CN116185236A - Spaced touch system with high anti-interference capability - Google Patents
Spaced touch system with high anti-interference capability Download PDFInfo
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- CN116185236A CN116185236A CN202211681695.5A CN202211681695A CN116185236A CN 116185236 A CN116185236 A CN 116185236A CN 202211681695 A CN202211681695 A CN 202211681695A CN 116185236 A CN116185236 A CN 116185236A
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0416—Control or interface arrangements specially adapted for digitisers
- G06F3/04166—Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0416—Control or interface arrangements specially adapted for digitisers
- G06F3/0418—Control or interface arrangements specially adapted for digitisers for error correction or compensation, e.g. based on parallax, calibration or alignment
- G06F3/04182—Filtering of noise external to the device and not generated by digitiser components
Abstract
The invention aims to provide a space-apart touch system with high anti-interference capability, which has the advantages of simple circuit, low cost and low power consumption and can accurately identify touch operation. The invention comprises a capacitor charge collector, a voltage comparator, a spreading module, a constant current source module and a touch recognition module, wherein the capacitor charge collector and the constant current source module are both connected with an electric signal of the spreading module, the output end of the spreading module is connected with the input end of the voltage comparator, and the output end of the voltage comparator is connected with the input end of the touch recognition module. The invention is applied to the technical field of touch systems.
Description
Technical Field
The invention is applied to the technical field of touch systems, and particularly relates to a spaced touch system with high anti-interference capability.
Background
As important man-machine interaction and information input and output media, an industrial control touch system becomes an indispensable part of the construction of interaction terminals in numerous industrial scenes by virtue of excellent performances. The performance of the industrial control touch system in the dimensions of energy consumption, stability, wide-temperature running, earthquake resistance, antimagnetic resistance and the like makes the industrial control touch system an indiscriminate choice. Industrial control touch systems are widely used in the fields of smart home, logistics, environmental protection supervision, power industry and the like.
The touch control is used as an input means of equipment to replace a keyboard and a mouse, and is directly operated on a display screen in a touch control mode, so that the visual, quick and easy-to-use mode brings great benefits to industrial application. The touch screen is used as a man-machine interaction terminal, is widely applied to electric power, factories, municipal administration, chemical industry, mechanical equipment and the like, and brings more vivid and visual experience for operation monitoring.
Touch screens can be classified into four types, namely, resistive, capacitive, infrared, and surface wave types, according to the operating principle of the touch screen and the transmission medium of information. Among them, resistor and capacitor applications are the most widely used. The existing smart phones are basically in a capacitive touch mode, and the principle of the capacitive touch screen of the industrial personal computer is the same. The reaction is made by fingertip contact, rather than with a glove or conventional stylus. Because the capacitive screen uses the upper layer to transmit signals to the lower layer, the lower layer can receive information and perform calculations when the upper layer is in contact with the conductor. Therefore, the two screens are not necessarily in direct contact, and the position of finger contact can be determined by only calculating information received by the upper layer. Because of this, the capacitive screen can not only support a plurality of points at the same time, but also greatly improve the sensitivity of touch.
Different touch circuits have been developed for different application scenarios. For example, a prior patent document with publication number CN114895809a proposes a blank touch circuit, a touch key and a touch product for improving anti-interference capability, a charge transfer scanning module of the circuit converts a capacitance signal generated by the touch key into a voltage signal, and a filter filters an interference signal in the voltage signal to obtain a touch signal; and the control module performs recognition processing on the touch signal. The circuit can greatly improve the capability of the touch key for resisting various interferences, and can still recognize effective weak capacitance change under the condition that the interferences exist, thereby realizing a reliable blank touch function. But the defects are obvious, namely, the system is complex, the cost is high and the power consumption is high.
Another patent document with publication number CN107508586B proposes an ultra-low power touch key circuit and a method for using the same, which eliminates the analog-to-digital converter and uses a counter to count the number of beats during the charge and discharge of the capacitor on C1. When the touch operation changes in C1, the number of counter outputs also changes, so as to determine whether the touch operation has occurred. The advantage of this circuit is low power consumption and low cost, but disadvantages include: 1. the circuit has the advantages that the circuit does not have a control module, different touch signals cannot be screened, the anti-interference capability is weak, and the circuit cannot judge capacitance changes caused by false touch; 2. the achievable precision of the circuit is not high, the precision of S1 has a large influence on the charge and discharge time of C1, and the precision of a simple CMOS switch is not high.
Disclosure of Invention
The invention aims to solve the technical problem of overcoming the defects of the prior art, and provides a spaced touch system which has simple circuit, low cost and low power consumption and can accurately identify touch operation and has high anti-interference capability.
The technical scheme adopted by the invention is as follows: the invention comprises a capacitor charge collector, a voltage comparator, a spreading module, a constant current source module and a touch recognition module, wherein the capacitor charge collector and the constant current source module are both connected with an electric signal of the spreading module, the output end of the spreading module is connected with the input end of the voltage comparator, and the output end of the voltage comparator is connected with the input end of the touch recognition module.
Further, the spread spectrum module includes first switch, second switch, first electric capacity and second electric capacity, constant current source module's output with the input of electric capacity charge collector all with the one end of first switch is connected, the second switch with the one end of first electric capacity all with the other end of first switch is connected, the one end of second electric capacity with the other end of second switch is connected, the first electric capacity with the other end of second electric capacity all ground connection.
Further, the touch recognition module comprises a trigger, a counter and an MCU module, wherein the output end of the comparator is connected with one end of the first switch, the output end of the comparator is connected with the input end of the trigger, the output end of the trigger is connected with the input end of the counter, and the output end of the counter is connected with the input end of the MCU module.
Further, the isolated touch system with high anti-interference capability further comprises a first resistor and a third switch, one end of the first resistor is connected with the input end of the voltage comparator, the other end of the first resistor is connected with the third switch, and the other end of the third switch is grounded.
The beneficial effects of the invention are as follows:
1. the invention uses the constant current source and the switch capacitance circuit, reduces the interference of power supply noise, and simultaneously reduces the error caused by the technological deviation of the semiconductor resistor;
2. the invention uses spread spectrum technology, improves the signal to noise ratio of the capacitance charge collector, and can greatly improve the anti-interference capability of the spaced touch through digital processing;
3. compared with the traditional touch scheme, the analog-digital converter is removed, the touch system is simpler in circuit, lower in cost and power consumption and higher in reliability.
Drawings
FIG. 1 is a circuit block diagram of the present invention;
FIG. 2 is a schematic diagram of the change in duty cycle of a data stream with and without touch of the present invention.
Detailed Description
As shown in fig. 1 and 2, in this embodiment, the present invention includes a capacitor charge collector a, a voltage comparator B, a spread spectrum module C, a constant current source module D, and a touch recognition module E, where the capacitor charge collector a and the constant current source module D are both electrically connected to the spread spectrum module C, an output end of the spread spectrum module C is connected to an input end of the voltage comparator B, and an output end of the voltage comparator B is connected to an input end of the touch recognition module E. The capacitor charge collector A is used for sampling the change of the capacitance value at high frequency; the spread spectrum module C is a non-overlapping spread spectrum clock and is used for converting the change of the capacitance value into the change of the equivalent resistance; the constant current source module D is used for outputting constant current; the comparator B is used for comparing the difference between the capacitor voltage Vmod on the spread spectrum module C and the reference voltage Vth and outputting a group of data streams to the touch recognition module E; the touch recognition module E is used for analyzing and processing the data stream so as to recognize whether normal key touch or error touch is performed.
In this embodiment, the spread spectrum module C includes a first switch K1, a second switch K2, a first capacitor C1 and a second capacitor C2, an output end of the constant current source module D and an input end of the capacitor charge collector a are all connected with one end of the first switch K1, one ends of the second switch K2 and the first capacitor C1 are all connected with the other end of the first switch K1, one end of the second capacitor C2 is connected with the other end of the second switch K2, and the other ends of the first capacitor C1 and the second capacitor C2 are all grounded.
In this embodiment, the touch recognition module E includes a trigger F, a counter G, and an MCU module, where an output end of the comparator is connected to one end of the first switch K1, an output end of the comparator is connected to an input end of the trigger F, an output end of the trigger F is connected to an input end of the counter G, and an output end of the counter G is connected to an input end of the MCU module. Wherein the trigger F is configured to resample a continuous time domain signal into a discrete domain; the counter G is used for counting the number of high levels in a period of time, and the number of the high levels is inversely proportional to the capacitance value; the MCU module is used for analyzing and processing the data stream Raw_data < n:0>, so that normal key touch or error touch is identified, and the anti-interference capability of the invention is greatly improved.
In this embodiment, the isolated touch system with high anti-interference capability further includes a first resistor R1 and a third switch K3, where one end of the first resistor R1 is connected to the input end of the comparator, the other end of the first resistor R1 is connected to the third switch K3, and the other end of the third switch K3 is grounded.
In the embodiment, the scheme of combining the constant current source with the non-overlapping spread spectrum clock is innovatively used, so that various interferences caused by power supply fluctuation can be effectively avoided, and meanwhile, errors caused by semiconductor resistor process deviation can be reduced. The voltage comparator B is configured to compare a difference between the voltage Vmod on the first capacitor C1 and a reference voltage Vth. When the circuit is powered on, the constant current source module D outputs current to charge the first capacitor C1, and the first capacitor C1 may be equivalently a second resistor R2, rs=1/cs×fsw. Wherein Rs is the resistance of the second resistor R2, and Cs is the capacitance of the first capacitor C1; fsw is the frequency of the non-overlapping spread spectrum clock when the first switch K1 is turned on or off, and the voltage Vmod rises along with the charging time.
In this embodiment, when the voltage Vmod is greater than the reference voltage Vth, the voltage comparator B turns over to ground the first resistor R1, at this time, the first resistor R1 is connected in parallel with the first capacitor C1, the charge at the voltage Vmod will be discharged, the voltage Vmod decreases until the voltage Vmod is equal to the reference voltage Vth, then the voltage comparator B turns over again, and finally the voltage comparator B will output a set of data streams with dense and alternate phases, and the duty ratio thereof is inversely proportional to the capacitance of the first capacitor C1.
In this embodiment, when a finger or a key pen is close to the touch key, the second capacitor C2 is turned on, the total self-inductance capacitance value will change, so that Rs' =1/(cs+cf) ×fsw, the voltage Vmod on the capacitor plate will change slightly, the duty ratio of the data stream output by the voltage comparator B will also change accordingly, and the change of the duty ratio acquired by the system is perceived as touching. Wherein Rs' is the resistance of the second resistor R2 after the change; cf is the capacitance of the second capacitor C2.
In this embodiment, when there is no touch, the output value of the counter G fluctuates in a small range, and the peak-to-peak value of the fluctuation is referred to as noise; when there is a touch, the output value of the counter G becomes smaller, and the difference of the average values is called a signal. Where the ratio of signal to noise is referred to as the signal-to-noise ratio (SNR), an SNR of greater than 5 (14 dB) is typically used to ensure effective detection.
Claims (4)
1. A spaced apart touch system with high tamper resistance, characterized by: the novel capacitive charge display device comprises a capacitive charge collector (A), a voltage comparator (B), a spread spectrum module (C), a constant current source module (D) and a touch identification module (E), wherein the capacitive charge collector (A) and the constant current source module (D) are electrically connected with the spread spectrum module (C), the output end of the spread spectrum module (C) is connected with the input end of the voltage comparator (B), and the output end of the voltage comparator (B) is connected with the input end of the touch identification module (E).
2. A spaced apart touch system with high tamper resistance as recited in claim 1, wherein: the spread spectrum module (C) comprises a first switch (K1), a second switch (K2), a first capacitor (C1) and a second capacitor (C2), wherein the output end of the constant current source module (D) and the input end of the capacitor charge collector (A) are connected with one end of the first switch (K1), one end of the second switch (K2) and one end of the first capacitor (C1) are connected with the other end of the first switch (K1), one end of the second capacitor (C2) is connected with the other end of the second switch (K2), and the other ends of the first capacitor (C1) and the second capacitor (C2) are grounded.
3. A spaced apart touch system with high tamper resistance as recited in claim 2, wherein: the touch recognition module (E) comprises a trigger (F), a counter (G) and an MCU module, wherein the output end of the comparator is connected with one end of the first switch (K1), the output end of the comparator is connected with the input end of the trigger (F), the output end of the trigger (F) is connected with the input end of the counter (G), and the output end of the counter (G) is connected with the input end of the MCU module.
4. A spaced apart touch system with high tamper resistance as recited in claim 1, wherein: the isolated touch system with the high anti-interference capability further comprises a first resistor (R1) and a third switch (K3), one end of the first resistor (R1) is connected with the input end of the voltage comparator (B), the other end of the first resistor (R1) is connected with the third switch (K3), and the other end of the third switch (K3) is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211681695.5A CN116185236A (en) | 2022-12-27 | 2022-12-27 | Spaced touch system with high anti-interference capability |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211681695.5A CN116185236A (en) | 2022-12-27 | 2022-12-27 | Spaced touch system with high anti-interference capability |
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| CN116185236A true CN116185236A (en) | 2023-05-30 |
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| CN202211681695.5A Pending CN116185236A (en) | 2022-12-27 | 2022-12-27 | Spaced touch system with high anti-interference capability |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117170522A (en) * | 2023-11-01 | 2023-12-05 | 深圳市锦锐科技股份有限公司 | High anti-interference method and device for household appliance touch panel and storage medium |
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2022
- 2022-12-27 CN CN202211681695.5A patent/CN116185236A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117170522A (en) * | 2023-11-01 | 2023-12-05 | 深圳市锦锐科技股份有限公司 | High anti-interference method and device for household appliance touch panel and storage medium |
| CN117170522B (en) * | 2023-11-01 | 2024-02-27 | 深圳市锦锐科技股份有限公司 | High anti-interference method and device for household appliance touch panel and storage medium |
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