A Saturation-Free 3.6V/1.8V DM/CM Input Range 46.6mV/μs Artifacts Recovery Sensor Interface using CT Track-and-Zoom

Artifacts in ExG recordings resulting from motion, environment interferences and stimulation can manifest as common mode (CM), differential mode (DM) or hybrid of CM/DM signals with up to hundreds of mV. To mitigate these artifacts and minimize information loss, a sensor interface (SI) with high input range and fast response speed is required. In contrast to the use of power-hungry high dynamic range (DR) ADCs, various artifact recovery approaches including adaptive filter [1], track-and-zoom [2], adaptive gain control [3] and common-mode charge pump [4] have been developed demonstrating impressive power efficiency, but at the cost of reduced signal resolution or limited recovery speed. This paper presents a continuous-time track-and-zoom (CT-TAZ) technique to address large artifact events with a saturation-free SI with 3.6V/1.8V DM/CM full-scale input range, owing to a hybrid analog-digital asynchronous signal folder (ASF) that constrains the signal within the predefined constant window in current domain. The signal can be recovered within 73 μs under 3.6V stimulation artifacts, achieving 46.6mV/μs artifact recovery speed, which is 2.25~47.3X larger and 3.56~311X faster than the state-of-the-art.