Abstract
Compared with Si-IGBT, a silicon carbide (SiC) -MOSFET is expected to reduce the switching loss and conduction loss of the low-current region, and also remove external freewheeling diode. However, because the SiC-MOSFET body diode has high forward voltage, the diode conduction loss increases during dead time, and therefore, its loss reduction effect decreases. This work proposes a novel dead time control circuit using a current sensing transistor integrated with SiC-MOSFET. The proposed circuit has a high responsiveness and high robustness against switching noise, and the dead time can be shortened to within 0.1µs without using external components. In addition, it has not only the dead time control but also the short-circuit current detection, which is the radical function of a current sensor. In the experimental result of using a 10kW boost converter with SiC-MOSFET, the efficiency of the proposed circuit was 1% higher than that without it.
