Patent ID: 7863966

Claim:
A readout circuit for a touch panel comprising: a first switch having a first terminal serving as an input terminal of the readout circuit; an operational amplifier (OP-AMP) having a first input terminal coupled to a second terminal of the first switch, having a second input terminal receiving a reference voltage; a feedback capacitor having a first terminal coupled to the first input terminal of the OP-AMP, having a second terminal coupled to an output terminal of the OP-AMP; a second switch having a first terminal couple to the first input terminal of the OP-AMP, having a second terminal coupled to the output terminal of the OP-AMP; a comparison unit having an input terminal coupled to the output terminal of the OP-AMP; a controller for controlling the comparison unit, the first switch and the second switch in accordance with an output of the comparison unit, wherein the controller controls the comparison unit for comparing the output of the OP-AMP with a first threshold voltage if the output of the comparison unit is a first logic value, and the controller controls the comparison unit for comparing the output of the OP-AMP with a second threshold voltage if the output of the comparison unit is a second logic value; and a counter having an input terminal receiving the output of the comparison unit, having an output terminal serving as an output terminal of the readout circuit.