Electronic device and method for determining a touch input applied to a capacitive touch panel system incorporated therein

A method for an electronic device to determine a touch input applied to a capacitive touch panel system of the electronic device so as to account for time-varying noise affecting the touch panel system, the touch panel system including a plurality of sensing points, the method comprising:

• detecting a capacitance at each sensing point of the plurality of sensing points to produce a plurality of sensed values;
• normalizing each of the plurality of sensed values to account for static, spatial-varying noise and static, spatial-varying gain to produce a plurality of normalized values;
• determining an average of the plurality of normalized values to produce an average value;
• comparing each of the plurality of normalized values to the average value to produce a plurality of comparison results;
• determining a subset of the plurality of normalized values based on the plurality of comparison results;
• determining an average of the subset of normalized values to produce a time-varying, common mode noise value;
• and
• determining the touch input based on filtering of the time-varying, common mode noise value from each of the plurality of sensed values.

An electronic device comprising:

• a capacitive touch panel system that includes a plurality of sensing points, at least some of the plurality of sensing points being operable to detect application of a touch input from a user of the electronic device;
• an analog-to-digital conversion (ADC) unit operably coupled to the plurality of sensing points for converting analog output signals from the plurality of sensing points to digital signal values;
• and
• a processing unit operably coupled to the ADC unit and operable in accordance with a set of operating instructions to:
• receive digital signal values from the ADC unit representing capacitances detected by the plurality of sensing points to produce a plurality of sensed values;
• adjust at least one sensed value of the plurality of sensed values to account for static, spatial-varying noise to produce at least one adjusted value;
• determine a time-varying noise value corresponding to a time-varying noise based on the at least one adjusted value, the time-varying noise affecting the capacitive touch panel system;
• adjust at least one sensed value of the plurality of sensed values based at least on the time-varying noise to produce at least one noise-adjusted value;
• and
• determine the touch input based on the at least one noise-adjusted value.

A method for an electronic device to determine a touch input applied to a capacitive touch panel system of the electronic device, the capacitive touch panel system including a plurality of sensing points, the method comprising:

• detecting capacitance at each of the plurality of sensing points to produce a plurality of sensed values;
• detecting time-varying noise at one or more input-protected sensing points of the plurality of sensing points, wherein the one or more input-protected sensing points are protected from application of the touch input and wherein the time-varying noise affects the capacitive touch panel system;
• adjusting at least one sensed value of the plurality of sensed values based at least on the time-varying noise to produce at least one noise-adjusted value;
• and
• determining the touch input based on the at least one noise-adjusted value.

An electronic device comprising:

• a capacitive touch panel system that includes a plurality of sensing points, the plurality of sensing points including a plurality of input-accepting sensing points operable to detect application of a touch input from a user of the electronic device and one or more input-protected sensing points that are protected from application of the touch input;
• an analog-to-digital conversion (ADC) unit operably coupled to the plurality of sensing points for converting analog output signals from the plurality of sensing points to digital signal values;
• and
• a processing unit operably coupled to the ADC unit and operable in accordance with a set of operating instructions to:
• receive digital signal values from the ADC unit representing capacitances detected by the plurality of sensing points to produce a plurality of sensed values;
• detect time-varying noise at the one or more input-protected sensing points, the time-varying noise affecting the capacitive touch panel system
• adjust at least one sensed value of the plurality of sensed values based at least on the time-varying noise to produce at least one noise-adjusted value;
• and
• determine the touch input based on the at least one noise-adjusted value.