Hi,
I have designed a PFC circuit using the UCC28056A. When I power on the circuit, the output voltage oscillates. When looking at the current on the shunt resistor, I can see that everytime the converter starts switching, the current reference reaches its maximum value and triggers the OCP. Because of this the output voltage overshoots. I have not managed to fix this issue regardless of what kind of compensation components I use.
Why is the current reference so high and why is it not lower as to regulate the output voltage smoothly?
On the capture you can see the AC coupled output voltage and the shunt current. The current reaches 3.75A which equals 750mV on the 200mR shunt, which triggers the OCP threshold.
Input voltage is 230Vac, output setpoint is 600Vdc. Maximum output power is 50W.
I am attaching the Altium project for reference.
