An asymmetric waveform pulse generator comprises a metallic oxide semiconductor field effect transistor (MOSFET) bridge circuit, which includes a plurality of MOSFETs for inverting high voltage DC voltage to asymmetric waveform pulses. The asymmetric waveform pulse generator further comprises a pulse-width modulating (PWM) circuit for generating PWM signals, and a plurality of isolation driving circuits corresponding to the plurality of MOSFETs, for controlling switching on/off of the plurality of MOSFETs in the MOSFET bridge circuit based on the PWM signals generated by the PWM circuit. Each of the isolation driving circuits comprises an isolation transformer for isolating the MOSFET bridge circuit from the PWM circuit. A FAIMS ion detector employing the asymmetric waveform pulse generator is also disclosed.