I had formed a full bridge using IR2110 driver IC and IRF840 Mosfet to Drive a motor of 24vdc at 1khz PWM frequency for a duty cycle from 10-90% it operates fine even at 72vdc, but I face a problem, every time High Side mosfet burnt out and remaining all 3 Mosfets also damaged when I gaves a 320vdc.I connect 2x220v incandescent lamp as a load accross a full bridge output. PWM is generated by PIC 16F886. Please help me out to solve the problem.