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HWickham
HWickham
Associate II
May 4, 2022
Question

STM32 WLE5 VBat measurement at low temperatures

  • May 4, 2022
  • 1 reply
  • 1485 views

Hi,

I am currently doing some tests measuring the battery voltage on a system using the STM32WLE5, I am measuring both v_sys and v_bat. I am running into an issue with the v_bat measurement, I am seeing alot of noise compared to the v_sys measurement. I am using a bench supply currently to prevent any fluctuations due to the supply. I have attached an image below of the plot of voltage against time, and then below that is voltage against temperature (the same data points)

0693W00000NpF3iQAF.png0693W00000NpF1SQAV.png

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1 reply

Louis AUDOLY
Louis AUDOLY
ST Employee
May 16, 2022

Hello @HWickham​ ,

First thank you for your question !

In fact v_bat is connected to a switch that power or not the backup domain in case you have an issue with your VDD. So this pin need to be plugged on stable power source, but not stayed unconnected.

This could explain this behavior !

Regards

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