Patent ID: 8692142

Claim:
A circuit for determining positions of contacts on a capacitive position sensing panel, wherein the capacitive position sensing panel comprises a plurality of sensing lines and a plurality of driving lines, and the sensing lines and the driving lines are intersected, the circuit comprising: a plurality of first amplifiers, respectively coupled to the sensing lines, for detecting whether the sensing lines have contact(s) presented thereon, wherein regarding each of the first amplifiers, a first input terminal of the first amplifier is coupled to a first input signal source, and a second input terminal of the first amplifier is coupled to an output terminal of the first amplifier via a first capacitor; and a plurality of second amplifiers, respectively coupled to the driving lines, for detecting whether the driving lines have contact(s) presented thereon, wherein regarding each of the second amplifiers, a first input terminal of the second amplifier is selectively coupled to the first input signal source or a second input signal source via a switch, and a second input terminal of the second amplifier is coupled to an output terminal of the second amplifier via a second capacitor; wherein when the circuit operates in a first operating mode, the first input terminal of each of the second amplifiers is coupled to the first input signal source, and when the circuit operates in a second operating mode, first input terminals of a plurality of specific second amplifiers included in the second amplifiers are coupled to the second input signal source.