Abstract: A capacitive sensor circuit includes a sensor for providing a sensing voltage, a pre-processing circuit electrically connected to the sensor via an input connection line, and an impedance transformation circuit electrically connected between the input connection line and a bias point. The impedance transformation circuit includes a first impedance unit and a second impedance unit. The first impedance unit includes a first current mirror, and the second impedance unit includes a second current mirror configured as an invented matching current mirror of the first current mirror. The first current mirror is electrically connected to the input connection line, and the second current mirror is electrically connected to the bias point to receive a bias voltage.

Abstract: A circuit module for a silicon condenser microphone of the present disclosure includes a transducer, a charge pump, an isolator, a first amplifier, a second amplifier, a reaction circuit, a first bias circuit, and a second bias circuit. The charge pump electrically connects to an input port of the transducer, and an output port of the transducer electrically connects to an input port of the first amplifier via the isolator. An output port of the first amplifier electrically connects to an input port of the second amplifier. The reaction circuit is arranged between the output port of the first amplifier and the input port of the transducer. The isolator isolates the direct-current components of the first electrical signal, and therefore, the oscillations of the direct-current components will not affect the performance of the first amplifier.

Abstract: A circuit module for a silicon condenser microphone of the present disclosure includes a transducer, a charge pump, an isolator, a first amplifier, a second amplifier, a reaction circuit, a first bias circuit, and a second bias circuit. The charge pump electrically connects to an input port of the transducer, and an output port of the transducer electrically connects to an input port of the first amplifier via the isolator. An output port of the first amplifier electrically connects to an input port of the second amplifier. The reaction circuit is arranged between the output port of the first amplifier and the input port of the transducer. The isolator isolates the direct-current components of the first electrical signal, and therefore, the oscillations of the direct-current components will not affect the performance of the first amplifier.

Abstract: A capacitive sensor circuit includes a sensor for providing a sensing voltage, a pre-processing circuit electrically connected to the sensor via an input connection line, and an impedance transformation circuit electrically connected between the input connection line and a bias point. The impedance transformation circuit includes a first impedance unit and a second impedance unit. The first impedance unit includes a first current mirror, and the second impedance unit includes a second current mirror configured as an invented matching current mirror of the first current mirror. The first current mirror is electrically connected to the input connection line, and the second current mirror is electrically connected to the bias point to receive a bias voltage.