Hi there,
Im using UCC28711 based flyback converter for one of our application.The requirement is as follows
1. The Input voltage range is 30VDC to 90VDC (the turn on voltage is 30V)
2.It has 3 outputs 15.4V, 6V_1 and 6V_1, (with 6V"s having different ground reference)
2a. 650mA , 125mA, 125mA Current respectively
3.We are using auxiliary winding output for 15.4V output .
4.The output rating is 14W. (giving 2W extra)
We are not able to get proper document/reference for designing multiple output converter with UCC28711.
we used tiduag6a.pdf
We are facing some problem with our design .
1.when 15V is loaded to its max value, 6V_1 and 6V_2 seems to go out of regulation. 6V_1=around 9V and 6V_2=around 9V.
2. Adding preload resistors @6V1 and 6V2 improves regulation a bit. But it cause too much of no load power consumption.
3.There seems to be a little buzzing noise from transformer.
4. Suppose if we design the flyback (overkill) lilttle higher than the actual working parameter, what are the ill effects.
5. Plese go through my calculator and correct me if my doing any wrong .Calculator.xlsx
Im attaching our design calculation and schematic
Thank you :)
