CN105610422A - Touch sensing system - Google Patents

Abstract

A touch sensing system comprises a signal generator, a touch sensing signal generator comprising a switch, a first constant current source, a first touch pad and a touch comparator, a reference signal generator comprising a switch, a second constant current source, a second touch pad and a reference comparator, and a processing module; the signal generator transmits an input signal to the switch, the first constant current source and the second constant current source respectively charge the first touch pad and the second touch pad when the switch is conducted, and the touch comparator and the reference comparator respectively transmit a high-potential signal to the processing module when the reference voltage is reached; when the first touch pad is touched or not touched, the touch comparator outputs a first high potential signal through first delay time and second delay time respectively, and the reference comparator outputs a second high potential signal through third delay time; the processing module outputs a touch result according to the delay time.

Description

touch sensing system

technical field

The invention relates to a touch sensing system, in particular to a touch sensing system using a constant current source to charge a touch pad.

Background technique

With the rapid advancement of science and technology, the development of the Internet has filled people's lives with various electronic devices, and the electronic devices are now mainly touch-sensitive, and the touch-sensitive circuits need to be tested, so that the actual application It can be relatively smooth and not prone to problems on electronic devices.

And the existing touch-control circuit such as the patent document of Patent Publication No. 200701639, please refer to Fig. 1, Fig. 1 shows the block schematic diagram of the touch sensing system of the prior art, as shown in Fig. The formula circuit PA1 includes an input signal generator PA11, a plurality of touch sensing signal generators PA12, PA13 (only one is marked in the figure), a plurality of variable delay elements PA14 (only one is marked in the figure), a plurality of D-type Flip-flop PA15 and a controller PA16.

However, as can be seen from Figure 1, the touch sensor signal generators PA12 and PA13 are mainly composed of resistors and capacitors (there is a capacitor in the touch pad), but this design is likely to cause the signal to fluctuate with temperature and voltage and cause instability The situation makes it easy to misjudgment when sensing whether there is a touch.

Contents of the invention

In view of the fact that the signal of the existing touch-control circuit is easy to fluctuate with the temperature and voltage and cause instability, it generally has the problem of touch misjudgment. Therefore, the present invention mainly provides a touch sensing system, which mainly replaces the original resistor with a current source, thereby solving the problems of the prior art.

To achieve the above object, the present application provides a touch sensing system, comprising: a signal generator for generating an input signal; at least one touch sensing signal generator electrically connected to the signal generator, and comprising : a first constant current source, used to provide a first constant current; a first switch, electrically connected to the first constant current source and the signal generator, for receiving the input signal, thereby according to the input signal Turn on or off; a second switch, electrically connected to the first constant current source and the signal generator, for receiving the input signal, so as to turn on or off according to the input signal; a first touch pad, electrically connected to the first constant current source, the first switch and the second switch, and used for touch control; and a touch comparator with a first input point and a second input point, the first input point receives A first reference voltage, the second input point is electrically connected to the first constant current source, the first switch, the second switch and the first touch pad, for outputting a first low potential output signal; When the input signal turns on the first switch and turns off the second switch at a first time, and the first touch pad is touched, the first constant current charges the first touch pad, so that The touch comparator switches from the first low potential output signal to output a first high potential output signal at a second time after a first delay time; the first switch is activated at the first time by the input signal Turn on and close the second switch, and when the first touch pad is not touched, the first constant current charges the first touch pad, so that the touch comparator is activated after a second delay time a third time from the first low potential output signal to output the first high potential output signal; a reference signal generator, including: a second constant current source for providing a second constant current; a third a switch, electrically connected to the second constant current source and the signal generator, for receiving the input signal, so as to turn on or off according to the input signal; a fourth switch, electrically connected to the second constant current source and the signal generator The signal generator is used to receive the input signal, so as to be turned on or off according to the input signal; a second touch pad is electrically connected to the second constant current source, the third switch and the fourth switch, and for charging the second constant current; and a reference comparator having a third input point and a fourth input point, the third input point receives a second reference voltage, and the fourth input point is electrically connected to the first Two constant current sources, the third switch, the fourth switch and the second touch pad are used to output a second low potential output signal; when the input signal is at the first time, the third switch is turned on and the When the fourth switch is turned off, the second constant current charges the second touch pad, so that the reference comparator switches from the second low potential output signal to an output signal at a fourth time after a third delay time. a second high potential output signal; and a processing module electrically connected to the touch comparator and the reference comparator for receiving the second high potential output signal and for receiving the first low potential output signal and the first low potential output signal One of the first high potential output signals, whereby the first low potential output signal and the first high potential One of the potential output signals and the second high potential output signal output at least one touch result; wherein, the first delay time is longer than the third delay time, and the second delay time is shorter than the third delay time.

In the above touch sensing system, the first switch and the third switch are a PMOS switch, and the second switch and the fourth switch are an NMOS switch.

In the above touch sensing system, the second touch pad is one of a fixed capacitance and an adjustable capacitance.

In the above touch sensing system, the current value of the second constant current is greater than the current value of the first constant current and is a multiple of the current value of the first constant current.

In the above touch sensing system, the processing module includes:

a first latch, electrically connected to the touch comparator and the reference comparator, for receiving one of the first low potential output signal and the first high potential output signal, and comparing the The second high potential output signal output by the device controls the output of the first low potential output signal and the first high potential output signal; and

a controller electrically connected to the first latch and the reference comparator for receiving one of the first low potential output signal and the first high potential output signal and the second high potential output signal , and output at least one touch result according to one of the first low potential output signal and the first high potential output signal and the second high potential output signal.

In the above touch sensing system, the controller is one of a micro processing unit and a digital signal processor.

In the above-mentioned touch sensing system, the processing module further includes a digital delayer electrically connected between the reference comparator, the first latch and the controller for receiving the second A high-potential output signal, so as to trigger the first latch to output one of the first low-potential output signal and the first high-potential output signal according to the second high-potential output signal, and output the second high-potential output signal signal output to the controller.

In the above touch sensing system, the digital delayer includes:

At least one second latch, electrically connected to the reference comparator and the controller, for receiving the second high potential output signal and a delay control signal sent by the controller, so that the controller can control the second latch outputs a delayed output signal according to the second high potential output signal; and

a multiplexer, electrically connected to the reference comparator, the first latch, the second latch and the controller, for receiving the second high potential output signal transmitted by the reference comparator and The delayed output signal transmitted by the second latch is used to transmit a multiplex signal including the second high potential output signal to the first latch and the controller.

In the above touch sensing system, the first latch and the second latch are D-type flip-flops.

After passing through the main technical means of the touch sensing system adopted by the present invention, because the constant current source is used to charge the touch pad, therefore, the signal instability will not be caused by the change of temperature or voltage, so the practical The judgment of the upper touch is not prone to misjudgment, which improves the stability of judgment.

The specific embodiments adopted by the present invention will be further described through the following embodiments and accompanying drawings.

Description of drawings

FIG. 1 is a schematic block diagram showing a touch sensing system of the prior art;

FIG. 2 is a schematic block diagram showing a touch sensing system according to a preferred embodiment of the present invention;

3 is a schematic diagram showing the waveform of the first touch pad being touched in the touch sensing system of a preferred embodiment of the present invention; and

FIG. 4 is a schematic diagram of waveforms showing that the first touch pad of the touch sensing system of the preferred embodiment of the present invention is not touched.

Among them, reference signs:

PA1 touch circuit PA11 input signal generator

PA12, PA13 touch sensor signal generator

PA14 variable delay element PA15D flip-flop

PA16 Controller 1 Touch Sensing System

11 Signal Generator 12 Touch Sensing Signal Generator

121 first constant current source 122 first switch

123 second switch 124 first touch pad

125 touch comparator 1251 first input point

1252 second input point 13 reference signal generator

131 second constant current source 132 third switch

133 fourth switch 134 second touch pad

135 reference comparator 1351 third input point

1352 fourth input point 14 processing module

141 first latch 142 controller

143 digital delayer 1431 second latch

1432 multiplexer I1 first constant current

I2 second constant current S1 input signal

S2 first low potential output signal S3 first high potential output signal

S4 second low potential output signal S5 second high potential output signal

S6 delay control signal S7 delay output signal

S8 multitasking signal S9 touch results

V1 first reference voltage V2 second reference voltage

T1 first delay time T2 second delay time

T3 third delay time t1 first time

t2 second time t3 fourth time

t4 delay time t5 third time

detailed description

Since the combination of the touch sensing system provided by the present invention is too numerous to enumerate, it is not repeated here one by one, and only a preferred embodiment is listed for specific description.

Please refer to FIG. 2 . FIG. 2 shows a schematic block diagram of a touch sensing system according to a preferred embodiment of the present invention. As shown in Figure 2, the touch sensing system of the preferred embodiment of the present invention includes a signal generator 11, a touch sensing signal generator 12 (there may be multiple in other embodiments, for example, three Black dots indicate that there may be multiple touch sensing signal generators 12 ), a reference signal generator 13 and a processing module 14 .

The signal generator 11 can be a signal generator capable of generating a clock signal or an AC signal, and the above-mentioned clock signal can be a signal of 0 and 1, or a signal with a voltage valley value of 0 and a voltage peak value of a fixed voltage .

The touch sensing signal generator 12 includes a first constant current source 121 , a first switch 122 , a second switch 123 , a first touch pad 124 and a touch comparator 125 . The first constant current source 121 can provide a first constant current I1. The first switch 122 and the second switch 123 are electrically connected to the first constant current source 121 and the signal generator 11, and the first switch 122 is a PMOS switch. The second switch 123 is an NMOS switch.

The first touch pad 124 is electrically connected to the first constant current source 121, the first switch 122 and the second switch 123, and is used for the operator to use a touch object (such as a finger, a stylus, etc. with capacitance) To touch, in addition, generally speaking, the first touch pad 124 has capacitance, and the first touch pad 124 is electrically connected to the first switch 122 through the first constant current source 121 .

The touch comparator 125 has a first input point 1251 and a second input point 1252, the first input point 1251 receives a first reference voltage V1, and the first reference voltage V1 depends on practical design, the second input point The point 1252 is electrically connected to the first constant current source 121, the first switch 122, the second switch 123 and the first touch pad 124. Specifically, the second input point 1252 is electrically connected to the first constant current source 121. the first switch 122 .

The reference signal generator 13 includes a second constant current source 131 , a third switch 132 , a fourth switch 133 , a second touch pad 134 and a reference comparator 135 . The second constant current source 131 is used to provide a second constant current I2, and the current value of the second constant current I2 is generally greater than the current value of the first constant current I1, and is a multiple of the current value of the first constant current I1, specifically In other words, the above multiple can be determined according to the number of touch sensing signal generators 12, for example, when there are two touch sensing signal generators 12, it can be set to 2 times, and three times is 3 times, and the above multiple It can be determined according to the capacitance of the second touch pad 134 and the first touch pad, but it is not limited thereto. It can also be a multiple of 1.5 times, depending on the practical design. In addition, in other embodiments, the current value of the second constant current I2 can also be made smaller than the current value of the first constant current I1, which depends on practical design.

The third switch 132 and the fourth switch 133 are electrically connected to the second constant current source 131 and the signal generator 11 , the third switch 132 is a PMOS switch, and the fourth switch 133 is an NMOS switch. The second touch pad 134 is electrically connected to the second constant current source 131, the third switch 132 (specifically, electrically connected to the third switch 132 via the second constant current source 131) and the fourth switch 133, and provides The second constant current I2 charges, and the second touch pad 134 is one of a fixed capacitor and an adjustable capacitor, that is to say, the second touch pad 134 is actually a capacitor, but the better one can be adjusted The capacitance value is matched with the current value of the second constant current I2.

The reference comparator 135 has a third input point 1351 and a fourth input point 1352, the third input point 1351 receives a second reference voltage V2, and the second reference voltage V2 depends on the practical design, for example, it can be greater than or equal to the first reference voltage V1. The fourth input point 1352 is electrically connected to the second constant current source 131 , the third switch 132 , the fourth switch 133 and the second touch pad 134 , and the fourth input point 1352 is electrically connected to the second constant current source 131 The third switch 132 .

The processing module 14 is electrically connected to the touch comparator 125 and the reference comparator 135. Specifically, the processing module 14 includes a first latch 141, a controller 142 and a digital delay 143. The first latch 141 It is electrically connected to the touch comparator 125 and the reference comparator 135, and the first latch 141 is a D-type flip-flop (the D terminal of the first latch 141 is electrically connected to the touch comparator 125, and the CLK terminal The digital delayer 143 is electrically connected to the reference comparator 135 , and the Q terminal is electrically connected to the controller 142 ).

The controller 142 is one of a Micro Control Unit (MCU) and a Digital Signal Processor (DSP), and is electrically connected to the first latch 141 and electrically connected to the reference comparator 135 .

Specifically, the controller 142 is electrically connected to the reference comparator 135 via a digital delayer 143, and the digital delayer 143 includes at least one second latch 1431 (multiple in other embodiments) and a multiplexer 1432 . The second latch 1431 is a D-type flip-flop, and is electrically connected to the reference comparator 135 and the controller 142 (the D terminal is electrically connected to the reference comparator 135, the CLK terminal is electrically connected to the controller 142, and the Q terminal electrically connected to the multiplexer 1432). The multiplexer 1432 is electrically connected to the reference comparator 135, the first latch 141, the second latch 1431 and the controller 142, that is, it receives the inputs of the reference comparator 135 and the second latch 1431 at the same time, so as to output to the first latch 141 (output to the CLK terminal of the first latch 141 ) and the controller 142 .

In addition, what needs to be mentioned here is that when the digital delay 143 includes multiple second latches 1431, the Q terminals of the second latches 1431 are all electrically connected to the D terminals of another latch. input, and the controller 142 is electrically connected to the CLK terminal of the latch to control the delay time.

The status of the first touch pad 124 being touched and not being touched will be described respectively below. The status of the first touch pad 124 being touched will be described below. Please refer to FIG. 2 and FIG. 3 together. FIG. 3 shows the A schematic diagram of the waveform of the first touch pad being touched in the touch sensing system of the preferred embodiment of the invention. As shown in the figure, the signal generator 11 transmits an input signal S1 which is a clock signal (the waveform at the top of FIG. 3 ), and the first switch 122 and the second switch 123 of the touch sensing signal generator 12 follow the input signal S1 is turned on or off (that is, conduction or non-conduction).

Wherein, at the moment of the first time t1, the touch comparator 125 continuously outputs a first low potential output signal S2, and the input signal S1 drops from high potential to low potential (High to Low), so that the first switch 122 is turned on. (conducting) and the second switch 123 is closed (cut off and not conducting), and when the first touch pad 124 is touched, the first constant current I1 has an effect on the capacitance in the first touch pad 124 and the touch in the first touch pad 124 The touch object (assuming it is a finger, which can be regarded as a capacitor) on the first touch pad 124 is charged, and then the voltage of the second input point 1252 of the touch comparator 125 gradually increases (as shown in FIG. As shown in the two waveform diagrams), and when the voltage of the second input point 1252 reaches the first reference voltage V1, the touch comparator 125 will output a first high potential output signal S3 (as shown in Figure 3 from top to bottom shown in the third waveform diagram), and in a preferred embodiment of the present invention, the voltage of the second input point 1252 reaches the first reference voltage V1 at a second time t2, so the touch comparator 125 passes through a first A delay time T1 is converted from the first low level output signal S2 to the output of the first high level output signal S3, and the first delay time T1 is a value of t2-t1.

In addition, the input signal S1 is also transmitted to the third switch 132 and the fourth switch 133 of the reference signal generator 13. Similarly, at the instant of the first time t1, the reference comparator 135 continuously outputs a second low-level output signal S4 , and the input signal S1 drops from a high potential to a low potential (High to Low), so that the third switch 132 is turned on (conducted) and the fourth switch 133 is turned off (turned off and not turned on), and the second constant current I2 has an effect on the first The capacitance in the second touch pad 134 is charged, and then the voltage of the fourth input point 1352 of the reference comparator 135 gradually rises (as shown in the fourth waveform diagram from top to bottom in FIG. 3 ), and when the fourth input point When the voltage of 1352 reaches the second reference voltage V2, the reference comparator 135 will output a second high potential output signal S5 (as shown in the bottom waveform diagram in FIG. 3 ), and in a preferred embodiment of the present invention, The voltage of the fourth input point 1352 reaches the second reference voltage V2 at the fourth time t3, so the reference comparator 135 switches from outputting the second low potential output signal S4 to outputting the second high potential output after a third delay time T3 signal S5, and the third delay time T3 is the value of t3-t1.

In addition, it can be clearly understood from FIG. 3 that since the first touch pad 124 is touched, the first constant current I1 charges the first touch pad 124 slowly, so that the first delay time T1 is longer than the third delay time T3, and in a preferred embodiment of the present invention, the third delay time T3 must be less than the first delay time T1, which can be adjusted by adjusting the second constant current I2 of the second constant current source 131 of the reference signal generator 13 and The capacitance of the second touch pad 134 is used to achieve this purpose.

Wherein, in a preferred embodiment of the present invention, after receiving the first high-potential output signal S3 and the second high-potential output signal S5, the processing module 14 may first delay according to one of the first delay time T1 and the third delay time T3. The difference is to output at least one touch result S9.

Specifically, after the first high-potential output signal S3 is output to the first latch 141, the first latch 141 first latches the first high-potential output signal S3 and does not send it out, so as to wait for receiving the second high-potential output signal S3. The potential output signal S5 or a signal including the second high potential output signal S5.

Furthermore, after the second high potential output signal S5 is transmitted to the second latch 1431, the second latch 1431 receives the second high potential output signal S5 and a delay control signal S6 sent by the controller 142, so as to The controller 142 controls the second latch 1431 to output a delayed output signal S7 according to the second high-potential output signal S5 (generally, the output is triggered by an instant from a low potential to a high potential, so it only needs to control the clock pulse), and The delay control signal S6 can cause the second latch 1431 to output the delay output signal S7 with delay. The multiplexer 1432 receives the second high potential output signal S5 transmitted by the reference comparator 135 and the delayed output signal S7 transmitted by the second latch 1431, so as to process and convert a signal containing the second high potential output signal S5 The multiplexing signal S8 is sent to the first latch 141 and the controller 142 .

After the first latch 141 receives the multiplexing processing signal S8 (it can also be a signal from low potential to high potential in the waveform diagram shown at the bottom of Figure 3, that is to say, the multiplexing processing signal S8 can actually be The second high-potential output signal S5 (the difference is the delayed output), directly outputs the first high-potential output signal S3 to the controller 142, so that the controller 142 can be based on the first delay time T1 and the third delay time T3 A difference value is used to output at least one touch result S9, and in this description, the touch result S9 is expressed as "touch", and when there are multiple touch sensing signal generators 12, there will be multiple touch control result S9.

In addition, what needs to be mentioned here is that in the above description, the multiplexer 1432 is delayed until a delay time t4 before the multiplex processing signal S8 is transmitted to the first latch 141 and the controller 142, so that the controller The 142 can directly confirm whether there is a touch according to the first difference between the first delay time T1 and the third delay time T3 . In other embodiments, since the digital delayer 143 may not be provided, the reference comparator 135 directly outputs the second high potential output signal S3 to the first latch 141 at the fourth time t3, thereby making the first latch The controller 141 directly outputs the first low potential output signal S2 (because the voltage of the second input point 1252 has not yet reached the first reference voltage V1 at this time, the first low potential output signal S2 is low potential) to the controller 142, and The controller 142 can know that the first low potential output signal S2 is low potential, and the second high potential output signal S3 is high potential, and can further determine that there is a touch at this time.

Please refer to FIG. 2 and FIG. 4 together. FIG. 4 shows a schematic waveform diagram of the first touch pad not being touched in the touch sensing system according to a preferred embodiment of the present invention. As shown in the figure, the signal generator 11 also transmits the input signal S1 (the waveform at the top of FIG. 4 ), and at the moment of the first time t1, the touch comparator 125 continuously outputs a first low potential output signal S2, The input signal S1 drops from a high potential to a low potential (High to Low), so that the first switch 122 is turned on (conducting) and the second switch 123 is turned off (off and not conducting), and when the first touch pad 124 is not When being touched, the first constant current I1 directly charges the capacitance in the first touch pad 124, thereby causing the voltage of the second input point 1252 of the touch comparator 125 to gradually increase (as shown in FIG. As shown in the two waveform diagrams, and the voltage rising speed is faster than when being touched), and when the voltage of the second input point 1252 reaches the first reference voltage V1, the touch comparator 125 will output the first high Potential output signal S3 (as shown in the third waveform diagram from top to bottom in Fig. 4), and in a preferred embodiment of the present invention, the voltage of the second input point 1252 reaches the first reference point at the third time t5 Therefore, the touch comparator 125 outputs the first high potential output signal S3 after a second delay time T2, and the second delay time T2 is a value of t5-t1.

In addition, the input signal S1 is also transmitted to the third switch 132 and the fourth switch 133 of the reference signal generator 13. Similarly, at the instant of the first time t1, the reference comparator 135 continuously outputs a second low-level output signal S4 , while the third switch 132 is turned on (conducting) and the fourth switch 133 is turned off (off and not conducting), the second constant current I2 charges the capacitance in the second touch pad 134, thereby making the second constant current I2 of the reference comparator 135 The voltage of the four input points 1352 gradually increases (as shown in the fourth waveform diagram from top to bottom in FIG. 3 ), and when the voltage of the fourth input point 1352 reaches the second reference voltage V2, the touch comparator 125 will be activated Output a second high potential output signal S3 (as shown in the waveform diagram at the bottom of Fig. 3), and in a preferred embodiment of the present invention, the voltage of the fourth input point 1352 is also at the fourth time t3 (as shown in Fig. 3) reaches the second reference voltage V2, so the reference comparator 135 outputs the second high potential output signal S5 after the third delay time T3, and the third delay time T3 is the value of t3-t1.

In addition, it can be clearly understood from FIG. 4 that since the first touch pad 124 is not touched, the first constant current I1 charges the first touch pad 124 faster, so that the second delay time T2 is shorter than the third delay time T2. The delay time T3 is less than the first delay time T1 in Figure 3, and in a preferred embodiment of the present invention, the third delay time T3 must be greater than the second delay time T2, and the third delay time T3 is also less than the first delay time T1, which can be achieved by adjusting the second constant current I2 of the second constant current source 131 of the reference signal generator 13 and the capacitance of the second touch pad 134 .

After receiving the first low level output signal S2 and the second high level output signal S5, the processing module 14 can output at least one touch result S9 according to the second difference between the second delay time T2 and the third delay time T3 .

Specifically, after the first high-potential output signal S3 is output to the first latch 141, the first latch 141 first latches the first high-potential output signal S3 and does not send it out, so as to wait for receiving the second high-potential output signal S3. The potential output signal S5 or a signal including the second high potential output signal S5.

Furthermore, after the second high potential output signal S5 is transmitted to the second latch 1431, the second latch 1431 receives the second high potential output signal S5 and a delay control signal S6 sent by the controller 142, so as to The controller 142 controls the second latch 1431 to output a delayed output signal S7 according to the second high-potential output signal S5 (generally, the output is triggered by an instant from a low potential to a high potential, so it only needs to control the clock pulse), and The delay control signal S6 can cause the second latch 1431 to output the delay output signal S7 with delay. The multiplexer 1432 receives the second high potential output signal S5 transmitted by the reference comparator 135 and the delayed output signal S7 transmitted by the second latch 1431, so as to process and convert a signal containing the second high potential output signal S5 The multiplexing signal S8 is sent to the first latch 141 and the controller 142 .

After the first latch 141 receives the multiplexing processing signal S8, it directly outputs the first high-level output signal S2 to the controller 142, so that the controller 142 can be based on the difference between the second delay time T2 and the third delay time T3. The second difference is to output at least one touch result S9, and in this description, the touch result S9 is expressed as "not touched", and when there are multiple touch sensing signal generators 12, how many A touch result S9.

In addition, what needs to be mentioned here is that in the above description, the multiplexer 1432 is delayed until the delay time t4 before the multiplex processing signal S8 is transmitted to the first latch 141 and the controller 142, so that the controller 142 Whether there is a touch can be directly confirmed according to the second difference between the second delay time T2 and the third delay time T3 . In other embodiments, since the digital delayer 143 may not be provided, the reference comparator 135 directly outputs the second high potential output signal S5 to the first latch 141 at the fourth time t3, thereby making the first latch The controller 141 directly outputs the first high potential output signal S3 (because the voltage of the second input point 1252 has reached the first reference voltage V1 at this time) to the controller 142, and the controller 142 knows that the first high potential output signal S2 is high Potential, the first high potential output signal S3 is high potential, and it can be judged that it is not touched at this time.

In addition, the first touch pad 124 and the second touch pad 134 are respectively discharged when the first switch 122 is turned off and the second switch 123 is turned on, and the third switch 132 is turned off and the fourth switch 133 is turned on.

To sum up the above, after adopting the touch sensing system provided by the present invention, since the touch pad is charged by a constant current source, the signal instability will not be caused by the change of temperature or voltage, so In practice, the judgment of touch is not prone to misjudgment, which improves the stability of judgment.

Through the above detailed description of the preferred embodiments, it is hoped that the features and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various changes and equivalent arrangements within the scope of the patent application for the present invention.

Claims (9)

1. a touch-control sensing system, is characterized in that, comprises:

One signal generator, in order to produce an input signal;

At least one touch-control sensing signal generator, is electrically connected at this signal generator, and comprises:

One first constant current source, in order to provide one first to determine electric current;

One first switch, is electrically connected at this first constant current source and this signal generator, in order to receiveThis input signal, so as to opening or close according to this input signal;

One second switch, is electrically connected at this first constant current source and this signal generator, in order to receiveThis input signal, so as to opening or close according to this input signal;

One first touch pad, is electrically connected at this first constant current source, this first switch and this second and opensClose, and in order to touch-control; And

One touch-control comparator, has one first input point and one second input point, and this first input point connectsReceive one first reference voltage, this second input point be electrically connected at this first constant current source, this first switch,This second switch and this first touch pad, in order to export one first electronegative potential output signal; At this input letterNumber make this first switch open and this second switch is closed in a very first time, and this first touch pad is touchedWhen control, this first determines electric current to the charging of this first touch pad, makes this touch-control comparator through one first time delayAnd be converted to output one first high potential output signal in one second time from this first electronegative potential output signal;Make this first switch open and this second switch closed in this very first time at this input signal, and this firstTouch pad is during by touch-control, and this first determines electric current to this first touch pad charging, makes this touch-control comparator through oneThe second time delay and in one the 3rd time from this first electronegative potential output signal be converted to output this first heightCurrent potential output signal;

One reference signal generator, comprises:

One second constant current source, in order to provide one second to determine electric current;

One the 3rd switch, is electrically connected at this second constant current source and this signal generator, in order to receiveThis input signal, so as to opening or close according to this input signal;

One the 4th switch, is electrically connected at this second constant current source and this signal generator, in order to receiveThis input signal, so as to opening or close according to this input signal;

One second touch pad, is electrically connected at this second constant current source, the 3rd switch and the 4th is openedClose, and for this second constant-current charge; And

One reference comparator, has one the 3rd input point and one the 4th input point, and the 3rd input point connectsReceive one second reference voltage, the 4th input point be electrically connected at this second constant current source, the 3rd switch,The 4th switch and this second touch pad, in order to export one second electronegative potential output signal; At this input letterNumber in the time that this very first time makes the 3rd switch open and the 4th switch cuts out, this second determines electric current to thisThe second touch pad charging, make this reference comparator through one the 3rd time delay and in one the 4th time from this secondElectronegative potential output signal is converted to output one second high potential output signal; And

One processing module, is electrically connected at this touch-control comparator and this reference comparator, in order to receive thisTwo high potential output signals, and in order to receive this first electronegative potential output signal and this first high potential output letterOne in number, so as to according to one of in this first electronegative potential output signal and this first high potential output signalPerson and this second high potential output signal are exported at least one touch-control result;

Wherein, be greater than for the 3rd time delay this first time delay, be less than the 3rd this second time delayTime delay.

2. touch-control sensing system as claimed in claim 1, is characterized in that this first switch and the 3rdSwitch is a PMOS switch, and this second switch and the 4th switch are a nmos switch.

3. touch-control sensing system as claimed in claim 1, is characterized in that, this second touch pad is one solidDetermine the one in electric capacity and a tunable capacitor.

4. touch-control sensing system as claimed in claim 1, is characterized in that, this second electric current of determining electric currentValue is greater than this and first determines the current value of electric current, and is this first multiple of determining the current value of electric current.

5. touch-control sensing system as claimed in claim 1, is characterized in that, this processing module comprises:

One first latch unit, is electrically connected at this touch-control comparator and this reference comparator, in order to receive thisOne in one electronegative potential output signal and this first high potential output signal, and according to this reference comparator instituteThis this first electronegative potential output signal of the second high potential output signal control and this first high potential of output are defeatedGo out signal output; And

One controller, is electrically connected at this first latch unit and this reference comparator, first low in order to receive thisOne in current potential output signal and this first high potential output signal and this second high potential output signal,And according to the one in this first electronegative potential output signal and this first high potential output signal and this secondHigh potential output signal is exported at least one touch-control result.

6. touch-control sensing system as claimed in claim 5, is characterized in that, this controller is a micro-processingOne in unit and digital signal processor.

7. touch-control sensing system as claimed in claim 5, is characterized in that, this processing module more comprises oneDigital delay, this digital delay is electrically connected at this reference comparator, this first latch unit and this controlBetween device processed, in order to receive this second high potential output signal, so as to according to this second high potential output signalTrigger this first latch unit and export in this first electronegative potential output signal and this first high potential output signal itOne, and export this second high potential output signal to this controller.

8. touch-control sensing system as claimed in claim 7, is characterized in that, this digital delay comprises:

At least one the second latch unit, is electrically connected at this reference comparator and this controller, in order to receive thisTwo high potential output signals and this controller one of send out delayed control signal, so as to making this controller controlMake this second latch unit and export a delay output signal according to this second high potential output signal; And

One multiplexer, is electrically connected at this reference comparator, this first latch unit, this second latch unit and is somebody's turn to doController, this second high potential output signal and this second door bolt that transmit in order to receive this reference comparatorLock this delay output signal that device sent out, so as to comprising work more than this second high potential output signal by oneProcessing signals is sent to this first latch unit and this controller.

9. touch-control sensing system as claimed in claim 8, is characterized in that, this first latch unit and thisTwo latch units are D type flip-flop.