UCC28740: Is it possible extend the HV pin range upto 1KV by adding series resistors ?

Harshal

First off I'd like to recommend considering our SSR flyback controller UCC28742.  It's very similar to UCC28740, except it uses a resistor for startup.  Since no high voltage is directly applied to this IC it is straightforward to scale it to support 1kW input.

For UCC28740, you are correct that if you clamp the voltage on the HV pin you can use it with higher voltage inputs.  You can either use a resistor, followed by a zener clamp to limit the voltage seen on HV pin to below 700V, or if you have a stacked capacitor on the input you can connect the HV pin to the mid point, allowing the voltage the HV pin sees to be half of the input voltage.

Best Regards,

Eric

Got it

Thank you !!!