Capacitance detection circuit, touch detection device and terminal equipment

Abstract

The present application provides a capacitance detection circuit and a touch detection device, which can improve the sensitivity of capacitance detection. The capacitance detection circuit includes a front-end circuit and a processing circuit; wherein, the front-end circuit includes a first drive circuit, a first offset circuit, and a PGA circuit, and the first drive circuit, the first offset circuit, and the PGA circuit all connected to the first end of the capacitor under test, the second end of the capacitor under test is grounded, the first drive circuit is used to charge and discharge the capacitor under test, and the first offset circuit is used to offset The basic capacitance of the capacitor under test, the PGA circuit is used to convert the capacitance signal of the capacitor under test after offsetting the basic capacitance into a voltage signal; the processing circuit is connected to the output terminal of the front-end circuit, It is used for determining the capacitance variation of the capacitance of the capacitor under test relative to the basic capacitance according to the voltage signal output by the front-end circuit.

Description

technical field [0001] The present application relates to the field of electronic technology, and in particular to a capacitance detection circuit, a touch detection device and a terminal device. Background technique [0002] Capacitive sensors are widely used in the field of human-computer interaction of electronic products. Specifically, a capacitance (or called basic capacitance or initial capacitance) will be formed between the detection electrode and the ground. When a conductor (such as a finger) approaches or touches the detection electrode , the capacitance between the detection electrode and the ground will change, and the information of the conductor approaching or touching the detection electrode can be obtained by detecting the change in capacitance, so as to judge the user's operation. However, since the basic capacitance is often relatively large, the capacitance change caused when the conductor approaches or touches the detection electrode is small, so the exi...

AI Technical Summary

Problems solved by technology

However, since the basic capacitance is often relatively large, the capacitance change caused by the conductor approaching or touching the detection electrode is small, so the existing capacitance detection method has low sensitivity and cannot accurately detect capacitance

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