Managing nRF52832 with a 3,7V Li-Po-battery

[Ray Breslin]

Hello,

I am currently evaluating concepts on how I can power my nRF52832-custom-board with a LiPo-battery, in order to get a good tradeoff between lifetime and form-factor.

First of all, I came across this topic here, that states to never use a 3,7V-Li-Po-battery directly as power-supply due to its maximum voltage of 4,2V when fully charged. As far as I know pretty much every Li-Po-battery has a 4,2V-level at its charged-state, but only as long as there is no power-consuming-circuit attached. If you connect a component that draws current, then the voltage-level will immediatly drop from 4,2V to 3,7V while being in operation-state (open to corrections here!).

Now even those 3,7V exceed the recommended operation-conditions for the nRF52832, so I assume there needs to be some kind of regulation circuit integrated. Is it better to use f.ex. a 3,3V-voltage-regulator like the NCP161 or can you use just a simple shottky-diode/hot-carrier-diode with a 0,2V-forward-voltage? What about the suggested Torex XC9265 PFM-module (see link above) - does anyone have any experience with that?

Kind regards,

Ray

[Ray Breslin]

One thing that I thought about is the usage of a 3V-step-up-/step-down-regulator in order to handle the voltage-regulation for the 3,7V-LiPo-battery in order to power the nRF52832 and optional sensor components.

Question here is now wether it is possible to measure the actual voltage-level of the LiPo-battery by using a GPIO of the nRF52832 - considering that the voltage connected to that GPIO is reduced with a proper diode.

Is that realistic?

[Edit #1:] Seems like Turbo J already suggested the usage of a voltage-divider here - now the only question that remains is on how to readout the voltage-level from that GPIO?

[Edit #2:] Now after a quick check of all the other provided links for a designing a voltage-divider-circuit, the nRF51-manual (which should be pretty close to the nRF52-manual) and also some code-example for ADC-measurements there are no more questions left so far! (Ill check back when I ran some tests with the hardware!)

[Edit #3:] In order to have the ADC-example working, do I need explicitly need that nRF51 DK or nRF52 DK? Because I need to run it on my custom-board and I am not sure on how to handle the ADC-pins...