| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent false detection of touch particularly by noise related to voltage switching of a common electrode. <P>SOLUTION: Switches 411 and 412 are mutually exclusively ON or OFF in a settling period, and the switch 411 is thereafter OFF while the switch 412 is ON in a counting period. Touch detection in a detection electrode 202 is performed based on the time for the voltage of a node A to reach a preset reference voltage Vref in the counting period. A common signal Vcom is reversed by an operational amplifier 453, and further differentiated by a capacitative element 457 and added to the node A, whereby the noise propagating through the detection electrode 202 is canceled. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
