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 metaloxide semciconductor TSMC process.

Original languageEnglish (US)
Article number5611627
Pages (from-to)201-213
Number of pages13
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number3
Publication statusPublished - Jun 2011



  • Continuous time sigma-delta modulation
  • digital hearing aids
  • directional microphone array
  • microelectromechanical-systems (MEMS) microphone

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Biomedical Engineering

Cite this