Buck Converting Voltage, to Switch Original Voltage

Question

I'm learning electronics, so I want to sanity check this approach in case I'm missing something.

I have an arduino (at 5V) controlling power to a set of lights at 12V, via a mosfet. This is all fine, using a separate 5V and 12V power supply.

Is there anything to stop me using 12V for both in parallel, taking one of the parallel branches, passing it through a Buck converter to 5V, and supplying the Aruino, then using the other branch, raw 12V to power my lights, with the arduino switching the 12V via the mosfet.

I've plenty of available power in the 12V supply, but is that in-parallel structure what I need.

I feel like it is an obvious question, but I was unable to google it. Examples seem to use different power supplies for the control + switched circuit. Is my suggestion the way complex circuits use a single power supply for different voltages?

Answer 1

Yup that's fine. Just make sure the output of the buck converter to 5V is regulated well enough to not have too much ripple to cause the Arduino problems.

It's not recommended to control the buck by the Arduino because if you don't do it right, you could fry the Arduino or cause it to power itself off. It is possible to do that though.

Easiest setup is to just get a separate buck regulator IC and have it create your 5V from the 12V line.

Answer 2

Yes, you can certainly do that.

Or, if you are open to it, buy one of the Arduino models that accept 12V power inputs. i.e. Arduino Uno. There is a nice table of Arduino specs here that show 10 models which accept 12 V DC input.

As long as the 12 VDC input is a clean, regulated supply (or at least has transient suppression) to guarantee that the voltage doesn't exceed the maximum safe voltage for Arduino, then you should be fine. If you are running off of a battery or a lab power supply, then you should be fine.

Good luck!