Strange power consumptions on nrf9160DK with blinky sample

[harry4951]

Hi,

Hardware:

-nrf9160DK PCA10090 1.1.3

-PPK2

Software:

-ncs 2.6.1, blinky sample

-Power Profiler v4.0.0

Setup:

Both source meter mode and amprere meter way following the link below, external power supply is 5V:

 Getting started with current measurements on the nRF9160 

Issue:

I tested blinky sample on nrf9160DK with and without CONFIG_SERIAL=n, CONFIG_TFM_LOG_LEVEL_SILENCE=y, following this link: 

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/test_and_optimize/optimizing/power_general.html

But the results is not the same as the above link and the power consumptions look strange.

Why one is in uA, one is in mA; one has roughly 700uA diff before and after optimization, one has 70uA?

Before optimization source meter mode:

Before optimization ampere meter mode:

After optimization source meter mode:

After optimization ampere meter mode:

Thanks

/CJ

[runsiv]

Hi Li

Have you prepared  the DK as mentioned here?

Regards

Runar

[harry4951]

Hi, yes. and strictly following the connection in two different modes with the link devzone.nordicsemi.com/.../getting-started-with-current-measurements-on-the-nrf9160

[runsiv]

Hi and thanks

I ran the plots over with a co-worker who have done more work on the 91dk. The source mode measurements looks correct and shows that the modem has the known current issue. However there is something strange with the amp measurement. How did you power the device? I would not be surprising  if the noise on the measurement comes from the USB if the device is powered by it, 

Regards

Runar

[harry4951]

Hi,

It is powered using an external power supply suppling 5V, and the setup is following the link 

 Getting started with current measurements on the nRF9160 

I am not concerned about whether it is noise or not, my question is why it is not 3mA as in the source mode scenario.

Can you maybe just try to duplicate what I have done in my original post at your side, to see whether you had the same issue?

[runsiv]

Hi

I just did a quick test on my desk with blinky sample. However I have added the modem fix (so the modem is initialized) together with CONFIG_SERIAL=n, CONFIG_TFM_LOG_LEVEL_SILENCE=y

Could you show me your setup? I was not able to reproduce what you are seeing 

Regards

Runar

[harry4951]

Hi,

PPK2 VOUT -> VDD_nRF

PPK2 VIN -> VDD_nRF'

PPK2 GND -> DK External supply -

Power supply 5V red-> DK External supply +

Power supply 5V black-> DK External supply -

Software: just the original blinky sample

[runsiv]

Thanks. The setup is like you would expect and no different from mine. Do you have access to a multimeter or similar just so we can see if it gives the same readings as the PPK? 
I just have to ask, outside preparing the DK for the measurement, has there been any modification to the PPK or the DK? 

Regards

Runar