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

[Turbo J]

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!).

Nope:

As you can see, it can take may hours for a LiPo to reach its 3,7 volts. This is an NRF52 setup consuming about 20mA altogether, powered with an 1000mAh LiPo cell. It was already running for some hours before the recording started.

[Ray Breslin]

Oh thank you very much for that clarification... learned something new there. Then it is obviously even more essential to work on a proper voltage-regulation-concept!