Current measurements in low power modes

[sara]

Hello, I am working on a project that uses nrf52832 and I need to put that device and in the system on mode. For that, I want to measure the current in the system on and system off mode which is 1-2 uA and 0.2 uA respectively, but I do not get these values. Can you provide me with the code for which I can measure the current in system on and system off mode to get the above values? I had used ble_app-pwr-profiling example to get the values but I did not get the desired values.

[awneil]

sara said:

I do not get these values

So what values do you get?

And how, exactly, are you measuring?

At these levels, you need to be very careful about how you take the measurements - and to ensure that you are actually measuring just the DUT, and not leakage to other parts of your system ...

[sara]

I get 287.099 uA in system on mode. I am measuring using PPK and measuring only the DUT. I am using ble_app_pwr_profiling example.

SDK used is 15.3.0 

[Edvin]

What HW are you running the ble_app_pwr_profiling on? An nRF52832 DK? Did you cut SB9 before measureing?

[sara]

And I am trying since last two weeks but not able to get the current values. Please if possible share code with me even a simple code just to put the device in system off and system on mode  without softdevice will also do

[awneil]

Again, it's not just about the code - it's about how you are doing your measurements, and your hardware design.

Hence Edvin's question about hardware ...

[Edvin]

Check out this example (doesn't use the softdevice). If you want to minimize the current consumption, disable logging in sdk_config.h by setting NRF_LOG_ENABLED to 0.

Please read the testing description in the link for how to put it in system off mode.

[sara]

hello Edvin,

I tried the above example but still not getting the desired output:

My test Description: I programmed the nrf52 DK with NRF_LOG_ENABLED to 0, and then measured the current without pressing any button and I got avg current as 842.426 uA and max current as 869.029 uA.But then I am not able to press the button as for measuring current I have short SB12 and cut SB9 so buttons do not get any power (I think so ) so not able to go in system off mode. 

And when LOG was enabled I was showing on the terminal that device is going in shutdown mode but when i measured current there was no much change in it.

So now what next should I do? Am I testing and measuring current in the correct way?

My nrf52 DK board is PCA10040 v1.1.0   2016.21   682540651

And also when I short SB12 and cut SB9 all board 4 LEDs are powered on. I am using Segger Embedded Studio  for building the hex file.

[Edvin]

The buttons are still powered as long as the PPK is mounted on top of the DK. Press button 1 to go to system off mode. Did you try this?

And if you want to measure a device in system off mode, you could just use any of the BLE examples. They will go to system off mode when the advertising times out. Try to change the advertising interval from 18000 (180sec) to 500 (5 sec), and it will go to system off mode after 5 seconds. It will hit the event BLE_ADV_EVT_IDLE() which, at least in most examples, will call sleep_mode_enter(), which will call sd_power_system_off().

[sara]

Yes I did press button 1 but there was no change in the current measurements and will let you know what happens when I do what you suggested for BLE examples