I have completed the PWM compressor design and created a layout to fit a 1590B enclosure. The design has been simplified some and has excellent performance both in feed forward or feedback mode. I removed the full wave rectifier circuit. A simple compensated peak detector works fine. I also implemented a analog switch instead of the PFET. It provides a little more duty cycle range and significantly more input headroom.
The original blog post for reference:
The schematic is highly annotated – the original PFET switch can be used in place of the analog switch if desired.
Schematic Here: updated(9/12/2013)
Link to Design Files: (Done in epresspcb single sided thru-hole)
To scale PDF image of layout for toner transfer: (you will still need to look at the expresspcb layout to see part designators)