signal conditioning

[Anonymous]

A sinusoid having amplitude 100mv and frequency 1khz is an input from function generator to PSOC. Using capacitive buttions, I want that after reset, amplitude become 0 volt; by pressing positive button amplitude increase by 100mv and negative button will decrease amplitude by 100mv. Moreover, using slider at 50% position, the offset will become zero; at 0% position, offset become -1 volt, and at 100 %, the offset is +1volt. The output should be shown on oscilloscope. How this can be accomplished using PSOC3?

[ETRO_SSN583]

Basically you would use a DAC as the offset to an OpAmp summer that

   

is passing the generator signal. This would be an offset between

   

ground and Vdd, so now you have to use 1 external OpAmp with a

   

negative supply and a fixed offset to shift the PSOC developed signal

   

so it is symmetrical about ground. This is nothing more than another

   

summer, but external.

       

There are a number of ways to develop - supplies, see attached, as

   

well as various charge pumps, switchers, etc.. TI, NSC, Philips, On,

   

Fairchild.....

       

Regards, Dana.

[ETRO_SSN583]

You might also look at audio amps, as they have a power output stage,

   

thermally and current protected, are consumer cheap, and have OpAmp

   

like front ends in many versions.

       

Regards, Dana.