Here I am applying 3-phase rectified dc to the non-isolated boost converter, the magnitude of applied voltage is 450V and desired o/p voltage is 475V. Switching frequency of PWM is 28k. I am using TC4420 driver IC to drive the IGBT (IKW40N123H3). But when I am starting PWM circuit IGBT's temperature is increasing at a very high rate and this causing igbt failure. I have captured gate to emitter waveform and collector to emitter waveform and I found that collector to emitter waveform is not right. Its voltage is not approaching to zero when GATE PULSE is high. What might be the reason for such a collector-emitter waveform?