Hi, this query is more of something for the Arduino forum, but folks there are quite inactive about ArduinoPro devices, hence am asking here:
I have plans to power my Portenta-based IOT system through VIN (GPIO) pin of the microcontroller. I just realised that the official documents indicate that the VIN (HDC) should be used if 5V output is required for other devices like a PIR sensor. Why is that so?
Nonetheless, is there a way I could simply use the VIN pin of GPIO instead for ease of PCB designing? Is there a workaround?
Regards,
PC
Hi, if you check the schematic you can see that VIN(GPIO) and VIN(HDC) are the same net. So, you can supply power from either: Altium.WebViewer.Files.WebViewerJob_PDF_SCHPrint
There’s a diode connecting USB 5V to VIN. So, if you inject 5V onto VIN this just means USB won’t supply power. Note that the 5V pin on the board is supplied from USB.
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I was able to verify on my board that there’s a voltage drop between 5V and VIN on the Portenta. So, I believe the above to be true. I say this because there’s a bidirectional USB switch for USB OTG on the board. If this were turned off there would be no voltage drop. So, you don’t need to worry about it.
However, note that the Portena uses a diode to connect USB to VIN. So, I’d avoid drawing too much power from USB through that didoe as it’s going to burn 0.3V*(A^2) power and turn that into board heat.
Hi @kwagyeman, thanks for the response and a quick experiment to confirm!
Thanks a ton for this, I did not know. I’ve come across general warnings on accidentally powering Arduinos through 2 sources (like USB and VIN as we’re discussing) and worrying about corrupting the board.
Does this confirm that if I power my board through VIN(GPIO), I won’t be able to get a constant 5V output from the 5V GPIO pin?
Regards,
PC
Yes. Unless that bidirectional switch is enabled the diode would block that.
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