Arduino Nano Every power considerations

Regarding a genuine Arduino Nano Every, I would like to nail a few things down before causing damage to the board or my computer. I have done some searching and found information that hints at the answers I am looking for, however I would just like to get some solid confirmation.

  1. Can the Nano Every be powered externally through the +5V out pin, bypassing the onboard regulator?

  2. If I do this while connected to USB on my computer, will it backfeed voltage to my computer?

Thank you kindly…

Moved your topic to a mores suitable section.

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Bob.

Hello KevinJones,

Thank you for sharing your questions with Arduino community.

Please find answers to your questions below:

  1. Can the Nano Every be powered externally through the +5V out pin, bypassing the onboard regulator?

It is possible though not recommended under any circumstances. As you said, the current would bypass the voltage regulator and this can damage other parts of the circuit. The board is not designed to be fed through this pin. Use only the designated input pin for this: VIN (voltage input range: 6V to 21V).

  1. If I do this while connected to USB on my computer, will it backfeed voltage to my computer?

There is indeed a possibility that the USB can backfeed voltage straight back to the USB port of your PC thus damaging it.

I hope this was useful.

Regards!

nachoherrera:
It is possible though not recommended under any circumstances. As you said, the current would bypass the voltage regulator and this can damage other parts of the circuit. The board is not designed to be fed through this pin. Use only the designated input pin for this: VIN (voltage input range: 6V to 21V).

Is this germane to the Nano Every?

I am asking this because in this post (My maiden post on this forum) I was actually encouraged to feed power this way, although the responders were mostly referring to Uno and Mega boards. Using the onboard regulator was actually discouraged as it is not capable of delivering much power, and if it is fed by much more than +6v (such as +12v if such a supply were already being used for the project) then the power capacity drops significantly as it is a linear regulator, not allowing much available for even the outputs for the chip. (To be clear I was cautioned against connecting to USB while the board is powered this way, though someone suggested that other boards may have USB back-feed protection - eg, diode.)

So if I have a lot of peripherals that require regulated 5v, the onboard regulator will not be large enough to power them, thus I will need separate supplies, one 5v regulated for the peripherals, and another 6 or so volts to supply the Nano. Also, 6 or 7 volts is a power supply output configuration which is not very common, and as stated, going to the next common output configuation (12v or maybe 9v) lowers the capacity of the onboard regulator.

I'm not meaning to whine here, just stating the challenges I would be faced with if I am unable to power the Nano directly, and the discrepancy against what I've been told regarding the Uno and Mega.

Is it possible the Nano has a more robust voltage regulator, ie, PWM rather than linear?

I should be clear to say I was referring to powering the board with a regulated +5v supply, if that makes a difference.

Looking at the schematic, there is a diode between the USB power input and the 5v line on the board, so it should not backfeed.

david_2018:
Looking at the schematic, there is a diode between the USB power input and the 5v line on the board, so it should not backfeed.

Ah yes, I didn't think of hunting for a schematic, but yes you are correct. Thanks!

Hello.
I’d powered, today, Nano Every by external power system, directly on +5v pin’s Every. In fact, i put a voltage to 4,95v .
No problem. All work fine whithout any problem. No feedback (diode) on USB port.

jc_buntu:
Hello.
I'd powered, today, Nano Every by external power system, directly on +5v pin's Every. In fact, i put a voltage to 4,95v .
No problem. All work fine whithout any problem. No feedback (diode) on USB port.

I powered up my Nano Every through the 5V pin, and there was no problem, which seems reasonable to me. The only thing I could imagine I might damage would be the voltage regulator by back-feeding it, but I don't plan to use it anyway.

I was able to read 5V back through the USB port however. The schematic for the vanilla Nano shows a blocking diode, but perhaps the Every does not have one. I did not find a schematic for the Every per se.

Anyway, I am just going to hack a USB cable and disconnect the 5V wire.

KevinJones:
I powered up my Nano Every through the 5V pin, and there was no problem, which seems reasonable to me. The only thing I could imagine I might damage would be the voltage regulator by back-feeding it, but I don't plan to use it anyway.

I was able to read 5V back through the USB port however. The schematic for the vanilla Nano shows a blocking diode, but perhaps the Every does not have one. I did not find a schematic for the Every per se.

Anyway, I am just going to hack a USB cable and disconnect the 5V wire.

Update: I hacked the USB cable, and everything works fine. I also tested out the regulator, and it appears to still be working. I'll be logging plenty of test time while experimenting to prove it, but I am convinced at this point that this set-up will be just fine.

KevinJones:
Update: I hacked the USB cable, and everything works fine. I also tested out the regulator, and it appears to still be working. I'll be logging plenty of test time while experimenting to prove it, but I am convinced at this point that this set-up will be just fine.

I will note that using the hacked USB cable (5V power line disconnected) might be risky if it were connected while the board is not powered up. I suppose a safer approach might be to insert a schottky diode in the cable so it will be assured the board is powered up while sending serial pulses.