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PSoC™ 5, 3 & 1

Anonymous
Not applicable

Hello there,    

   

I have a project that required a bidirectional ADC which can take negative and positive voltages.    

   

What is the best solution to do so using PSoC 5LP? I have MAXREFDES5#, and I am thinking about using it, but I know the design will be complex. If these is a suggestion or an example code that would help me to build my design faster I would be grateful. 

   

 

   

Thanks! 

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1 Solution
Bob_Marlowe
Expert II

You need a resistor network to shift the expected input voltage into the range (roughly) GND .. VDDA.

   

Look at this thread which I found by putting "negative voltage" into the search field at top of this page.

   

 

   

Bob

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5 Replies
Bob_Marlowe
Expert II

You need a resistor network to shift the expected input voltage into the range (roughly) GND .. VDDA.

   

Look at this thread which I found by putting "negative voltage" into the search field at top of this page.

   

 

   

Bob

View solution in original post

odissey1
Honored Contributor II

Alqasir, since you already have MAXREFDES5 why not to try it? All it takes is to connect some wires to read an SPI. At the end it all depends on specs requirements: isolation, input range, bit resolution, sampling speed etc.

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EvPa_264126
Valued Contributor II

Perhaps a simpler version is required

   

using PSoC (TIA +DAC)

ADS7835   ±2.5V  Analog Input        psoc projects   

ads8675 (SPI )

And you can use  CY7C65211( PSoC® 4 CY8CKIT-049 )   as an  USB to I2C/SPI bridge
http://mylab.wmsite.ru/moi-razrab/cy7c65211/

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Anonymous
Not applicable

Thank you all for replying. The info you provided is very helpful. Do you have a sample working project for the level shifter method?

   

Something like variant 2 in the picture attached.

   

Thanks!

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EvPa_264126
Valued Contributor II

Option 2 I use when there is no free DAC.
Unfortunately I do not have a ready project.
Another version of the scheme (the shift and amplification are independent):

   

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