A low-power cochlear implant system

Cochlear implants, or bionic ears, restore hearing to the profoundly deaf by bypassing missing inner-ear hair cells in the cochlea and electrically stimulating the auditory nerve. For miniaturized cochlear implants, including behind-the-ear (BTE) models, power consumption is the chief factor in determining cost and patient convenience. This thesis reports on the design of a low-power bionic ear system by addressing three critical signal and power processing subsystems in low-cost CMOS ICs. First, the design of a low-power current-mode front-end for subminiature microphones demonstrates 78dB dynamic range performance with attention to RF noise and supply immunity. Second, hearing-impaired patients need strategies that decide intelligently between listening conditions in speech or noise. This work describes an automatic gain control (AGC) design which uses programmable hybrid analog-digital current-mode feedback to implement a dual-loop strategy, a well-known algorithm for speech in noisy environments. The AGC exhibits level-invariant. stability, programmable time constants and consumes less than 36pW. Third, a feedback-loop technique is explored for analyzing and designing RF power links for transcutaneous bionic ear systems.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Baker, Michael W. (Michael Warren), 1977-

Advisor dc:contributor.advisor

• Rahul Sarpeshkar.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40494

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40494