Knowles Electronics, Inc.

Ams Ag

Ams International Ag

Austriamicrosystems Ag

S. C. Johnson Son, Inc.

Mark Niederberger

Thomas Froehlich

Vincenzo Leonardo

Luca Bettini

Lukas Perktold

Colin Steele

Jeffrey J Wolf

Weiwen Dai

Thomas Christen

Vezio Malandruccolo

Rene Scheuner

Scott W Demarest

Jose Porchia

David C Belongia

Thomas Jaworski

Steven B Mineau

Mohammad Shajaan

Michael Kuntzman

David J Schram

Dean R Holzberger

Mohsin Nawaz

Christian Lillelund

Urs Denier

Kara J Mackey

Shenjie Wang

Thomas Gautschi

René Scheuner

Roger Ehrensperger

Adrian Ryser

Thomas Mueller

Duy-Dong Pham

René Blattmann

Thomas Fröhlich

Dominik Hollinger

A capacitive sensor assembly is disclosed, including a capacitive motor coupled to a charge pump circuit via a low pass filter, and a frontend amplifier circuit having an input coupled to the capacitive motor interface and an output coupled to an output of the electrical circuit. An injection current source (ICS) is coupled to the charge pump circuit output and configured to control voltage across a diode-based resistive element of the low pass filter during a transient startup phase of the charge pump circuit, wherein a settling time of the charge pump is reduced.

Capacitive sensor assembly and electrical circuit therefor

A microelectromechanical systems (MEMS) sensor, a capacitive MEMS motor sensing circuit and a method are provided. The MEMS sensor includes a housing having electrical contacts disposed on an exterior of the housing. The MEMS sensor further includes a capacitive MEMS motor disposed in the housing, and an electrical circuit disposed in the housing and being electrically coupled to the electrical contacts. The electrical circuit includes a bias voltage source having an output coupled to an input of the MEMS motor. The electrical circuit further includes an amplifier including an amplifier input stage having an input, coupled to an output of the MEMS motor, the amplifier input stage having a negative input resistance, where a sum of a series resistance of the MEMS motor at the input and the negative input resistance is less than zero, and wherein application of a signal from the output of the MEMS motor to the input of the amplifier input stage produces a negative real part of input current. The electrical circuit still further includes a stabilization circuit having an output coupled to the input of the amplifier input stage, where the stabilization circuit injects a compensation current at the input of the amplifier input stage that offsets at least a portion of the negative real part of input current.

Microelectromechanical systems sensor with stabilization circuit

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. The interface circuit still further includes a compensation circuit coupled to the amplifier circuit for producing a balance signal based on an output signal being produced by the amplifier circuit, wherein the balance signal compensates for any difference in amplitude in the first and second electrical signals that are received by the amplifier circuit from the sensor.

Method and apparatus for balancing detection sensitivity in producing a differential signal

The disclosure relates generally to microphone and vibration sensor assemblies () having a transducer (), like a microelectromechanical systems (MEMS) device, and an electrical circuit () disposed in a housing () 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 () that compensates for transducer sensitivity drift caused by variation in an environmental condition of the transducer, and electrical circuits therefor.

Microphone assembly with transducer sensitivity drift compensation and electrical circuit therefor

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

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.

Sensor arrangement and method

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.

Input current-tolerant amplifier input stage for MEMS sensors and other devices

An arrangement () to calibrate a capacitive sensor interface () includes a capacitive sensor () having a capacitance (cmem, cmemsp, cmemsm) and a charge storing circuit () having a changeable capacitance (cdum, cdump, cdumm). A test circuit () applies a test signal (vtst) to the capacitive sensor () and the charge storing circuit (). An amplifier circuit () has a first input connection (E) coupled to the capacitive sensor () and a second input connection (E) coupled to the charge storing circuit (). The amplifier circuit () provides an output signal (Vout) in dependence on a first input signal (&#x394;Verr) applied to the first input connection (E) and a second input signal (&#x394;Verr) applied to the second input connection (E). A control circuit () is configured to trim the capacitance (cdum, cdump, cdumm) of the charge storing circuit () such that the level of the output signal (Vout) tends to the level of zero.

Arrangement to calibrate a capacitive sensor interface

The microphone comprises a housing (), which has an inner volume () filled with a gas, an opening () of the housing, an acoustic sensor () arranged in the housing, a diaphragm () of the acoustic sensor located above the opening, and a heater () 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 (). This signal can be used for self-calibration of the sensitivity or for self-diagnostics to check the function of the microphone.

Microphone and method of testing a microphone

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.

Charge pump circuit and method for voltage conversion

A MEMS sensor () comprises a MEMS transducer () being coupled to a MEMS interface circuit (). The MEMS interface circuit () comprises a bias voltage generator (), a differential amplifier (), a capacitor () and a feedback control circuit (). The bias voltage generator () generates a bias voltage (Vbias) for operating the MEMS transducer. The variable capacitor () is connected to one of the input nodes (I) of the differential amplifier (). At least one of the output nodes (A, A) of the differential amplifier is coupled to a base terminal (T) of an output filter () of the bias voltage generator (). Any disturbing signal from the bias voltage generator () is a common-mode signal that is divided equally on the input nodes (I, I) of the differential amplifier () and is therefore rejected.

MEMS sensor

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 (A) 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).

Amplifier circuit for amplifying an output signal of a capacitive sensor

A voltage reference source includes a source block, a first resistor having a first terminal coupled to a first terminal of the source block, a reference output for providing a reference voltage, and a first and a second mirror transistor forming a first current mirror. The first mirror transistor couples a second terminal of the source block to a supply voltage terminal and the second mirror transistor couples the reference output to the supply voltage terminal. A series connection of a second resistor and a diode is arranged between the reference output and the first terminal of the first resistor. A mirror current flows through the second mirror transistor and the series connection to the first terminal of the first resistor.

Voltage reference source and method for generating a reference voltage

In an embodiment a shunt driver circuit has a first and a second connection terminal (N, N) forming a two-wire interface (N, N), the first connection terminal (N) being prepared to receive a supply power and to provide an output signal (Sout), the second connection terminal (N) being connected to a reference potential terminal (), an Operational Transconductance Amplifier, OTA, () comprising a first input coupled to the first connection terminal (N), a second input for receiving a first reference signal (Sref) and an output () for providing a signal (S) depending on a difference between an input signal on the first input and the first reference signal (Sref), a capacitor (C) coupled between the output () and the first input of the OTA () via the second connection terminal (N) in a control loop, and a controlled current source () coupled between the output () of the OTA () and the second connection terminal (N). The controlled current source () is controlled to provide an additional current (Ifall) during a transient phase of the output signal (Sout).

Shunt driver circuit and method for providing an output signal

A detection circuit has a detection path and a control path. The detection path comprises a signal limiter () with a signal input (), which is connected to a detection node (OUT), and a filter () which is coupled to a signal output () of the signal limiter (). The detection path also comprises a short circuit detector () with a first and a second detector input () and a detector output (), wherein the first detector input () is coupled to the filter (). The control path comprises a control circuit () for controlling a switch () which is coupled to the detector output () and to the filter () by means of a control input () and is connected to the switch () by means of a control output (). The switch () is coupled to the detection node (OUT) and to a supply node (VSS, VHV).

Growing community of inventors

Einsiedeln, Switzerland

Mark Niederberger