Patent ID: 9030429
Filing Date: 2015-05-12
Classification: G06F

Abstract:
1. A capacitance sensing apparatus comprising: a driving circuit unit to apply a driving signal, having a common level potential and a first level potential and a second level potential that are different from the common level potential, to a first capacitor which detects a touch of a user; a sensing circuit unit comprising a first switch connected between a sensing circuit gain control input and a sensing circuit input of an amplifying circuit, a second switch connected between the sensing circuit gain control input and a common level potential, the sensing circuit input is connected to the first capacitor through the first switch to detect a change in capacitance generated in the first capacitor, the sensing circuit gain control input to control a gain of the sensing circuit unit, and a sensing circuit output to output the sensing circuit input according to the gain of the sensing circuit unit which is controlled by the sensing circuit gain control input; and a gain controlling circuit unit connected to the sensing circuit gain control input and to control the gain of the sensing circuit unit, the sensing circuit unit including a second capacitor charged by the change in capacitance generated in the first capacitor when a level of the driving signal is changed from the first level potential to the common level potential or when the level of the driving signal is changed from the common level potential to the second level potential, and the gain controlling circuit unit including at least one gain controlling capacitor, which is charged and/or discharged by an input signal, to control the gain of the sensing circuit unit.