Variable voltage Dc supply

2 posts / 0 new

I am making a variable voltage DC supply(3.3V to 30 V) from 230V AC mains. I am thinking about using the same fly-back topology and TOP264 IC as done for fixed voltage supply, and making some change in the feedback circuit to make the output variable. The current range is from 0 to 1.5A. Please help me figure out how to proceed and how to design the feedback circuit for this or if i should change the idea entirely. The information about the voltage to be set will come from a micro-controller. Changing this input should change the output voltage of the circuit.

You can use the microcontroller to vary the feedback resistors, however, I think that it is more important to evalue the transformer design when you vary the output voltage. The transformer design that works at 3.3V may be illegal for the 30V design.