RAK19007 + RAK4631 - USB and J12 VDD can be connected at the same time?

Power related question:

I am providing the core with externally regulated 3V3 on the VDD pin of the board (J12 - pin 1).

According to the schematics of the board (RAK19007 - fig.15), it seems that there is no mechanism to turn off VBUS while 3V3 are fed to the core. Am I right?

Alternatively, if I supply regulated ~4V to the battery pins and desolder the TP4054, can USB programming and external power source cohexist?

Before releasing magic smoke, I’d like to have your confirmation.


The RAK4631 is designed to be supplied by two voltages, VBat and 3.3V from the voltage regulator.

Powering the RAK4631 only from 3V3 can work, but will cause a higher power consumption.

About your second proposal, it would be better to use the “Green Power” connector P2 to supply a regulated voltage with up to 5.5V to supply the WisBlock independent of the USB connector. There is no need to desolder the TP4054 in this case.

I am using that solution in many of my test devices that I built and that are not powered by a USB cable, but by an simple 5V output wall-plug.

sounds good!

Thanks for your help

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