Semtech Corporation

Sébastien Grisot

Chaouki Rouaissia

Jerald George Ott, Iii

A capacitive sensor device with a capacitance-measuring circuit, a main sense input and a reference sense input, wherein the capacitive sensor device is configured to measure, using the capacitance-measuring circuit, a current main value of capacitance seen by the main sense input and a current reference value of capacitance seen by the reference sense input, wherein the capacitive sensor device is configured to store one previously measured reference value, and wherein the capacitive sensor device is configured to use 1) the current main value, 2) the current reference value and the previously measured reference value, and 3) a current correction coefficient, the capacitive sensor device being configured to adaptively determine the current correction coefficient based on the current reference value and the previously measured reference value, for determining a corrected current main value of capacitance; the capacitive sensor device can be used in a portable electronic device.

Capacitive sensor device with drift compensation

A proximity sensor, and a portable device equipped therewith, with at least two superposed sense electrodes, one partially screening the other. By reading the capacity first of one electrode, then of the other, while setting the potential of the counter-electrode either to ground or to guard, the sensor of the invention discriminates between a body part, or another electrically equivalent object, and water drops at closer distance.

Water-rejection proximity detector and method

A portable device including drift-compensated capacitive proximity sensor that exploits a special method of drift compensation based on the variation of the measured proximity signal. The drift is tracked when the variation is within a stated interval, and frozen when the variation is outside. The sensor is capable of following a drift not only when the phone is inactive, but also when it is close to the body of the user, by freezing the tracking when the capacity varies steeply, as when the user moves the device, and resuming it when the variation is within acceptable limits.

Drift suppression filter, proximity detector and method

A proximity sensor for detecting proximity of a body portion in a first region while avoiding unwanted detection of a body portion in a second region, based on the capacities seen by a plurality of electrodes. An application of the inventive detector to a mobile phone, whereby the display is switched off, or various energy saving measure are taken, when the proximity sensor determines directional proximity with a body part, indicating that the user has brought the phone to the ear for placing a call.

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Boudry, Switzerland

Sébastien Grisot