title: Analog front-end measuring biopotential signal with effective offset rejection loop.
abstract: This paper presents an analog front-end (AFE) IC design for recording biopotential signals. The AFE employs a capacitively coupled instrumentation amplifier to achieve a low-noise and high-common mode rejection ratio (CMRR) system. A ripple reduction loop is proposed to reduce the ripple generated by the up-modulating chopper. The low frequency noise is attenuated by an input AC coupling capacitor, and is attenuated again by a DC servo loop. The proposed AFE features a differential gain of 71 dB, and a CMRR of 89 dB, at 50 Hz. Furthermore, the proposed AFE can robustly acquire biopotential signals even in the presence of an input offset and ripples.
authors.affiliation: Department of Electronics, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Lim
authors.affiliation: Department of Electronics, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Hyunho
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Electronics, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Haryong
authors.initials: H
authors.lastname: Song
authors.affiliation: School of Electrical Engineering, ASRI/ ISRC, Seoul National University, Seoul 151-744, Korea.
authors.forename: Dong-il Dan
authors.initials: DI
authors.lastname: Cho
authors.affiliation: Department of Electronics, Chungnam National University, Daejeon 305-764, Korea.
authors.forename: Hyoungho
authors.initials: H
authors.lastname: Ko
mesh_terms: D000465:Algorithms; D000669:Amplifiers, Electronic; D004562:Electrocardiography / Q000295:instrumentation* / Q000379:methods; D055724:Electrophysiological Phenomena; D004867:Equipment Design; D006801:Humans
keywords: Biopotential analog front-end (AFE); DC servo loop; electrocardiogram (ECG); electroencephalograph (EEG); ripple reduction loop