Ams International Ag

Ams Ag

Lukas Perktold

Mark Niederberger

Colin Steele

Thomas Froehlich

Thomas Christen

Rene Scheuner

Duy-Dong Pham

René Scheuner

Thomas Fröhlich

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

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

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Hinwil, Switzerland

Lukas Perktold