Freescale Semiconductor,inc.

Nxp Usa, Inc.

Marco Fuhrmann

Todd Frederick Miller

Andrew C McNeil

Yizhen Lin

Keith L Kraver

Dubravka Bilic

Thomas D Ohe

Tom D Ohe

A sensor with continuous self test is provided. An exemplary inertial sensor may include one or more self test electrodes so that one or more test signals may be applied to the electrodes during normal operation of the sensor. Normal sensor output may be read and stored during normal operation, when self test signals are typically not applied to the sensor. The normal sensor output provides a baseline for comparison to a sensor offset error detection signal produced when a test signal may be applied to one self test electrode, and also to a sense error detection signal when a test signal may be applied to both self test electrodes.

Continuous selftest for inertial sensors at 0 Hz

A pressure sensor includes a first set of electrodes, a second set of electrodes, and a common electrode. The first and second sets of electrodes overlie an insulative surface, wherein the first set of electrodes represent sense capacitor bottom electrodes and the second set of electrodes represent reference capacitor bottom electrodes. The second set of electrodes is configured in an interleaved arrangement with the first set of electrodes, wherein the geometry of individual electrodes of the first set of electrodes substantially matches the geometry of individual electrodes of the second set of electrodes. In addition, the common electrode represents a sense and reference capacitor top electrode that is (i) overlying, (ii) spaced from, and (iii) configured in connection with the first and second sets of electrodes to form a common pressure cavity, wherein the common electrode includes first portions corresponding to sense membrane portions and second portions corresponding to reference membrane portions, further wherein an area of a sense membrane portion is greater than an area of a reference membrane portion.

Pressure sensor featuring offset cancellation and method of making

An apparatus () and method () for sensing acceleration are provided. The method includes producing () a first signal in response to an acceleration sensed by a transducer, producing () a second signal based on the first signal, and actuating () the transducer in response to the second signal to remove offset in the transducer. The first signal represents the acceleration, and the second signal represents a low frequency component associated with an offset in the transducer. The apparatus () includes a transducer () producing a capacitance in response to the acceleration, a sensing system () producing a first signal from the capacitance representing the acceleration, and a compensation system () coupled between the sensing system and transducer. The compensation system produces a second signal based on the first signal for substantially removing an offset of the transducer.

Method and apparatus for closed loop offset cancellation

A symmetrical differential capacitive sensor () includes a movable element () pivotable about a geometrically centered rotational axis (). The element () includes sections (). Each of the sections () has a stop () spaced equally away from the rotational axis (). Each of the sections () also has a different configuration () of apertures (). The configurations () of apertures () create a mass imbalance between the sections () so that the element () pivots about the rotational axis () in response to acceleration. The apertures () also facilitate etch release during manufacturing and reduce air damping when the element () rotates. Apertures () are formed in electrodes () underlying the apertures () to match the capacitance between the two sections () of movable element () to provide the same bi-directional actuation capability.

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Mesa, AZ, United States of America

Marco Fuhrmann