How to accurately measure active USB current on nRF52840?

RE: How to accurately measure active USB current on nRF52840?

catsunami — Fri, 11 Jan 2019 15:58:56 GMT

Thanks Simon. I'm using a Keysight 34465A DMM, I think it should be accurate enough. I'll try longer packets and let you know what happens.

RE: How to accurately measure active USB current on nRF52840?

Simonr — Fri, 11 Jan 2019 08:13:17 GMT

I am sorry for the initial misunderstanding. However I still would recommend using the PPK for a more accurate measruement. What DMM are you using?

As for your code I'd say it looks good, but you can try sending bigger packets than just "a". As you would use less time executing the app_usb_cdc_acm_write() function.

Best regards,

Simon

RE: How to accurately measure active USB current on nRF52840?

catsunami — Thu, 10 Jan 2019 15:39:05 GMT

Hi Simon, I am already using a DMM. My question isn't about equipment, but rather the code required to see active current without the dips down to 6.8mA (which is just CPU current).

RE: How to accurately measure active USB current on nRF52840?

Simonr — Thu, 10 Jan 2019 09:06:03 GMT

The most accurate way to measure active current consumption on your development kit would be to use the Power Profiler Kit (PPK) that Nordic Semiconductor offers, although this requires the PPK board PCA63511.

Other ways to measure the current consumption include using an oscilloscope, an amperemeter or a power analyzer. More info on these methods can be found here.

Best regards

Simon