I am trying to get an output varying from 0-1000V at load capacitor . For that , a PWM signal is applied to the gate of the MOSFETs . As the PWM signal is generated from the 555 timer , so the pulse signal voltage varies from 0-15V. But couldn't able to observe any switching operation. what minimum voltage need to be applied for the switching operation ? How can I make output to switch between 0 to 1000V.