An Improved Proportional Base Driver for Minimizing Driver Power Consumption of SiC BJT Over Wide Current and Temperature Range

SiC bipolar junction transistor (BJT) still offers an attractive alternative to the more popular SiC MOSFET because of its several advantages, such as low fabrication cost, fast switching speed, and high temperature durability. However, it has not been widely accepted in the market partially because the large constant base current induces large power consumption on its base driver during on-state. In this paper, a new proportional base driver is proposed to provide adaptive base current for SiC BJT and thus minimize its driver power consumption when operating within a wide range of load current and operation temperature in SiC BJT-based power converters. It simply uses a silicon BJT serially connected with a current sensor as a current/temperature-controlled current source in the base driver circuit, promptly supplying adaptive base current for SiC BJT whenever the SiC BJT's junction temperature and/or operation current varies. The operation principle of this proportional base driver is theoretically analyzed and then experimentally verified in a 600-V/20-A SiC BJT-based dc/dc boost converter. Experimental results show that the proposed proportional base driver is capable of driving the SiC BJT much more efficiently than the GeneSiC's constant base driver, greatly reducing the power consumption of base driver by more than 50% over wide ranges of operation currents and temperatures.