Motion artifact reduced bio-signal sensor for sleep monitoring system

Abstract

Motion artifact reduced multi-channel bio-signal sensor for sleep monitoring system is introduced. To prevent signal saturation due to large motion artifact, adaptive DC level control (ADLC) is adopted at the analog-front-end and independent component analysis (ICA) is implemented in FPGA to reduce large motion artifact at the digital domain. The bio-signal sensor is implemented to 4 channels and analog-front-end is reconfigurable to gather 4 kinds of bio-signal at once. The current-controlled level shifter (CCLS) is used in ADLC for the shifting voltage step as small as 3mV and the largest shifting voltage step is 100mV. The shift-ed DC level is extracted and removed with motion artifact through ICA. To reduce standby power dissipa-tion, the ICA also detects the channels suffered from motion artifact and enables ADLC circuit of those se-lected channels. The proposed 4-channel sleep monitoring sensor is implemented in a 0.13μm CMOS process, and consumes only 46μW to 73μW. With the proposed ADLC, 17.7 times larger motion artifact cannot saturate signal.