Multi-channel high common-mode rejection ratio signal acquisition system based on idle phase common-mode elimination technology

Abstract

This invention relates to the field of analog front-end technology and discloses a multi-channel high common-mode rejection ratio (CMRR) signal acquisition system based on idle-phase common-mode cancellation technology. The system includes: a multi-channel presampler based on a floating dynamic operational amplifier and idle-phase common-mode cancellation technology, used to sample weak input signals. Simultaneously, the output signal is periodically short-circuited during idle phases at the presampler's output to eliminate common-mode signals and improve the CMRR; a multi-channel noise-shaping successive approximation analog-to-digital converter (ADC), which takes the weak signal acquired by the presampler as input and outputs a digital signal; and an ADC that provides a time-division multiplexed clock to drive the presampler, achieving phase-synchronized clock control. The presampler technology based on idle-phase common-mode cancellation proposed in this invention has advantages such as low power consumption and high CMRR, and is suitable for low-gain multi-channel neural signal acquisition systems, effectively eliminating common-mode interference during neural signal acquisition.

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