13 Replies Latest reply on Nov 28, 2012 5:09 AM by rajiv.vasanth.badiger

    some problems about INSAMP

    li.gong

      hello everyone!

         

      I have some problems when I try to implement a project with amplifiers. the PSoC is CY8C29466, the input is a dc voltage from 0 to 15mv from a sensor, I want to achieve an output in the range 0 to 5V. 

         

       I selected a 3 op-amps and set the gain. however when I want to add a PGA after the INSAMP I find it seems impossible, can anybody tell me how to do that? btw, if i use a 2 op-amps it's possible...

         

      the second problem is about the AGND, as is showed in the data sheet, the AGND is Vdd/2, and also can be set by the parameter ref mux in the global resource. since my interest signal is alwasy positive, so I tried to set Vss as  reference voltage for 2 op-amp INSAMP and PGA, but the noise is quite big and  I even can't observe the output signal...what's more, this method is impossible for 3 op-amp INSAMP. so I want to know may I set the "ref mux" p2[4]+/-p2[6] then connect p24 to GND and p26 to VSS?
       
      thank you for your help!