SiC BJT proportional base driver with collector-emitter voltage measurement and a switching regulator

The biggest concern about SiC BJTs is the power consumed by its driver since a continuous current is needed through the base to maintain the BJT on. This paper focuses on the optimization of SiC BJT base drivers during the conducting state. Previous proportional base drivers used measurements of the collector current to adjust the base current. A different approach is presented in this paper, based on measurements of the collector-emitter voltage. This solution avoids the need for costly high bandwidth current sensors and a DSP/FPGA to process the current measurement. Also, a new method to avoid high voltage decoupling devices is presented to measure the BJT voltage drop, which is later used as a reference for a high speed switching regulator that serves as the voltage supply for the driver. As a result, the base current is instantaneously adjusted to the collector current, minimizing the driver consumption.