A design framework for low power analog filter banks

We detail the design of multiresolution analog filter banks, linear models of cochlear function, with power dissipation being a prime engineering constraint. We propose that a reasonable goodness criterion is the information rate through the system, per watt of power dissipated. Speech applications requiring filter banks with a wide frequency tuning range, from 20 Hz to 20 kHz, and low power consumption make the transconductance-C integrator in subthreshold CMOS the preferable integrator structure. As an example, the dynamic range of a lowpass filter is computed and subsequently used to design a filter bank that models faithfully cochlear micro-mechanics. The power consumption of the entire filter bank is computed from analytical expressions and is estimated as 355 nW, at 68 kb/s overall information rate at the output of the system.