Artifact-Tolerant Electrophysiological Sensor Interface with 3.6V/1.8V DM/CM Input Range and 52.3mVpp/μs Recovery Using Asynchronous Signal Folding.

Abstract

In the practical implementations of wearable sensors, motion artifacts with large amplitudes often cause signal chain saturation, significantly degrading biopotential signal integrity. Similarly, rapid stimulation artifacts are inevitable during closed-loop brain stimulation therapy, posing additional challenges for real-time signal acquisition. To address motion and stimulation artifacts with amplitudes reaching hundreds of mV while minimizing information loss, a sensor interface with high input range and fast artifacts recovery capability is essential. This paper presents a continuous-time track-and-zoom (CT-TAZ) technique designed to handle large artifacts events without saturation. The proposed system achieves a 3.6V/1.8V differential-mode/common-mode full-scale input range. Fabricated in a 180nm CMOS process, the prototype chip occupies an area of 0.694mm² and consumes 12/32.6/51.6μW for recordings without/with single-end/ with differential rail-to-rail artifacts. The system demonstrates an average artifacts recovery time of 65.3 μs under 3.6V stimulation artifacts, achieving an average artifacts recovery speed of 52.3mV_pp/μs, which is 2.25× larger input range and 3× faster recovery compared to the state-of-the-art.