I have only one PWM channel.
but I have found PWM and inverted PWM signal is required to run the full H bridge to convert DC to AC.
a square AC signal is more than enough for my application
is it possible to use a CMOS NOT logic ic to invert the PWM and give it to the full h bridge?
PWM frequency range will be 0-300Hz
also, I have found 3ns switching time NOT gates available in market 
power supply source will 150-220V DC 50mA