A Bio-Realistic Analog CMOS Cochlea Filter With High Tunability and Ultra-Steep Roll-Off

Shiwei Wang, Thomas Jacob Koickal, Alister Hamilton, Rebecca Cheung, Leslie S. Smith

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

This paper presents the design and experimental results of a cochlea filter in analog very large scale integration (VLSI) which highly resembles physiologically measured response of the mammalian cochlea. The filter consists of three specialized sub-filter stages which respectively provide passive response in low frequencies, actively tunable response in mid-band frequencies and ultra-steep roll-off at transition frequencies from pass-band to stop-band. The sub-filters are implemented in balanced ladder topology using floating active inductors. Measured results from the fabricated chip show that wide range of mid-band tuning including gain tuning of over 20dB, Q factor tuning from 2 to 19 as well as the bio-realistic center frequency shift are achieved by adjusting only one circuit parameter. Besides, the filter has an ultra-steep roll-off reaching over 300 dB/dec. By changing biasing currents, the filter can be configured to operate with center frequencies from 31 Hz to 8 kHz. The filter is 9 th order, consumes 59.5 ~ 90.0 μW power and occupies 0.9 mm 2 chip area. A parallel bank of the proposed filter can be used as the front-end in hearing prosthesis devices, speech processors as well as other bio-inspired auditory systems owing to its bio-realistic behavior, low power consumption and small size.
Original languageEnglish
Pages (from-to)297 - 311
Number of pages15
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number3
Early online date31 Jul 2014
Publication statusPublished - 30 Jun 2015

Keywords / Materials (for Non-textual outputs)

  • Analog VLSI
  • CMOS cochlea
  • auditoty filter
  • bio-inspired circuits
  • floating active inductor


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