Q1 & Q2 get PWM from the control block, while D1 & D2 together with Zener D3 eliminate overvoltage spikes on the MOSFETs. D1 & D2 should therefore be fast, low capacitance parts. Also, ... as I know ...

Capacitors play three important roles in an electronic circuit: charging and discharging; maintaining the voltage at the same level; and removing noise. Diode: The diode is a two-terminal electronic ...