DK Li-Po battery

RE: DK Li-Po battery

Roger — Tue, 30 May 2017 13:30:36 GMT

That is very helpful! Many thanks.

RE: DK Li-Po battery

AmbystomaLabs — Tue, 30 May 2017 13:19:48 GMT

The RF core is only 1.3V. 1.8V is well above its spec. Plus the brown out reset keeps the nRF from operating if VDD is too low.

RE: DK Li-Po battery

Roger — Tue, 30 May 2017 07:38:58 GMT

Yes, measured 1.8V over VDD when SW9 is in the Li-Po position and 3V in the VDD position when connected to the coin cell battery. I'm just wondering if the low voltage 1.8V supply will affect the radio transmitting range? The Vdd nominal voltage of the SoC is specified at 3V. At the moment I have the TX output set at 0 dBm and eventually would like to take it up to +4 dBm. I'm running the OpenThread examples.

RE: DK Li-Po battery

AmbystomaLabs — Mon, 29 May 2017 20:35:14 GMT

According to the spec the default is 1.8V. You can confirm this with a DMM by measuring vdd.

RE: DK Li-Po battery

AmbystomaLabs — Mon, 29 May 2017 20:24:31 GMT

You are correct. The REOUT0 registers allows you to set the value of VDD. Without know what code you are running, I can't help you out with setting REGOUT0. Also, according to the spec if you leave sw9 in it's normal position then the LiPo is routed through the 5V buck/boost and a fixed 3V buck converter will drive VDD. Then you don't have to worry about setting REGOUT.

RE: DK Li-Po battery

Roger — Mon, 29 May 2017 19:20:34 GMT

I connected an external battery to Li-Po connector and switched SW9 to Li-Po position with SW6 to default. The battery potential is 4.2V when fully charged. I noticed the leds on the DK appears much more dimmer (barely visible) compared to when supplied by the coin cell battery (3V) or the USB supply (5V). Just a bit strange, is this normal?

I read that in the Li-Po position, the high voltage regulator of the SoC is directly supplied by the Li-Po battery and that the VDD voltage can be set by firmware? Please see this link on page 20.

RE: DK Li-Po battery

Roger — Tue, 09 May 2017 13:47:50 GMT

Actually, I want to use a NiMH AA batteries because I can easily a charger for it here. Was just curious about the Li-Po marking on the nRF52840 DK. Thanks for getting back to me.

RE: DK Li-Po battery

AmbystomaLabs — Tue, 09 May 2017 13:34:47 GMT

Likely it is because they get a lot of questions about running nRF from LiPo. The converter on the board is a basic buck converter. You can run it with anything up to 6 volts. I don't know what your plan is with running from LiPo, but I didn't see any provision for recharging the LiPo, so you might find it more convenient using a different type of battery.

RE: DK Li-Po battery

Roger — Tue, 09 May 2017 13:15:12 GMT

Is there a particular reason why Nordic recommends a Li-Po battery for connection to the nRF52840 DK?

RE: DK Li-Po battery

Roger — Mon, 08 May 2017 20:09:20 GMT

Got it. Many thanks.

RE: DK Li-Po battery

AmbystomaLabs — Mon, 08 May 2017 12:07:46 GMT

All component descriptions and part numbers are always listed in the bill of material for a DK. They can be downloaded from the Nordic website. The BOM for the DK is in the Production Files/Assembly folder.

See link: www.nordicsemi.com/.../116086