NRF52 DK: High current consumption

[Martin Andersen]

Hi,

I am trying to measure the current consumption on my application, and measured some quite high values even after calling sd_app_evt_wait(). After reading through some similar questions here I tried to use the System on/off mode examples as mentioned in this thread.

After flashing the system_off_wakeup_on_gpiote example on my development kit, i tried to measure the current and are getting an average consumption around 450 uA.

I have mounted a 10 ohm (I measured it to 10,4 ohm) as described in the "Preparing the development kit board" section.

I am using a Agilent MSO6014A oscilloscope for the measurement.

Any suggestions to why my current consumption is so high?

EDIT: I am making the measurements while running on the battery. Battery voltage is 2.965V.

Best regards Martin

[Stian Røed Hafskjold]

Measuring current with an oscilloscope in differential mode is not that easy. It might just be that it's not accurate enough. Seems like you get a lot of noise there. You can check out this post for some tips on how to set up the equipment.

First, you should check with a simple amperemeter (like one of the cheap general purpose multimeters; they can usually measure quite accurate down to around 1uA) to see if you actually get 450uA.

Then, you should connect both probes on the oscilloscope to the same side of the measurement resistor. If differential voltage is not 0 then you have an error in the measurement which will give you an idea on how accurate you are able to measure.

Make sure that the offset on both channels are equal and similar to the battery voltage (3V). Use 1x attenuation on the probes to reduce noise.

In many cases just using a simple multimeter is a good way to measure current.