INDEPENDENTLY CHARGE PUMPS FOR DIFFERENTIAL MICROPHONE

摘要

Systems and methods of generating independent adjustable bias voltages for a differential microphone. The microphone system includes a positive adjustable charge pump, a positive sense capacitor, a negative adjustable charge pump, a negative sense-capacitor, and a differential amplifier. The positive adjustable charge pump is configured to generate a positive bias voltage. The positive sense-capacitor is configured to generate a positive sense voltage based on acoustic pressure from a first direction and the positive bias voltage. The negative adjustable charge pump is configured to generate a negative bias voltage. The negative sense-capacitor is configured to generate a negative sense voltage based on the acoustic pressure from the first direction and the negative bias voltage. The differential amplifier is configured to receive the positive and negative sense voltages. The differential amplifier is also configured to generate a differential voltage based on the positive and negative sense voltages.

主权项

1. A microphone system comprising:
a positive adjustable charge pump configured to generate a positive bias voltage; a positive sense-capacitor configured to
receive acoustic pressure from a first direction,receive the positive bias voltage, andgenerate a positive sense voltage based on the acoustic pressure and the positive bias voltage; a negative adjustable charge pump configured to generate a negative bias voltage; a negative sense-capacitor configured to
receive the acoustic pressure from the first direction,receive the negative bias voltage, andgenerate a negative sense voltage based on the acoustic pressure and the negative bias voltage; and a differential amplifier configured to
receive the positive sense voltage,receive the negative sense voltage, andgenerate a differential voltage based on the positive sense voltage and the negative sense voltage; wherein a magnitude of the positive bias voltage is different than a magnitude of the negative bias voltage; and wherein the positive adjustable charge pump includes
a plurality of positive stages coupled in a series configuration and configured to generate the positive bias voltage based on a positive reference voltage and a positive input voltage, anda positive clock circuit configured to apply the positive reference voltage to the plurality of positive stages in a clocked manner based on a first frequency; and wherein the negative adjustable charge pump includes
a plurality of negative stages coupled in a series configuration and configured to generate the negative bias voltage based on a negative reference voltage and a negative input voltage, anda negative clock circuit configured to apply the negative reference voltage to the plurality of negative stages in a clocked manner based on a second frequency.