I'm only a hobbyist, so there is probably an obvious/better solution that i am simply unaware of.

Project description: I'm trying to build a quiet linear power supply to power a mini DSP that can be turned on by the remote trigger output of my stereo receiver. My goal is to keep it all solid state, and as low noise as possible.

This is what I have so far... I've purchased a SolaHD SLS-12-017T linear power supply module. I had intended on switching the 12V out with a Fairchild FCP650N80Z N-channel MOSFET. I had intended on isolating the 12V source circuit from the trigger signal from the amp with an optocoupler.

So here is where I get stuck: I had assumed the trigger from the amp would go to 0V when turned off. But it doesn't, it reads 3.3 V in the off position and 14.4 V in the on position.

Any suggestions on how to make this work would be greatly appreciated.


A simple level shifter should work.

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