NRF9160 eDRX Power Draw Question

[Jameson]

Hello,

I've been running some power measurements on our prototype board that is using the nRF9160.  I've measured current draw on the VDD and the VDD_GPIO when the modem is in eDRX mode.  When at an eDRX cycle of 10.24 seconds and a PTW of 3.84 seconds I'm seeing an average current consumption over a couple minute run of ~677 uA.  I'm seeing that in idle the current is getting down to ~50 uA, which doesn't seem that far off considering the SIM draws ~30 uA. 

When using the same values in the online power profiler (eDRX=10.24 sec, no PSM, no data transmittion), its showing an average current of 147.53 uA.  I noticed that the online power profiler isn't allowing for adjusting in PTW, as well as the iDRX length of time is only showing 114.4 ms.  So I'm wondering if this isn't taking into account the PTW at all.  Can you confirm whether the online profiler takes PTW into account and how to adjust the average current numbers based on adjustments for the PTW?

https://devzone.nordicsemi.com/nordic/power/w/opp/3/online-power-profiler-for-lte

Any information would be greatly appreciated!

[Martin Lesund]

Hi Jameson,

Please check out the User Guide: 

• PDCCH repetitions during iDRX paging. This is set to 1 (no repetitions) in the OPP.

also note the disclaimer in the user guide: "This controlled test environment represents in many cases ideal conditions which may not be reproducible in a real network."

So measurements in real networks are to be expected higher than in this controlled estimator. We are working on improving the calculator more precises compared to real networks.

---

When it comes to the parameters you have set, have you verified that the network actually grants the eDRX interval and the PTW ? (can be done with the AT command: AT+CEDRXRDP)

Have you made sure to disable all uart and peripherals to avoid any unnecessary consumption?

Best regards,
Martin L.