A New User-Configurable Method to Improve Short-Circuit Ruggedness of 1.2-kV SiC Power MOSFETs
Ajit Kanale, B. Jayant Baliga
Abstract
Silicon carbide (SiC) power MOSFETs have been commercialized to replace silicon insulated gate bipolar transistors (IGBTs) in power conversion applications. However, the short-circuit ruggedness of SiC power MOSFETs must be enhanced to match that of Si IGBTs for application in motor drives for electric vehicles. A new, user-configurable method with a series-connected, Si enhancement mode MOSFET (EMM) is demonstrated to improve the short-circuit withstand time of commercially available 1.2-kV SiC power MOSFETs by 86% with a 4.2% increase in on-resistance and a 13% increase in switching loss. In contrast, operating the 1.2-kV SiC power MOSFET with a reduced gate bias of 15 V produces an 80% improvement in short-circuit withstand time with 31% increase in on-resistance and a 31% increase in switching loss. It is demonstrated that the drain of the EMM can be used as a sensing node to monitor on-state current and to detect short-circuit events.