Semtech Corporation

Pascal Monney

Olivier Nys

Mathieu Hoffmann

Chaouki Rouaissia

Terrence Lee Van Ausdall

Daniel Aebischer

Terrence Lees Van Ausdall

A capacitive sensor with a plurality of sense inputs connectable to capacitive sense electrodes and a common reference input, each sense input and the reference input can be put in a measure state, in a ground state, or in a shield state. The sensor can be equipped with external reference capacitors between each of the sense input and the common reference terminal. The reference capacitor can be read individually by selectively pulling one of the input terminals to ground and driving the other to be equipotential with the reference input.

Multichannel capacitive sensor device

Described herein are systems, methods and apparatuses that can detect the proximity of an object and differentiate between a human body and a non-human object. The detection and differentiation are facilitated by a first capacitive sensor of a first shape and a second capacitive sensor of a second shape. The detection and determination can be made based on a comparison between a first capacitance from the first sensor and a second capacitance from the second sensor.

Capacitive body proximity sensor system

A readout system for capacitive touch panel, particularly for single-ended capacity sensing matrixes, capable of internally calibrate and equalize the response of its capacity-to-digital converters (CDC). The readout system includes reference lines for interconnecting together different sub-circuits, and measuring the response of CDC in different circuits on common reference capacitors.

Touch panel calibration system

A measuring circuit connectable to a capacitive touch-sensitive panel, the panel including a plurality of sense electrodes and optionally a common guard electrode, adapted to measure variations in the instantaneous electric capacity of the sense electrodes in response to proximity to conductive bodies, wherein the sense electrodes are biased at a fixed voltage relative to the common guard electrode, the measuring circuit comprising: a power management integrated circuit comprising a voltage source generating a modulation voltage that is available at a guard terminal of the power management integrated circuit that is in electric connection with the guard electrode; one or more slave integrated circuits, each connected to a plurality of sense electrodes and comprising a Capacity-to-Digital converter or a plurality of Capacity-to-Digital converters that are operatively arranged for generating digital measure codes representing the instantaneous electric capacity of sense electrodes; a means for varying the frequency of the modulation voltage.

Measuring circuit and measuring method for a capacitive touch-sensitive panel

A proximity sensor includes a capacitive touch controller. A first shielding area is coupled to a first shield terminal of the capacitive touch controller. A second shield area is coupled to a second shield terminal of the capacitive touch controller. A first sensing element is disposed adjacent to the first shielding area. The first sensing element is coupled to a first sensing terminal of the capacitive touch controller. A second sensing element is disposed adjacent to the second shielding area. The second sensing element is coupled to a second sensing terminal of the capacitive touch controller. The capacitive touch controller is configured to associate the first sensing element with the first shielding area. A self-capacitance of the first sensing element is measured while the second shielding area is inactive. The self-capacitance of the first sensing element is measured at a first frequency.

Multi-shield capacitive sensing circuit

A sampling circuitry for a plurality of electrodes the circuitry comprising a plurality of charge amplifiers and a plurality of modulators, wherein each charge amplifier and each modulator, comprised in the plurality of charge amplifiers and the plurality of modulators, respectively, corresponds to an electrode of the plurality of electrodes, wherein each modulator is capable of generating a residue signal and a rough code corresponding to each sampled electrode of the plurality of electrodes, a multiplexer capable of receiving a plurality of residue signals generated by the plurality of modulators, a residue analog to digital converter capable of receiving a multiplexed residue signal from the multiplexer and outputting a digitized multiplexed residue signal, and a digital summation circuitry capable of receiving the digitized multiplexed residue signal and a plurality of rough codes, comprising each rough code corresponding to each sample electrode, and outputting a plurality of output codes.

Sampling circuitry and sampling method for a plurality of electrodes

A capacitive touch sensor and LED driver device achieves a reduction in pin count by multiplexing LED drive functionality and capacitive sense functionality on each input/output pin. A control circuit switches between LED drive mode and capacitive sense mode at a frequency of approximately 200 Hz, although other switching frequencies can be used. A bias driver functions as a current sink for LEDs in LED drive mode and can also be used to drive a bias voltage to the LEDs during capacitive sense mode to improve noise immunity.

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San Diego, CA, United States of America

Pascal Monney