Can I use a TDA2030 (power op-amp) to build a switched mode PSU?

Question

TDA2030 connections:

Pin 1 (non inv input) - potential divider (to give reference voltage)

Pin 2 (inv input) - connected to final output

Pin 4 (output) - connected to pin 1 via large resistor (to give some hysteresis), cathode of Schottkey diode (anode to 0V) and one end of toroid

Other end of toroid to capacitor, output and pin 2

So this is basically like the standard op-amp relaxation oscillator, but with a coil in series with the capacitor (where a resistor normally would be) and a diode to discharge the back EMF from the coil into the capacitor. Obviously I'd need the feedback resistor to the + input to be larger than the resistors setting the reference voltage, since this puts ripple on the output.

Will this work, or will it just go into some steady state where it dissipates the excess power as heat in the IC?

Answer 1

I drew out the circuit you described and:

1) it does not look like a standard op-amp relaxation oscillator - the voltage divider thing seems wrong-headed

2) I cannot reconcile what's really going on at the "other end of toroid" - it appears like your description is a bit muddy.  You also did not say where the other end of the capacitor goes.

Sorry, I cannot provide you more assistance at this time with the information provided.

(EDIT)

I understand your circuit now.  I predict that, at a minimum, you will have some stability problems with this realization - introducing that tank circuit at the high-gain amplifier input will probably put some poles where you don't want them to be.

You might want to try a different approach.  If I better understood exactly where you were trying to end up, I might be better able to provide some suggestions.