NRF9151 DK Supply Current Measurement

[tc531]

We're trying to measure supply current used by the NRF9151 DK but have discovered that the current measurment connector (P22) only includes current supplied to VDD, and that VDD_GPIO isn't measured since it comes from the nPM1300 (U9) which is supplied direct from 5V.  U9 also supplies power to U3A, the debugger, which is not present on our target.  

Is there a way measure the total supply current into the NRF9151, to simulate our target, without including the debugger?

Kind regards

Tim

[Stian Røed Hafskjold]

Hello,

You need to isolate the VDD_GPIO domain from the rest of the DK, and measure the current going into this domain.

You can cut SB31, to isolate VDD_GPIO, then power directly on VDD_GPIO on P20 with an SMU or similar. Note that the voltage needs to match the VDD voltage on the DK, which is 1.8V. 

If you want to measure at a higher voltage you need to cut SB33 as well, and supply VDD on P20 separately (so that you don't include this current in your measurements), with the same voltage as VDD_GPIO. Note that the VDD_GPIO allowed voltage ranges are different than for VDD_nRF

The USB should always be plugged in to power the remaining components on the DK.

Best regards,
Stian