Reconfigurable Filter Design for Implantable Auditory Prosthesis

Abstract

Multichannel sound processing approaches are used in Cochlear Implant (CI) applications for increased performance. Filterbanks are required for this purpose. Тhe implementation of a fully reconfigurable bandpass filter (BPF) with digital control is presented. Subthreshold transconductors (OTA) are used for lower power consumption and smaller capacitor values. The digital control of the OTA bias currents allows for a fine tuning of the BPF frequency characteristic. The full reconfigurability proves itself useful for non-simultaneous stimulation strategies. The BPF is implemented at transistor level. It covers the 300Hz-5.5kHz audio range and splits it into 6 logarithmically spaced channels. Simulations of the resulting circuit prove the efficiency of the digitally controlled reconfigurable analog blocks. Ill. 12, bibl. 14 (in English; summaries in English, Russian and Lithuanian).