CMTI Improvement Circuit for SiC MOSFET Isolated Gate Driver

An improved isolated gate drive common mode transient immunity (CMTI) circuit is proposed. A capacitor with an isolation medium of SiO
2
is used as the isolator, and the modulation and demodulation is on/off keying modulation (OOK). CMTI is an important parameter of the isolator. When a transient voltage change occurs at the reference ground on both sides of the isolation capacitor, a high transient voltage change rate dV/dt can cause the circuit to transmit incorrect information within the corresponding time range. In this paper, a common-mode voltage filter circuit and a high pass filter circuit are designed to enhance the CMTI performance so that it can reach 200kV/us.