A Smart Gate Driver for SiC Power MOSFETs with Aging Compensation and Ringing Suppression

The application of a segmented gate driver (SGD) to detect aging and provide automated compensation for SiC MOSFETs is presented. By dynamically modifying the gate resistance during switching transients, we can stretch the Miller plateau (MP) duration. The MP level is used as an indicator for the health condition of the SiC power MOSFET. A digital control circuit analyzes the aging effect and provides a control signal to an integrated boost converter, which powers the gate drive voltage. In this manner, the gate drive voltage can be adjusted to compensate for changes in the MOSFET performance. The same SGD can also be used to suppress gate ringing to protect the SiC power device against over/undershoot damage. This is of particular importance at elevated gate voltage.