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Accurately measuring board current consumption.

Karthik.ganesan
Associate

Hi, I'm trying to get as accurate a power measurement as possible on an NUCLEO-F103RB board. I set it up using STM-CUBE to run at 1MHz and all peripherals in the default state. The only code I am running (once initialization is complete) is an empty while(1) loop.

I have bypassed all the ST-LINK circuitry and I am providing 3.3V using a Keithley 2450 SourceMeter. I am also performing the current measurement using the same meter. I have soldered off SB2 and SB12 as well.

I am getting different current measurements from different runs, without changing anything else in the setup. The current ranges from 2.43 all the way to 2.89 mA between runs. I just press the on-board RESET and wait for the current to settle.

Is there something else that could be happening in the background to cause this variation in power between runs? Any help/suggestions would be much appreciated!

2 REPLIES 2
Piranha
Chief II

Could be floating input pins catching noise. Read AN4899 section 6.

Karthik.ganesan
Associate

Hi, Thank you! I'll try out those optimizations and see if the problem goes away. I also saw AN3430 when I googled your suggestion so I'll try that out too and report back.