Enable VIPER26K

[PScheerer]

Hi there,

My question is if there is a way to enable or disable the Viper26K with for example an optocoupler.

In the isolated flyback topology this is done cycle by cycle. But we want to enable/disable it in the high voltage buck configuration. Can we short-circuit the comp network for long periods of time? How is the internal startup circuit designed?

Thanks in advance!

[Peter BENSCH]

Welcome @PScheerer, to the community!

That's a very interesting question that, as far as I know, nobody has ever asked!

Most probably this works with an optocoupler between COMP pin and GND pin (with a galvanically non-isolated buck, not GND of the circuitry). The supply via VDD is then no longer guaranteed because the switching has been stopped, but according to the data sheet, section 4.4, paragraph 2, the Viper26K should then be supplied again via the internal power source and the switching should start again.

I would be pleased to see confirmation of this assumption.

Good luck!
/Peter