nRF51 current consumption for common scenarios

RE: nRF51 current consumption for common scenarios

MJ Ma — Tue, 17 Jan 2017 07:00:30 GMT

Hi guys, I cannot see the exact time period of each state ,so how could I calculate the total power consumption ?

RE: nRF51 current consumption for common scenarios

Robert — Thu, 25 Aug 2016 13:23:05 GMT

First I would like to say that this examples are really great. Second, is it possible to provide code examples of each scenario ? If will be great to have a better overview through source code.

RE: nRF51 current consumption for common scenarios

Stefan Birnir Sverrisson — Thu, 11 Feb 2016 13:49:53 GMT

@John These numbers were measured with a power analyzer on a single nRF51422 QFAC third revision chip. All RAM active. 3.3V supply voltage. Current consumption is however independent of supply voltage when using LDO mode, i.e. not DCDC mode or Low Voltage mode, see explanation on this thread.

@sruthi I think these measurements were performed with S110 7.1.0 and S120 1.0.1. The DCDC mode was not recommended to use with nRF51 third revision until S110 8.0.0 / S120 2.0.0 / S130 1.0.0. So when using nRF51 third revision together with S110 8.0.0 or S120 2.0.0 or S130 1.0.0, the current consumpiton is slightly better than stated here, how much better depends on your application and supply voltage. The current consumption should be the same for S130 1.0.0 as for S110 8.0.0 when S130 is configured in peripheral mode. The current consumption should be the same for S130 1.0.0 as for S120 2.0.0 when S130 is configured in central mode.

RE: nRF51 current consumption for common scenarios

sruthi.k.s — Sat, 06 Feb 2016 12:15:01 GMT

Hi Nordic,

Can you please add the current consumption for S130 application also ?

RE: nRF51 current consumption for common scenarios

John Chinnick — Wed, 15 Jul 2015 20:19:06 GMT

Was this data calculated or empirically gathered? If empirically gathered what was the hardware configuration? I.e. which processor, how much RAM active, battery voltages, etc.

RE: nRF51 current consumption for common scenarios

Tom Russell — Thu, 11 Jun 2015 02:08:36 GMT

Very helpful. Thanks.

If you have a key fob type or keyboard application where you are rarely sending any data but want quick response time, then the connection interval will be set low but the slave latency high since you can skip connections. If the connection interval is 0.040 seconds and latency is perhaps 25 intervals, what sort of current will you have? Would it be roughly equivalent to a connection interval of 1 second? What do you think are reasonable numbers for interval and latency for a remote shutter release for a camera?

Thanks, Tom

RE: nRF51 current consumption for common scenarios

Stefan Birnir Sverrisson — Wed, 20 May 2015 10:25:29 GMT

@muhkuhns: The connection interval is 1200ms so the application processing utilization (proportional CPU usage) is 0.002/1.2=0.001667. For 0.001667 CPU utilization the nRF51 consumes 33.4-35.7=7.7uA. So for 0.01 (10ms) utilization you would cost you 7.7uA*0.01/0.001667=46.2uA.

Another way to calculate this is to look at table 34 in the nRF51822 PS v3.1, which says that the CPU consumes 4.1mA when executing code from RAM. The calculated current consumption with 0.01 utilization is then 0.0041*0.01=41uA.

If you process for 10ms every 6 seconds then the utilization is 0.01/6=0.002 and the current consumption is 0.0041*0.002=8.2uA. The 4dBm is just TX power of the radio and does not affect the current consumption for the application processing (CPU processing)

RE: nRF51 current consumption for common scenarios

muhkuhns — Tue, 21 Apr 2015 18:17:16 GMT

Looking at advertising 2 and 3 can I conclude that 2ms application processing takes the difference of 33,4-25,7=7,7µA ?

So for 10ms processing it will be ~80µA + 25µA = ~ 105µA

And looking at adv 1+2 each, the intervall and the current consumtion is ~factor 60

Does it mean I can roughly assume 105µA/5 = 21µA average consumption for 10ms processing every 6seconds at +4dBm?

RE: nRF51 current consumption for common scenarios

michaeld — Wed, 15 Apr 2015 12:01:29 GMT

Great post thank you!

To bad there isn't an current consumption calculator like in nRFgo Studio for the nRF8001. That would be very usefull indeed.