Patent ID: 8829927

Claim:
An apparatus for measuring capacitance in a touch sensor, the apparatus comprising: a panel driver configured to drive a panel load in the touch sensor according to a reference voltage; and a capacitive load detector configured to measure capacitance of the panel load by sensing a panel load driving current that is applied to the panel load by the panel driver, wherein the capacitive load detector includes: a rising current detector configured to detect a rising current component of the panel load driving current; and a falling current detector configured to detect a falling current component of the panel load driving current, wherein the capacitive load detector further includes a sensing capacitor that is charged by the rising current component or the falling current component, wherein the capacitive load detector is configured to measure the capacitance of the panel load when the sensing capacitor is fully charged by one of the rising and falling current components, wherein the capacitance of the panel load is measured when there is no variation in a sensing voltage obtained by the capacitive load detector, and wherein the capacitive load detector is configured to measure the capacitance of the panel load if a product of a load voltage for driving the panel load and capacitance of a load capacitor in the panel load is substantially the same as a product of the sensing voltage and capacitance of the sensing capacitor.