Hello Sir, In our application of Auxiliary Supply for motors we are using your made LNK520 Power Integrated device with Input voltage 85-265V & Output voltage 15V @ 100mA(max) with optocoupler Feedback for voltage regulation. While testing we found that it's load regulation is very poor. There is a dip in the output voltage level as we increase the load to its max. value(100mA). It takes 2-3 sec to build the Output voltage level, if load is increased from 10mA to our required max. value. Also at no load condition or load of 10mA it works properly. Please let us know the flaw in the design . Transformer Design is as per following : Core Size : E16 Primary Turns(Np) : 100 Secoundry Turns(Ns) : 22 Control Turns(Nc) : 27 Primary Inductance(Lp) : 2.5mH Your Early response will be highly appreciated.