Idle Current in eDRX

[Chongchun Moon]

Hello,

  I am using a nRF9160-DK(PCA10090, 1.0.0) and v1.6.1 SDK

  I am trying to estimate battery consumption in some scenario.

  For this test, UDP sample is used.

  When PSM mode is enabled, it looks that sleep current is okay as shown image below.

   

 I just changed option to check current consumption when eDRX is enabled as image below.

 

But, In Idle situation, It looks that idle current is a little bit higher than specification.

I am worried that I missed something to configure in UDP example.

Can you help me out to configure option for this?

Thanks in advance.

Regards,

  Chongchun Moon

  

[Stian Røed Hafskjold]

Hi, this is most likely current consumed by the SIM card.

Please have a look at how the SIM current affects the eDRX idle current (green area) in the online power profiler: https://devzone.nordicsemi.com/nordic/power/w/opp/3/online-power-profiler-for-lte

In PSM the power to the SIM card is cut off, so there will be no current drawn by the SIM.

In order to turn off the SIM during eDRX you can use the AT%XDATAPRFL command at set the power_level to 0. The SIM will also have to support shutdown in eDRX mode (i.e. allowed through the EFAD register in the SIM). Now the modem will turn off power to the SIM whenever the eDRX interval is configured to be longer than 60 seconds.

If you want to verify SIM card current consumption you can measure current going through the "SIM current measurement" header (P30) on the DK.