Darlington Power Switches using Si-SJBJT and SiC-MOSFET

In this study, we proposed a Darlington power switch comprising a Si superjunction BJT (Si SJBJT) as a main transistor and an SiC-MOSFET as an auxiliary transistor (SiC-SJBMD), and the typical electrical characteristics of 7-A SiC-SJBMD of a breakdown voltage with 600V were experimentally investigated. The VCE(sat) of the SiC-SJBMD is 0.84V at room temperature and 0.95V at 150°C at 7A. The power loss and delay time during the turn-off operation can be successfully reduced by decreasing the resistance in a charge-extraction circuit connected to the auxiliary gate of the SJBMD. The simulations revealed that the trade-off relationship between the VCE(sat) and switching loss of the SiC-SJBMD is better than that of the SJBMD using a conventional Si-MOSFET as an auxiliary transistor. The simulations also compared the trade-off relationship of the SiC-SJBMD with that of the Si-IGBT and Si-SJMOSFET.