Low power SAADC 394uA

RE: Low power SAADC 394uA

fhfs — Thu, 22 Apr 2021 08:30:55 GMT

This must be the answer, I tested it on a Nordic development board and I'm getting better results

RE: Low power SAADC 394uA

Jørgen Holmefjord — Wed, 21 Apr 2021 12:35:57 GMT

I can't think of anything in the chip that will consume ~150 uA. How have you connected the PPK to your module/custom board? Is there something else on your board that could consume the additional current? Your plots does not look like they are caused by the functions in the provided example alone.

RE: Low power SAADC 394uA

fhfs — Wed, 21 Apr 2021 12:06:38 GMT

I used the "main.c" and "sdk_config.h" from your example. Just to clarify, I build using the makefile and not using SES.

Here are the power profiler results without BSP

And without advertising and BSP

Why is the average current in the selected part of the graph around 150uA?

I was hoping since the SAADC was not used except for every 5 seconds, the power consumption would go well below 50uA.

RE: Low power SAADC 394uA

Jørgen Holmefjord — Fri, 16 Apr 2021 09:52:50 GMT

I created my own project and tested this on a nRF52840 DK with RC oscillator enabled for 32.768 kHz clock. I'm seeing about 90 uA average current with advertising enabled:

Can you try out this project on your board? devzone.nordicsemi.com/.../ble_5F00_app_5F00_beacon_5F00_lp_5F00_saadc_5F00_nrf52840.zip

RE: Low power SAADC 394uA

fhfs — Fri, 16 Apr 2021 07:12:18 GMT

Hi Jørgen,

[quote userid="14926" url="~/f/nordic-q-a/74004/low-power-saadc-394ua/305084#305084"]The BMD-341 contains a nRF52840 chip, while the project you have linked are for nRF52832 only (PCA10040 - nRF52 DK). Have you ported the project to pca10056/nRF52840?[/quote]

The project was ported to nrf52840, but I used the main.c and sdk_config.h from the example.

[quote userid="14926" url="~/f/nordic-q-a/74004/low-power-saadc-394ua/305084#305084"]

Have you made any other modifications to the example?

The peak current also looks a bit odd to me. The expected TX current of the radio (when sending the beacons) in nRF52840 should be closer to 6-6.5mA, while in your screenshot the maximum is below 4mA. Are you seeing the beacons being sent from the board?

[/quote]

This screenshot indeed is from when I disabled the advertising, with the advertising there were indeed higher peaks and a little higher average.

[quote userid="14926" url="~/f/nordic-q-a/74004/low-power-saadc-394ua/305084#305084"] Do you have another PPK that you can use to double-check the current measurements?[/quote]

No I do not have another PPK, but I don't suspect the PPK being wrong. I have used the PPK in other projects, the measurements were as expected.

RE: Low power SAADC 394uA

Jørgen Holmefjord — Thu, 15 Apr 2021 12:04:07 GMT

Hi,

The BMD-341 contains a nRF52840 chip, while the project you have linked are for nRF52832 only (PCA10040 - nRF52 DK). Have you ported the project to pca10056/nRF52840?

Have you made any other modifications to the example?

Best regards,
Jørgen