2 Replies Latest reply on Apr 15, 2014 4:31 PM by user_14586677

    Amplifying Sine wave for odd gains 1,3,5,7 etc

    maheen.islam

       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

        • 1. Re: Amplifying Sine wave for odd gains 1,3,5,7 etc
          user_14586677

          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.

          • 2. Re: Amplifying Sine wave for odd gains 1,3,5,7 etc
            user_14586677

            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.