title: A Bio-Realistic Analog CMOS Cochlea Filter With High Tunability and Ultra-Steep Roll-Off.
abstract: 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 20 dB, 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 9th order, consumes 59.5 ∼ 90.0 μW power and occupies 0.9 mm2 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.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Wang
authors.forename: Thomas Jacob
authors.initials: TJ
authors.lastname: Koickal
authors.forename: Alister
authors.initials: A
authors.lastname: Hamilton
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cheung
authors.forename: Leslie S
authors.initials: LS
authors.lastname: Smith
mesh_terms: D000818:Animals; D003051:Cochlea / Q000502:physiology*; D004582:Electronics, Medical / Q000295:instrumentation*; D004867:Equipment Design / Q000379:methods; D006801:Humans; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*