Integrated All Electrical Pulse Wave V elocity and Respiration Sensors Using Bio-Impedance

Abstract

In this paper , we propose wire-free integrated sen- sors that monitor pulse wave velocity (PWV) and respiration, b oth non-electrical vital signs, by using an all-electrical method. The key techniques that we employ to o btain all-electrical and wire- free measurement are bio-impedance (BI) and analog- modulated body-channel communication (B CC), respectively. For PWV , time difference between ECG signal from the heart and BI signal from the wrist is measured. To remove wires and avoid sam pling rate mismatch between ECG and BI sensors, ECG signal is sent to the BI sensor via analog BCC without any sampling. For respiration measurement, BI sensor is located at the abdomen to detect volume change during inhalation and exhalation. A prototype chip fabri- c a t e di n0 . 1 1 m CMOS process consists of ECG, BI sensor and BCC transceiver. Measurement results sh ow that heart rate and PWV are both within their normal physiological range. The chip consumes 1.28 mW at 1.2 V supply while occupying 5 mm×2.5 mm of area.