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Power measurement with external power supply

Hello everyone,

I am trying to measure the current being consumed by nrf52840 using an external power supply.

Setup: I have connected 3.3V DC power supply to connector P21 and switch 10 is in ON position and switch 9 is in VDD position. As specified in the picture below. 

However, the board is not running with this setup.

As mentioned in the second screenshot, supply VDD domain from a different source, I tried connecting USB to power the remaining board. But it does not work.

Kindly help me understand how I can power the rest of the board? If I have to power the rest of the board with USB what extra changes do I have to make on the board?

Regards,

Sameer 

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  • Hi, seems like your setup is correct. When you say "the board is not running" with this setup, do you mean the nRF52 chip or the board itself? What do you need to run on the board? So the point of SW10 is to bypass the components on the DK powering the nRF52 chip directly. You should also set SW6 to nRF ONLY. Now you can measure current. If you need to use the JLink on the DK you need to set SW10 back to the OFF position.

    It's true that USB has to be connected on order to power "the rest" of the board. This is so that the components are not floating and not interfering with the operation of the nRF52 (more specifically the reset and SWD lines).

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  • Hi, seems like your setup is correct. When you say "the board is not running" with this setup, do you mean the nRF52 chip or the board itself? What do you need to run on the board? So the point of SW10 is to bypass the components on the DK powering the nRF52 chip directly. You should also set SW6 to nRF ONLY. Now you can measure current. If you need to use the JLink on the DK you need to set SW10 back to the OFF position.

    It's true that USB has to be connected on order to power "the rest" of the board. This is so that the components are not floating and not interfering with the operation of the nRF52 (more specifically the reset and SWD lines).

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