Patent ID: 8294678

Claim:
An image display system, comprising: a touch sensing circuit comprising at least one voltage storing unit to generate a corresponding voltage when a capacitance variation caused by a touch event occurs, wherein the voltage storing unit comprises: a first capacitor having a first terminal coupled to an alternating current (AC) common voltage from a common electrode and a second terminal coupled to a first node; a first switching element having a first terminal coupled to the second terminal of the first capacitor and a second terminal coupled to the AC common voltage; and a second switching element having a first terminal coupled to the second terminal of the first capacitor, wherein the touch sensing circuit further comprises an integration unit coupled to the second terminal of the second switching element to integrate the corresponding voltage thereby generating an output signal, and wherein the integration unit comprises: a third switching element having a first terminal coupled to the second terminal of the second switching element, and a second terminal; a second capacitor having a first terminal coupled to the second terminal of the third switching element, and a second terminal; a fourth switching element having a first terminal coupled to the second terminal of the third switching element, and a second terminal coupled to a low voltage level of the AC common voltage; a fifth switching element having a first terminal coupled to the second terminal of the second capacitor, and a second terminal; a sixth switching element having a first terminal coupled to the second terminal of the second capacitor, and a second terminal coupled to the low voltage level; an operational amplifier having an inversion input terminal coupled to the second terminal of the second capacitor, a non-inversion input terminal coupled to the low voltage level, and an output terminal; a third capacitor coupled between the inversion input terminal and the output terminal of the operational amplifier; a seventh switching element coupled between the inversion input terminal and the output terminal of the operational amplifier; and an eighth switching element coupled to the output terminal of the operational amplifier to output the output signal.