External circuitry needed to power nRF52840 by Li-Po battery

RE: External circuitry needed to power nRF52840 by Li-Po battery

khelmutlord — Wed, 16 Aug 2023 13:28:30 GMT

From the perspective of the chip there is no issue with using the lipo or any other power supply. If you don’t want to use external circuitry for battery management, consider adding a voltage divider to an analog input to measure battery voltage. This can give you a crude idea of battery level.

For your hardware specific question:

LiPo pouch cells often have integrated protection circuits. Cells like 18650s often do not. For sanity, I include reverse polarity protection. The circuit differs it you intend to charge this battery on device, I would look at including the nPM1300 as this includes battery fuel gauging (estimation of battery life) as well as two buck regulators and two LDO regulators.
www.nordicsemi.com/.../development hardware

App note from AD on battery reverse polarity protection when charging:

www.analog.com/.../an-171.html

RE: External circuitry needed to power nRF52840 by Li-Po battery

swood — Wed, 16 Aug 2023 13:19:40 GMT

Sorry, one more thing, are there any configurations I need to set in software to indicate that I'm using a Li-Po? Or as long as hardware is good, everything else should be the same?

RE: External circuitry needed to power nRF52840 by Li-Po battery

swood — Wed, 16 Aug 2023 13:15:47 GMT

I planned to use the design on page 36 and put the li-po output into VDDH, but wondered if there was anything else I needed to support the li-po specifically! It seems that there isn't (right?), though I was having trouble following the rendered DK PDF hardware design. Thank you so much! You always give wonderful responses.

RE: External circuitry needed to power nRF52840 by Li-Po battery

khelmutlord — Tue, 15 Aug 2023 21:09:37 GMT

The VDDH regulator can be used to supply VDD when supply voltage is expected to be greater than the maximum of 3.6V.

The module you intend to use has documented examples for how to supply with voltages >3.6V. I would refer to the manufacturer's datasheet (page 36) for the module:

https://www.raytac.com/download/index.php?index_id=43

KiCAD has an MDBT50Q schematic symbol and footprint available in the library it is provided with. Additionally, the devkit files are open source and are rendered as a pdf for your reference (i.e. if you do not have access to Altium).

www.nordicsemi.com/.../Download

EDIT: FYI LiPo batteries are typically 3.7V which is the reason VDDH is used here