A common mode interference suppression circuit and touch sensing system

Abstract

This invention relates to the field of touch sensing technology, and discloses a common-mode interference suppression circuit and a touch sensing system. The common-mode interference suppression circuit includes a Gm module, a feedback module, and an integrating capacitor. The first input terminal of the Gm module receives a sensing signal superimposed with an interference signal, which characterizes the state of the system under test. A reference voltage is connected to the second input terminal. The first output terminal generates a first current based on the voltage difference between the first and second input terminals, and the second output terminal outputs a second current proportional to the first current. The feedback module is connected to the first output terminal and generates a feedback voltage based on the first current, feeding the feedback voltage back to the second input terminal. This allows the first output terminal to adjust the first current based on the feedback voltage to suppress the interference signal. The integrating capacitor is connected to the second output terminal. This invention can directly suppress common-mode interference at the analog front end, avoid circuit saturation, and improve the accuracy and stability of touch detection.

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