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phantom power FRDM i.MX 91S UART?

Has anyone observed incorrect readings on power meters when measuring power consumption of the FRDM i.MX 91S board with UART attached? 


I managed to get a probably faulty reading of 50mW of power consumption recording with a USB tester as once the secondary USB cable is removed (UART) power reading goes up to 520mW. 

TomasA_0-1766837050506.png

Could the  Net "DEBUG_VBUS_5V" or "VIO" feeding more than just the UART chip?


Thank you, 

Tomás

Re: phantom power FRDM i.MX 91S UART?

Sorted, it was a ground loop. I recommend separating the power to the device and the power from your PC.


E.G Device is powered though USB C PD charger (J1) as it is isolated from mains. While UART is from your laptop/pc

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Last update:
‎12-28-2025 02:24 AM
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