Power Consmuption issue in nrf51 during advertising packets

[Brajesh]

Hi All,

My goal is to advertise the generic packets untill a GPIO interrupt occurs. So in order to achieve low power consumption I have increased the time interval of those packets being advertised from 40ms to 3 seconds. While scanning i am able to see the packets in every 3 sec, but as intended i don't see any reduction in power consumption. With both the intervals, it consumes same 10mA. Am i missing something on this, please suggest.

Any suggestion would be well appreciated.

Thanks

[Hung Bui]

@Brajesh: Constant consumption of 10mA, is way to0 high if you just doing advertising. It should be about 30uA when doing advertising with 1 second interval. Could you let me know about your set-up? Schematics, layout, how you measure the current consumption ? Which firmware did you use (SDK, softdevice version ) ?

[Brajesh]

Thanks Hung Bui for response. I am using Softdevice_6.0.0 and SDK-5.2.0.39364. I have made some modifications now to reduce power consumption. I'm running a timer which wakes up system from sleep mode in every 15 seconds and start advertising for 5 seconds(TIMEOUT). Now the cosmuption has reduced to 4mA and 5mA (while advertising for 5 seconds). And after connection it consmumes 9mA continuously. does it sound alright to you or still this is high than expected ?

[Hung Bui]

@Brajesh: No it's still too high. As I mentioned it should be on average 0.03mA.

Have you tried with the default example in the SDK v5.2 ? The BLE HRS project , for examle ? How did you measure the current consumption ?

[Brajesh]

@Hung Bui. I am measuring consumption using a multi point Power supply. Now i come up with correct measurements as previous power supply had issues with resolution. Following are the observations based on power supply monitor. System starts and goes to Sleep(using sd_evt_wait API) mode immediately after all initialization. Timer starts (for 15 seconds) to wake up device in every 15 seconds. For first 15 seconds(when device is in sleep), the current consumption is 5uA. After 15 sec, timer handler starts advertisement (with TIMEOUT 5 seconds) and consumes ~250 uA (for 5 seconds) and then for next 10 seconds consumes 30uA. Afterwards, It keep on toggling between 250uA and 30uA . Not sure Why it doesn't show 5uA again ? After connection, device consumes 2-3mA. Does this sound alright now ?

[Brajesh]

Hi, I have noticed on this thread " devzone.nordicsemi.com/.../ " that in Idle (sleep) mode " The base current consumption in this mode is given in table 32 in the nRF51822 PS v3.1 as I_ON, 2.6 µA. ". But in my case as i explained above minimum current drawn is 5uA and afterwards it never returns to 5uA, it keeps on toggling between 250uA and 30uA as per timer and advertisement. Please suggest why i don't get 2.6uA in sleep mode.

Thanks in advance.