Thermal stress reduction and lifetime improvement of power switches with dynamic gate driving strategy

The thermal stress and lifetime of semiconductor power switches are largely determined by thermal cycling. Considerable thermal stress and reduced lifetime problems occur especially at low frequency operation. In this paper, an analytical model and the equivalent circuit model of power MOSFETs are derived to investigate their thermal behavior. After that, a dynamic gate driver that supplies an adjustable gate voltage is proposed to shape the power losses, thus mitigate thermal stress for lifetime improvement. Finally, the resulting semiconductor lifetime is estimated, which shows an improvement by a factor of two after applying the proposed strategy.