Abstract: A microphone device, an interface circuit and method are provided for managing a potential difference in sensitivity to a detected environmental stimulus associated with a sensor arrangement, where multiple electrical signals forming a differential signal can be produced, and the multiple electrical signals can be better balanced. Such an interface circuit, which can be used within a microphone device includes a bias voltage generator having one or more bias output voltage terminals, where a respective one of one or more DC bias voltages is produced at each of the bias output voltage terminals, for being coupled to a pair of transduction elements of a sensor. The interface circuit further includes an amplifier circuit having a first input terminal coupled to a first one of the pair of output terminals of the sensor and having a second input terminal coupled to a second one of the pair of output terminals of the sensor, the amplifier circuit producing a differential output signal.

Abstract: The disclosure relates generally to microphone and vibration sensor assemblies (100) having a transducer (102), like a microelectromechanical systems (MEMS) device, and an electrical circuit (103) disposed in a housing (110) configured for integration with a host device. The electrical circuit includes a transducer bias circuit that applies a bias to the transducer and a bias control circuit (204) that compensates for transducer sensitivity drift caused by variation in an environmental condition of the transducer, and electrical circuits therefor.

Abstract: The disclosure relates generally to microphone and vibration sensor assemblies (100) having a transducer (102), like a microelectromechanical systems (MEMS) device, and an electrical circuit (103) disposed in a housing (110) configured for integration with a host device. The electrical circuit includes a variable gain signal processing circuit (203) that processes an electrical signal from the transducer and a gain control circuit (204) that compensates for transducer sensitivity drift caused by variation in an environmental condition of the transducer, and electrical circuits therefor.

Abstract: A sensor arrangement is provided, including a first capacitive sensor and a second capacitive sensor. A charge pump is coupled to the first capacitive sensor and to the second capacitive sensor, the charge pump being operable to deliver a positive bias voltage. A differential output has a first terminal coupled to the first capacitive sensor and a second terminal coupled to the second capacitive sensor.

Abstract: A microphone device, an interface circuit and method are provided for managing a potential difference in sensitivity to a detected environmental stimulus associated with a sensor arrangement, where multiple electrical signals forming a differential signal can be produced, and the multiple electrical signals can be better balanced. Such an interface circuit, which can be used within a microphone device includes a bias voltage generator having one or more bias output voltage terminals, where a respective one of one or more DC bias voltages is produced at each of the bias output voltage terminals, for being coupled to a pair of transduction elements of a sensor. The interface circuit further includes an amplifier circuit having a first input terminal coupled to a first one of the pair of output terminals of the sensor and having a second input terminal coupled to a second one of the pair of output terminals of the sensor, the amplifier circuit producing a differential output signal.

Abstract: The disclosure relates generally to microphone and vibration sensor assemblies (100) having a transducer (102), like a microelectromechanical systems (MEMS) device, and an electrical circuit (103) disposed in a housing (110) configured for integration with a host device. The electrical circuit includes a variable gain signal processing circuit (203) that processes an electrical signal from the transducer and a gain control circuit (204) that compensates for transducer sensitivity drift caused by variation in an environmental condition of the transducer, and electrical circuits therefor.

Abstract: The disclosure relates generally to microphone and vibration sensor assemblies (100) having a transducer (102), like a microelectromechanical systems (MEMS) device, and an electrical circuit (103) disposed in a housing (110) configured for integration with a host device. The electrical circuit includes a transducer bias circuit that applies a bias to the transducer and a bias control circuit (204) that compensates for transducer sensitivity drift caused by variation in an environmental condition of the transducer, and electrical circuits therefor.

Abstract: An interface circuit comprises a signal path including a front-end charge amplifier coupling an input of the interface circuit to an output of the interface circuit, and a DC control loop separate from the signal path. In some implementations, the interface circuit is part of a MEMS sensor that includes a MEMS transducer having an output coupled to the input of the interface circuit. The interface circuit can, in some cases, allow faster settling of the circuit to its steady-state operating point.

Abstract: An arrangement (2) to calibrate a capacitive sensor interface (1) includes a capacitive sensor (10) having a capacitance (cmem, cmemsp, cmemsm) and a charge storing circuit (20) having a changeable capacitance (cdum, cdump, cdumm). A test circuit (30) applies a test signal (vtst) to the capacitive sensor (10) and the charge storing circuit (20). An amplifier circuit (40) has a first input connection (E40a) coupled to the capacitive sensor (10) and a second input connection (E40b) coupled to the charge storing circuit (20). The amplifier circuit (40) provides an output signal (Vout) in dependence on a first input signal (?Verr1) applied to the first input connection (E40a) and a second input signal (?Verr2) applied to the second input connection (E40b). A control circuit (60) is configured to trim the capacitance (cdum, cdump, cdumm) of the charge storing circuit (20) such that the level of the output signal (Vout) tends to the level of zero.

Abstract: The microphone comprises a housing (1, 2), which has an inner volume (12) filled with a gas, an opening (10) of the housing, an acoustic sensor (3) arranged in the housing, a diaphragm (13) of the acoustic sensor located above the opening, and a heater (14) in the inner volume. The acoustic sensor may especially comprise a microelectromechanical system. The gas is heated from inside the inner volume to increase the pressure and generate a corresponding signal of the acoustic sensor (3). This signal can be used for self-calibration of the sensitivity or for self-diagnostics to check the function of the microphone.

Abstract: A charge pump circuit comprises a series circuit of a number N of stage circuits. A stage circuit comprises a converter circuit, a stage output, a stage input coupled via the converter circuit to the stage output, a first clock input and a second clock input coupled to the converter circuit, a control input and an activation transistor having a control terminal coupled to the control input and a first terminal coupled to the stage output.

Abstract: A MEMS sensor (1) comprises a MEMS transducer (10) being coupled to a MEMS interface circuit (20). The MEMS interface circuit (20) comprises a bias voltage generator (100), a differential amplifier (200), a capacitor (300) and a feedback control circuit (400). The bias voltage generator (100) generates a bias voltage (Vbias) for operating the MEMS transducer. The variable capacitor (300) is connected to one of the input nodes (I200a) of the differential amplifier (200). At least one of the output nodes (A200a, A200b) of the differential amplifier is coupled to a base terminal (T110) of an output filter (110) of the bias voltage generator (100). Any disturbing signal from the bias voltage generator (100) is a common-mode signal that is divided equally on the input nodes (I200a, I200b) of the differential amplifier (200) and is therefore rejected.

Abstract: A charge pump circuit comprises a series circuit of a number N of stage circuits. A stage circuit comprises a converter circuit, a stage output, a stage input coupled via the converter circuit to the stage output, a first clock input and a second clock input coupled to the converter circuit, a control input and an activation transistor having a control terminal coupled to the control input and a first terminal coupled to the stage output.

Abstract: An interface circuit comprises a signal path including a front-end charge amplifier coupling an input of the interface circuit to an output of the interface circuit, and a DC control loop separate from the signal path. In some implementations, the interface circuit is part of a MEMS sensor that includes a MEMS transducer having an output coupled to the input of the interface circuit. The interface circuit can, in some cases, allow faster settling of the circuit to its steady-state operating point.

Abstract: A sensor arrangement is provided, including a first capacitive sensor and a second capacitive sensor. A charge pump is coupled to the first capacitive sensor and to the second capacitive sensor, the charge pump being operable to deliver a positive bias voltage. A differential output has a first terminal coupled to the first capacitive sensor and a second terminal coupled to the second capacitive sensor.

Abstract: An arrangement (2) to calibrate a capacitive sensor interface (1) comprises a capacitive sensor (10) having a capacitance (cmem, cmemsp, cmemsm) and a charge storing circuit (20) having a changeable capacitance (cdum, cdump, cdumm). A test circuit (30) applies a test signal (vtst) to the capacitive sensor (10) and the charge storing circuit (20). An amplifier circuit (40) has a first input connection (E40a) coupled to the capacitive sensor (10) and a second input connection (E40b) coupled to the charge storing circuit (20). The amplifier circuit (40) provides an output signal (Vout) in dependence on a first input signal (?Verr1) applied to the first input connection (E40a) and a second input signal (?Verr2) applied to the second input connection (E40b). A control circuit (60) is configured to trim the capacitance (cdum, cdump, cdumm) of the charge storing circuit (20) such that the level of the output signal (Vout) tends to the level of zero.

Abstract: An amplifier circuit (AC) for amplifying an output signal (OS) of a capacitive sensor (M) comprises a first input terminal (AIN) to receive the output signal (OS) of the capacitive sensor (M) and a second input terminal (BIN) to receive a bias voltage (Vbias) of the capacitive sensor (M). The amplifier circuit (AC) comprises an amplifier (A) for amplifying the output signal (OS) and a control circuit (CF) arranged in a feedback loop (FL) of the amplifier (A) being configured to control a DC voltage level at an input connection (A1) of the amplifier (A). A bias voltage sensing circuit (BVS) senses a change of the level of the bias voltage (Vbias) at the second input terminal (BIN) and changes the bandwidth of the feedback loop (FL) in dependence on the sensed change of the level of the bias voltage (Vbias).

Abstract: The microphone comprises a housing (1, 2), which has an inner volume (12) filled with a gas, an opening (10) of the housing, an acoustic sensor (3) arranged in the housing, a diaphragm (13) of the acoustic sensor located above the opening, and a heater (14) in the inner volume. The acoustic sensor may especially comprise a microelectromechanical system. The gas is heated from inside the inner volume to increase the pressure and generate a corresponding signal of the acoustic sensor (3). This signal can be used for self-calibration of the sensitivity or for self-diagnostics to check the function of the microphone.

Abstract: A MEMS sensor (1) comprises a MEMS transducer (10) being coupled to a MEMS interface circuit (20). The MEMS interface circuit (20) comprises a bias voltage generator (100), a differential amplifier (200), a capacitor (300) and a feedback control circuit (400). The bias voltage generator (100) generates a bias voltage (Vbias) for operating the MEMS transducer. The variable capacitor (300) is connected to one of the input nodes (I200a) of the differential amplifier (200). At least one of the output nodes (A200a, A200b) of the differential amplifier is coupled to a base terminal (T110) of an output filter (110) of the bias voltage generator (100). Any disturbing signal from the bias voltage generator (100) is a common-mode signal that is divided equally on the input nodes (I200a, I200b) of the differential amplifier (200) and is therefore rejected.

Abstract: An amplifier circuit (AC) for amplifying an output signal (OS) of a capacitive sensor (M) comprises a first input terminal (AIN) to receive the output signal (OS) of the capacitive sensor (M) and a second input terminal (BIN) to receive a bias voltage (Vbias) of the capacitive sensor (M). The amplifier circuit (AC) comprises an amplifier (A) for amplifying the output signal (OS) and a control circuit (CF) arranged in a feedback loop (FL) of the amplifier (A) being configured to control a DC voltage level at an input connection (A1) of the amplifier (A). A bias voltage sensing circuit (BVS) senses a change of the level of the bias voltage (Vbias) at the second input terminal (BIN) and changes the bandwidth of the feedback loop (FL) in dependence on the sensed change of the level of the bias voltage (Vbias).