Random power peaks

[Yashodha]

Hi everyone,

I'm using nrf52840 as a connectable advertiser. Used ble_app_blinky example with some modifications. And I reduced the advertising interval to 2 seconds. However, the BLE function worked as expected. 

But when I analyze the power consumption I saw random power peeks. I can't figure out what is the reason. 

Anyone can explain this and how to reduce these peaks ??

pow

Thanks

[Kenneth]

I suspect it can be that the internal regulator is operating in refresh mode while maintaining system ON mode (e.g. to power clocks and ram). In refresh mode it will draw short "spikes" of current, I would expect this to happen much faster than your plot show, but it can be that the resolution of the power analyzer you are using are not able to measure them all and/or are combining them somehow. The average idle current should be around 2uA, as for instance shown here:
https://devzone.nordicsemi.com/power/w/opp/2/online-power-profiler-for-bluetooth-le 

Kenneth

[Yashodha]

Hi, Thank you for your reply.

If it is, how I can reduce those short spikes? any suggestion?

[Kenneth]

They are this way by design, it require on average less current to periodically refresh a regulator than having a regulator ON continously.

Not related to your questions, but if you are measuring on the nRF52840-DK, then make sure you are powering the DK from a steady power supply or battery, I have seen that the USB can cause much noise on measurements.

Kenneth

[Yashodha]

These spikes only appear when the device is in advertising mode. When it's connected to the device average current is only a few uA. 

And I'm using Sparkfun nRF52840 board with bypassing all unnecessary components.

if it turned off ADC will it save considerable energy?