I am trying to test an SMPS controller IC (like KA3882) by isolating the controller from the PWM FET circuit and de-coupling the SMPS output (to optocoupler and the feedback pin of the controller). By applying the required feedback voltage to the Vfb pin (2.5v in my case), I expect to get the square wave pulses on the output pin. Is this procedure good enough? I also felt that I-sense pin must be for protection against shorting of SMPS output power supply. Hence , I skip applying a current to this pin, but I am not sure and need advice.
What is the purpose of I-Sense current in a PWM controller IC?