Capacitance detection circuit, touch chip and electronic equipment

Abstract

A capacitance detection circuit, a touch chip and electronic equipment, the capacitance detection circuit, which includes: a control module, a drive module, an offset module and a charge transfer module, the drive module is used to pass the first The charging branch forwardly charges the detection capacitor, or reversely charges the detection capacitor through the second charging branch; the canceling module is used to charge the detecting capacitor through the first canceling branch under the control of the control module The detection capacitor performs the offset processing of the basic capacitance, or, under the control of the control module, performs the offset processing of the basic capacitance on the detection capacitor through the second offset branch; the charge transfer module is used for Transfer processing is performed on the charge of the detection capacitor to generate an output voltage. The capacitance detection circuit improves the sensitivity of self-capacitance detection, and finally improves the accuracy of self-capacitance detection.

Description

technical field [0001] The embodiments of the present application relate to the technical field of capacitance detection, and in particular, to a capacitance detection circuit, a touch control chip, and an electronic device. Background technique [0002] For self-capacitance detection, the principle is that a capacitance is formed between the detection electrode and the system ground, which is called self-capacitance detection. The capacitance formed between the detection electrode and the system ground has a basic capacitance or an initial capacitance. When a finger approaches or touches the detection electrode, the capacitance between the detection electrode and the system ground will increase. By detecting the change in the capacitance, the user's related touch operation can be determined. [0003] In the field of capacitive touch, flexible screen is an important development direction. When the above-mentioned self-capacitance principle is used to realize capacitive touc...

AI Technical Summary

Problems solved by technology

A small capacitance change means that a higher circuit gain is required so that the detection circuit can detect the electrical signal generated by the capacitance change when touched, but since the basic capacitance is much higher than the capacitance change, if a higher circuit is used Gain can easily cause the detection circuit to saturate

[0004] In addition, the electrical signal generated by the small change in capacitance is also small, which is easily overwhelmed by circuit noise and cannot be detected

It can be seen that the existing technology has the defect of low self-capacitance detection sensitivity, which eventually leads to low accuracy of self-capacitance detection.

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