Patent ID: 7880479
Filing Date: 2011-02-01
Classification: H03K

Abstract:
1. A capacitive sensor, comprising: a pair of sensing electrodes, wherein the pair of sensing electrodes comprises a first electrode and a second electrode, the first sensing electrode comprising a first conductor and the second sensing electrode comprising a second conductor; a first comparator, a positive input terminal thereof coupled to the first conductor, a negative input terminal thereof coupled to the second conductor, wherein the output terminal thereof outputs a first comparing signal according to voltages of the positive input terminal thereof and the negative input terminal thereof; a second comparator, a positive input terminal thereof coupled to the second conductor, the negative input terminal thereof coupled to the first conductor, wherein the output terminal thereof outputs a second comparing signal according to voltages of the positive input terminal thereof and the negative input terminal thereof; and a control unit, receiving the first comparing signal and the second comparing signal, a first output terminal thereof coupled to the first conductor, a second output terminal thereof coupled to the second conductor, outputting a sensing signal according to the first comparing signal and the second comparing signal, wherein the first output terminal thereof charges the first conductor when the first comparing signal is a first logic voltage and the second comparing signal is a second logic voltage, the second output terminal thereof charges the second conductor when the first comparing signal is the second logic voltage and the second comparing signal is the first logic voltage.