Power Profiler 2. Spikes during measurement leading to data inaccuracy.

[mounika]

I am trying to measure the current using power profiler 2. The profile seems to contain irregular spikes which is incorrect. 

Is there any way to make adjustments to the range setting? Or is there any way to calibrate the power profiler to reduce this switching in the measurement range.

Thanks in advance.

[Marjeris Romero]

Hi,

The internal regulator of the chip in the PPK will draw current in bursts, so it's normal to see high regulator spikes.

In addition to this, when the current goes from low to high so will the PPK switch the measurement resistor, this switching will also generate high spikes. These spikes should be filtered by the PPK software.

We will do some experiments to see if there is any reason why the switching noise is not filtered out by the software, it could be perhaps a setting in software, but the spikes per se should not be any concern.

Best regards,

Marjeris

[mounika]

Hi Marjeris,

Thanks for the response. 

It not just the spikes. I also noticed that the Bluetooth advertising peaks look incorrect(only notice 2 peaks instead of 3, and the current values are way off). The current consumption is higher than anticipated. Those spikes do contribute to 30mA current consumption even if its for a few milliseconds. Hence, the reading is not accurate. 

Prior to the software update, I hadn't had this issue (atleast with bluetooth). The spikes are occurring even if there is no switching, so I tried to downgrade the PPK version to 3.0.0 but I still see this happening. I'd appreciate any help in this regards.

Thank You,

Mounika

[Marjeris Romero]

Hi,

I have some questions for you, what CPU are you using? AMD or Intel? We think the problem could be because of packet loss over USB since you say the Bluetooth advertising peaks look incorrectly, so it's important to rule that out.

If you are using a USB hub, try connecting the PKK directly to the PC, not via the hub.

You can also try to test with another USB cable that the one you are using.

BR,

Marjeris

[mounika]

Hi Marjeris,

Thanks for looking into the issue.

The CPU that I am using is Intel. I had tried using the PPK2 on Windows OS and MacX OS as well. I still see the same issue. I am not using a USB hub. I always connect my PPK2 directly to the PC.

I has also tried both source meter and ampere meter mode. I had tried switching the USB as well. I tried changing the end device with a different one too.

Thank you in advance,

Mounika T 

[Marjeris Romero]

Hi Mounika,

OK, at least it was worth a try to check for USB issues.

Could you post your measurements where for BLE advertising? It should be possible to export the measurements to CSV format from the PPK software. It's easier for us to check if the measurements made sense when looking at the whole measurement instead of just an screenshot.

You could also run an SDK example, for example ble_app_pwr_profiling example on your DK and take new measurements, export to CVS and share with us so we can compare these with a functioning PPK2 board. This power profiling application example starts in system off, and you need to push button 1 or 2 to start advertising.

Best regards,

Marjeris