I'm basically going to use the example layout provided by the chip's datasheet for buck converters with some modifications.

The area highlighted in red will be controlled through an opto-isolater from the MC34063. I will be using a combination of a NPN transistor to turn on the P-Fet as fast as possible with a low resistance pull up resistor for quick turnoff.

The main reason why i want this kind of isolation is so i can tie the channels together in series or have a +V to GND to -V rails.

Later this week, I will be testing if directly applying a voltage to the feed back pin will allow me to manipulate the output. Those results (among others) will determine if i continue with these project.

Any feedback will be greatly appreciated.

PS. Can someone suggest an opto-isolater that can work above 200 KHz ? I'm not sure on what to look for in a opto-isolater.