on-line detection of gate leakage for SiC MOSFETs.
