Author Topic: Bipolar ADC or Unipolar ADC with summing amplifier?  (Read 1805 times)

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Offline Felicitus

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Bipolar ADC or Unipolar ADC with summing amplifier?
« on: January 10, 2014, 07:43:33 am »
Hi,

not sure if this is a beginners question, and may be more of a philosophical question.

I'm designing a board which measures voltage. To be protected against user error, I decided to make it accept any polarity, thus I need to measure negative voltages as well. Most ADCs I have looked at are unipolar, so I digged into shifting the input voltage by a summing amplifier. The question is:

Should I really use a summing amplifier in order to shift negative voltages into the positive range, or should I use a bipolar ADC?

I have googled quite lots, but most designs I came across don't care about negative voltages at all.
 

Offline Rerouter

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Re: Bipolar ADC or Unipolar ADC with summing amplifier?
« Reply #1 on: January 10, 2014, 08:56:32 am »
if the input impedance changes the sum voltage rises so if its a controlled input device your ok, if its any old voltage not so much
 


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