Detection of Cross-Turn-On and Selection of Off Drive Voltage for an SiC Power Module

Cross-turn-on happens in a phase leg comprising high-side switch(es) and low-side switch(es) when the turn-on of one switch inadvertently triggers the channel current to flow in the off-switch. The terminal current does not reflect the internal channel current because of the numerous parasitic inductances from the package. Detection of the cross-turn-on in a power module is difficult since the dice are usually encapsulated and the channel currents are hard to measure. A nonintrusive method to identify the cross-turn-on based on the changing ringing current is introduced in this paper. The detection method is analyzed theoretically and validated by experiments using a 1.2-kV SiC module. The negative drive voltage and gate resistance for safe operation can be determined by the detection method.