TWO WIRE AUTOBIAS VEHICULAR MICROPHONE SYSTEM HAVING USER INPUT FUNCTIONALITY AND METHOD OF FORMING SAME

摘要

An autobias vehicular microphone system (300) includes a microphone (301) which uses an amplifier (306) for amplifying an output of the microphone. A first feedback path (308) provides an amplifier output signal to the amplifier input for providing amplifier linearity, and a second feedback path (305) is used for providing bias to a voltage reference (303). The voltage reference (303) operates to provide an autobias to the amplifier (306) based upon amplifier load-ing. By holding the bias point to a constant voltage, a constant clip level can be maintained depending on varying load conditions of electronic devices (307, 309, 311) using the microphone (301). Additionally, one or more switches can be used to vary the bias point which can be interpreted to control functionality of the electronic devices (307, 309, 311).