Nucleo WB55rg powering CPU only

[whati001]

Hi ST Team,

I have found this post here, which explains how to power the Nucleo WB55RG board with an external power source. https://community.st.com/t5/power-management/powering-nucleo-wb55-externally/m-p/632719#M10752

Now I have a followup question: Is it actually possible to only power the CPU without the LED and onboard ST Link, to measure the current consumption? If I power the board via 5V EXT, LED5 is always ON, which makes my current measurement invalid.

Regards,

Andi

[STTwo-32]

Hello @whati001 

If you are using 5V_EXT as power source, you can make a current measurement by removing the JP3 and connecting his two pins to both amperemeter pins. That should work and give credible measurements.

Best Regards.

STTwo-32 

[whati001]

Hi STTwo-32,

thank you very much for your feedback, but your solution does not work for me.

If I power the device via 5V EXT (CN7.6) and removed JP3, the board still draws to much current. In addition, LED5 still remains ON. Please find a board picture attached.

As firmware, I have flashed the power management blinky sample from zephyr:

https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/boards/stm32/power_mgmt/blinky

I would expect a sleep current from < 10 uA, but I receive multiple mAs.

Regards

Andi