Capacitive touch key detection circuit and detection method thereof

Abstract

The invention discloses a capacitive touch key detection circuit and method, and the circuit comprises a first-order charging and discharging unit, a second-order charging and discharging unit, a filtering unit, and a key capacitor composed of a spring key, and the key capacitor is connected between the first-order charging and discharging unit and the second-order charging and discharging unit. An input signal charges and discharges the key capacitor through the first-order charging and discharging unit, an oscillation signal processed by the first-order charging and discharging unit is charged and discharged through the second-order charging and discharging unit, and then the oscillation signal is filtered by the filtering unit to form a stable voltage signal. According to the capacitive touch key detection circuit, the stable voltage signal is output after the input oscillation signal is processed through the constructed capacitive touch key detection circuit, the current state of the touch key is recognized through the amplitude of the voltage signal, the detection precision is high, the oscillation frequency is adjustable and programmable, and the capacitive touch key detection circuit can adapt to various different occasions.

Description

technical field [0001] The invention relates to key detection, more specifically to a capacitive touch key detection circuit and a detection method thereof. Background technique [0002] At present, the touch button detection solutions on the market are roughly divided into two categories. One is the highly integrated capacitive touch button detection chip, which has the advantages of small size, high integration, and accurate detection. The disadvantage is that the application is not flexible and cannot Randomly match the number of buttons, and the application cost is relatively high; the other is a discrete detection scheme, which can be divided into a resistive detection scheme and a capacitive detection scheme, and most of the market uses a capacitive detection scheme. , capacitors, resistors, comparators, single-chip microcomputers and other discrete components, but due to the large number of components and relatively large volume, it is not suitable for applications wi...

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Problems solved by technology

[0002] At present, the touch button detection solutions on the market are roughly divided into two categories. One is the highly integrated capacitive touch button detection chip, which has the advantages of small size, high integration, and accurate detection. The disadvantage is that the application is not flexible and cannot Randomly match the number of buttons, and the application cost is relatively high; the other is a discrete detection scheme, which can be divided into a resistive detection scheme and a capacitive detection scheme, and most of the market uses a capacitive detection scheme. , capacitors, resistors, comparators, single-chip microcomputers and other discrete components, but due to the large number of components and relatively large volume, it is not suitable for applications with relatively high space requirements, and the oscillation frequency is fixed, and the detection accuracy is low. It is difficult to uniformly apply to multiple occasions;

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