A Design of Neural Signal Sensing LSI with Multi-Input-Channels

Takeshi YOSHIDA  Takayuki MASHIMO  Miho AKAGI  Atsushi IWATA  Masayuki YOSHIDA  Kazumasa UEMATSU  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E87-A    No.2    pp.376-383
Publication Date: 2004/02/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)
Category: 
Keyword: 
neural signal sensing LSI,  multi-input-channels probe,  flicker noise,  chopper amplifier,  multi-mode ADC,  

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Summary: 
A neural-signal sensing system with multi-input-channels was designed utilizing a new chopper amplifier with direct connected to a multiplexer. The proposed system consists of multiplexers, chopper amplifiers, a multi-mode analog-to-digital converter (ADC), and a wireless transmitter. It enables to measure 50-channel signals at the same time, which are selected out of 100 channels to detect useful information. The test chip including 10-channel-inputs chopper-amplifier and multi-mode ADC, that was designed and fabricated with a mixed signal 0.35-µm CMOS technology. Utilizing the proposed direct chopper input scheme and the shared chopper amplifier, the circuits was designed with a small area of 9.4 mm2. High accuracy channel selecting and multiplexing operations were confirmed, and an equivalent input noise of 10-nV/root-Hz was obtained with test chip measurements. Power dissipation of the chopper amplifier and the ADC were 6.0-mW and 2.5-mW at a 3-V supply voltage, respectively.