Patent ID: 8466899

Claim:
A touch panel, comprising: a plurality of panel capacitors, wherein a second terminal of each panel capacitor is electrically connected to one another and, when one of the panel capacitors is selected as an object capacitor, a first terminal of each panel capacitor other than the first terminal of the object capacitor is coupled to a ground terminal; a first switching unit, switching the first terminal of the object capacitor to a first voltage, a floating state, and a second voltage during a first time interval, a second time interval, and a third time interval respectively; a second switching unit, coupled to the second terminals of the panel capacitors, conducting the second terminals of the panel capacitors to a basic voltage during the first time interval, switching the second terminals of the panel capacitors from the floating state to a signal detecting terminal during the second time interval, and conducting the second terminals of the panel capacitors to the signal detecting terminal persistently during the third time interval; a first charging unit, coupled to the signal detecting terminal and referring to a charging control signal to determine whether a first charging current is to be provided during the third time interval; a control unit, coupled to the signal detecting terminal and integrating a signal from the signal detecting terminal to generate an integrated voltage, and comparing the integrated voltage and a reference voltage to output a comparison signal and the charging control signal when the control unit is triggered; and a counter, counting the comparison signal to generate a count value, wherein the touch panel identifies a variation in a capacitance value of the object capacitor by using the count value.