Full Bridge Inverter

Hi,

I am trying to implement a full-bridge inverter. I've got PMOS on top, NMOS on bottom.

I'm stumped - can't seem to get it working. Tried using just a resistor as the load and im still getting the problem. When i simulate, Va and Vb are always at the same voltage, oscillating as a square wave between 120V and 119.5V

All of the mosfet gate signals are 1kHz square waves at 10V. If you look closely the logic signals should sync so that Q1 = 1 (closed), Q2 = 1 (open), Q3 = 0 (open), Q4 = 0 (closed), and vice-versa.

Also,does anyone know how to implement bootstrap for this circuit if I want to use all nmos.

Any suggestions would be greatly appreciated.

Thanks!