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.