Atmel Corporation

Tajeshwar Singh

Terje Saether

Trond Jarle Pedersen

In one embodiment, a method includes modifying a voltage at a capacitance of a touch sensor to a first voltage level. The method also includes modifying the voltage at the capacitance to a second voltage level, resulting in a first current. The method also includes modifying a voltage at an integration capacitor to a charging-voltage level based on the first current. The method also includes determining whether a touch input to the touch sensor has occurred based on the charging-voltage level.

Self-capacitance detection using trans-conductance reference

In one embodiment, an apparatus comprises a pulse driver configured to generate an electrical pulse for transmission to a capacitive touch sensor. The apparatus further comprises a timing circuit configured to hold a first switch closed and a second switch open during a first edge of the electrical pulse, and hold the second switch closed and the first switch open during of a second edge of the electrical pulse. The apparatus further comprises a first capacitor configured to receive a first amount of charge that is indicative of a capacitance of an area of the capacitive touch sensor and a second capacitor configured to discharge a second amount of charge that is indicative of the capacitance of the area of the capacitive touch sensor. The apparatus further comprises a differential output configured to provide a measure of the voltage difference between the first capacitor and second capacitor.

Capacitive touch sensor control unit with sampling capacitors for differential integration

A first signal from a first sense line of a touch sensor is received. A second signal from a second of the touch sensor is received. The first signal is inverted. The inverted first signal and the second signal are summed to produce a differential signal. The differential signal is output to a touch sensor controller.

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Klaebu, Norway

Tajeshwar Singh