Multimodal Analog Front End for Wearable Bio-Sensors

Wearable sensors afford convenience in daily health monitoring, though many challenges in the development of such systems need to be overcome. Here, we present a low-power, multi-modal analog front end (AFE) for wearable health monitoring sensors based on novel system architecture and very large scale integration circuit design methods. The AFE integrated circuit was designed with the standard 65-nm CMOS technology. Three sensor AFEs, bio-potential, photoplethysmography (PPG), and bioelectrical impedance analyser (BIA) were integrated on the same die with an area of 2.5 x 2.5 mm(2). The power consumption for each AFE mode was <0.4 mW and did not exceed 2 mW for all three modes with a 1.2 V power supply. Results from each individual AFE showed high-quality, motion-robust signals (electrocardiogram, PPG, and BIA) that correlated with those obtained from clinical grade gold-standard devices for similar applications. Such multi-functional, non-intrusive systems permit users to effortlessly self-monitor multiple clinically relevant physiological parameters.