Electret microphone circuit with low battery disable

摘要

A battery circuit for coupling a battery source to an electret microphone. The circuit includes impedance circuitry for providing appropriate bias impedance for a desired microphone sensitivity, and disconnect circuitry for automatically disconnecting the battery source from the electret microphone in response to detecting a low voltage state in order to prevent distortion and low output level of the microphone. In an alternative embodiment of the invention there is provided second impedance circuitry for driving corresponding inputs with minimal loss. In another alternative embodiment of the invention there is provided a compensation circuit which operates to extend battery source life and prevent lower output at lower voltage.