An adaptive microphone preamplifier for low power applications

In this paper, we present a microphone preamplifier that adapts its power consumption according to the input signal´s instantaneous bandwidth. The preamplifier´s dynamic range and gain keep reasonably constant, regardless of the power consumption. The preamplifier was fabricated with a 0.5-μm CMOS process. The measurement results show it has over 79.5-dB dynamic range with 53.4% power saving compared to its non-adaptive counterpart.