Avalanche Capability Characterization of Si MOSFETs in Unclamped Inductive Switching Conditions

The avalanche capability of Si MOSFETs with different power sizes is experimentally compared and analyzed in this paper. The variation of device current and voltage during the avalanche of Si MOSFET is reported. Use temperature-sensitive parameters to calculate the change in junction temperature during the device avalanche. The comparison shows that in the same package, the smaller R
DS(on)
, the better the avalanche capability of the device. The avalanche capability of the device is related to the heat dissipation capability of the device. In tests with different inductance sizes, it is concluded that the ability of the device to dissipate heat at large inductances is the main factor affecting the avalanche tolerance of the device.