Design and evaluation of area-efficient and wide-range impedance analysis circuit for multichannel high-quality brain signal recording system. (29th March 2016)

• Record Type: Journal Article
• Authors: Iwagami, Takuma; Tani, Takaharu; Ito, Keita; Nishino, Satoru; Harashima, Takuya; Kino, Hisashi; Kiyoyama, Koji; Tanaka, Tetsu
• Is Part Of: Japanese journal of applied physics. Volume 55:Number 4(2016:Apr.)Supplement 4
• Publication Date: 2016-03-29
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.55.04EM12
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: To enable chronic and stable neural recording, we have been developing an implantable multichannel neural recording system with impedance analysis functions. One of the important things for high-quality neural signal recording is to maintain well interfaces between recording electrodes and tissues. We have proposed an impedance analysis circuit with a very small circuit area, which is implemented in a multichannel neural recording and stimulating system. In this paper, we focused on the design of an impedance analysis circuit configuration and the evaluation of a minimal voltage measurement unit. The proposed circuit has a very small circuit area of 0.23 mm 2 designed with 0.18 µm CMOS technology and can measure interface impedances between recording electrodes and tissues in ultrawide ranges from 100 Ω to 10 MΩ. In addition, we also successfully acquired interface impedances using the proposed circuit in agarose gel experiments.