Ams Ag

Knowles Electronics, Inc.

Ams International Ag

Thomas Christen

Colin Steele

Thomas Froehlich

Mark Niederberger

Rene Scheuner

Andreas Fitzi

Lukas Perktold

Dusan Prelog

Duy-Dong Pham

René Blattmann

Thomas Fröhlich

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

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

A signal processing arrangement has a signal input for connecting a capacitive sensor. An amplifier circuit is coupled between the signal input and a feedback point. A loop filter is coupled downstream to the feedback point. A quantizer is connected downstream to the loop filter and provides a multi-bit output word. The multi-bit output word consists of one or more higher significance bits and one or more lower significance bits. A first feedback path is coupled between a quantizer and the feedback point for providing a first feedback signal to the feedback point being representative of the one or more lower significance bits. A second feedback path is coupled to the quantizer for providing a second feedback signal to the signal input being representative of the one or more higher significance bits.

Signal processing arrangement, sensor arrangement and signal processing method

A delta-sigma modulator () comprises a modulator loop () and a code generator (). The modulator loop () comprises a loop filter (). The code generator () is configured to generate a generator signal (BS) that is realized as an extended Barker code. The code generator () comprises a generator output () that is coupled to the loop filter ().

Delta-sigma modulator and method for signal conversion

An amplifier arrangement comprising an amplifier (AMP) with a terminal (SPL) for a supply signal (VSPL) and a bias circuit (BIAS) for providing the supply signal (VSPL) at the terminal (SPL). The bias circuit holds an operating point (OP) of the amplifier (AMP) constant by means of the supply signal (VSPL). The bias circuit (BIAS) comprises a reference circuit (REF) for providing a reference signal (VREF) and a correction device (COR) by means of which the supply signal (VSPL) is regulated based on the reference signal (VREF) and a correction signal (Vfeed), the correction signal (Vfeed) being dependent on the operating point (OP) of the amplifier (AMP). A method for operating an amplifier arrangement is also described.

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Zurich, Switzerland

Thomas Christen