This is a TL494 pwm I've built for the P-Channel mosfets. It will work with the N-channel mosfets also but you need to reverse pins 15 and 16 inputs.

Attachment 1214

This pwm does everything that the ZFF does and more. Although I only show here current limiting, duty cycle adjust, and PRF ( frequency ) adjust, there's also Dead time and a control that allows for two outputs with 48% max duty cycle at 180 degrees out of phase.