Power the expansion board with alternative 5V
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Hello,
I would like to power with 5Vcc, my expansion board as if it was powered by microUSB but without using it: may I use the welding points named - "GND" and "VUSB" under the expansion board? Or any other welding points?
Thank you for your answers.
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@robert-hh Sorry for my late answer I did not see yours.
I measured 5V between GND and VUSB so that I powered the expansion board with these 2 points. It works the lopy is running but it has a consequence on the pin effects. It is not a reliable solution.
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@almeos I do not have an expansion Board 3.x here, but if you have a multimeter, you could check whether the VUSB pad is directly connected to the USB plug's 5V. Then you can power though that pin. You could also check, whether VCC pad is connected to the Vin pin for the xPy development module. That could also be used for powering. In any case I would feed power through a diode to prevent back-currents, when other power sources are used. It does not matter if the resulting Voltage is below 5V then. The 3.3V regulator works at any input voltage and will go into pass-through mode below 3.5V.
Better knowledge should be available at Pycom. I guess they have the schematics of their boards. But feedback from Pycom itself was always pretty spare, and it almost disappeared these days.
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@robert-hh
Thank you for your interest, my system needs to keep USB plug free to use it in case of maintenance and I already use the battery connector to prevent power failure.
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@almeos Why don't you use the USB plug for supply? Besides that, you should also be able to supply through the battery connector, if the voltage is between 3.6 and 4.2 Volt.
