Low-voltage CMOS log-companding techniques for audio applications

Abstract

This paper presents a collection of novel current-mode circuit techniques for the integration of very low-voltage (down to 1 V) low-power (few hundreds of μA) complete SoCs in CMOS technologies. The new design proposal is based on both, the Log Companding theory and the MOSFET operating in subthreshold. Several basic building blocks for audio amplification, AGC and arbitrary filtering are given. The feasibility of the proposed CMOS circuits is illustrated through experimental data for different design case studies in 1.2 and 0.35 μm VLSI technologies.