Design of a Wireless Neural-Sensing LSI

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

Publication
IEICE TRANSACTIONS on Electronics  Vol.E87-C  No.6  pp.996-1002
Publication Date: 2004/06/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit and Device Technologies)
Category: 
Keyword: 
neural-sensing LSI,  wireless communication,  multi-input-channels,  chopper amplifier,  flicker noise,  multi-mode ADC, 

Full Text: PDF

Summary: 
We propose a neural-sensing LSI with a bi-directional wireless interface, which is capable of detecting 5-channel neural signals in a living animal. The proposed sensing LSI consists of a multiplexer with 5-channels selectable from 10 channels, a chopper amplifier using a new direct-chopper-input scheme, a programmable multi-mode analog-to-digital converter (ADC), and a wireless-transmitter/receiver with BPSK modulation signals. The test-chip was implemented by mixed-signal 0.35-µm CMOS technology. We measured the test chip and confirmed basic operations of these blocks. The chopper-amplifier achieved 66-dB DC gain, bandwidth of 400 kHz, and 4-µV noise with power dissipation of 6-mW with a 3-V supply. We observed real nerve signals in a living cricket using the proposed chopper amplifier. ADC achieved 52-ksps operation with power dissipation of 0.43-mW at 3-V supply. The wireless transmitter achieved 1-Mbps data transmission at a distance of 1-m with 1.5-mW power dissipation at 3-V supply.