CN108287638B - Touch detection circuit and touch detection method thereof - Google Patents
Touch detection circuit and touch detection method thereof Download PDFInfo
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- CN108287638B CN108287638B CN201810316822.9A CN201810316822A CN108287638B CN 108287638 B CN108287638 B CN 108287638B CN 201810316822 A CN201810316822 A CN 201810316822A CN 108287638 B CN108287638 B CN 108287638B
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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
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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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D10/00—Energy efficient computing, e.g. low power processors, power management or thermal management
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Abstract
The invention discloses a touch detection circuit, which comprises a power supply module, an induction detection unit and a controller module, wherein the power supply module is connected with the induction detection unit; the power supply module supplies power; the sensing detection unit detects the signal uploaded by the touch sensing part and uploads the signal to the controller module; the controller module detects a touch action according to the uploaded signal. The invention also discloses a touch detection method of the touch detection circuit, which completes touch detection by detecting the influence of the capacitance to ground formed by the touch sensing part of the human body on the oscillation frequency output by the oscillation circuit. The touch detection circuit and the touch detection method thereof can accurately detect and identify the touch action of the induction touch part, and the touch induction part can be adjusted and expanded according to the needs, so that the application range and flexibility of the touch detection circuit are greatly increased, and the use experience of a user is greatly improved.
Description
Technical Field
The invention particularly relates to a touch detection circuit and a touch detection method thereof.
Background
Along with the development of economic technology and the improvement of living standard of people, touch operation has become an indispensable part in daily life of people, and endless convenience is brought to the production and living of people.
The core of the touch operation is to detect a touch action of a person. The conventional touch detection circuit and the corresponding detection method have various methods, such as a capacitive sensor is adopted in the touch sensing part to sense the touch of a user, or the capacitance sensing of a human body is utilized to convert the change of the capacitance into the change of voltage, charge and charging period, and the like to determine. However, in either touch detection mode, the sensing portion of the circuit as part of the circuit cannot be adjusted and expanded once the circuit for touch detection is determined. If the length of the touch sensing portion is to be prolonged, the size and position of the touch area are to be changed, or the sensing portion is to be replaced by a conductive object (such as a touch lamp using a key) according to the user's requirement, the circuit parameters need to be readjusted, and even the touch sensing portion cannot work. When the sensing part reaches a certain length or area, the sensitivity of receiving touch sensing is reduced due to the change and uncertainty of external interference, the touch signal cannot be accurately identified, and the received electric interference is increased, so that the stability of touch sensing is reduced, and the touch detection method has certain limitation and cannot well meet the requirements of users.
Disclosure of Invention
One of the purposes of the present invention is to provide a touch detection circuit that has high touch detection accuracy and is suitable for the case where the touch sensing portion is adjustable and expandable.
The second object of the present invention is to provide a touch detection method of the touch detection circuit.
The touch detection circuit provided by the invention comprises a power supply module, an induction detection unit and a controller module; a power supply module supplies power to the touch detection circuit; the controller module, the induction detection unit and the touch induction part are sequentially connected in series; the sensing detection unit is connected with the touch sensing part and is used for detecting the data signals uploaded by the touch sensing part and uploading the data signals to the controller module; the controller module detects the touch action of the touch sensing part according to the detection signal uploaded by the sensing detection unit.
The induction detection unit is an oscillating circuit.
The induction detection unit also comprises an input filter circuit; the input filter circuit is connected in series with the input end of the oscillating circuit and is used for filtering out the electric interference signals coupled in from the touch sensing part.
The induction detection unit also comprises an input protection circuit; the input protection circuit is connected in series between the input filter circuit and the oscillating circuit and is used for electrically protecting the oscillating circuit.
The oscillating circuit comprises an oscillating circuit formed by analog circuit devices and an oscillating circuit formed by integrated chips.
The oscillating circuit formed by the analog circuit device is an RC oscillating circuit built by circuit components, an LC oscillating circuit built by circuit components, an RL oscillating circuit built by circuit components, an RLC oscillating circuit built by circuit components, an RC oscillating circuit integrated by a circuit chip, an LC oscillating circuit integrated by a circuit chip, an RL oscillating circuit integrated by a circuit chip and an RLC oscillating circuit integrated by a circuit chip, a voltage-controlled oscillating circuit built by circuit components, a square wave generator circuit built by circuit components and a crystal oscillator square wave oscillating circuit built by circuit components.
The oscillating circuit formed by the integrated chip is an oscillating circuit formed by a voltage-controlled oscillating module, an oscillating circuit formed by a square wave generator or an oscillating circuit formed by the integrated oscillating chip.
The touch sensing part is provided with a plurality of conductive points, and the conductive points are connected through conductors; the user can directly touch any one conductive point or any part of the conductive body connected with the conductive point through the human body or any conductive body to realize touch sensing.
The invention also discloses a touch detection method of the touch detection circuit, and the touch detection of the touch detection circuit is completed by detecting the influence of the capacitance to ground formed by the touch sensing part of the human body on the oscillation frequency output by the oscillation circuit.
The touch detection method specifically comprises the following steps of:
s1, sampling square wave frequency output by an oscillating circuit;
s2, acquiring the frequency of the harmonic wave with the greatest interference in the sampling sequence acquired in the step S1;
s3, sampling square wave frequency output by the oscillating circuit by adopting the frequency obtained in the step S2;
s4, normalizing the sampling sequence obtained in the step S3 to a target value, so that the sampling sequence shakes around the target value;
s5, touch detection is carried out on the sampling sequence obtained in the step S4, and therefore the process of touch detection is completed.
The step S2 of acquiring the frequency of the harmonic with the greatest interference in the sampling sequence is specifically implemented by adopting the following steps:
A. the controller module samples the period T s Sampling the square wave frequency output by the oscillating circuit, thereby forming a sampled square wave frequency x (n);
B. performing FFT operation on the sampled square wave frequency X (n) to obtain a sequence X (k);
C. b, obtaining a positive correlation value A (k) of the magnitude spectrum according to the sequence X (k) obtained in the step B;
D. c, obtaining the maximum value except the A (0) item in the amplitude spectrum positive correlation value A (k) obtained in the step C;
E. obtaining fundamental wave frequency f corresponding to the maximum value obtained in the step D a And at a fundamental frequency f a Is the sampling frequency.
The step S4 of normalizing the obtained sampling sequence to the target value specifically includes the following steps:
a. calculating a postterm differential value of the sampling sequence y (m);
b. c, calculating an accumulated backward difference maximum value and an accumulated backward difference minimum value in m times of sampling according to the backward difference value obtained in the step a;
c. b, judging the difference value between the maximum value of the accumulated backward difference and the minimum value of the accumulated backward difference obtained in the step b and the preset threshold value;
d. c, calculating the average value of the sampling sequence y (m) obtained in the step a;
e. calculating a normalized weight value w=target value/average value;
f. multiplying each term of the sampling sequence y (m) obtained in the step a by a normalization weight value, thereby normalizing the sampling sequence to a target value.
The step S5 of performing touch detection on the sampling sequence specifically includes the following steps:
(1) Acquiring a difference D between the normalized target value obtained in the step S4 and the peak value of the detected suspected touch waveform;
(2) Acquiring a falling value P1 of a falling edge and a rising value P2 of a rising edge of a suspected touch waveform in a set time period delta t;
(3) Acquiring a time point t1 when the falling edge of the suspected touch waveform starts, a time point t2 when the rising edge ends, and an area S1 enclosed between the suspected touch waveform and a normalized target value in a time period of t 1-t 2;
(4) Acquiring an area S2 surrounded by a normalized target value and a peak value of a suspected touch waveform in a time period from t1 to t 2;
(5) Calculating the touch area occupancy ratio
(6) D, P1, P2, |t 2 -t 1 The values of S1 and Ps are compared with a predetermined threshold value to determine whether the detected suspected touch waveform is a valid touch signal.
According to the touch detection circuit and the touch detection method thereof, the signals of the induction touch part are converted into the output signals of the oscillating circuit and detected, so that the touch detection circuit can accurately detect and identify the touch action of the induction touch part, and the touch induction part can be adjusted and expanded according to the needs, so that the application range and flexibility of the touch detection circuit are greatly increased, and the use experience of a user is greatly improved.
Drawings
Fig. 1 is a functional block diagram of a touch detection circuit of the present invention.
Fig. 2 is a functional block diagram of the sensing unit of the present invention.
FIG. 3 is a schematic circuit diagram of an embodiment of an inductive sensing unit of the present invention.
Fig. 4 is a schematic circuit diagram of an oscillating circuit according to the present invention when an RC oscillating circuit is used.
Fig. 5 is a schematic circuit diagram of an LC oscillating circuit used in the oscillating circuit of the present invention.
Fig. 6 is a schematic circuit diagram of an oscillating circuit according to the present invention when a voltage-controlled oscillating module is used.
Fig. 7 is a schematic circuit diagram of an oscillating circuit of the present invention using a square wave generator.
Fig. 8 is a schematic circuit diagram of an oscillating circuit of the present invention using an integrated oscillating chip.
Fig. 9 is a schematic diagram of an inductive touch portion of the present invention.
Fig. 10 is a flow chart of the method of the present invention.
Detailed Description
FIG. 1 is a functional block diagram of a touch detection circuit according to the present invention: the touch detection circuit provided by the invention comprises a power supply module, an induction detection unit and a controller module; a power supply module supplies power to the touch detection circuit; the controller module, the induction detection unit and the touch induction part are sequentially connected in series; the sensing detection unit is connected with the touch sensing part and is used for detecting the data signals uploaded by the touch sensing part and uploading the data signals to the controller module; the controller module detects the touch action of the touch sensing part according to the detection signal uploaded by the sensing detection unit.
Fig. 2 is a functional block diagram of the induction detecting unit according to the present invention: the induction detection unit adopts an oscillating circuit, and an input filter circuit and an input protection circuit are connected in series before the oscillating circuit; the input filter circuit is used for filtering the electric interference signals coupled in from the touch sensing part; the input protection circuit is used for electrically protecting the oscillating circuit.
Fig. 3 is a schematic circuit diagram of an embodiment of the sensing unit according to the present invention: the input filter circuit in this embodiment adopts an inductance L1 (other filter circuits such as magnetic beads may also be adopted) to filter most of the high-frequency interference signals of the induction touch unit, that is, the external electric interference coupled into the oscillation circuit through the induction touch unit; the input protection circuit adopts protection diodes D1 and D2, and the two diodes are used for avoiding static electricity from damaging the oscillating circuit. The capacitance CY in the figure is an equivalent capacitance generated between the human body and the ground when the human body touches or indirectly touches the sensing touch unit through the conductor, and the addition of the equivalent capacitance changes the capacitance value of the input end of the oscillating circuit, so that the frequency of the square wave output by the oscillating circuit is affected, and the touch action of the human body on the sensing touch unit is converted into the change of the electric signal. The controller module detects the change of the electric signal, so that the touch detection of the induction touch part is achieved.
The core device of the touch sensing unit is an oscillating circuit. The oscillating circuit includes an oscillating circuit constituted by analog circuit devices and an oscillating circuit constituted by an integrated chip.
The oscillating circuit formed by the analog circuit device is an RC oscillating circuit built by circuit components, an LC oscillating circuit built by circuit components, an RL oscillating circuit built by circuit components, an RLC oscillating circuit built by circuit components, an RC oscillating circuit integrated by circuit chips, an LC oscillating circuit integrated by circuit chips, an RL oscillating circuit integrated by circuit chips and an RLC oscillating circuit integrated by circuit chips, a voltage-controlled oscillating circuit built by circuit components, a square wave generator circuit built by circuit components and a crystal oscillator square wave oscillating circuit built by circuit components; the definition of the circuit component is as follows: instead of using a circuit formed by integrated chips, a designer uses independent components such as resistors, capacitors, inductors, integrated op-amps to build or assemble the circuit.
The oscillating circuit formed by the integrated chip is an oscillating circuit formed by a voltage-controlled oscillating module, an oscillating circuit formed by a square wave generator or an oscillating circuit formed by the integrated oscillating chip
The types of oscillating circuits are numerous, and the following will list a few typical examples of oscillating circuits:
fig. 4 is a schematic circuit diagram of an oscillating circuit according to the present invention when an RC oscillating circuit is used: in the embodiment, an RC oscillating circuit formed by an operational amplifier U1, a resistor R and a capacitor C is adopted as the oscillating circuit; in the circuit diagram, a resistor R2, a capacitor C1, a resistor R4 and a capacitor C2 form a series-parallel frequency selection network, a negative feedback branch is formed by R3 and R5, an output voltage Vout is input into a positive feedback end of an operational amplifier U1 through positive feedback voltage division of the frequency selection network, and Vout is input into the negative feedback end of the U1 through the negative feedback branch, so that an output sine waveform with stable amplitude and frequency is achieved. When r2=r4=r and c1=c2=c, the oscillating circuit outputs a square wave frequency at its output end (output end of the op-amp U1) when no touch signal is presentWhen a touch signal is applied, the equivalent capacitance is equivalent to the capacitance C2 in parallel, and the capacitance of the oscillating circuit is changed, so that the outputThe square wave frequency of the output square wave is changed.
Fig. 5 is a schematic circuit diagram of an LC oscillating circuit used in the oscillating circuit according to the present invention: in this embodiment, the oscillating circuit is an LC oscillating circuit formed by a triode VT, a capacitor C, an inductance L, and a resistor R, where the core oscillating frequency is determined by L, C and C, the frequency is mainly adjusted by C, C3 is a trimming capacitor, the function of the resistor portion provides a reasonable static working point for the oscillator, and guarantees the starting and stability of the oscillator, and C2 is a circuit feedback portion, guaranteeing the stability of the oscillating amplitude. The oscillating circuit outputs square wave frequency at its output end (signal OUT in the figure) when no touch signal is presentWhen a touch signal exists, the equivalent capacitance is equivalent to the capacitance loaded between the point A and the ground signal, the capacitance value of the oscillation capacitance of the oscillation circuit is changed, and the frequency of the square wave output is changed.
Fig. 6 is a schematic circuit diagram of an oscillating circuit according to the present invention when the oscillating circuit employs a voltage-controlled oscillating module: in this embodiment, a voltage-controlled oscillation (VCO) module is employed to constitute an oscillation circuit; the voltage-controlled oscillation (VCO) module can be implemented by a chip (such as a VCO functional part in a PLL logic chip of a HEF4046 BPN) with a VCO functional module, the 6 pin of the chip is directly connected to the inductive touch part, the 7 pin is connected to the 6 pin through an oscillation capacitor C1, the 11 pin is connected to an oscillation resistor R1, and the 12 pin is connected to R2, and other functional modules of the chip can be omitted, so that the VCO module can work only by supplying power to the chip; when the oscillating circuit is not touched, the square wave frequency output by the output end (4 pins of a chip in the figure) can be obtained according to a table in a chip manual, the values of the square wave frequency are related to R1 and C1 according to the table, and when the touch signal exists, the equivalent capacitance is equivalent to the capacitance loaded between the 6 pins of the chip and the ground signal, the capacitance of the oscillating circuit is changed, and the frequency of the square wave output is changed.
Fig. 7 is a schematic circuit diagram of the oscillating circuit according to the present invention when a square wave generator is used: in this embodiment, the oscillating circuit is an oscillating circuit constituted by a schmitt square wave generator; the input end (2 feet) of the Schmitt trigger is connected with a power supply signal VCC through an oscillation capacitor CT, and is also connected with the output end (4 feet) through an oscillation resistor R1, wherein CT serves as a charge-discharge capacitor, R1 provides a charge-discharge loop, U1A provides an oscillation condition, the input voltage of the Schmitt trigger has two thresholds, jitter interference of the input end near the thresholds can be eliminated, so that output is more stable, when the oscillation circuit is free of a touch signal, square wave frequency output by the output end (2 feet of the trigger in the figure) of the oscillation circuit is related to R1 and C1, and specific numerical values can be obtained according to the values of R1 and C1 and the threshold value of a Schmitt trigger chip manual; when a touch signal exists, the equivalent capacitance is loaded between the 2 pins of the trigger and the ground and VCC, the capacitance value of the oscillation capacitance of the oscillation circuit is changed, and the frequency of the square wave output is changed.
Fig. 8 is a schematic circuit diagram of an oscillating circuit according to the present invention when an integrated oscillating chip is used: in this embodiment, the oscillating circuit is formed by an integrated oscillating chip (such as MIC 1557); the 1 pin and the 2 pin of the chip are both connected with a power supply signal VCC, the 3 pin of the chip is grounded, the 4 pin of the chip is connected with the 5 pin of the output pin of the chip through an oscillating resistor R1, and meanwhile, the 4 pin of the chip is also grounded through an oscillating capacitor CT; when the oscillating circuit is not touched, the square wave frequency output by the output end (5 pins of the chip in the figure) isWherein k is 1 The values of (2) may be obtained from the data manual of the chip; when a touch signal exists, the equivalent capacitance is equivalent to the capacitance loaded between the 4 pins of the chip and the ground, the capacitance value of the oscillation capacitance of the oscillation circuit is changed, and the frequency of the square wave output is changed.
FIG. 9 is a schematic diagram of the inductive touch portion of the present invention: the touch sensing part is provided with a plurality of conductive points, and the conductive points are connected through conductors (black thick solid lines in the figure); the user can directly touch any one conductive point or any part of the conductive body connected with the conductive point through the human body or any conductive body to realize touch sensing.
A method flow chart of the invention is shown in fig. 10: according to the touch detection method of the touch detection circuit, the influence of the capacitance to ground formed by the touch sensing part of the human body on the oscillation frequency output by the oscillation circuit is detected, so that the touch detection of the touch detection circuit is completed.
The touch detection method comprises the following steps of:
s1, sampling square wave frequency output by an oscillating circuit;
s2, acquiring the frequency of the harmonic wave with the greatest interference in the sampling sequence acquired in the step S1; the method comprises the following steps:
A. the controller module samples the period T s Sampling the square wave frequency output by the oscillating circuit, thereby forming a sampled square wave frequency x (n);
B. performing FFT operation on the sampled square wave frequency X (n) to obtain a sequence X (k);
C. b, obtaining a positive correlation value A (k) of the magnitude spectrum according to the sequence X (k) obtained in the step B;
D. c, obtaining the maximum value except the A (0) item in the amplitude spectrum positive correlation value A (k) obtained in the step C;
E. obtaining fundamental wave frequency f corresponding to the maximum value obtained in the step D a And at a fundamental frequency f a Is the sampling frequency;
s3, sampling square wave frequency output by the oscillating circuit by adopting the frequency obtained in the step S2;
s4, normalizing the sampling sequence obtained in the step S3 to a target value, so that the sampling sequence shakes around the target value; specifically, the normalization is carried out by adopting the following steps:
a. calculating a postterm differential value of the sampling sequence y (m);
b. c, calculating an accumulated backward difference maximum value and an accumulated backward difference minimum value in m times of sampling according to the backward difference value obtained in the step a;
c. b, judging the difference value between the maximum value of the accumulated backward difference and the minimum value of the accumulated backward difference obtained in the step b and the preset threshold value;
d. c, calculating the average value of the sampling sequence y (m) obtained in the step a;
e. calculating a normalized weight value w=target value/average value;
f. multiplying each term of the sampling sequence y (m) obtained in the step a by a normalization weight value, so as to normalize the sampling sequence to a target value;
s5, performing touch detection on the sampling sequence obtained in the step S4, so as to finish the process of touch detection; specifically, the method comprises the following steps of:
(1) Acquiring a difference D between the normalized target value obtained in the step S4 and the peak value of the detected suspected touch waveform;
(2) Acquiring a falling value P1 of a falling edge and a rising value P2 of a rising edge of a suspected touch waveform in a set time period delta t;
(3) Acquiring a time point t1 when the falling edge of the suspected touch waveform starts, a time point t2 when the rising edge ends, and an area S1 enclosed between the suspected touch waveform and a normalized target value in a time period of t 1-t 2;
(4) Acquiring an area S2 surrounded by a normalized target value and a peak value of a suspected touch waveform in a time period from t1 to t 2;
(5) Calculating the touch area occupancy ratio
(6) D, P1, P2, |t 2 -t 1 The values of I, S1 and Ps are compared with a preset threshold value, so that whether the detected suspected touch waveform is a valid touch signal is judged;
the method comprises the following steps: setting a threshold D in advance min ，P1 min ，P2 min ，|t 2 -t 1 | min ，S1 min And Ps min If D>D min 、P1>P1 min ，P2>P2 min ，|t 2 -t 1 |>|t 2 -t 1 | min ，S1>S1 min And Ps>Ps min Then the detected suspected touch is identifiedAnd if the waveform is a valid touch signal, otherwise, the suspected touch waveform is determined to be an invalid touch signal.
Claims (7)
1. The touch detection circuit is characterized by comprising a power supply module, an induction detection unit and a controller module; a power supply module supplies power to the touch detection circuit; the controller module, the induction detection unit and the touch induction part are sequentially connected in series; the sensing detection unit is connected with the touch sensing part and is used for detecting the data signals uploaded by the touch sensing part and uploading the data signals to the controller module; the controller module detects the touch action of the touch sensing part according to the detection signal uploaded by the sensing detection unit;
the touch detection circuit also comprises a touch detection method, and the touch detection method is used for completing the touch detection of the touch detection circuit by detecting the influence of the capacitance to ground formed by the touch sensing part of the human body on the oscillation frequency output by the oscillation circuit;
the touch detection method specifically comprises the following steps of:
s1, sampling square wave frequency output by an oscillating circuit;
s2, acquiring the frequency of the harmonic wave with the greatest interference in the sampling sequence acquired in the step S1; the method comprises the following steps:
A. the controller module samples the period T s Sampling the square wave frequency output by the oscillating circuit, thereby forming a sampled square wave frequency x (n);
B. performing FFT operation on the sampled square wave frequency X (n) to obtain a sequence X (k);
C. b, obtaining a positive correlation value A (k) of the magnitude spectrum according to the sequence X (k) obtained in the step B;
D. c, obtaining the maximum value except the A (0) item in the amplitude spectrum positive correlation value A (k) obtained in the step C;
E. obtaining fundamental wave frequency f corresponding to the maximum value obtained in the step D a And at a fundamental frequency f a Is the sampling frequency;
s3, sampling square wave frequency output by the oscillating circuit by adopting the frequency obtained in the step S2;
s4, normalizing the sampling sequence obtained in the step S3 to a target value, so that the sampling sequence shakes around the target value; specifically, the normalization is carried out by adopting the following steps:
a. calculating a postterm differential value of the sampling sequence y (m);
b. c, calculating an accumulated backward difference maximum value and an accumulated backward difference minimum value in m times of sampling according to the backward difference value obtained in the step a;
c. b, judging the difference value between the maximum value of the accumulated backward difference and the minimum value of the accumulated backward difference obtained in the step b and the preset threshold value;
d. c, calculating the average value of the sampling sequence y (m) obtained in the step a;
e. calculating a normalized weight value w=target value/average value;
f. multiplying each term of the sampling sequence y (m) obtained in the step a by a normalization weight value, so as to normalize the sampling sequence to a target value;
s5, performing touch detection on the sampling sequence obtained in the step S4, so as to finish the process of touch detection; specifically, the method comprises the following steps of:
(1) Acquiring a difference D between the normalized target value obtained in the step S4 and the peak value of the detected suspected touch waveform;
(2) Acquiring a falling value P1 of a falling edge and a rising value P2 of a rising edge of a suspected touch waveform in a set time period delta t;
(3) Acquiring a time point t1 when the falling edge of the suspected touch waveform starts, a time point t2 when the rising edge ends, and an area S1 enclosed between the suspected touch waveform and a normalized target value in a time period of t 1-t 2;
(4) Acquiring an area S2 surrounded by a normalized target value and a peak value of a suspected touch waveform in a time period from t1 to t 2;
(5) Calculating the touch area occupancy ratio
(6) D, P1, P2, |t 2 -t 1 The values of I, S1 and Ps are all equal to the threshold value set in advanceAnd comparing to judge whether the detected suspected touch waveform is a valid touch signal.
2. The touch detection circuit of claim 1, wherein the sensing unit is an oscillating circuit.
3. The touch detection circuit of claim 1, wherein the sensing detection unit further comprises an input filter circuit; the input filter circuit is connected in series with the input end of the oscillating circuit and is used for filtering out the electric interference signals coupled in from the touch sensing part.
4. The touch detection circuit of claim 3, wherein the sensing detection unit further comprises an input protection circuit; the input protection circuit is connected in series between the input filter circuit and the oscillating circuit and is used for electrically protecting the oscillating circuit.
5. The touch detection circuit according to any one of claims 2 to 4, wherein the oscillation circuit includes an oscillation circuit composed of analog circuit devices and an oscillation circuit composed of integrated chips.
6. The touch detection circuit according to claim 5, wherein the oscillating circuit formed by the analog circuit device is an RC oscillating circuit formed by a circuit element, an LC oscillating circuit formed by a circuit element, an RL oscillating circuit formed by a circuit element, an RLC oscillating circuit formed by a circuit element, an RC oscillating circuit integrated by a circuit chip, an LC oscillating circuit integrated by a circuit chip, an RL oscillating circuit integrated by a circuit chip and an RLC oscillating circuit integrated by a circuit chip, a voltage-controlled oscillating circuit formed by a circuit element, a square wave generator circuit formed by a circuit element, a crystal oscillator square wave oscillating circuit formed by a circuit element.
7. The touch detection circuit of claim 6, wherein the oscillating circuit is an oscillating circuit comprising a voltage controlled oscillating module, an oscillating circuit comprising a square wave generator, or an oscillating circuit comprising an integrated oscillating chip.
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| CN109117020B (en) * | 2018-07-19 | 2022-09-20 | 北京集创北方科技股份有限公司 | Positioning method and device of touch position, storage medium and electronic device |
| CN108874010A (en) * | 2018-09-06 | 2018-11-23 | 深圳市中微半导体有限公司 | A kind of strong anti-interference LDO module and anti-interference touch detection circuit |
| US11320941B2 (en) * | 2019-07-03 | 2022-05-03 | Samsung Electro-Mechanics Co., Ltd. | Sensing device with fingerprint sensor |
| CN113137980A (en) * | 2021-04-02 | 2021-07-20 | 屈新苗 | Variable narrow-band differential capacitance sensing circuit, sensing method and application thereof |
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| WO2003094352A1 (en) * | 2002-05-02 | 2003-11-13 | Essdesign Corp., Ltd. | Indirect touch switch for electrical apparatus |
| CN101419522A (en) * | 2008-11-28 | 2009-04-29 | 深圳市汇顶科技有限公司 | Capacitance touch detection device and detection method thereof |
| CN201302712Y (en) * | 2008-11-28 | 2009-09-02 | 深圳市汇顶科技有限公司 | Capacity type touch detector |
| CN103259517A (en) * | 2013-05-20 | 2013-08-21 | 百利通电子(上海)有限公司 | Capacitor type touch circuit and capacitor detection method thereof |
| WO2014101553A1 (en) * | 2012-12-31 | 2014-07-03 | 深圳市汇顶科技股份有限公司 | Capacitive screen touch detection system |
-
2018
- 2018-04-10 CN CN201810316822.9A patent/CN108287638B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003094352A1 (en) * | 2002-05-02 | 2003-11-13 | Essdesign Corp., Ltd. | Indirect touch switch for electrical apparatus |
| CN101419522A (en) * | 2008-11-28 | 2009-04-29 | 深圳市汇顶科技有限公司 | Capacitance touch detection device and detection method thereof |
| CN201302712Y (en) * | 2008-11-28 | 2009-09-02 | 深圳市汇顶科技有限公司 | Capacity type touch detector |
| WO2014101553A1 (en) * | 2012-12-31 | 2014-07-03 | 深圳市汇顶科技股份有限公司 | Capacitive screen touch detection system |
| CN103259517A (en) * | 2013-05-20 | 2013-08-21 | 百利通电子(上海)有限公司 | Capacitor type touch circuit and capacitor detection method thereof |
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| CN108287638A (en) | 2018-07-17 |
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