Tool/software:
Hello TI Team,
I am using UCC256404 llc resonant controller for my AC to DC converter with out PFC.My input voltage range is 103VAC to 127VAC,50W converter .I am facing startup issues with full load,I kept the OCP protection resistor 50ohm to check whether the issue due to startup current at 50 ohms i could fix the startup issue but it is not as per the design calculator value which is around 350 ohms.if i keep the current sense resistor as 50 ohms the internal OCP will be bypassed,I could not use the internal OCP.I tried to keep the current sense resistor around 100 ohm by adjusting the the VCR capacitor combination i could slightly increase the current sense resistor but still could not use the internal OCP feature as per my expected calculation.I tried with different Lm,Lr,Cr combinations as well but couldnt fix the startup issues at full load. Please find the startup resonant current for your reference it is around 18A peak when the OCP is bypassed by keeping it 50ohm
