I am trying to find out if anyone makes a device that can take 12V+/12- INPUT.... use a 12V trigger wire..... output 9+/9-V and also stay on for 10-15 seconds after I remove power. This all has to do with a car audio project I am working on. Keep in mind my input voltage coming from the car will vary 11-14V... the output must stay at 9V. I had thought about using a relay with delay off timer and feeding that into a DC to DC Step down device.... .throw that all in a black plastic project box and call it done. Not sure if there is a device like this that I can purchase and will work or not.. Thank you for any help.