NRF52840 power consumption under different RSSI

RE: NRF52840 power consumption under different RSSI

Einar Thorsrud — Thu, 31 Mar 2022 14:25:29 GMT

The area you have marked with "link layer retries" are not that. The current consumption is too low. I cannot say what happens there based on the current consumption pattern, but it is something else.

RE: NRF52840 power consumption under different RSSI

Domneck — Thu, 31 Mar 2022 08:12:50 GMT

Hi,

I'm attaching the plots here.

One is captured for 90 rssi and another one is 40 rssi.

RSSI 40:

RSSI 90

RE: NRF52840 power consumption under different RSSI

Einar Thorsrud — Wed, 30 Mar 2022 08:14:13 GMT

Hi,

If you see increased packet exchange duration without more data sometimes during low RSSI conditions, that matches perfectly with retransmissions. (You can confirm that by using a sniffer if you like). I am not able to get 1.5 mA to match what I would expect, as the radio in both Tx and Rx would be significantly higher, but perhaps there is something about how you are measuring? Perhaps you can share a plot?

RE: NRF52840 power consumption under different RSSI

Domneck — Tue, 29 Mar 2022 15:24:23 GMT

Thanks for the info. I’m performing power profiling for the poor RSSI levels and I see some extra peaks. I’ve configured tx power level as 0dbm and for this as expected I’m seeing peaks up to 3-4mA but I’m also seeing some peaks upto 1.5mA. These 1.5mA peaks are not seen every time. When these peaks are seen the packet exchange duration is increasing for same amount of data.

RE: NRF52840 power consumption under different RSSI

Einar Thorsrud — Fri, 25 Mar 2022 08:20:26 GMT

Hi Reedomneck,

There is no practical difference in the current consumption required to receive a packet regardless of the RSSI. So any additional current consumption will come from retransmissions.

Einar