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Capacitance change detection method and circuit for capacitive sensor

A capacitive sensor, capacitance change technology, applied in capacitance measurement, measurement of electrical variables, measurement of resistance/reaction/impedance, etc., can solve the problems of high noise and power consumption, high benchmark requirements, complex circuits, etc., to achieve simple circuit, Clock-free, low-noise effects

Active Publication Date: 2020-02-11
上海芯凌微电子有限公司
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AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of complex circuits, high benchmark requirements, and large noise and power consumption in the prior art. According to the principle that the charge stored in the capacitor remains unchanged, the present invention proposes a relatively static capacitive sensor capacitance change detection Method and circuit

Method used

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  • Capacitance change detection method and circuit for capacitive sensor
  • Capacitance change detection method and circuit for capacitive sensor
  • Capacitance change detection method and circuit for capacitive sensor

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Embodiment

[0025] A capacitive sensor capacitance change detection circuit of the present invention, the circuit comprises:

[0026] The measured capacitor charging circuit is used to charge the measured capacitor and generate a bias voltage;

[0027] The reference voltage value supply circuit is used to generate a reference voltage value of a post-stage comparator to compare the measured capacitance change;

[0028] The post-stage comparator is used to judge that the voltage variation on the measured capacitor reaches or exceeds the voltage value at both ends of the reference capacitor, and then the output OUT is reversed.

[0029] figure 1 with image 3 It is one of the two structural forms of the present invention. The difference between them is that the detection capacitance value becomes larger or smaller, and there are other forms. When the capacitance becomes larger or smaller indefinitely, or both become larger or smaller, it is possible to detect it. The above two situations ...

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Abstract

The invention provides a capacitance change detection method and circuit for a capacitive sensor. The method comprises: an initialization stage in which a detected capacitor and a reference capacitorare charged at the same time to generate corresponding voltage biases in numerical relation, and the bias voltage of the reference capacitor is increased or decreased by a reference voltage value in proportional relation with the reference capacitance change; and a detection state in which OUT is overturned to detect the capacitance change when the voltage change quantity of the detected capacitorreaches, or is higher than, or is lower than, a voltage value between the two ends of the reference capacitor. Thus, the circuit is simple, power consumption and noise are low, no clock is included,the detection precision is high, and the detection range is wide.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a capacitance change detection method and circuit of a capacitive sensor. Background technique [0002] In the era of intelligence, there are more and more types and quantities of sensors required. Among them, the capacitive sensor is a simple and very effective type of sensor. It can be used as displacement and position sensing, liquid level sensing, humidity sensing, acceleration, and a cavity-type membrane capacitance sensor for measuring negative air pressure. [0003] In capacitive sensing, one type needs to detect the capacitance value, and the other type only needs to detect the relative change of capacitance, so as to know the relative change of the object under test, thus triggering the system to make various needs. Such as switching, driving, protection and other actions. [0004] The current capacitive sensor mainly adopts to actively apply a natural frequency to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R27/26
CPCG01R27/2605
Inventor 周华文
Owner 上海芯凌微电子有限公司
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