RE: Power profiling in nRF52832

Stian Røed Hafskjold — Mon, 09 Aug 2021 14:46:18 GMT

Hi, the PCA10040 can be a bit tricky to measure current consumption correctly on.

If the USB cable is plugged in and you are measuring through the current measurement header (PPK2 in ampere meter mode), you will see around 10 uA additional current in sleep. This is due to 1kHz noise from the USB interface. If you want to measure idle currents correctly on the current measurement header, unplug the USB cable, and power the DK with a stable supply on the External supply header.

If you want to power the DK using PPK2 in SMU mode, you need to connect the positive lead to the current measurement header (closest to the debug out connector), and the negative lead on one of the GND connections. You will have to set the output voltage to match the DK VDD voltage exactly (should be around 2.7V) and this time you need to leave the USB cable plugged in to power the rest of the board.

You can have a look at this blog: https://devzone.nordicsemi.com/nordic/cellular-iot-guides/b/hardware-design/posts/getting-started-with-current-measurements-on-the-nrf9160
Even though it's written for the nRF91 DK, the two measurement methods shown in the picture are the same for the nRF52 DK.

I would recommend using the PPK2, not the PPK1.