nRF9160 custom board power consumption

RE: nRF9160 custom board power consumption

Sigurd — Fri, 11 Oct 2019 11:26:14 GMT

Hi,

[quote userid="78843" url="~/f/nordic-q-a/52856/nrf9160-custom-board-power-consumption/214306"]Wouldn't that make sense if power consumption is improved when we disable bsdlib?[/quote]

Yes, the 30uA you see is the sim-card current. (It's initialized as part of bsd_init ).

[quote userid="78843" url="~/f/nordic-q-a/52856/nrf9160-custom-board-power-consumption/214306"]As I understand it, using PSM would shut down the SIM? I[/quote]

Correct. Note that cheap SIM cards may have longer minimum shut down time, or in some cases not allow for shutdown at all.

[quote userid="78843" url="~/f/nordic-q-a/52856/nrf9160-custom-board-power-consumption/214306"]I tried to use this but it didn't have any effect.[/quote]

You might not be able to enter PSM mode with the iBasis card. Be aware that some carriers put limitations on use of IoT features with roaming SIM cards. Power Saving Mode (PSM) is a feature that is not always available with roaming cards. In that case, you would need to order an IoT SIM from your local carrier.

Use +CEREG with level 5, to see if you are able to enter PSM or not. Alternatively %XMONITOR

[quote userid="78843" url="~/f/nordic-q-a/52856/nrf9160-custom-board-power-consumption/214306"]Is there any other way to shut the SIM down to see if that is the culprit?[/quote]

No. AFAIK 3GPP only allows you to shutdown in PSM and eDRX(not supported by all sim-cards). But again, the culprit for the 30 uA is the SIM card.

[quote userid="78843" url="~/f/nordic-q-a/52856/nrf9160-custom-board-power-consumption"]If I use bsd_shutdown it will consume a couple of mA during sleep.[/quote]

See this sample on how to use system off mode.

RE: nRF9160 custom board power consumption

joakimsaaz — Thu, 10 Oct 2019 09:05:22 GMT

Hi, Sigurd. Thanks for the answer 🙂

100uA is for the whole system, measuring from power supply. It is me looking at the multimeter and see it not change, so I guess it is the static base-line current. :)

As I said, there are other components and they are most likely responsible for 60-70uA. We will soon make some changes to confirm this. As we can lower the consumption by around 30uA if we disable bsdlib, I believe that is the main problem. After I made the first post I found some info that the SIM-card could be responsible for a current draw of around 30uA. Wouldn't that make sense if power consumption is improved when we disable bsdlib?

As I understand it, using PSM would shut down the SIM? I tried to use this but it didn't have any effect.
(Tested RPTAU=10mins, RAT=1min and RPTAU=31hours, RAT=1min)
However, after sending a message and before going to sleep, we set AT+CGATT=0, AT+CFUN=4, AT+CFUN=0. If that can somehow affect anything.

Is there any other way to shut the SIM down to see if that is the culprit? I couldn't find any AT-command for it, but perhaps I am stupid.

To answer your other questions, there shouldn't be any timers. At least not any that I am aware of. And CONFIG_SERIAL=n should also be set for SPM and MCUboot.

Thanks again!

RE: nRF9160 custom board power consumption

Sigurd — Tue, 08 Oct 2019 15:28:17 GMT

Hi,

Is 100uA the average current, or static base-line current? How are you measuring it?

Do you have any timers running, that is waking up the CPU ?

Do you have CONFIG_SERIAL=n for SPM and MCUboot also ?