measure ripple voltage and current

Dear mhkvy4,

mhkvy4 said:

need to measure the ripple voltage due to the chopping. Is using peaktoPeak function and clipping the waveform after steady state has been reached a good approximation of current/v

I don't know your specific application from your description, but the use of the peaktoPeak function may lead to misleading results. Specifically, the ripple on any chopper based amplifier has a number of sources. One mechanism that will lead to ripple is charge feedthrough. This will produce high frequency transients at the output. These high frequency transients are not attenuated by the feedback loops many chopper amplifiers have to minimize the output ripple as much of their frequency content is filtered out by the ripple detection circuits. However, the peaktoPeak function will detect the minimum and maximum of the ripple and include the impact of these high frequency transients. If your application's requirement is for the lower frequency components of the ripple (i.e., without these high frequency transients), the peak-to-peak computation will not provide the desired result. On the other hand, if your ripple requirement includes the impact of feedthrough charge injection, the peak-to-peak computation peaktoPeak provides will provide an accurate estimate. Figure 1 shows an example of the ripple of chopper amplifier where the high frequency ripple components are shown with the low frequency components.

Shawn

Figure 1 from reference [1]

[1] J. Zheng, W. Ki and C. Tsui, "Analysis and Design of a Ripple Reduction Chopper Bandpass Amplifier," in IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 65, no. 4, pp. 1185-1195, April 2018, doi: 10.1109/TCSI.2017.2751970.