Patent ID: 10684726

Abstract:
A capacitive touch sensing circuit includes a first switch˜a fifth switch, an internal capacitor, an integrator and a capacitor. The first switch and an external capacitor are coupled in series between a first voltage and a ground voltage, one terminal of the second switch is coupled between the first switch and the external capacitor, and one terminal of the third switch is coupled to the other terminal of the second switch. The fourth switch and the internal capacitor are coupled in series between a second voltage and the ground voltage, wherein the second voltage is a negative value of the first voltage, and one terminal of the fifth switch is coupled to the other terminal of the second switch and the other terminal of the fifth switch is coupled between the fourth switch and the internal capacitor. One input terminal of the integrator is coupled to the other terminal of the third switch, the other input terminal of the integrator is coupled to a reference voltage, and the output terminal of the integrator outputs an output voltage. The capacitor is coupled between the input terminal and the output terminal of the integrator.