A MEMS-Based Power-Scalable Hearing Aid Analog Front End.

Area of Science:

• Electrical Engineering
• Auditory Neuroscience
• Biomedical Engineering

Background:

• Hearing aids require efficient front-end processing for improved audibility.
• Miniaturization and power efficiency are critical for wearable hearing aid devices.
• Integration of microelectromechanical-systems (MEMS) microphones offers enhanced directional audio capture.

Purpose of the Study:

• To present a dual-channel directional digital hearing aid front end.
• To detail an adaptive-power analog processing signal chain.
• To demonstrate a power-efficient and high-performance analog front end.

Main Methods:

• Utilized microelectromechanical-systems (MEMS) microphones for directional audio input.
• Implemented a double differential amplifier-based capacitance-to-voltage conversion circuit.
• Incorporated a 40-dB variable gain amplifier (VGA) and a power-scalable continuous-time sigma-delta analog-to-digital converter (ADC).

Main Results:

• Achieved a 68-dB signal-to-noise ratio (SNR) for the analog front end.
• Demonstrated a power dissipation of 67 μW from a 1.2-V supply.
• Fabricated MEMS microphones using standard surface micromachining and integrated VGA/ADC on a 0.25-μm CMOS process.

Conclusions:

• The developed digital hearing aid front end offers a power-efficient solution.
• The integration of MEMS microphones and advanced analog circuits enhances directional audio processing.
• This design represents a significant advancement in hearing aid technology for improved performance and reduced power consumption.