On-Chip Active Turn-Off Driving Technique to Prevent Channel Current From Disappearing Prematurely in SiC MOSFET’s Applications

Silicon carbide (SiC) MOSFET has significant advantages in high-voltage (HV) and high-frequency (HF) applications due to its electrical characteristics. In order to make use of its merits, the active driver is necessary for SiC MOSFET. During the turn-off operation of SiC MOSFET, it is critical to prevent the channel current from disappearing prematurely, which has not been addressed in existing active drivers. This brief proposes an on-chip active turn-off driver to realize the fast turn-off speed and low EMI noises. The mechanism is that the turn-off driving current needs to be adjusted rapidly according to the operating state of SiC MOSFET, which can also ensure that EMI noises and overshoots are under control. Then, the proposed turn-off driver is fabricated in a $0.18~\mu \text{m}$ BCD process and occupies a 0.99mm2 active area. Finally, using the proposed active turn-off driver, the turn-off operation of SiC MOSFET has experimented with the 15A and 90A load current, respectively. SiC MOSFET realizes a high turn-off performance, about 200ns turn-off time with low EMI noises, demonstrating that the proposed on-chip active turn-off driving technique is suitable for SiC MOSFET under different loads.