If I may add to the wish list.
Will the final design allow them to be connected in Series / paralleled / cascade configurations to provide more current, more voltage or a tracking +/- Supply?
It is often stated that it is cheaper to buy a good bench supply than to make one, but the joy of building it and understanding exactly how it works, thanks to your tutorials, is priceless. I would love to build this just for the practical experience and my power requirements, for the foreseeable future, are low. 12V at 500mA is more than I envisage needing, but if the PSU's are isolated then 2 could possibly give +/-12V at 500mA or 12V at ~1Amps or 24V at 500mA.
This will be a step up from my Velleman LAB1 PSU and a great addition to any hobby lab.
Any chance of releasing it in Kit form?
Good on you Mate.
I look forward to Part 5.
Cheers
Chris
If you write your own MCU firmware, tracking will be easy:
Build 2 identical floating PSUs and add an optoisolator to the microcontroller (use standard serial ASCII characters over the UART or custom protocol if you want) and send the current voltage from the master supply, and the slave should receive the data and track the master accordingly.
If you leave an optoisolated serial interface for computer control (useful for automated tests or extremely low frequency function generator) you can just connect the 2 supplies directly to one another and the master supply will issue commands as if it were the computer.
Or if you leave them connected to the computer, the computer can read the voltage from the master supply and send it to the slave, or you can have both a dedicated computer interface and tracking interface.
The key is the optical isolation on the communication so that you can connect the ground of one supply to the positive of another.
Now the difficult is to choose between all of this communication methods.
(I'm not a native english speaker, so, if it sounds confuse, feel free to ask for clarification)