Capacitive sensing circuit and self-capacitive touch panel

Abstract

The present invention falls within the technical field of touch screens, and provides a capacitance sensing circuit, comprising a plurality of channels and at least one buffer unit, any one of the buffer units is coupled between a channel to be detected and another channel among the plurality of channels, wherein the channel to be detected receives an input signal and generates an output signal, the channel to be detected transmits the output signal to a capacitance judgement module, and the capacitance judgement module judges the capacitance change of the channel to be detected according to the output signal. The present invention utilizes a unit gain buffer coupled between a channel to be detected and a channel neighbouring same to decrease the potential difference between the channel to be detected and the channel neighbouring same and also decrease the frequency of an input signal so as to decrease the crosstalk effect between the channels, consequently, troubles caused by crosstalk capacitance while correcting the inconsistency between the channels can be reduced, and furthermore, the inconsistency between the channels which results from factors, such as circuit wiring or a production process, can be corrected in the right way.

Description

technical field [0001] The invention belongs to the technical field of touch screens, in particular to a capacitance sensing circuit capable of eliminating crosstalk between channels and a self-capacitance touch panel. Background technique [0002] With the advancement of science and technology, the operation interfaces of various electronic products have gradually become humanized in recent years. For example, through the touch panel, the user can directly operate and input information / text / pattern on the screen with fingers or a stylus, saving the trouble of using input devices such as keyboards or keys. Actually, the touch panel is usually composed of a sensing panel and a display disposed under the sensing panel. The electronic product judges the meaning of the touch according to the position touched by the user on the sensor panel and the picture displayed on the display at that time, and executes the corresponding operation result. [0003] The existing capacitive to...

AI Technical Summary

Problems solved by technology

[0005] In the prior art, due to the circuit routing or its own mutual capacitance, there will be a crosstalk effect between the channels, which will affect the judgment of the capacitance change of each channel, resulting in misjudgment

Furthermore, the self-capacitance or screen resistance between channels will cause inconsistency due to factors such as circuit routing or manufacturing process, but in fact it needs to correct the inconsistency, and the existence of crosstalk will make the correction between channels Consistency is more difficult, which affects the judgment of channel capacitance changes, and even causes misjudgment

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