I am building a Boost PFC(Pout:50W, Vout: 60V) circuit using UCC28180 PFC CCM controller. The AC input range is 30-40V rms. I was using a 0.01ohm current sense resistor. Compensation circuit was desined and IC functionality was tested by giving 1V at Vsense and -0.1V at Isense.
When I set the Input voltage to 32Vrms (before turning on controller Vout= 34Vdc, Iin=0.7A) and turn on the controller, the output voltage dropped to 9Vdc and input current shoots up to 10A. I found mosfet got burnt and IC failed.
Later I changed the current sense resistor value to 0.03ohms and started test again, the controller was working fine now. How the current sense resitor value affects the IC operation even though the voltage to Icomp was below 5.7V with 0.01Ohms Current sense resistor as per the UCC28180 design calculator .
