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PSoC 5, 3 & 1 MCU

Anonymous
Not applicable

 Hi

   

I am working on PSoC creator 3, I am using PGA to amplify my wave. I want gain of 1,3 5,7 using slider. But what I have searched is that PGA gain can only be set to 1,2,4 etc. Can anyone please share any Cypress document explaining how can my problem be solved. Also I cannot find any way to make PSoC 3 input based. Can anyone please help me with that?

   

Regards

   

Maheen

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2 Replies
Esteemed Contributor

You could -

   

 

   

1) Use TIA or OpAmp with an input mux to several G settings R's, although

   

this eats up pins, one per G setting.

   

2) Use A/D, then simply use a G factor before passing back to VDAC.

   

3) Use IDAC and control currents, hence G, in external amp of some

   

basic configuration, like a transconductance OpAmp.

   

 

   

Making PSOC input, not sure what you mean. If you want to input signals, you simply

   

select pin and sets its properties to HiZ analog in. Then route that to components of

   

interest.

   

 

   

Regards, Dana.

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Esteemed Contributor

Eliminate 1) as a suggestion, as TIA fdbg R tolerance is very poor, so your

   

G accuracy would be bad as well. The OpAmp with external R's and

   

mux for input R's to set G probably best solution. You could use PGA

   

and throw away G with a muxed R divider at PGA output, then buffer that

   

with an OpAmp in follower mode.

   

 

   

So question -

   

 

   

1) Why the odd valued G's ?

   

2) Nature of signal you are processing ?

   

 

   

Regards, Dana.

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