Very Low-Cost CMOS Audio Amplifier for 1-V Portable Applications

• Published in: 2008 3rd International Conference on Design and Technology of Integrated Systems in Nanoscale Era pp. 1 - 4
• Main Authors: Azzolini, C., Ricciardi, A., Boni, A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-03-2008
• Subjects: Auditory system; Batteries; Circuit noise; class AB amplifiers; CMOS audio amplifiers; Energy consumption; Loudspeakers; low-cost hearing aid; Low-voltage amplifier; Noise cancellation; offset cancellation circuit; Power amplifiers; Power generation; Silicon; Voltage
• ISBN: 1424415764; 9781424415762
• DOI: 10.1109/DTIS.2008.4540229

The design of a very low-cost full-analog audio amplifier IC for hearing aid devices is presented. The overall circuit consumes 460-muA from a 1.3-V battery supply (excluded loudspeaker, without signal) but the hearing aid is able to operate with a depleted battery down to 1-V. The nominal THD of the circuit is lower than 1-% at 10-mW output power whereas the input referred equivalent noise voltage is 3.2-muV RMS . An effective analog offset cancellation circuit ensures a low quiescent power consumption in case of strong process mismatch. The silicon area is as low as 1.5-mm 2 in a 0.35-mum CMOS process.