1.
IEEE Trans Biomed Circuits Syst
; 5(3): 201-13, 2011 Jun.
Article
in English
| MEDLINE
| ID: mdl-23851471
ABSTRACT
A dual-channel directional digital hearing aid front end using microelectromechanical-systems microphones, and an adaptive-power analog processing signal chain are presented. The analog front end consists of a double differential amplifier-based capacitance-to-voltage conversion circuit, 40-dB variable gain amplifier (VGA) and a power-scalable continuous time sigma delta analog-to-digital converter (ADC), with 68-dB signal-to-noise ratio dissipating 67 µ W from a 1.2-V supply. The MEMS microphones are fabricated using a standard surface micromachining technology. The VGA and power-scalable ADC are fabricated on a 0.25-µ m complementary metal-oxide semciconductor TSMC process.