A Silicon Cochlea With Active Coupling

We present a mixed-signal very-large-scale-integrated chip that emulates nonlinear active cochlear signal processing. Modeling the cochlea's micromechanics, including outer hair cell (OHC) electromotility, this silicon (Si) cochlea features active coupling between neighboring basilar membrane (...

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Main Authors: Wen, Bo, Boahen, Kwabena
Other Authors: Massachusetts Institute of Technology. Research Laboratory of Electronics
Format: Article
Language:en_US
Published: Institute of Electrical and Electronics Engineers (IEEE) 2012
Online Access:http://hdl.handle.net/1721.1/71802
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author Wen, Bo
Boahen, Kwabena
author2 Massachusetts Institute of Technology. Research Laboratory of Electronics
author_facet Massachusetts Institute of Technology. Research Laboratory of Electronics
Wen, Bo
Boahen, Kwabena
author_sort Wen, Bo
collection MIT
description We present a mixed-signal very-large-scale-integrated chip that emulates nonlinear active cochlear signal processing. Modeling the cochlea's micromechanics, including outer hair cell (OHC) electromotility, this silicon (Si) cochlea features active coupling between neighboring basilar membrane (BM) segments-a first. Neighboring BM segments, each implemented as a class AB log-domain second-order section, exchange currents representing OHC forces. This novel active-coupling architecture overcomes the major shortcomings of existing cascade and parallel filter-bank architectures, while achieving the highest number of digital outputs in an Si cochlea to date. An active-coupling architecture Si cochlea with 360 frequency channels and 2160 pulse-stream outputs occupies 10.9 mm[superscript 2] in a five-metal 1-poly 0.25-mum CMOS process. The chip's responses resemble that of a living cochlea's: Frequency responses become larger and more sharply tuned when active coupling is turned on. For instance, gain increases by 18 dB and Q 10 increases from 0.45 to 1.14. This enhancement decreases with increasing input intensity, realizing frequency-selective automatic gain control. Further work is required to improve performance by reducing large variations from tap to tap.
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spelling mit-1721.1/718022022-09-23T11:09:49Z A Silicon Cochlea With Active Coupling Wen, Bo Boahen, Kwabena Massachusetts Institute of Technology. Research Laboratory of Electronics Wen, Bo Wen, Bo We present a mixed-signal very-large-scale-integrated chip that emulates nonlinear active cochlear signal processing. Modeling the cochlea's micromechanics, including outer hair cell (OHC) electromotility, this silicon (Si) cochlea features active coupling between neighboring basilar membrane (BM) segments-a first. Neighboring BM segments, each implemented as a class AB log-domain second-order section, exchange currents representing OHC forces. This novel active-coupling architecture overcomes the major shortcomings of existing cascade and parallel filter-bank architectures, while achieving the highest number of digital outputs in an Si cochlea to date. An active-coupling architecture Si cochlea with 360 frequency channels and 2160 pulse-stream outputs occupies 10.9 mm[superscript 2] in a five-metal 1-poly 0.25-mum CMOS process. The chip's responses resemble that of a living cochlea's: Frequency responses become larger and more sharply tuned when active coupling is turned on. For instance, gain increases by 18 dB and Q 10 increases from 0.45 to 1.14. This enhancement decreases with increasing input intensity, realizing frequency-selective automatic gain control. Further work is required to improve performance by reducing large variations from tap to tap. 2012-07-25T16:20:52Z 2012-07-25T16:20:52Z 2009-10 2008-11 Article http://purl.org/eprint/type/JournalArticle 1932-4545 1940-9990 http://hdl.handle.net/1721.1/71802 Bo Wen, and K. Boahen. “A Silicon Cochlea With Active Coupling.” IEEE Transactions on Biomedical Circuits and Systems 3.6 (2009): 444–455. © Copyright 2009 IEEE en_US http://dx.doi.org/10.1109/tbcas.2009.2027127 IEEE Transactions on Biomedical Circuits and Systems Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Electrical and Electronics Engineers (IEEE) IEEE
spellingShingle Wen, Bo
Boahen, Kwabena
A Silicon Cochlea With Active Coupling
title A Silicon Cochlea With Active Coupling
title_full A Silicon Cochlea With Active Coupling
title_fullStr A Silicon Cochlea With Active Coupling
title_full_unstemmed A Silicon Cochlea With Active Coupling
title_short A Silicon Cochlea With Active Coupling
title_sort silicon cochlea with active coupling
url http://hdl.handle.net/1721.1/71802
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