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# PSoC 5, 3 & 1 MCU

Anonymous
Not applicable

## HELP PLEASE amplification using only PSoC 5lp components

Hi, for my college thesis I'm trying to implemet ecg amplifer without any external components(!!!), and I need some help. I'm using PSoC 5lp cy8ckit-059. I found this picture of ecg amplifier circuit somewhere (attached 1st pic). First two PGAs are instrumentation amplifier. I also found that for instrumentation amplifier PGA gain has to be 2. (2nd pic). But I have to achieve amplification somewhere aroud 1000. So if i put the 3rd PGA (after filters) G=50, with first two PGAs (before filter) G=2, where can i squeeze the rest needed amplificaiton=5 (or 4) so the whole amplification is 2*2*50*5=1000 (or 2*2*50*4=800)?

Thank you

1 Solution
Honored Contributor II

## Re: HELP PLEASE amplification using only PSoC 5lp components

And why ECG needs gain of 1000? Let's calculate resolution at the input of 20-bit DelSig_ADC in differential more with buffer scale set to V(-) +/-.125Vref: V=(+/-) 0.125 * 1.024V / 2^20 = 0.12uV. This is very high precision without using any amplifier in front of ADC, input noise will be much higher than that. Should you use ADC_SAR, OpAmp would be appropriate.
3 Replies
Honored Contributor II

## Re: HELP PLEASE amplification using only PSoC 5lp components

And why ECG needs gain of 1000? Let's calculate resolution at the input of 20-bit DelSig_ADC in differential more with buffer scale set to V(-) +/-.125Vref: V=(+/-) 0.125 * 1.024V / 2^20 = 0.12uV. This is very high precision without using any amplifier in front of ADC, input noise will be much higher than that. Should you use ADC_SAR, OpAmp would be appropriate.
Anonymous
Not applicable

## Re: HELP PLEASE amplification using only PSoC 5lp components

How should I configure DelSig_ADC if I want to measure ECG signal?

So, input mode-differential, resolution-20, and what about other parameters (such as input range etc)?

Thank you very much in advance

Valued Contributor II