Short-Circuit protection for 650 V p-gate GaN HEMTs based on gate current sensing

GaN HEMTs are prone to Short-Circuit (SC) robustness issues and therefore they need a proper and fast protection to avoid catastrophic failure during the operation of a power converter. State-of-art solutions are based on desaturation methods, that are very sensitive to the parasitic elements in the circuit. In this paper the gate leakage current is used as the sensitive parameter for the detection of the SC. The gate current behavior is analyzed and the operation principle of the protection circuit as well as its design procedure are presented, showing the applicability to different GaN HEMTs. The detection circuit does not require the modification of the gate and drain loops, so no parasitic elements are added in the power path and the sensing is very robust to the switching noise. Based on experimental characterization, simulation results are reported, obtaining an intervention time of about 400 ns.