i am building an AC-DC smps from 230V AC to 5V, 2.5A DC using TOP258 based on design by PI Expert online. I am able to get 5V DC output without any load. But as soon as load is applied, voltage drops to zero. Then again ic tries to start voltage goes up a little and transformer makes some noise and voltage drops to zero all within 1-2 sec. Can anyone detect any problem?
Note: I am using PC817 as octocoupler due to unavailability of given one. Also not using choke and using SR360 as output diode instead of MBR340