Touch detection circuit
By designing a touch detection circuit, the change in capacitor charging time is converted into a voltage change, achieving low-power, high-resolution capacitance detection. This solves the problems of insufficient detection speed and power consumption in existing technologies, making it suitable for non-contact detection and protecting the object being tested.
Patent Information
- Application Number
- CN202520200409.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2026-01-20
- Estimated Expiration
- 2035-02-10
AI Technical Summary
Existing touch detection circuits have shortcomings in power consumption and detection speed, making it difficult to detect capacitance changes quickly and accurately, and may cause physical damage to the object being tested.
A touch detection circuit was designed, including a driving module and a detection module. The charging time is changed by changing the capacitance value, and the capacitance change is converted into voltage change by a voltage amplifier and a capacitance detection module to achieve high-sensitivity touch detection and avoid physical contact.
It achieves low-power, high-resolution capacitance detection, accurately determines touch status, avoids physical damage to the object being measured, and is suitable for applications requiring high-sensitivity measurements.
Smart Images
Figure CN223815544U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to touch detection technical field, concretely is a kind of touch detection circuit. BACKGROUND
[0002] Touch detection is a kind of detection method by detecting the capacitance variation after finger touches touch point, judges whether finger touches and makes corresponding algorithm processing.Touch detection circuit is an indispensable part in modern electronic equipment, especially in the application of touch screen and touch key, plays a key role.With the continuous updating of electronic product and the improvement of intelligent requirement, therefore, it is also very important to design a circuit with low power consumption and can quickly detect capacitance variation. UTILITY MODEL CONTENT
[0003] The utility model aims at providing a kind of touch detection circuit, to solve the problem presented in the above background technology.
[0004] To achieve the above object, the utility model provides the following technical scheme: a kind of touch detection circuit, including touch screen, drive module, touch point and detection module, drive module and detection module are electrically connected, the drive module is configured as when finger touches screen, the size of electric capacity is changed, and then the charging time of electric capacity is changed, the information changed by electric capacity is transmitted to detection module, the detection module includes voltage amplifier and electric capacity detection module, the detection module is configured as when receiving the information transmitted by drive circuit, the variation of electric capacity and charging time change are converted into the variation of voltage, the tiny voltage variation caused by electric capacity change is amplified, then is connected to electric capacity detection module, the touch point includes finger touch point, the touch screen is provided with sensing electrode and electronic component.
[0005] Preferably, the touch point on the screen of the drive module receives the signal of finger touch, triggers the drive circuit.
[0006] Preferably, the drive module has the charging circuit of electric capacity, charges and discharges electric capacity, when there is no finger touch, the charge amount of electric capacity does not change, and the charging time does not change.
[0007] Preferably, in the drive module, when there is finger touch, electric capacity increases, charge amount increases, and the charging time of electric capacity becomes longer, and the information changed by electric capacity is transmitted to detection module.
[0008] Preferably, the touch detection circuit is the electric capacity formed between human body and sensing electrode, and the electric capacity and the stray capacitance between original sensing electrode and ground form parallel capacitance, when there is touch, the value of the parallel capacitance increases, and then affects charging and discharging time.
[0009] Preferably, the sensing electrode is provided with a filter circuit for filtering the electric interference signal entering when touch occurs.
[0010] Preferably, the electronic components form a crystal oscillator square wave oscillation circuit, the crystal oscillator square wave oscillation circuit and the filter circuit are connected in series, and form a reaction with the parallel capacitor to realize touch sensing.
[0011] Preferably, the detection module receives the signal sent by the driving circuit, and converts the change of the capacitor and the change of the charging time into the change of the voltage.
[0012] Preferably, the capacitor detection module is a voltmeter, an oscilloscope voltage measuring device, which directly observes the change of the voltage and further judges the touch state.
[0013] Compared with the prior art, the utility model has the beneficial effects that: the utility model discloses a touch detection circuit, when the finger touches, the size of the capacitor is changed, and the charging time of the capacitor is changed, the information of the change of the capacitor is transmitted to the detection module, in the detection module, the information transmitted by the driving circuit is received, the change of the capacitor and the change of the charging time are converted into the change of the voltage, the slight voltage change caused by the change of the capacitor is amplified, and the touch state is judged, the detection circuit can detect very small capacitor change, which makes them very suitable for high-resolution measurement applications, the high sensitivity makes the detection circuit can capture slight voltage change, thereby providing accurate measurement results, and physical contact with the measured object is not needed during detection, so the detection circuit can be used in applications where contact may damage the object or the sensor itself, the non-contact measurement mode avoids the damage caused by physical contact, and the measured object and the detection circuit are protected. BRIEF DESCRIPTION OF DRAWINGS
[0014] Figure 1 It is a touch detection circuit structure schematic view of the utility model embodiment.
[0015] Figure 2 It is a circuit diagram of the touch detection circuit structure of the utility model embodiment.
[0016] In the drawing: 1 touch point, 11 finger touch point, 2 driving module, 3 detection module, 31 operational amplifier, 32 capacitor detection module. DETAILED DESCRIPTION
[0017] In order to deepen the understanding and understanding of the utility model, the technical solutions in the utility model embodiments will be clearly and completely described and introduced in combination with the drawings in the utility model embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments, and do not limit the embodiments in any form. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model.
[0018] Please refer to Figures 1-2 The utility model provides a technical scheme: a touch detection circuit, including touch screen, drive module 2, touch point 1 and detection module 3, drive module 2 and detection module 3 are electrically connected, drive module 2 is configured as when finger touches screen, the size of capacitance is changed, and then the charging time of capacitance is changed, and the information of capacitance change is transmitted to detection module 3, detection module 3 includes voltage amplifier and capacitance detection module 3, detection module 3 is configured as when receiving the information transmitted by drive circuit, the change of capacitance and charging time is converted into the change of voltage, the tiny voltage change caused by capacitance change is amplified, and then connected to capacitance detection module 32, touch point 1 includes finger touch point 11, touch screen is provided with sensing electrode and electronic component, drive module 2 is touched by touch point 1, the size of capacitance is changed, and the charging time of capacitance will change accordingly, because the charging time of capacitance is related to capacitance value, when capacitance value changes, charging time will change accordingly, and then lead to the voltage change at both ends of capacitance, when touch occurs, assuming that capacitance changes ΔC, then the output voltage of charge amplifier 103 will change ΔV= ΔC × (VH-VL) / Cint, Cint is the capacitance value of integration capacitor, obviously, the output voltage is proportional to the size of touch capacitance, so whether touch occurs can be judged by measuring the size of ΔV, a voltage comparator or amplifier circuit is constructed using operational amplifier 31 and other circuit elements, the tiny voltage change caused by capacitance change is amplified, and then connected to voltmeter and other voltage measuring equipment, so that the voltage change condition can be observed directly, and then the touch state is detected.
[0019] When the touch point on the screen of the driving module 2 receives the signal of the finger touch, the driving circuit is triggered, the charging circuit with the capacitor in the driving module 2 charges and discharges the capacitor, when there is no finger touch, the charge amount of the capacitor does not change, the charging time does not change, in the driving module 2, when there is a finger touch, the capacitor will increase, the charge amount will increase, and the charging time of the capacitor will be longer, the information of the change of the capacitor is transmitted to the detection module 3, the touch detection circuit is the capacitor formed between the human body and the sensing electrode, the capacitor and the original stray capacitance between the sensing electrode and the ground form a parallel capacitor, when there is a touch, the value of the parallel capacitor will increase, and then affect the charging and discharging time, the filter circuit is arranged in the sensing electrode, which is used to filter the electric interference signal entering when the touch occurs, the electronic components build a crystal oscillator square wave oscillation circuit, the crystal oscillator square wave oscillation circuit and the filter circuit are connected in series, and form a reaction with the parallel capacitor, realize touch sensing, the user can be inducted with the touch screen when touching, the detection module 3 receives the signal sent by the driving circuit, converts the change of the capacitor and the change of the charging time into the change of the voltage, the capacitor detection module 32 is a voltmeter, an oscilloscope voltage measuring device, which directly observes the change of the voltage, and then judges the touch state, when the finger touches, the capacitor Cx will increase, the charge amount will increase, and the charging and discharging time will be longer, at the same time, the release voltage of the capacitor will also be larger, because the output voltage is proportional to the size of the touch capacitor, by measuring the voltage change, the change of the capacitor can be indirectly reflected, the operational amplifier circuit element is used to build a voltage comparator or amplifier circuit, the small voltage change caused by the change of the capacitor is amplified, and then connected to the capacitor detection module, the capacitor detection module can directly observe the change of the voltage, and then judge the touch state, when the finger does not touch, the capacitor does not change, the charging and discharging time does not change, and the output voltage does not change, the measurement result is stable.
[0020] As Figure 2As shown, the driving module 2 includes a capacitor charging and discharging circuit, with switches S1 and S2, capacitors C1 and Cx and current sources I1 and I2, the detection module 3 includes a voltage amplifier 31 and a capacitor detection module 32, wherein the capacitor detection module 32 mainly includes a voltmeter for detecting the change of voltage, while there are also resistors Rfb and capacitors Cfb, the positive electrode of the capacitor C1 is electrically connected with the negative electrode of the touch point 11, the negative electrode of the current source I1 and the positive electrode of the current source I2 are respectively connected with the positive electrode and the negative electrode of the capacitor Cx, the positive electrode of the current source I1 is connected with the current source, which mainly plays a charging role for the capacitor Cx, the negative electrode of the current source I2 is connected with the ground, which mainly plays a discharging role for the capacitor Cx, the reverse input end of the operational amplifier is connected with the capacitor Cx, the same input end is connected with the ground, while the same input end is also connected with the resistors Rfb and Cfb in parallel, which mainly plays a role of improving the stability of gain, expanding the passband, reducing the nonlinear distortion and suppressing the feedback loop noise and interference, and improving the stability of gain. The output end of the operational amplifier is connected with the capacitor detection module 32, and the capacitor detection module mainly includes a voltmeter and other voltage measuring devices, which observes the change of voltage and further detects the touch state.
[0021] Although the embodiments of the utility model have been shown and described, it needs to be emphasized that: the above description is only the introduction and description of the use mode of the embodiments of the utility model, and is not any form of limitation to the utility model. For ordinary skilled in the art, it can be understood that the embodiments can be changed, modified, replaced and modified in many ways without departing from the principles and spirits of the utility model, and the scope of the utility model is defined by the appended claims and their equivalents.
Claims
1. A touch detection circuit comprising a touch screen, a driving module, a touch point and a detection module, characterized in that: The driving module and the detecting module are electrically connected, the driving module is configured to change the size of the capacitance when the finger touches the screen, and then change the charging time of the capacitance, and transmit the information of the changed capacitance to the detecting module, the detecting module includes a voltage amplifier and a capacitance detecting module, the detecting module is configured to receive the information transmitted by the driving circuit, and convert the change amount of the capacitance and the charging time change into the change amount of the voltage, amplify the slight voltage change caused by the capacitance change, and then connect to the capacitance detecting module, the touch point includes a finger touch point, and the touch screen is provided with sensing electrodes and electronic components.
2. The touch detection circuit of claim 1, wherein: When the touch point on the screen of the driving module receives the signal of the finger touch, the driving circuit is triggered.
3. The touch detection circuit of claim 1, wherein: The driving module has a charging circuit of the capacitance, and the capacitance is charged and discharged, when there is no finger touch, the charge amount of the capacitance does not change, and the charging time does not change.
4. The touch detection circuit of claim 1, wherein: When the finger touches, the capacitance increases, the charge amount increases, and the charging time of the capacitance becomes longer, and the information of the changed capacitance is transmitted to the detecting module.
5. The touch detection circuit of claim 1, wherein: The touch detecting circuit is the capacitance formed between the human body and the sensing electrode, which forms a parallel capacitance with the original stray capacitance between the sensing electrode and the ground, when the touch occurs, the value of the parallel capacitance increases, and then the charging and discharging time is affected.
6. The touch detection circuit of claim 1, wherein: The sensing electrode is provided with a filter circuit for filtering the electric interference signal entering when the touch occurs.
7. The touch detection circuit of claim 1, wherein: The electronic components build a crystal oscillator square wave oscillation circuit, the crystal oscillator square wave oscillation circuit and the filter circuit are connected in series, and form a reaction with the parallel capacitance, and realize touch sensing.
8. The touch detection circuit of claim 1, wherein: The detecting module receives the signal sent by the driving circuit, converts the change of the capacitance and the charging time into the change of the voltage.
9. The touch detection circuit of claim 1, wherein: The capacitance detecting module is a voltmeter, an oscilloscope voltage measuring device, which directly observes the change of the voltage, and then judges the touch state.