Raydium Semiconductor Corporation

Meng-Yi Chen

Chih-Hsiung Chen

Yu-Chin Hsu

Chih Yuan

A self-capacitive touch sensing circuit including an operational amplifier, an internal capacitor, a first switch and a second switch is disclosed. A first input terminal and a second input terminal of operational amplifier are coupled to a capacitor and ground respectively and an output terminal of operational amplifier outputs an output voltage. The internal capacitor is coupled between the output terminal and first input terminal of operational amplifier. One terminal of first switch is coupled to a first external charging voltage and another terminal of first switch is coupled between the capacitor and the first input terminal. The first external charging voltage is higher than the second external charging voltage. The first switch and second switch are switched according to a specific order, so that the first external charging voltage or second external charging voltage will charge the capacitor.

Self-capacitive touch sensing circuit and noise suppressing method applied to self-capacitive touch panel

A mutual-capacitive touch sensing circuit includes an operational amplifier, an internal capacitor, a first switch&#x2dc;a third switch. A first input terminal and a second input terminal of operational amplifier are coupled to a capacitor and ground respectively and an output terminal of operational amplifier outputs an output voltage. The internal capacitor is coupled to output terminal and first input terminal. The first switch is coupled to a first external charging voltage, capacitor and first input terminal. The second switch is coupled to a second external charging voltage and the capacitor. The third switch is coupled to a third external charging voltage, the second switch and capacitor. The second external charging voltage and third external charging voltage have same magnitude but opposite polarities. The first switch, second switch and third switch are switched in a specific order to selectively charge the capacitor with different external charging voltages.

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Kaohsiung, Taiwan

Meng-Yi Chen