Load Regulation Problem
I have design 5V/2.5A supply using top256YN. Input voltage for this design is 35-290Vdc and Power supply is working with the bias voltae of the transformer is 15V. The problem I had was the bias voltage increase while the load current increases. If load current became 2.5A, bias voltage increses to 35V and output voltage gets lower down to 4.72V. I was able to limit the bias voltage to 18V by replacing diode with 1n4004 which is standard recovery time diode but output voltage is still goes down to 4.72V.
What can I try to regulate the load voltage and what could effect the feedback signal?