Can Nano Every be destroyed by drawing power from VIN when powered via USB?

Official Hardware Nano Family Nano Every
1

Hello everybody,

In my basic setup I am powering my Arduino Nano Every from a 12V source via the VIN and GND pin. In a parallel circuit the 12V supply is also used to supply a display which consumes about 1A. At the same time the Arduino is connected to a PC via USB. This setup is working completely fine.

My concern is the following: I have observed that when disconnecting the 12V source but leaving the USB cable connected to the PC the Arduino still provides 4.16V at the supply pin. Can the display (or any other device connected to the VIN pin) destroy the Arduino by drawing too much current?

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2

Add a diode

3

Yes, this would be a solution. But is it really necessary or does the Nano already have anything inside to prevent this scenario?

4

https://docs.arduino.cc/static/1d097e7f46445e1d9a88348af88dcb4f/schematics.pdf who knows

5

I studied the documentation of the switching power supply. You will get current through the reverse diode of the driver mosfet. High current wiil burn it out. Use the diode!

6

Thank you!
Tis looks like a design fault to me. It should not be possible to destroy the Arduino by disconnecting the power source, just because there are other power sinks and the Arduino is connected to a PC.

7

The switching power supply was designed for 1.2 Amps. Fatal current will be higher. Secondly, a USB port should not be able to source more than 0.5 Amps. That's why your board still lives. The diode is better safe than sorry.