In the original nano every design, the +5V is either come from a VIN generate by MPM3610 or directly come from the USB bus (VUSB). They were connected together via a schottky diode, so if there is no VIN connected, and the USB is connected, the board can be powered by the USB bus. If the VIN is connected and the regulated 5V is higher than the VUSB, it will be used for all the other 5V circuits.
Now, I have 2 more potential 5V source directly come in from two different external 5V supply. May I connect them together also using the schottky diode?
Should I get all 4 of them in equal place, mean each have a schottky? or should I choose one as default?
In this board, I am allowing user provide power through a barrel connector.
The system under test might be 24V, 12V, 5V source 1, 5V source 2 or all of them.
No matter which power is connected, I hope it can power the arduino as well. For the 24/12V I am using the regulator to generate 5V. Plus the 2 different 5V and VUSB, I have 4 different 5V sources.
I only plan to use USB when programming the arduino.
I hope the arduino code can run no matter which source is powered or even more than one is powered.
Do you think the circuit will work?
Any comment on how to make the circuit work?
Diode-ORing of power sources is as old as the hills. Yes, you can do it. In the case of more than one supply being provided simultaneously, the current will be drawn from whichever source is the highest. If two are equal, both will provide some current.
This becomes a bit of a tangle, as if one source is of lesser quality(for example, high ripple on some nominally 5V power supplies intended only for LEDs, and/or poor fold-back current limiting performance for some el-cheapo buck converters), debugging can be challenging because you may not realize the relative contributions of each supply, but that's only a possible.
If your use case has only one supply present as the dominant case, then I'd proceed. If your typical user won't discern a difference and will probably connect more than one, or your circuit in fact demands more than one be present, my preference would be to provide a jumper or other method of selecting the source for the Arduino. It can be as simple as a dual row header pin array, that's up to you. Cumbersome, but less likely to give you/them problems down the road.
There is something you need to be aware of when powering your Nano Every from multiple sources:
The MOSFET in the regulator has a body diode (all MOSFETs have ‘m). The current limit of this body diode is not mentioned in the datasheet, and may be lower than the current limit in forward direction.
