Patent ID: 9013444
Filing Date: 2015-04-21
Classification: G06F

Abstract:
1. A method comprising: coupling a capacitance of a touch sensor in series with a compensation capacitor; applying a supply voltage at the compensation capacitor, thereby dividing a first amount of charge between the capacitance of the touch sensor and the compensation capacitor, the division of the first amount of charge resulting in a first voltage at an input node; isolating the capacitance of the touch sensor from the compensation capacitor; applying a reference voltage at the input node and the supply voltage at the compensation capacitor, the application of the reference voltage at the input node inducing a second amount of charge proportional to a difference between the first voltage and the reference voltage on an integration capacitor; determining a first difference between the first voltage and the reference voltage based on a second amount of charge on the integration capacitor; and determining whether a touch input to the touch sensor has occurred based on the first difference.