Capacitive Measurement Circuit for a Touch Sensor Drive

A capacitance measurement circuit, comprising:

• a plurality of scaling units operable to scale a plurality of partial capacitances, respectively, associated with a plurality of sense lines, respectively, of a touch sensor to create a plurality of respective scaled capacitances;
• a first capacitance determination unit operable to determine an average capacitance of the plurality of respective scaled capacitances;
• a second capacitance determination unit operable to subtract the average capacitance from a total capacitance associated with one of the plurality of sense lines to determine a capacitance associated with a touchscreen input;
• and
• at least one processor operable to determine a location on the touch sensor associated with the touchscreen input based on the determined capacitance associated with the touchscreen input.

An apparatus comprising:

• a touch sensor comprising a plurality of sense electrodes;
• a plurality of scaling units operable to scale a plurality of partial capacitances, respectively, associated with the plurality of sense electrodes, respectively, to create a plurality of respective scaled capacitances;
• a first capacitance determination unit operable to determine an average capacitance of the plurality of respective scaled capacitances;
• a second capacitance determination unit operable to subtract the average capacitance from a total capacitance associated with one of the plurality of sense electrodes to determine a capacitance associated with a touchscreen input;
• and
• at least one processor operable to determine a location on the touch sensor associated with the touchscreen input based on the determined capacitance associated with the touchscreen input.

A method comprising:

• scaling a plurality of partial capacitances associated with a plurality of sense lines, respectively, of a touch sensor to create a plurality of respective scaled capacitances;
• determining an average capacitance of the plurality of respective scaled capacitances;
• subtracting the average capacitance from a total capacitance associated with one of the plurality of sense lines to determine a capacitance associated with a touchscreen input;
• and
• determining a location on the touch sensor associated with the touchscreen input based on the determined capacitance associated with the touchscreen input.