So, in a move of "hey lets do something crazy to get soemthing working here" I decided to detour on a spinoff project and makea lower voltage, 1 channel version of this supply using a Dell power supply and a linear regulator stage.

The dell supply can put out "6.7A" at 19.5V, I wanted to test if it could sustain much of any power so I broke out my linear load bank and had it slowly dial up to 5A (which is its limit, damn me for using a 1 ohm feedback resistor and a 0-5V refernce) It took the 5A fine, so I decided to do a time test for a modest 3A over a 20 mins period or so and see if the adapter heated up at all. about 5 minutes into the process I checked the adapter and its temp was ok, a bit warm but nothing significant. then I touched the load bank to make sure it was ok, and it was burning hot.

My load bank uses a large heatsink, about 48inch^2, with fins, the heatsink I had slated for the power supply was about 8 inch^2. This is a problem, if my large heatsink couldn't handle 60W continious, the heatsink for the power supply, operated in linear mode wouldn't have a chance.

So, yes, I need to use a switching converter.

I assembled a quick and dirty pushpull converter for it that should be able to take up to 150W, only designed to operate at about 40Khz, and even put some extra turns on it so that I can get 24V output. so quick it uses PNP bipolar transistors. Now, I need a pwm controller, has to be 2 phase cause its operating a pushpull. I decided to take a closer look at the TL494, which is starting to look a lot like the circuit I developed for the amin project here. Cheating it, to make it operate as a pwm genorator, I'm able to drive in voltage and get an output duty from 0% to 78%, and thats all she wrote. The TL494 cant go over 78%.

That is just like having dropout on a regulator. If I wanted to have an output of, for example 10V, I'd need about 13V going in, and thats not accounting for transistor or diode loss (which put it up to about 15.3V) My converter goes from 0-100%

ok, so far I'm on the right track. sometimes it just dosn't feel like it.