A Fast Overcurrent Protection IC for SiC MOSFET Based on Current Detection

This paper proposes a fast overcurrent protection integrated circuit (IC) for SiC MOSFET based on current detection. With the proposed protection IC, the voltage between the Kelvin source and power source of SiC MOSFET is sensed through an off-chip resistance. Thus, a detection voltage proportional to the drain current of SiC MOSFET is obtained. Comparing the detection voltage to on-chip reference voltages, the proposed protection IC can provide both overload (OL) and short circuit (SC) protections for SiC MOSFET. Moreover, a soft turn-off circuit is integrated into the protection IC. The proposed protection IC is implemented in a 0.5-μm BCD process and the die size is about 2 mm2. With the 1200 V/80 mΩ SiC MOSFET, the proposed protection IC is verified on our test bench. With the proposed protection IC, the response time of the SC protection is 24 ns and the SC duration time of the SiC MOSFET is 43 ns. Owing to the soft turn-off circuit of the protection IC, the drain voltage overshoot of the SiC MOSFET is lower than 90 V during the OL and SC protections.