Electric amplifier circuit for amplifying an output signal of a microphone

摘要

An electric amplifier circuit for amplifying an output signal of a microphone comprises a supply input terminal (V10) to apply a supply potential (VDDA) for operating the electric amplifier circuit and a differential amplifier (110) having a first input terminal (E110a) for applying the output signal of the microphone (20), a second input terminal (E110b) and an output terminal (A110) for outputting an amplified output signal (OUT) of the microphone (20). A feedback path (FP) is provided between the output terminal (A110) of the differential amplifier (110) and the second input terminal (E110b) of the differential amplifier (110). A charge supplying circuit (120) is coupled to the feedback path (FP) to supply an amount of the charge to the feedback path (FP) in dependence on the supply potential (VDDA). The amount of charge supplied to the feedback path may be dependent on a change of the supply potential (VDDA).

主权项

1. An electric amplifier circuit for amplifying an output signal of a microphone, comprising:
a supply input terminal to apply a supply potential for operating the electric amplifier circuit; an input terminal to apply the output signal of the microphone; an output terminal to output an output signal of the amplifier circuit; a differential amplifier having a first input terminal for applying a first input signal, a second input terminal for applying a second input signal and an output terminal for outputting the output signal of the amplifier circuit, wherein the first input terminal of the differential amplifier is coupled to the input terminal of the amplifier circuit, and the output terminal of the differential amplifier is coupled to the output terminal of the amplifier circuit; a feedback path being coupled between the output terminal of the differential amplifier and the second input terminal of the differential amplifier; and a charge supplying circuit for supplying a charge, the charge supplying circuit being coupled to the feedback path, wherein the charge supplying circuit is configured to supply an amount of the charge to the feedback path in dependence on a change of the supply potential, wherein the charge supplying circuit comprises an electric storage circuit for storing the charge, and wherein the charge supplying circuit is configured such that the amount of charge being stored within the electric storage circuit is dependent on the change of the supply potential and the gain of the differential amplifier.