ADC Delsig Question

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Anonymous
Not applicable

Hello,

   

 

   

In my design I am trying to use to the ADC Delsig to measure the battery capacity of an on-board battery in my system by converting the battery input voltage to a digital value using the ADC Delsig component in the PSoC and then calculating the remaining battery life based on the output.

   

 

   

The battery I am measuring has an input range to the PSoC of 2.2 - 2.8 VDC.  My board has Vdda connected to +5VDC, so I configure the input range of the delsig to be single ended with an input range of "Vssa to Vdda."  However, when I make these settings, the Vref of the delsig is automatically set to "Internal Vdda / 4" or 1.25 volts.

   

 

   

How can the ADC delsig accurately measure a voltage input range of Vssa to Vdda when the reference voltage for the ADC is set to Vdda / 4?  Doesn't the reference voltage for the ADC need to be greater than the maximum input voltage?

   

 

   

Thank you.

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