CN105786273A - Capacitive touch screen, detection circuit of capacitive touch screen and electronic device - Google Patents
Capacitive touch screen, detection circuit of capacitive touch screen and electronic device Download PDFInfo
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- CN105786273A CN105786273A CN201410834667.1A CN201410834667A CN105786273A CN 105786273 A CN105786273 A CN 105786273A CN 201410834667 A CN201410834667 A CN 201410834667A CN 105786273 A CN105786273 A CN 105786273A
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Abstract
The invention discloses a capacitive touch screen, a detection circuit of the capacitive touch screen and an electronic device. The detection circuit comprises a conversion circuit, a touch sensing circuit, a reset triggering circuit and a touch driving signal generation circuit. The conversion circuit comprises a reset switch and an amplifier. A reset signal is provided for the reset switch through the reset switch, and an output signal of the amplifier can be reset, so that the influence of a low-frequency noise signal on the touch detection accuracy is relatively small or eliminated. Meanwhile the touch driving signal generation circuit is used for providing a touch driving signal, wherein the touch driving signal comprises at least one first pulse and a plurality of second pulses, and the amplitude of each first pulse is smaller than that of each second pulse. When an output voltage of the amplifier is reset, the problem of output voltage waveform lowering can be relieved or avoided, thereby further improving the touch detection accuracy.
Description
Technical field
The present invention relates to touch control technical field, in particular, relate to a kind of capacitive touch screen and testing circuit thereof and electronic equipment.
Background technology
The touch electrode of capacitive touch screen includes multiple drive electrode arranged in the first direction and multiple sensing electrode arranged in a second direction.Wherein, the plurality of drive electrode and the plurality of sensing electrode are coupled and form multiple sense capacitance.When carrying out touch location detection, by the output signal of corresponding testing circuit detection sensing electrode, determine touch location according to the change of output signal.
Refer to the structural representation of the testing circuit 10 that Fig. 1, Fig. 1 are a kind of common capacitive touch screen.Described testing circuit 10 includes: amplifier OP (OperationalAmplifier), the feedback capacity Cf being connected in parallel between negative-phase input and the outfan of described amplifier OP and feedback resistance Rf.Wherein, the negative-phase input of described amplifier OP connects the sensing electrode of multiple sense capacitance Cm of capacitive touch screen, and normal phase input end connects reference voltage VREF.When carrying out touching detection, the drive electrode being followed successively by multiple sense capacitance Cm according to the scanning sequency set provides the outfan driving signal TX, described amplifier OP to be the outfan of testing circuit 10, for source output voltage VO.
Existing testing circuit is easily subject to the interference of low-frequency noise signal, causes that the degree of accuracy touching detection is relatively low.
Summary of the invention
For solving the problems referred to above, the invention provides a kind of capacitive touch screen and testing circuit thereof and electronic equipment, improve the degree of accuracy touching detection.
For achieving the above object, the invention provides the testing circuit of a kind of capacitive touch screen, this testing circuit includes:
Change-over circuit, including amplifier, reset switch and negative-feedback circuit；
The positive input of described amplifier is used for receiving reference voltage, and its negative-phase input is connected by described negative-feedback circuit with its outfan, and described negative-phase input is connected with described outfan by described reset switch；
Touch-sensing circuit, described touch-sensing circuit has multiple touch-sensing branch road, each branch road includes a sense capacitance, described sense capacitance includes drive electrode and sensing electrode, described drive electrode is used for receiving touch and drives signal, described sensing electrode connects described negative-phase input, is used for exporting touch-sensing signal to described negative-phase input；
Reset trigger circuit, described reset trigger circuit is used for providing the first reset signal to described reset switch, and described reset switch closes when described first reset signal effect, so that the voltage amplitude of described outfan becomes described reference voltage；
Touching drive signal generation circuit, be used for providing described touch to drive signal, described touch drives signal to include at least one first pulse and multiple second pulse, and the amplitude of described first pulse is less than the amplitude of described second pulse；
Described reset trigger circuit provided the first reset signal for described reset switch before described touch drive signal generation circuit provides described first pulse, described negative-phase input and described outfan be short circuit when described first reset signal effect, so that described output end voltage resets to described reference voltage, described touch drive signal generation circuit provides described first pulse to described drive electrode further after described output end voltage resets to described reference voltage.
Preferably, in above-mentioned testing circuit, before described reset trigger circuit provides described first reset signal to described reset switch, described touch drive signal generation circuit provides the second pulse to described drive electrode.
Preferably, in above-mentioned testing circuit, described reset trigger circuit is additionally operable to before the trailing edge of described first pulse and provides the second reset signal for described reset switch, described negative-phase input and described outfan be short circuit when described second reset signal effect so that described output end voltage resets to described reference voltage.
Preferably, in above-mentioned testing circuit, described touch drive signal generation circuit includes: reference signal generation circuit, the first buffer, the second buffer and selection circuit；
Described reference signal generation circuit connects respectively with the first buffer and the second buffer, is used for providing reference signal to described first buffer and the second buffer；
Reference signal described in described first buffer inputs, and described first pulse of corresponding output；
Reference signal described in described second buffer inputs, and described second pulse of corresponding output；Described selection circuit includes: first input end, the second input, the first outfan and the second outfan；Its first input end connects described first buffer, its second input connects described second buffer, its first outfan connects described sense capacitance, its second outfan connects described reset trigger circuit, described selection circuit receives the first pulse by first input end, and receives the second pulse by the second input；
Described selection circuit is for controlling described first buffer and described second buffer and the conducting state of described drive electrode: when described first input end and described first buffer conducting, described selection circuit provides described first pulse for described sense capacitance；When described second input and described second buffer conducting, described selection circuit provides described second pulse for described sense capacitance；Described selection circuit is additionally operable to before the rising edge of described first pulse to control the first reset signal described in described reset trigger circuit evolving, control the second reset signal described in described reset trigger circuit evolving before the trailing edge of described first pulse.
Preferably, in above-mentioned testing circuit, described reference signal generation circuit is that square-wave signal produces circuit, described reference signal is a square-wave signal, described touch drive signal generation circuit is used for responding described square-wave signal, and the touch exporting square drives signal, wherein, the amplitude of described first pulse is the half of described second pulse amplitude.
Preferably, in above-mentioned testing circuit, described feedback circuit includes: feedback capacity and feedback resistance；
One pole plate of described feedback capacity is connected with the negative-phase input of described amplifier, and another pole plate is connected with the outfan of described amplifier；
One end of described feedback resistance is connected with the negative-phase input of described amplifier, and the other end is connected with the outfan of described amplifier.
Preferably, in above-mentioned testing circuit, when described touch drives signal to include multiple first pulse, described in any two, the first pulse is non-conterminous.
Present invention also offers a kind of capacitive touch screen, this capacitive touch screen includes: the testing circuit described in any of the above-described item.
Present invention also offers a kind of electronic equipment, this electronic equipment includes: above-mentioned capacitive touch screen.
Preferably, in above-mentioned electronic equipment, described electronic equipment is: mobile phone, or PDA, or GPS, or panel computer, or industry touch control device, or domestic touch-control electrical equipment.
By foregoing description it can be seen that the testing circuit described in the embodiment of the present application includes: change-over circuit, including amplifier, reset switch and negative-feedback circuit；The positive input of described amplifier is used for receiving reference voltage, and its negative-phase input is connected by described negative-feedback circuit with its outfan, and described negative-phase input is connected with described outfan by described reset switch；Touch-sensing circuit, described touch-sensing circuit has multiple touch-sensing branch road, each branch road includes a sense capacitance, described sense capacitance includes drive electrode and sensing electrode, described drive electrode is used for receiving touch and drives signal, described sensing electrode connects described negative-phase input, is used for exporting touch-sensing signal to described negative-phase input；Reset trigger circuit, described reset trigger circuit is used for providing the first reset signal to described reset switch, and described reset switch closes when described first reset signal effect, so that the voltage amplitude of described outfan becomes described reference voltage；Touching drive signal generation circuit, be used for providing described touch to drive signal, described touch drives signal to include at least one first pulse and multiple second pulse, and the amplitude of described first pulse is less than the amplitude of described second pulse；Described reset trigger circuit provided the first reset signal for described reset switch before described touch drive signal generation circuit provides described first pulse, described negative-phase input and described outfan be short circuit when described first reset signal effect, so that described output end voltage resets to described reference voltage, described touch drive signal generation circuit provides described first pulse to described drive electrode further after described output end voltage resets to described reference voltage.
Described testing circuit is provided with reset switch and reset trigger circuit, it is possible to the output signal of described amplifier is resetted, thus eliminating the low-frequency noise signal impact on described amplifier output signal, it is ensured that touch the degree of accuracy of detection.Technical scheme additionally provides a kind of capacitive touch screen with described testing circuit and electronic equipment, and capacitive touch screen and the electronic equipment of described testing circuit are it can be avoided that the interference of low-frequency noise signal, and the degree of accuracy touching detection is high.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, the accompanying drawing used required in embodiment or description of the prior art will be briefly described below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to the accompanying drawing provided.
Fig. 1 is the structural representation of the testing circuit of a kind of common capacitive touch screen；
The structural representation of a kind of testing circuit that Fig. 2 provides for the embodiment of the present application；
Fig. 3 is that testing circuit shown in Fig. 2 performs to touch signal waveforms when detecting；
The structural representation of the another kind of testing circuit that Fig. 4 provides for the embodiment of the present application
Fig. 5 is that testing circuit shown in Fig. 4 performs to touch a kind of signal waveforms when detecting；
Fig. 6 is that testing circuit shown in Fig. 4 performs to touch another kind of signal waveforms when detecting；
The structural representation of a kind of capacitive touch screen that Fig. 7 provides for the embodiment of the present application；
The structural representation of a kind of electronic equipment that Fig. 8 provides for the embodiment of the present application.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art obtain under not making creative work premise, broadly fall into the scope of protection of the invention.
Referring to figs. 2 and 3, the structural representation of a kind of testing circuit 20 that Fig. 2 provides for the embodiment of the present application, Fig. 3 is that testing circuit 20 shown in Fig. 2 performs to touch signal waveforms when detecting.When carrying out touching detection, significantly disturbing degree of accuracy when touching detection to eliminate low-frequency noise signal, testing circuit 20 shown in Fig. 2 adds reset switch Rst and reset trigger circuit 21 on the basis of testing circuit 10 shown in Fig. 1.Described reset switch Rst is connected in parallel between outfan and the negative-phase input of described amplifier OP.
When described reset trigger circuit 21 inputs reset signal RST to reset switch Rst, can so that reset switch Rst closes, by instantaneous short circuit between the negative-phase input of amplifier OP and outfan, described amplifier OP output end voltage is made to reset to described reference voltage VREF, it is possible to eliminate the interference that low frequency causes.
Concrete, when the drive electrode of a certain sense capacitance Cm is scanned, when described touch drives signal TX to make a reservation for a certain position before the first level saltus step is second electrical level from one, reset signal RST is inputted to reset switch Rst, reset switch Rst closes, instantaneous short circuit between negative-phase input and the outfan of amplifier OP, and then the output voltage VO of the outfan of testing circuit 20 is reset to reference voltage VREF, this reference voltage VREF is between the first level and the second electrical level of output voltage VO, wherein, described first level is different from described second electricity level, described first level is low level, described second electrical level is high level.
Although output voltage VO can be resetted by testing circuit 20 shown in Fig. 2, improve the degree of accuracy touching detection to a certain extent.But, as shown in Figure 3, after stopping providing reset signal RST to reset switch Rst, it is interim that adjacent touch drives signal TX to come, output voltage VO starts test from described reference voltage VREF, and test to final voltage be reset lower than output voltage VO before normal output time low level, and then make the whole output voltage shape VO ripple of testing circuit move down, through touching driving signal TX after date of several week, output voltage VO waveform is just gradually brought to normal condition.Therefore, transition period between dotted line L1 and dotted line L2, reset signal RST can make the fluctuation situation that output voltage VO waveform recovers after there is test gradually, and the test amplitude of output voltage VO waveform is crossed conference and is caused amplifier OP output saturated, causing the serious distortion of output signal, impact touches the degree of accuracy of detection.
For solving the problems referred to above, the embodiment of the present application provides a kind of testing circuit for capacitive touch screen, described testing circuit is avoiding low-frequency noise signal on while touching detection degree of accuracy impact, weaken or eliminate amplifier OP output voltage VO reset time waveform test problem, further increase touch detection degree of accuracy.
With reference to Fig. 4, the structural representation of the another kind of testing circuit 40 that Fig. 4 provides for the embodiment of the present application, described testing circuit 40 is for capacitive touch screen, and this testing circuit 40 includes: change-over circuit 41, touch-sensing circuit 42, reset trigger circuit 43 and touch drive signal generation circuit 44.
Described change-over circuit 41 includes: amplifier OP, reset switch Rst and negative-feedback circuit.Wherein, described negative-feedback circuit includes: feedback capacity Cf and feedback resistance Rf；One pole plate of described feedback capacity Cf is connected with the negative-phase input of described amplifier OP, and another pole plate is connected with the outfan of described amplifier OP；One end of described feedback resistance Rf is connected with the negative-phase input of described amplifier OP, and the other end is connected with the outfan of described amplifier OP.In other embodiments, described negative-feedback circuit can also only include the feedback capacity Cf of connected mode as shown in Figure 4, or only includes the feedback resistance Rf of connected mode as shown in Figure 4.
The positive input of described amplifier OP is used for receiving reference voltage VREF, and its negative-phase input is connected by described negative-feedback circuit with its outfan, and described negative-phase input is connected with described outfan by described reset switch Rst.
Described touch-sensing circuit 42 has multiple touch-sensing branch road, each branch road includes a sense capacitance Cm, described sense capacitance Cm includes drive electrode and sensing electrode, described drive electrode is used for receiving touch and drives signal, described sensing electrode connects described negative-phase input, is used for exporting touch-sensing signal to described negative-phase input.
Described reset trigger circuit 43 is used for providing the first reset signal to close when described first reset signal effect to described reset switch Rst, described reset switch Rst, so that the voltage amplitude of described outfan becomes described reference voltage VREF.By the output voltage VO of described amplifier OP is resetted, it is possible to eliminate the output signal VO distortion that low-frequency noise signal causes, improve the degree of accuracy touching detection.
With reference to Fig. 5, Fig. 5 is that testing circuit 40 shown in Fig. 4 performs to touch a kind of signal waveforms when detecting, when carrying out touching detection, described touch drive signal generation circuit 44 is used for providing described touch to drive signal TX, described touch drives signal TX to include at least one first pulse T1 and multiple second pulse T2, and the amplitude V1 of described first pulse T1 is less than the amplitude V2 of described second pulse T2.In the embodiment of the present application, described touch drives signal TX to include the first level, second electrical level, with the 3rd level, the electromotive force of described 3rd level is between electromotive force and the electromotive force of second electrical level of described first level, the electromotive force of described second electrical level is more than the electromotive force of described first level, described first pulse T1 is that relative first level of the 3rd level changes the pulse formed, described second pulse T2 is the pulse that relative first level of second electrical level is formed, with described first level for reference potential, the amplitude of described first pulse T1 is equal to the difference of the electromotive force of described 3rd level and the electromotive force of described first level, the amplitude of described second pulse T2 is equal to the difference of the electromotive force of described second electrical level and the electromotive force of described first level.
Described reset trigger circuit 43 provided the first reset signal RST1 for described reset switch Rst before described touch drive signal generation circuit 44 provides described first pulse T1, described negative-phase input and described outfan be short circuit when described first reset signal RST1 effect, so that described output voltage VO resets to described reference voltage VREF, described touch drive signal generation circuit 44 provides described first pulse T1 to described drive electrode further after described output voltage VO resets to described reference voltage VREF.
Described testing circuit 40, by the output voltage VO of described outfan is resetted, is reset to reference voltage VREF, such that it is able to eliminate the low-frequency noise signal impact on touching detection, improves and touches degree of accuracy.Further, after described output voltage VO is reset to reference voltage VREF, the amplitude of output voltage VO test is the amplitude V1 of described first pulse T1, owing to the amplitude V1 of described first pulse T1 is less than the amplitude V2 of described second pulse T2, therefore, compared to detection mode shown in Fig. 3, the amplitude of output voltage VO test is reduced, and then reduce output voltage VO distortion amplitudes between dotted line L1 and dotted line L2, further increase the degree of accuracy touching detection.Simultaneously as reduce the distortion amplitudes of output voltage VO, and then shorten the transitional time between dotted line L1 and dotted line L2, further increase the degree of accuracy touching detection.
In the present embodiment, before described reset trigger circuit 43 provides described first reset signal RST1 to described reset switch Rst, described touch drive signal generation circuit 44 provides the second pulse T2 to described drive electrode.Described first reset signal RST1 sequential is between described second pulse T2 described first pulse T1 adjacent thereto, and close described first pulse T1.
Although the distortion amplitudes of output voltage VO in transition period and transition period can be shortened by detection mode shown in Fig. 5, improve to a certain extent and touch detection degree of accuracy, but after output voltage VO is resetted, however it remains waveform test problem.It touches detection degree of accuracy and still has much room for improvement.
With reference to Fig. 6, Fig. 6 is that testing circuit 40 shown in Fig. 4 performs to touch another kind of signal waveforms when detecting, when carrying out touching detection, described reset trigger circuit 43 is additionally operable to before the trailing edge of described first pulse T1 and provides the second reset signal RST2 for described reset switch Rst, described negative-phase input and described outfan be short circuit when described second reset signal effect so that described output end voltage VO resets to described reference voltage VREF.Described second reset signal RST2 sequential is positioned at described first pulse T1 sequential, and near described first pulse T1 falling edge.
So, after described first reset signal RST1 effect, described output voltage VO is reset described reference voltage VREF, and at described second reset signal RST2, described output voltage VO is reset described reference voltage VREF.Output voltage waveforms test problem exists only in the sequential that first between described first reset signal RST1 with described second reset signal RST2 is corresponding for pulse T1, eliminates the transition period of waveform test.Can pass through to arrange the half of the amplitude V2 that amplitude V1 is described second pulse T2 of described first pulse T1, to eliminate output voltage VO waveform test problem simultaneously.
As shown in Figure 4, in the present embodiment, described touch drive signal generation circuit 44 includes: reference signal generation circuit the 204, first buffer the 201, second buffer 202 and selection circuit 203.
Described reference signal generation circuit 204 is connected respectively with the first buffer 201 and the second buffer 202, is used for providing reference signal TX0 to described first buffer 201 and the second buffer 202.Described reference signal TX0 is square-wave signal, and described reference signal generation circuit 204 can be square-wave signal generative circuit.
Described first buffer 201 receives described reference signal TX0 the described first pulse T1 of corresponding output；Described second buffer 202 receives described reference signal TX0 the described second pulse T2 of corresponding output.
Described selection circuit 203 includes: first input end, the second input, the first outfan and the second outfan；Its first input end connects described first buffer 201, its second input connects described second buffer 202, its first outfan connects described sense capacitance Cm, its second outfan connects described reset trigger circuit 43, described selection circuit 43 receives the first pulse T1 by first input end, and receives the second pulse T2 by the second input.
Described first outfan can include multiple output port, and the number of described output port and described sense capacitance Cm connect one to one.One output port connects the drive electrode of a sense capacitance Cm.Described first buffer 201 is the amplifier of different amplification with described second buffer 202, to generate the first corresponding pulse T1 and the second pulse T2 according to described reference signal TX0.
Described selection circuit 203 is for controlling the conducting state of described first buffer 201 and described second buffer 202 and described drive electrode: when described first input end turns on described first buffer 201, described selection circuit 203 provides described first pulse T1 for described sense capacitance Cm；When described second input turns on described second buffer 202, described selection circuit 203 provides described second pulse T2 for described sense capacitance；Described selection circuit 203 is additionally operable to before the rising edge of described first pulse T1 to control described reset trigger circuit 43 generate described first reset signal RST1, controls described reset trigger circuit 43 and generate described second reset signal RST2 before the trailing edge of described first pulse T1.
As above-mentioned, described reference signal generation circuit 204 produces circuit for square-wave signal, described reference signal TX0 is a square-wave signal, described touch drive signal generation circuit 44 is used for responding described square-wave signal, and the touch exporting square drives signal TX, preferably, the half of the amplitude that amplitude is described second pulse T2 of described first pulse T1 is set, to eliminate output voltage VO test problem.
In above-mentioned embodiment, in order to eliminate the impact of low-frequency noise signal, when carrying out touching detection, touch and drive signal TX to include a first pulse T1.Now, described reset signal RST is correspondingly arranged a first reset signal RST1, or arranges a first reset signal RST1 and the second reset signal RST2 simultaneously.
In other embodiments, described touch drives signal TX can also include multiple first pulse T1.Described in any two, the first pulse T1 is non-conterminous.Now, in described reset signal RST, one the first reset signal RST1 is set with each first corresponding timing position of pulse T1, or a first reset signal RST1 and the second reset signal RST are set 2 simultaneously.
By foregoing description, testing circuit described in the embodiment of the present application, the test of output voltage VO can be reduced or even eliminate by corresponding detection method, can shorten or even eliminate transition period when output voltage VO resets, eliminating or reducing on the low-frequency noise signal basis on touching detection degree of accuracy impact, improving the degree of accuracy touching detection further, and circuit implementations is simple, cost is low.
With reference to the structural representation of a kind of capacitive touch screen 70 that Fig. 7, Fig. 7 provide for the embodiment of the present application, described capacitive touch screen 70 includes testing circuit 71.Wherein, described testing circuit 71 is the testing circuit described in any of the above-described kind of embodiment.
Described capacitive touch screen 70 has the testing circuit described in above-mentioned embodiment, therefore, it is prevented from the interference of low-frequency noise signal work, simultaneously, when carrying out output voltage and resetting, can shortening the transition period even eliminating voltage amplitude, it is possible to reduce or even eliminate the test of output voltage VO, the degree of accuracy touching detection is high.
With reference to the structural representation of a kind of electronic equipment 80 that Fig. 8, Fig. 8 provide for the embodiment of the present application, described electronic equipment 80 includes the capacitive touch screen 70 described in above-mentioned embodiment.Described electronic equipment 80 can be: mobile phone, or PDA, or GPS, or panel computer, or industry touch control device, or domestic touch-control electrical equipment.
Described electronic equipment has above-mentioned capacitive touch screen 70, therefore, when carrying out touching detection, it is prevented from the low-frequency noise signal impact on touching degree of accuracy equally, meanwhile, when carrying out output voltage and resetting, it is possible to shorten the transition period even eliminating voltage amplitude, can reducing or even eliminate the test of output voltage VO, the degree of accuracy touching detection is high.
It should be noted that the described above of the disclosed embodiments, make professional and technical personnel in the field be capable of or use the present invention.The multiple amendment of these embodiments be will be apparent from for those skilled in the art, and generic principles defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention is not intended to be limited to the embodiments shown herein, and is to fit to the widest scope consistent with principles disclosed herein and features of novelty.
Claims (11)
1. the testing circuit of a capacitive touch screen, it is characterised in that including:
Change-over circuit, including amplifier, reset switch and negative-feedback circuit；
The positive input of described amplifier is used for receiving reference voltage, and its negative-phase input is connected by described negative-feedback circuit with its outfan, and described negative-phase input is connected with described outfan by described reset switch；
Touch-sensing circuit, described touch-sensing circuit has multiple touch-sensing branch road, each branch road includes a sense capacitance, described sense capacitance includes drive electrode and sensing electrode, described drive electrode is used for receiving touch and drives signal, described sensing electrode connects described negative-phase input, is used for exporting touch-sensing signal to described negative-phase input；
Reset trigger circuit, described reset trigger circuit is used for providing the first reset signal to described reset switch, and described reset switch closes when described first reset signal effect, so that the voltage amplitude of described outfan becomes described reference voltage；
Touching drive signal generation circuit, be used for providing described touch to drive signal, described touch drives signal to include at least one first pulse and multiple second pulse, and the amplitude of described first pulse is less than the amplitude of described second pulse；
Described reset trigger circuit provided the first reset signal for described reset switch before described touch drive signal generation circuit provides described first pulse, described negative-phase input and described outfan be short circuit when described first reset signal effect, so that described output end voltage resets to described reference voltage, described touch drive signal generation circuit provides described first pulse to described drive electrode further after described output end voltage resets to described reference voltage.
2. testing circuit according to claim 1, it is characterised in that before described reset trigger circuit provides described first reset signal to described reset switch, described touch drive signal generation circuit provides the second pulse to described drive electrode.
3. testing circuit according to claim 1, it is characterized in that, described reset trigger circuit is additionally operable to before the trailing edge of described first pulse and provides the second reset signal for described reset switch, described negative-phase input and described outfan be short circuit when described second reset signal effect so that described output end voltage resets to described reference voltage.
4. testing circuit according to claim 3, it is characterised in that described touch drive signal generation circuit includes: reference signal generation circuit, the first buffer, the second buffer and selection circuit；
Described reference signal generation circuit connects respectively with the first buffer and the second buffer, is used for providing reference signal to described first buffer and the second buffer；
Reference signal described in described first buffer inputs, and described first pulse of corresponding output；
Reference signal described in described second buffer inputs, and described second pulse of corresponding output；Described selection circuit includes: first input end, the second input, the first outfan and the second outfan；Its first input end connects described first buffer, its second input connects described second buffer, its first outfan connects described sense capacitance, its second outfan connects described reset trigger circuit, described selection circuit receives the first pulse by first input end, and receives the second pulse by the second input；
Described selection circuit is for controlling described first buffer and described second buffer and the conducting state of described drive electrode: when described first input end and described first buffer conducting, described selection circuit provides described first pulse for described sense capacitance；When described second input and described second buffer conducting, described selection circuit provides described second pulse for described sense capacitance；Described selection circuit is additionally operable to before the rising edge of described first pulse to control the first reset signal described in described reset trigger circuit evolving, control the second reset signal described in described reset trigger circuit evolving before the trailing edge of described first pulse.
5. testing circuit according to claim 4, it is characterized in that, described reference signal generation circuit is that square-wave signal produces circuit, described reference signal is a square-wave signal, described touch drive signal generation circuit is used for responding described square-wave signal, and the touch exporting square drives signal, wherein, the amplitude of described first pulse is the half of described second pulse amplitude.
6. testing circuit according to claim 1, it is characterised in that described feedback circuit includes: feedback capacity and feedback resistance；
One pole plate of described feedback capacity is connected with the negative-phase input of described amplifier, and another pole plate is connected with the outfan of described amplifier；
One end of described feedback resistance is connected with the negative-phase input of described amplifier, and the other end is connected with the outfan of described amplifier.
7. the testing circuit according to any one of claim 1-6, it is characterised in that when described touch drives signal to include multiple first pulse, described in any two, the first pulse is non-conterminous.
8. testing circuit according to claim 1, it is characterized in that, described touch drives signal to include the first level, second electrical level, with the 3rd level, the electromotive force of described 3rd level is between electromotive force and the electromotive force of second electrical level of described first level, the electromotive force of described second electrical level is more than the electromotive force of described first level, described first pulse is that relative first level of the 3rd level changes the pulse formed, described second pulse is the pulse that relative first level of second electrical level is formed, with described first level for reference potential, the amplitude of described first pulse is equal to the difference of the electromotive force of described 3rd level and the electromotive force of described first level, the amplitude of described second pulse is equal to the difference of the electromotive force of described second electrical level and the electromotive force of described first level.
9. a capacitive touch screen, it is characterised in that including: the testing circuit as described in any one of claim 1-8.
10. an electronic equipment, it is characterised in that including: capacitive touch screen as claimed in claim 9.
11. electronic equipment according to claim 10, it is characterised in that described electronic equipment is: mobile phone, or PDA, or GPS, or panel computer, or industry touch control device, or domestic touch-control electrical equipment.
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| CN106980411A (en) * | 2017-04-28 | 2017-07-25 | 北京集创北方科技股份有限公司 | Induction installation and driving method |
| CN108021271A (en) * | 2016-10-31 | 2018-05-11 | 乐金显示有限公司 | Drive circuit and touch display unit |
| CN109144329A (en) * | 2018-10-25 | 2019-01-04 | 深圳市谷粒科技有限公司 | Touch screen passive triggering device |
| CN112528585A (en) * | 2020-12-17 | 2021-03-19 | 北京集创北方科技股份有限公司 | Noise detection method and circuit |
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| CN105786273B (en) | 2018-12-11 |
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