Part Number: UCC28C56L
Tool/software:
I have designed a flyback circuit to convert 100V to 12V using UCC28C56L.
As per the reference design from Webench designer the Input supply is stepping down to 18V (VDD Pin) to turn on the IC.
However the IC is not turning on when we are giving the supply. Even Vref is not coming.
I have calculated as per the Datasheet and even tried to change voltage divider by reducing the resistance so that 10mA current can flow. But still the voltage across the IC is not building upto 18V nor IC is turning on.
When I give external 18V supply to the IC, it is turning on completely fine and I am getting proper 5V at Vref. In this case when I tried to give input supply the IC failed.
Can you please help in effectively calculating the Voltage divider so that I can make the IC turn on and work properly?
