Temperature Sensing for Power MOSFETs in Short-Duration Avalanche Mode

The purpose of this paper is based on the estimation of power MOSFET junction temperature during a short-duration avalanche mode. Therefore, an experiment has been developed and results have been correlated with simple electrothermal modeling. The simple electrothermal model allows monitoring of junction temperature by simple measurements of the I_D(t) and BV_dss(t) waveforms. Accurate extraction of model parameters is linked with precise recording of the instantaneous avalanche voltage. Indeed, avalanche voltage is impacted by two phenomena, namely, the current-induced ohmic voltage drop and the shift of the breakdown voltage due to self-heating effects. This paper highlighted that during avalanche behavior, MOSFETs exhibit a dynamic avalanche resistance R_av, which is far in excess of their classical on-state resistance R_dson.