HELP voltage regulator IC

HELP ! what kind of IC can i use to regulate the voltage of 300Volts? Is there any other way to regulate these high voltage?

what kind of current? what's your regulation accuracy (300V +/-???%)

Less than 300volts

There won't be a single IC that will work to that voltage, but there are many ways of doing it with an IC controller and some discreet parts.

But you need to give us more information.
- How much current?
- Where does the input power come from?
- Fixed at 300V, or variable?
- Do you need short circuit protection?
- What other requirements are there?