Use a standard LM7809 regulator circuit with the 12 V input switched on by a MOSFET gated with 3.3 V.Hi,
I have to design a power supply 12VDC to 9VDC.But this has to get turned on with 3.3VDC coming from different board.
Please suggest how can I turn on a power supply with 3.3VDC( what all components would be needed).
Thanks,
G