Hi all. I'm using a Buck voltage converter to power the Arduino Nano ESP32 via the VIN pin. Whenever I need to make some code changes, I then plug my computer in to the USB port, which also supplies power (no power is going to the Buck converter input when USB is connected). However, some voltage is finding it's way from the USB connector to the VIN (4.4v), which is causing the Buck Converter to get power to it's output, which I can see on it's voltage display. I would imagine that this may cause some damage to the Buck converter or Nano board. I've done some research, and found one post that mentioned I may be able to use a diode (1N4004 or 1N5817) between the Buck converter and VIN to prevent reverse voltage to the Buck converter output when the Nano is powered by the USB port. That post I found was 8 years ago, so wanted to ask if I can still do that with the Nano ESP32 board, and which diode should I use?
Thanks for the response, but I'm not sure I understand how it answers the question. I'm not an electronics expert; just trying to figure out if there is a way to solve the problem mentioned.
Vin is fed to a built-in buck converter capable to receive 6-21V (MP2322GQH). You do not need an external buck converter if your power supply is within these limits.
If you feel more comfortable using one, place an 1N4004 or similar to protect it. THis diode can handle up to 1A continuously, just consider its voltage drop of about 1V.
What happens next depends on your buck converter. Many (most?) buck converters do have a back feed path, allowing to supply power to circuitry that is meant to use the same source that supplies your buck converter, possibly damaging it. A diode between your buck converter and the Vin pin prevents that.
Some power supplies have a circuit that discharges the output capacitor under certain circumstances. If you are sure your converter doesn’t do that, it is energetically advantageous to place the diode at the input of the converter.
Thank you, somehow I missed that! Just to be sure, can I supply 12v from a marine battery (actually 12.8v) without a regulator directly to the Nano's VIN?
