Help with Time delay and dc to dc step down...

Thread Starter


Joined Jan 15, 2018
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.


Joined Aug 1, 2013
For output power to stay on for 10-15 seconds after input power is removed will take a battery or large capacitor for energy storage.

1. Is the input a bipolar power source, with +12 V, -12 V, and a common ground, or are you trying to describe vehicle power, +12 V and GND (ground)?

2. When you say 9+/9- V, do you mean two power supplies, +9 V and - 9 V, with a common ground? Or do you mean a single 9 V output?

3. What is the output current? This is necessary to determine how much energy storage you need.