Offset on VAGND

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User18174
Level 1
Level 1
Hello,

I actually work on a project where I measure every cell of a LiPo battery. Becuase the input voltage of the XMC4500 is limited to 3.6V (better 3.3V) I use a 1/2 differential amplifier to reduce the voltage to be measured. So the range lies between 1.6V and 2.1V on the analog input.
To increase the accuracy of the ADC I want to connect the VAGND pin to 1.2V but is this possible and what happen when I connect 0V to an analog input?
I hope someone can help me.

Thanks
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4 Replies
jferreira
Employee
Employee
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Hi,

Please check https://www.infineon.com/dgdl/Infineon-VADC-XMC4000-AP32305-AN-v01_02-EN.pdf?fileId=5546d4624e765da5...
See section 3.2.4 Using Two Different Voltage References - Alternate Reference

Regards
Jesus
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User18174
Level 1
Level 1
Thank you Jesus for your answer.
As I understand, I can use the Channel 0 (Pin 14.0) as a alternative reference.
If I use the DAC(Pin 14.8 or 14.9), do I have to connect the pins physically or set them internally with registers?

Thanks
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jferreira
Employee
Employee
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Hi,

I only see that possibility on group 1, since DAC_0 and ADC_G1_CH0 is on P14.8.

Regards,
Jesus
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User18174
Level 1
Level 1
Thank you, that's the solution.
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