Component having a micromechanical microphone structure, and method for operating such a microphone component

Abstract

A concept is proposed for a MEMS microphone which may be operated at a relatively low voltage level and still have comparatively high sensitivity. The component according to the present invention includes a micromechanical microphone structure having an acoustically active diaphragm which functions as a deflectable electrode of a microphone capacitor (1), and a stationary acoustically permeable counterelement which functions as a counter electrode of the microphone capacitor (1). The component also includes means for applying a high-frequency clock signal (2) to the microphone capacitor (1) and for applying the inverted clock signal (2′) to an adjustable but acoustically inactive compensation capacitor (7), an integrating operational amplifier (3) which integrates the sum of the current flow through the microphone capacitor (1) and the current flow through the compensation capacitor (7), a demodulator (4) for the output signal of the integrating operational amplifier (3), the demodulator being synchronized with the clock signal (2), and a low-pass filter for obtaining a microphone signal which corresponds to the changes in capacitance of the microphone capacitor (1), based on the output signal of the demodulator (4).

Dependencies are inferred from the claim text.