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UCC28050: Non Isolated flyback with PFC

Part Number: UCC28050


I am trying to use UCC28050 for flyback type PFC without isolation, so that I can avoid optocoupler. (Secondary ground, auxiliary ground is same as input DC bus ground)

I am giving voltage divider from Vout (Output voltage)  to VO_SNS. I am able to get output voltage as required at no load, but the input current during initial output voltage rise is very high and erratic. 

Can you please suggest how compensation network has to be done for this non isolated flyback PFC? Below is schematic for VO_SNS and COMP pin i have made.

1. Feedback from Output

2. Initial voltage to VO_SNS pin for first turn ON

3. Compensation pin network