Integrated Circuits and Electrode Interfaces for Noninvasive Physiological Monitoring

Sohmyung Ha, Chul Kim, Yu M. Chi, Abraham Akinin, Christoph Maier, Akinori Ueno, Gert Cauwenberghs
2014 IEEE Transactions on Biomedical Engineering  
This paper presents an overview of the fundamentals and state of the-art in noninvasive physiological monitoring instrumentation with a focus on electrode and optrode interfaces to the body, and micropower-integrated circuit design for unobtrusive wearable applications. Since the electrode/optrode-body interface is a performance limiting factor in noninvasive monitoring systems, practical interface configurations are offered for biopotential acquisition, electrode-tissue impedance measurement,
more » ... nd optical biosignal sensing. A systematic approach to instrumentation amplifier (IA) design using CMOS transistors operating in weak inversion is shown to offer high energy and noise efficiency. Practical methodologies to obviate 1/f noise, counteract electrode offset drift, improve common-mode rejection ratio, and obtain subhertz high-pass cutoff are illustrated with a survey of the state-of-theart IAs. Furthermore, fundamental principles and state-of-the-art technologies for electrode-tissue impedance measurement, photoplethysmography, functional near-infrared spectroscopy, and signal coding and quantization are reviewed, with additional guidelines for overall power management including wireless transmission. Examples are presented of practical dry-contact and noncontact cardiac, respiratory, muscle and brain monitoring systems, and their clinical applications. Index Terms-Biological signal sensing, biomedical electronics, body-electrode interface, electrode contacts, electrode-tissue impedance, functional near-infrared spectroscopy, health monitoring, instrumentation amplifier (IA), optrode interface, photoplethysmography, sensor interface.
doi:10.1109/tbme.2014.2308552 pmid:24759282 fatcat:wy75uz2hhvasvhm3mkcvguwhc4