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PPK2 strange current reporting after DUT goes into low power state

DevinCallahan

Hello!

I am starting to profile our device using the PPK2 and I am seeing some strange measurements when the device goes into its low power mode.

I'm attaching an image of what I mean:

The dense set of "spikes" at the end of the capture don't seem to correspond to anything in my system.

If I DON'T have the device go into its low power mode the capture looks like:

I am assuming the auto-ranging is struggling in this case, as the device moves from the mA range to 1-2uA in the low power state.

Is there something I can try to do to get rid of the "spikes" the current probe is reporting?

Bonus question:

Are the sample duration limits in the Power Profiler app set by some constraint in the PPK2 hardware or just the amount of RAM the host PC has to spare?  I have seen how I can modify the JS of the Power Profiler app to increase the sample duration's but I'm not confident enough to really try using it.

Thank you so much!

Cheers,

Devin

Parents
  • +1

    Hi

    Thank you. I've reported that DevZone is not able to upload .ppk files. Thank you for providing the error message. I have reported this issue internally.

    As for the PPK trace, I had one of the PPK developers take a look at it, and he does indeed seem to think that this is one of the switches causing this current consumption. You can also see that the measurements between these 700uA spikes are all the way to 0, indicating that there are some negative currents as well. These samples are not to be trusted I'm afraid. Our recommendation is to ignore these measurements, as the sleep current seems to run as expected after this "noisy period". Unfortunately, this is the greatest weakness of the PPK2, as the bandwidth does not support the switching occurring here.

    Best regards,

    Simon

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  • +1

    Hi

    Thank you. I've reported that DevZone is not able to upload .ppk files. Thank you for providing the error message. I have reported this issue internally.

    As for the PPK trace, I had one of the PPK developers take a look at it, and he does indeed seem to think that this is one of the switches causing this current consumption. You can also see that the measurements between these 700uA spikes are all the way to 0, indicating that there are some negative currents as well. These samples are not to be trusted I'm afraid. Our recommendation is to ignore these measurements, as the sleep current seems to run as expected after this "noisy period". Unfortunately, this is the greatest weakness of the PPK2, as the bandwidth does not support the switching occurring here.

    Best regards,

    Simon

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