Abstract: 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).

Abstract: The invention relates to an amplifier circuit (10a, 10b) for a two-wire interface, comprising a first current path (1), comprising a voltage-controlled current source (T1) having a gate (GT1), which is connected to an input connection (E1) of the amplifier circuit. A second current path (2) of the amplifier circuit comprises a voltage-controlled current source (T2), which is connected in series with the second resistor (R2). The first resistor (R1) and a parallel connection of the first and second current paths (1, 2) are connected in series between an output connection (A) and a reference voltage connection (B) of the amplifier circuit. The amplifier circuit (10a, 10b) makes it possible to adjust the gain and to provide a supply voltage and a useful signal over a common conducting track (L).

Abstract: 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).

Abstract: A microphone amplifier comprises a microphone terminal for connecting a microphone, particularly a MEMS microphone, and an amplifier circuit with an amplifier input that is connected to the microphone terminal, and with an amplifier output that is connected to an output of the microphone amplifier. The amplifier circuit is designed to amplify an input signal present at the amplifier input in order to generate an output signal at the amplifier output. The microphone amplifier further comprises an overload circuit that is designed to detect an overload state within the amplifier circuit and to connect the amplifier input via a switching element, in particular with a low impedance, to a reference potential terminal if the overload state is detected for more than a predetermined time span.

Abstract: A microphone amplifier comprises an input terminal (E100) for applying an input signal (IN), an output terminal (A100a) for outputting an output signal (OUT), and an additional output terminal (A100b) for outputting an additional output signal (VBIAS). The microphone amplifier also contains an amplifying circuit (10) for generating the output signal (OUT) by amplifying the input signal (IN), wherein the amplifying circuit (10) is connected between the input terminal (E100) and the output terminal (A100a), and a voltage generator (30) for generating the additional output signal (VBIAS). A supply voltage terminal (V30) of the voltage generator (30) is connected to the output terminal (A100a) of the microphone amplifier. Since the amplifying circuit (10) makes available a supply voltage (V) for the voltage generator (30), the microphone amplifier can be operated without a separate supply voltage terminal.

Abstract: The invention relates to an amplifier circuit (10a, 10b) for a two-wire interface, comprising a first current path (1), comprising a voltage-controlled current source (T1) having a gate (GT1), which is connected to an input connection (E1) of the amplifier circuit. A second current path (2) of the amplifier circuit comprises a voltage-controlled current source (T2), which is connected in series with the second resistor (R2). The first resistor (R1) and a parallel connection of the first and second current paths (1, 2) are connected in series between an output connection (A) and a reference voltage connection (B) of the amplifier circuit. The amplifier circuit (10a, 10b) makes it possible to adjust the gain and to provide a supply voltage and a useful signal over a common conducting track (L).

Abstract: A differential amplifier comprises a first amplifier (A1) with a signal input (Inp) and a signal output (Out1) that is fed back to a first feedback input (In1) of the first amplifier (A1) and is also connected to a first output (outp) of the differential amplifier. Furthermore, a buffer circuit (Buff) is connected to the first output (outp). A nonlinear resistor circuit (Rnl1, Rnl2) is coupled via a first output node (Vmid1) with the first output (outp) and via a second output node (Vmid2) with the buffer circuit (Buff).

Abstract: A microphone amplifier comprises a microphone terminal for connecting a microphone, particularly a MEMS microphone, and an amplifier circuit with an amplifier input that is connected to the microphone terminal, and with an amplifier output that is connected to an output of the microphone amplifier. The amplifier circuit is designed to amplify an input signal present at the amplifier input in order to generate an output signal at the amplifier output. The microphone amplifier further comprises an overload circuit that is designed to detect an overload state within the amplifier circuit and to connect the amplifier input via a switching element, in particular with a low impedance, to a reference potential terminal if the overload state is detected for more than a predetermined time span.

Abstract: A microphone amplifier comprises an input terminal (E100) for applying an input signal (IN), an output terminal (A100a) for outputting an output signal (OUT), and an additional output terminal (A100b) for outputting an additional output signal (VBIAS). The microphone amplifier also contains an amplifying circuit (10) for generating the output signal (OUT) by amplifying the input signal (IN), wherein the amplifying circuit (10) is connected between the input terminal (E100) and the output terminal (A100a), and a voltage generator (30) for generating the additional output signal (VBIAS). A supply voltage terminal (V30) of the voltage generator (30) is connected to the output terminal (A100a) of the microphone amplifier. Since the amplifying circuit (10) makes available a supply voltage (V) for the voltage generator (30), the microphone amplifier can be operated without a separate supply voltage terminal.

Abstract: A differential amplifier comprises a first amplifier (A1) with a signal input (Inp) and a signal output (Out1) that is fed back to a first feedback input (In1) of the first amplifier (A1) and is also connected to a first output (outp) of the differential amplifier. Furthermore, a buffer circuit (Buff) is connected to the first output (outp). A nonlinear resistor circuit (Rnl1, Rnl2) is coupled via a first output node (Vmid1) with the first output (outp) and via a second output node (Vmid2) with the buffer circuit (Buff).