CN101751193A - Sensing circuit of capacitance type touch panel - Google Patents
Sensing circuit of capacitance type touch panel Download PDFInfo
- Publication number
- CN101751193A CN101751193A CN201010002098A CN201010002098A CN101751193A CN 101751193 A CN101751193 A CN 101751193A CN 201010002098 A CN201010002098 A CN 201010002098A CN 201010002098 A CN201010002098 A CN 201010002098A CN 101751193 A CN101751193 A CN 101751193A
- Authority
- CN
- China
- Prior art keywords
- switch
- sensing circuit
- terminal
- period
- phase
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003990 capacitor Substances 0.000 claims abstract description 57
- 238000010586 diagram Methods 0.000 description 34
- 102100036576 Coiled-coil domain-containing protein 174 Human genes 0.000 description 6
- 101000715221 Homo sapiens Coiled-coil domain-containing protein 174 Proteins 0.000 description 6
- 101100329719 Schizosaccharomyces pombe (strain 972 / ATCC 24843) ctr5 gene Proteins 0.000 description 3
- 101100329720 Schizosaccharomyces pombe (strain 972 / ATCC 24843) ctr6 gene Proteins 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Images
Landscapes
- Electronic Switches (AREA)
Abstract
The invention relates to a sensing circuit of capacitance type touch panel, comprising a first switch, a second switch, a third switch, a feedback capacitor, a fourth switch and a computing amplifier; the first switch is provided with a first end to be connected to a receiving electrode of the capacitance type touch panel; the second switch is provided with a first end to be connected to the receiving electrode of the capacitance type touch panel; the third switch is provided with a first end to be connected to a second end of the first switch; the feedback capacitor is provided with a first end to be connected to a second end of the first switch; the fourth switch is provided with a first end to be connected to a second end of the feedback capacitor; the computing amplifier is provided with a positive input end to be connected to a grounding end, a negative input end to be connected to the first end of the fourth switch, and an output end to be connected to the second ends of the second switch, the third switch and the fourth switch, driving signals can be used for controlling the act sequence of the above switches in driving period, so that the computing amplifier can generate output voltage. The invention can cause SNR to increase, and vastly improve sensing capability of touch panel.
Description
Technical Field
The present invention relates to a sensing circuit of a touch panel (touch panel), and more particularly, to a sensing circuit of a capacitive touch panel (capacitive touch panel).
Background
Referring to fig. 1, a schematic diagram of a conventional capacitive touch panel system is shown. The capacitive touch panel system includes: driving units (driving units) u 1-u 6, sensing circuits (sensing circuits) s 1-s 6, and a touch panel. The touch panel includes driving electrodes (driving electrodes) d 1-d 6 and receiving electrodes (receiving electrodes) r 1-r 6 which are not in contact with each other, each of the driving electrodes d 1-d 6 is connected to the output end of a corresponding driving unit u 1-u 6, and each of the receiving electrodes r 1-r 6 is connected to the input end of a corresponding sensing circuit s 1-s 6. Furthermore, mutual capacitances (mutual capacitances) Cs11 to Cs66 are generated by the driving electrodes d1 to d6 and the receiving electrodes r1 to r6 which are not in contact with each other. Of course, the capacitive touch panel in fig. 1 only takes six driving electrodes d 1-d 6 and six receiving electrodes r 1-r 6 as examples, and the structure of the capacitive touch panel composed of more driving electrodes and receiving electrodes is similar, and therefore, the description thereof is omitted.
The capacitive touch panel of fig. 1 can be used as a multi-touch (multi-finger) touch panel. The operation principle is to calculate the position touched by the user by using the change of the mutual capacitance value (capacitance value). Generally, when a user generates a contact point (touch point) on the capacitive touch panel, a mutual capacitance value (capacitance value) at the position of the contact point changes, and at this time, a driving signal is provided to the mutual capacitance, and a charge amount charged by the mutual capacitance changes correspondingly. The sensing circuit detects the change of the charge quantity by utilizing the characteristic, judges the size change of the mutual inductance capacitance through the change of the voltage signal, and judges whether the grounding conductor is close to or in contact with the position of the touch panel or not through the size change of the mutual inductance capacitance. Of course, since the relationship between the charge amount (Q), the voltage (V) and the capacitance (C) is Q ═ C × V, the sensing circuit may also provide a change in voltage, so that the subsequent circuits determine the position of the user contact point according to the change in voltage.
As shown in FIG. 1, the six driving signals P1-P6 sequentially provide a pulse (pulse) to be transmitted to the driving electrodes d 1-d 6 via the driving units u 1-u 6. Since mutual capacitances Cs11 to Cs66 exist between the driving electrodes d1 to d6 and the receiving electrodes r1 to r6, the amount of induced charge (coupling charge) in the mutual capacitances Cs11 to Cs66 is transferred to the corresponding sensing circuits s1 to s6 via the receiving electrodes r1 to r 6. Therefore, the sensing circuits s 1-s 6 can generate the corresponding output voltages Vo 1-Vo 6.
Taking the first driving signal P1 as an example, the pulse generated in one driving period T charges the mutual inductances Cs11 to Cs16 on the first driving electrode d1, and the induced charges on the mutual inductances Cs11 to Cs16 are transferred to the sensing circuits s1 to s6 through the receiving electrodes r1 to r6, so that the sensing circuits s1 to s6 can generate the corresponding output voltages Vo1 to Vo 6.
Therefore, assuming that the contact point is located near the mutual inductance Cs11, the output voltage Vo1 of the first sensing circuit s1 is different from the output voltages Vo2 to Vo6 of the other sensing circuits s2 to s 6. Of course, if two contact points are located near the mutual inductance Cs11 and the mutual inductance Cs16, the output voltages Vo1 and Vo6 of the first sensing circuit s1 and the sixth sensing circuit s6 are different from the output voltages Vo2 to Vo5 of the other sensing circuits s2 to s 5.
By using the same principle, in the following driving period, the driving signals P2-P6 will sequentially provide pulses to the driving electrodes d 2-d 6, so that the sensing circuits s 1-s 6 generate the corresponding output voltages Vo 1-Vo 6.
As can be seen from the above, six driving cycles can be regarded as one scanning cycle (τ). That is, after a scanning period τ, all areas on the capacitive touch panel are scanned (scan) once, and the position of the contact point generated on the touch panel by the user can be accurately obtained.
Referring to fig. 2, a conventional sensing circuit is shown. The sensing circuit s is implemented by an integrator (integrator), comprising: an operational amplifier (operational amplifier)200, and a feedback capacitor (Cf). The operational amplifier 200 has a positive input terminal (+) receiving a reference voltage Vref, and a feedback capacitor Cf connected between a negative input terminal (-) and an output terminal Vo. Furthermore, the negative input (-) of the operational amplifier 200 is also connected to the receiving electrode r, and the mutual capacitance Cs is connected between the receiving electrode r and the driving electrode d.
Under normal operation of the operational amplifier 200, the voltages at the positive input terminal (+) and the negative input terminal (-) are the same and equal to the reference voltage Vref. Therefore, when the pulse amplitude of the driving electrode d is Vy, a voltage variation (Δ Vo) can be further obtained at the output Vo.
And Δ Vo ═ Vy × Cs/Cf- - - - (I). Therefore, taking the first driving signal P1 of fig. 1 as an example, when the user does not generate a touch point, the mutual capacitances Cs 11-Cs 16 will not change, and the voltage changes at the output terminals Vo 1-Vo 6 of the sensing circuits s 1-s 6 will be the same. On the contrary, if the user generates a contact point near the mutual inductor Cs11, the value (capacitance) of the mutual inductor Cs11 changes, so that the voltage variation of the output Vo1 of the first sensing circuit s1 is different from the voltage variations of the output Vo2 to Vo6 of the other sensing circuits s2 to s 6. The subsequent circuits can obtain the positions of the contact points according to the voltage variations at the output terminals Vo1 to Vo6 of the sensing circuits s1 to s 6.
However, when the mutual capacitance Cs at the contact point changes very little, the difference between the induced charge amount of the contact point and the induced charge amount of other mutual capacitances is too small, so that the difference between the voltage change amount generated by the sensing circuit corresponding to the contact point and the voltage change amount of other sensing circuits is too small, and the subsequent circuits cannot calculate the position of the contact point accordingly.
Referring to fig. 3, a schematic diagram of another conventional capacitive touch panel system is shown. As can be seen in fig. 3, the driving signals P1-P6 include two sub-periods (t1, t2) in one driving period, so that the mutual capacitance in the capacitive touch panel 300 can generate induced charges multiple times. Therefore, the sensing circuits s 1-s 6 can be designed to accumulate the induced charges on the mutual capacitance for multiple times, so that the voltage variation generated by the output voltages Vo 1-Vo 6 of the sensing circuits s 1-s 6 can be more easily distinguished.
As can be seen from fig. 3, there are six driving periods T in one scanning period τ, and there are two sub-periods T1, T2 in one driving period. That is, each of the driving signals P1-P6 generates a pulse in each of the two sub-periods T1 and T2 of the driving period T, so that the mutual capacitance generates the induced charges multiple times. The sensing circuits s 1-s 6 are designed to accumulate the induced charges generated by the mutual capacitance for many times and generate a large voltage variation. Therefore, after a scanning period τ, all areas on the capacitive touch panel are scanned (scan) once, and the position of the contact point generated on the touch panel by the user can be accurately obtained.
Fig. 3 only shows that two sub-periods T1 and T2 in one driving period T provide two pulses, but it is needless to say that more sub-periods and more pulses may be included in one driving period T, so that the sensing circuits s1 to s6 generate larger voltage variations. U.S. Pat. No. 6,514 discloses a Capacitive sensor and array (Capacitive sensor and array) that uses multiple pulses to accumulate charge generated by mutual capacitance.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a sensing circuit suitable for a capacitive touch panel, the sensing circuit is connected to a receiving electrode of the capacitive touch panel, and a mutual capacitance is provided between a driving electrode of the capacitive touch panel and the receiving electrode, and the driving electrode is used for receiving a driving signal, the sensing circuit includes: a first switch having a first end for connecting to the receiving electrode; a second switch having a first end for connecting to the receiving electrode; a third switch having a first end connected to a second end of the first switch; a feedback capacitor having a first end for connecting to the second end of the first switch; a fourth switch having a first end connected to a second end of the feedback capacitor; and an operational amplifier having a positive input terminal for connecting to a ground terminal, a negative input terminal connected to the first terminal of the fourth switch, and an output terminal connected to a second terminal of the second switch, a second terminal of the third switch, and a second terminal of the fourth switch, wherein the driving signal generates N sub-periods in a driving period, N is a positive integer, when a high level in the N sub-periods, the first switch and the fourth switch are in a closed state, the second switch and the third switch are in an open state, when a low level in the N sub-periods, the first switch and the fourth switch are in the open state, and the second switch and the third switch are in the closed state, and the output end of the operational amplifier generates an output voltage when the operational amplifier is at the low level in the Nth sub-period.
The present invention further provides a sensing circuit, which is suitable for a capacitive touch panel, the sensing circuit is connected to a receiving electrode of the capacitive touch panel, a mutual capacitance is provided between a driving electrode of the capacitive touch panel and the receiving electrode, and the driving electrode can receive a driving signal, the sensing circuit includes: a first switch having a first end for connecting to the receiving electrode; a second switch having a first end for connecting to the receiving electrode; a third switch having a first end connected to a second end of the first switch; a feedback capacitor having a first end for connecting to the second end of the first switch; a fourth switch having a first end connected to a second end of the feedback capacitor; and an operational amplifier having a positive input terminal for connecting to a ground terminal, a negative input terminal for connecting to the first terminal of the fourth switch, and an output terminal for connecting to a second terminal of the second switch, a second terminal of the third switch, and a second terminal of the fourth switch, wherein the driving signal has N sub-periods in a driving period, N being a positive integer, the N sub-periods respectively including a first phase, a second phase, a third phase, and a fourth phase, the driving signal being in a floating state when the driving signal is in the first phase, the first switch and the second switch being in an open state, the third switch and the fourth switch being in an off state, the driving signal being in a low level when the driving signal is in the second phase, the first switch and the fourth switch being in the off state, the second switch and the third switch being in the open state, when the driving signal is at a high level in the third phase, the first switch and the fourth switch are at the off state, the second switch and the third switch are at the open state, and when the driving signal is at a low level in the fourth phase, the first switch and the fourth switch are at the open state, the second switch and the third switch are at the off state, so that the output end of the operational amplifier generates an output voltage in the fourth phase of the nth sub-cycle.
The present invention further provides a sensing circuit, which is suitable for a capacitive touch panel, the sensing circuit is connected to a receiving electrode of the capacitive touch panel, a mutual capacitance is provided between a driving electrode and the receiving electrode of the capacitive touch panel, the driving electrode is connected to a ground terminal, and the sensing circuit includes: a first switch having a first end for connecting to the receiving electrode; a second switch having a first end for connecting to the receiving electrode; a third switch having a first end connected to a second end of the first switch; a feedback capacitor having a first end for connecting to the second end of the first switch; a fourth switch; an operational amplifier having a positive input terminal for connecting to the ground terminal, a negative input terminal connected to a first terminal of the fourth switch, and an output terminal connected to a second terminal of the second switch, a second terminal of the third switch, and a second terminal of the fourth switch; a fifth switch having a first end for connecting to a voltage source and a second end connected to a second end of the feedback capacitor; and a sixth switch having a first end connected to the second end of the feedback capacitor and a second end connected to the first end of the fourth switch, wherein a driving period has N sub-periods, N being a positive integer, the N sub-periods including a first phase and a second phase, when in the first phase, the first switch, the fourth switch and the fifth switch are in a closed state, the second switch, the third switch and the sixth switch are in an open state, and when in the second phase, the first switch, the fourth switch and the fifth switch are in the open state, the second switch, the third switch and the sixth switch are in the closed state, so that the output terminal of the operational amplifier generates an output voltage when in the second phase of the N sub-periods.
The present invention is advantageous in that a sensing circuit of a capacitive touch panel is provided, which can generate a large voltage variation at an output end, thereby improving a signal-to-noise ratio (SNR), and a subsequent circuit can easily calculate a position of a contact point according to an output voltage of the sensing circuit, thereby greatly improving a sensing capability of the touch panel.
For a better understanding of the features and technical aspects of the present invention, reference should be made to the following detailed description of the present invention, which is to be read in connection with the accompanying drawings, wherein the following description is provided for illustrative purposes only and is not intended to limit the present invention.
Drawings
Fig. 1 is a schematic diagram of a conventional capacitive touch panel system.
Fig. 2 shows a known sensing circuit.
Fig. 3 is a schematic diagram of another conventional capacitive touch panel system.
Fig. 4A and 4B show a first embodiment of the sensing circuit and its control signal according to the present invention.
Fig. 5A to 5G are schematic operation diagrams of the first embodiment.
FIGS. 6A and 6B illustrate a second embodiment of the sensing circuit and its control signals according to the present invention.
Fig. 7A to 7M are schematic operation diagrams of the second embodiment.
FIGS. 8A and 8B illustrate a third embodiment of the sensing circuit and its control signals according to the present invention.
Fig. 9A to 9G are schematic operation diagrams of the third embodiment.
The reference numbers in the above figures are as follows:
200 operational amplifier 300 capacitive touch panel
400. 600, 800 operational amplifier
Detailed Description
Referring to fig. 4A and 4B, a sensing circuit and a control signal thereof according to a first embodiment of the invention are shown. The sensing circuit s includes: an operational amplifier 400, a feedback capacitor Cf, four switch circuits sw 1-sw 4. Furthermore, the driving signal P can generate induced charges in the mutual capacitance Cs through the driving electrode d, and is transmitted to the input terminal of the sensing circuit s through the receiving electrode r.
The input end of the sensing circuit s is connected to first ends of a first switch sw1 (controlled by a first control signal ctr1) and a second switch sw2 (controlled by a second control signal ctr2), and a second end of the first switch sw1 is connected to a first end of a third switch sw3 (controlled by a third control signal ctr3) and a feedback capacitor Cf; the negative input (-) of the operational amplifier 400 is connected to the second terminal of the feedback capacitor Cf and the first terminal of the fourth switch sw4 (controlled by the fourth control signal ctr4), the positive input (+) of the operational amplifier 400 is connected to a ground terminal (GND), the output of the operational amplifier 400 is the output Vo of the sensing circuit s, and is connected to the second terminals of the second switch sw2, the third switch sw3 and the fourth switch sw 4.
Furthermore, as shown in fig. 4B, the driving signal P includes a reset period (resetcycle) and a driving period (T) in one scan cycle. A driving period T of the driving signal P includes three sub-periods T1, T2, and T3, which generate three pulses in total, and the rest of the time is the reset period. The four control signals ctr1 to ctr4 may turn off (close) the switches sw1 to sw4 at a high level, and turn on (open) the switches sw1 to sw4 at a low level. In fig. 4B, only three pulses are taken as an example, and actually, the number of sub-periods and pulses in the driving period T are not limited.
The detailed operation of the sensing circuit s of the first embodiment is described in detail below. Referring to fig. 5A, a schematic diagram of a sensing circuit during a reset period is shown. In the reset period, the first switch sw1 to the fourth switch sw4 are turned off. At this time, the drive signal P has not yet generated a pulse, and both ends of the feedback capacitance Cf and the mutual capacitance Cs are short-circuited (short circuit), so that the charge amount is 0. The operational amplifier 400 is connected as a unity gain amplifier (unity gain amplifier), so that the voltage of the output Vo is 0
Referring to FIG. 5B, a schematic diagram of the sensing circuit is shown as the high time T1a of the first sub-period T1 in the driving period T. As can be seen from fig. 4B, during the high time t1a of the first sub-period t1, the first switch sw1 and the fourth switch sw4 are turned off, and the second switch sw2 and the third switch sw3 are turned on.
At this time, the operational amplifier 400 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0. The pulse amplitude of the driving signal P is Vy, so the voltage on the feedback capacitor Cf is
Referring to FIG. 5C, a schematic diagram of the sensing circuit is shown as the low time T1b of the first sub-period T1 in the driving period T. As can be seen from fig. 4B, during the low-level time t1B of the first sub-period t1, the second switch sw2 and the third switch sw3 are in the off state, and the first switch sw1 and the fourth switch sw4 are in the open state.
At this time, the voltage Vo at the output terminal of the operational amplifier 400 is
Since the voltage of the driving signal P is 0, the voltage on the mutual capacitance Cs is also V1. Therefore, the charge stored on the mutual capacitance Cs is Cs × V1, and the charge stored on the feedback capacitance Cf is Cf × V1.
Referring to FIG. 5D, a schematic diagram of the sensing circuit is shown as the high time T2a of the second sub-period T2 in the driving period T. As can be seen from fig. 4B, during the high time t2a of the second sub-period t2, the first switch sw1 and the fourth switch sw4 are turned off, and the second switch sw2 and the third switch sw3 are turned on.
At this time, the operational amplifier 400 is connected as a unity gain amplifier, and the voltage of the output Vo is 0. While the pulse amplitude of the drive signal P is Vy and the voltage over the feedback capacitance Cf is assumed to be V2. Therefore, Cs × V1+ Cf × V1 ═ V2-Vy Cs + V2 × Cf.
Referring to FIG. 5E, a schematic diagram of the sensing circuit is shown as the low time T2b of the second sub-period T2 in the driving period T. As can be seen from fig. 4B, during the low time t2B of the second sub-period t2, the second switch sw2 and the third switch sw3 are turned off, and the first switch sw1 and the fourth switch sw4 are turned on.
Vo at the output of the operational amplifier 400 is
And the voltage on the mutual capacitance Cs is also made V2. At this time, the charge stored on the mutual capacitance Cs is Cs × V2; and the charge stored on the feedback capacitance Cf is Cf × V2.
Referring to FIG. 5F, a schematic diagram of the sensing circuit is shown as the high time T3a of the third sub-period T3 in the driving period T. As can be seen from fig. 4B, in the third sub-period t3 high-level time t3a, the first switch sw1 and the fourth switch sw4 are in the off state, and the second switch sw2 and the third switch sw3 are in the open state.
At this time, the operational amplifier 400 is connected as a unity gain amplifier, and the voltage of the output Vo is 0. While the pulse amplitude of the drive signal P is Vy and the voltage over the feedback capacitance Cf is assumed to be V3. Therefore, Cs × V2+ Cf × V2 ═ V3-Vy Cs + V3 × Cf.
Referring to FIG. 5G, a schematic diagram of the sensing circuit at the low time T3b of the third sub-period T3 in the driving period T is shown. As can be seen from fig. 4B, in the third sub-period t3, when the level is low for time t3B, the second switch sw2 and the third switch sw3 are turned off, and the first switch sw1 and the fourth switch sw4 are turned on.
Vo at the output of the operational amplifier 400 is
And the voltage on the mutual capacitance Cs is also made V3. That is, during the low time of the third sub-period t3, the output voltage is obtained at the output Vo of the sensing circuit s.
According to the first embodiment of the present invention, when the number of sub-periods in the driving period T is N pulses, at the high level of the pulses, charges are accumulated in the feedback capacitor Cf by a fixed amount. At the low level of the nth pulse, the output voltage Vo available at the output Vo of the sensing circuit s is Vo ═ N Δ
Therefore, the subsequent circuit can be used for judging reference according to the output voltage.
Referring to fig. 6A and 6B, a second embodiment of the sensing circuit and the control signal thereof according to the invention is shown. The sensing circuit s includes: an operational amplifier 600, a feedback capacitor Cf, four switch circuits sw 1-sw 4. Furthermore, the driving signal P is generated by switching the fifth switch sw5 (controlled by the fifth control signal ctr5) and the sixth switch sw6 (controlled by the sixth control signal ctr 6).
The input end of the sensing circuit s is connected to the first ends of the first switch sw1 (controlled by the first control signal ctr1) and the second switch sw2 (controlled by the second control signal ctr2), and the second end of the first switch sw1 is connected to the third switch sw3 (controlled by the third control signal ctr3) and the first end of the feedback capacitor Cf; the negative input (-) of the operational amplifier 600 is connected to the second terminal of the feedback capacitor Cf and the first terminal of the fourth switch sw4 (controlled by the fourth control signal ctr4), the positive input (+) of the operational amplifier 600 is connected to a ground terminal (GND), the output of the operational amplifier 600 is the output Vo of the sensing circuit s, and is connected to the second terminals of the second switch sw2, the third switch sw3 and the fourth switch sw 4.
The six control signals ctr1 to ctr6 may turn off (close) the switches sw1 to sw6 at a high level, and turn on (open) the switches sw1 to sw6 at a low level. As shown in fig. 6B, the driving signal P includes a reset period and a driving period T in one scan period. Furthermore, the driving signal P generates three sub-periods T1, T2, T3 in a driving period T, each of which includes four phases (phases). Taking the first sub-period t1 as an example, in the first phase t1a, the fifth switch sw5 and the sixth switch sw6 are both in an open state, and the driving signal is in a floating state (floating); in the second phase t1b, the fifth switch sw5 is in an open state and the sixth switch sw6 is in a closed state, and the driving signal P is at a low level (0V); in the third phase t1c, the fifth switch sw5 is turned off, the sixth switch sw6 is turned on, and the driving signal P is at a high level Vy; and, in the fourth phase t1d, the fifth switch sw5 is in an open state and the sixth switch sw6 is in a closed state, and the driving signal P is at a low level (0V). And the rest of the time except the driving period T is the reset period. In fig. 6B, only three sub-periods are taken as an example, and the number of sub-periods in the driving period T is not limited in practice.
The detailed operation of the sensing circuit s of the second embodiment is described in detail below. Referring to fig. 7A, a schematic diagram of a sensing circuit during a reset period is shown. In the reset period, the first switch sw1 to the fourth switch sw4 are turned off. Further, since the fifth switch sw5 is in an open state, the sixth switch sw6 is in a closed state, the drive signal P is at a low level (0V), and both ends of the feedback capacitance Cf and the mutual capacitance Cs are short-circuited (short circuit), the charge amount is 0. The operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 7B, a schematic diagram of the sensing circuit for the first phase T1a of the first sub-period T1 in the driving period T is shown. As shown in fig. 6B, in the first phase t1a of the first sub-period t1, the first switch sw1 and the second switch sw2 are in an open state, the third switch sw3 and the fourth switch sw4 are in a closed state, and the driving signal P is in a floating state. At this time, the two terminals of the feedback capacitor Cf are short-circuited so that the charge amount is 0, and the operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output terminal Vo is 0.
Referring to FIG. 7C, a schematic diagram of the sensing circuit for the second phase T1b of the first sub-period T1 in the driving period T is shown. As shown in fig. 6B, in the second phase t1B of the first sub-period t1, the first switch sw1 and the fourth switch sw4 are turned off, the second switch sw2 and the third switch sw3 are turned on, and the driving signal P is at a low level (0V). At this time, the feedback capacitor Cf is connected in series with the mutual capacitor Cs and connected to the ground, and the operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 7D, a schematic diagram of the sensing circuit in the third phase T1c of the first sub-period T1 of the driving period T is shown. As shown in fig. 6B, in the third phase t1c of the first sub-period t1, the first switch sw1 and the fourth switch sw4 are turned off, the second switch sw2 and the third switch sw3 are turned on, and the driving signal P is at the high level Vy. At this time, the feedback capacitance Cf is connected in series with the mutual capacitance Cs and to a high level Vy, so that the voltage on the feedback capacitance Cf. The operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 7E, a schematic diagram of a sensing circuit for the fourth phase T1d of the first sub-period T1 in the driving period T is shown. As shown in fig. 6B, in the fourth phase t1d of the first sub-period t1, the first switch sw1 and the fourth switch sw4 are in the open state, the second switch sw2 and the third switch sw3 are in the closed state, and the driving signal P is at the low level (0V). At this time, the voltage Vo at the output terminal of the operational amplifier 600 is
At the same time, the voltage on the mutual capacitance Cs is also V1. Therefore, the charge stored on the mutual capacitance Cs is Cs × V1; and the charge stored on the feedback capacitance Cf is Cf × V1.
Referring to FIG. 7F, a schematic diagram of the sensing circuit in the first phase T2a of the second sub-period T2 of the driving period T is shown. As shown in fig. 6B, in the first phase t2a of the second sub-period t2, the first switch sw1 and the second switch sw2 are in an open state, the third switch sw3 and the fourth switch sw4 are in a closed state, and the driving signal P is in a floating state. At this time, the two terminals of the feedback capacitor Cf are short-circuited, so that the charge amount is 0, the charge amount on the mutual capacitor Cs is not changed (Cs × V1), and the operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output terminal Vo is 0.
Referring to FIG. 7G, a schematic diagram of the sensing circuit for the second phase T2b of the second sub-period T2 in the driving period T is shown. As shown in fig. 6B, in the second phase t2B of the second sub-period t2, the first switch sw1 and the fourth switch sw4 are turned off, the second switch sw2 and the third switch sw3 are turned on, and the driving signal P is at a low level (0V). At this time, the feedback capacitor Cf is connected in series with the mutual capacitor Cs and connected to the ground, so the sum of the charge amounts on the feedback capacitor Cf and the mutual capacitor Cs is Cs × V1. The operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 7H, a schematic diagram of the sensing circuit for the third phase T2c of the second sub-period T2 in the driving period T is shown. As shown in fig. 6B, in the third phase t2c of the second sub-period t2, the first switch sw1 and the fourth switch sw4 are turned off, the second switch sw2 and the third switch sw3 are turned on, and the driving signal P is at the high level Vy. At this time, the feedback capacitance Cf is connected in series with the mutual capacitance Cs, and it is assumed that the voltage of the feedback capacitance Cf changes to V2. Therefore, Cs × V1 ═ (V2-Vy) × Cs + V2 × Cf,
wherein,
the operational amplifier 600 is connected as a unity gain amplifier, so that the voltage at the output (Vo) is 0.
Referring to FIG. 7I, a schematic diagram of the sensing circuit in the fourth phase T2d of the second sub-period T2 of the driving period T is shown. As shown in fig. 6B, in the fourth phase t2d of the second sub-period t2, the first switch sw1 and the fourth switch sw4 are in the open state, the second switch sw2 and the third switch sw3 are in the closed state, and the driving signal P is at the low level (0V). At this time, the voltage of the output terminal (Vo) of the operational amplifier 600 is V2 ═ a2+ a) Vy while the voltage on the mutual capacitance Cs is also V2. Therefore, the charge stored on the mutual capacitance Cs is Cs × V2; and the charge stored on the feedback capacitance Cf is Cf × V2.
Referring to FIG. 7J, a schematic diagram of the sensing circuit for the first phase T3a of the third sub-period T3 in the driving period T is shown. As shown in fig. 6B, in the first phase t3a of the third sub-period t3, the first switch sw1 and the second switch sw2 are in an open state, the third switch sw3 and the fourth switch sw4 are in a closed state, and the driving signal P is in a floating state. At this time, the two terminals of the feedback capacitor Cf are short-circuited so that the charge amount is 0, the charge amount of the mutual capacitor Cs is not changed (Cs × V2), and the operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output terminal Vo is 0.
Referring to FIG. 7K, a schematic diagram of the sensing circuit for the second phase (T3b) of the third sub-period T3 in the driving period T is shown. As shown in fig. 6B, in the second phase (t3B) of the third sub-period t3, the first switch sw1 and the fourth switch sw4 are turned off, the second switch sw2 and the third switch sw3 are turned on, and the driving signal P is at a low level (0V). At this time, the feedback capacitor Cf is connected in series with the mutual capacitor Cs and is connected to the ground, so the sum of the electric charges on the feedback capacitor Cf and the mutual capacitor Cs is (Cs × V2). The operational amplifier 600 is connected as a unity gain amplifier, so that the voltage at the output (Vo) is 0.
Referring to FIG. 7L, a schematic diagram of the sensing circuit in the third phase T3c of the third sub-period T3 of the driving period T is shown. As shown in fig. 6B, in the third phase t3c of the third sub-period t3, the first switch sw1 and the fourth switch sw4 are turned off, the second switch sw2 and the third switch sw3 are turned on, and the driving signal P is at the high level Vy. At this time, the feedback capacitance Cf is connected in series with the mutual capacitance Cs, and it is assumed that the voltage of the feedback capacitance Cf changes to V3. Therefore, Cs × V2 ═ (V3-Vy) × Cs + V3 × Cf,
wherein,
the operational amplifier 600 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 7M, a schematic diagram of the sensing circuit in the fourth phase T3d of the third sub-period T3 of the driving period T is shown. As shown in fig. 6B, in the fourth phase t3d of the third sub-period t3, the first switch sw1 and the fourth switch sw4 are in the open state, the second switch sw2 and the third switch sw3 are in the closed state, and the driving signal P is at the low level (0V). At this time, the voltage Vo at the output terminal of the operational amplifier 600 is V3 ═ a (a)3+A2+ a) Vy while the voltage on the mutual capacitance Cs is also V3. Therefore, the charge stored on the mutual capacitance Cs is Cs × V3; and the charge stored on the feedback capacitance Cf is Cf × V3. That is, in the fourth phase t3d of the third pulse t3, the output voltage is obtained at the output Vo of the sensing circuit s.
In the second embodiment of the present invention, when the number of sub-periods in the driving period T is N, charges are accumulated in the feedback capacitor Cf in the third phase of the sub-period. And at the fourth phase of the nth sub-period,the output voltage available at the output Vo of the sensing circuit s is
Wherein,therefore, the subsequent circuit can be judged according to the output voltage.
Referring to fig. 8A and 8B, a third embodiment of the sensing circuit and the control signal thereof is shown. The sensing circuit s includes: an operational amplifier 800, a feedback capacitor Cf, six switch circuits sw 1-sw 6. Furthermore, the driving electrode d is directly connected to the ground, and the receiving electrode r is connected to the input terminal of the sensing circuit s.
The input end of the sensing circuit s is connected to the first ends of the first switch sw1 (controlled by the first control signal ctr1) and the second switch sw2 (controlled by the second control signal ctr2), and the second end of the first switch sw1 is connected to the third switch sw3 (controlled by the third control signal ctr3) and the first end of the feedback capacitor Cf; a first end of a fifth switch (controlled by a fifth control signal ctr5) receives the Vy voltage, and a second end is connected to a second end of the feedback capacitor Cf and a first end of a sixth switch (controlled by a sixth control signal ctr 6); the negative input (-) of the operational amplifier 800 is connected to the second terminal of the sixth switch sw6 and the first terminal of the fourth switch sw4 (controlled by the fourth control signal ctr4), the positive input (+) of the operational amplifier 800 is connected to a ground terminal (GND), the output of the operational amplifier 800 is the output Vo of the sensing circuit s, and is connected to the second terminals of the second switch sw2, the third switch sw3 and the fourth switch sw 4.
Further, the six control signals ctr1 to ctr6 can turn off the switches sw1 to sw6 at a high level and turn on the switches sw1 to sw6 at a low level. As shown in fig. 8B, according to the fifth control signal ctr5 and the sixth control signal ctr6, one scan cycle can be divided into: a reset period and a driving period T. The driving period T is divided into three sub-periods T1, T2, T3, each of which includes a first phase and a second phase. Taking the first pulse t1 as an example, in the first phase t1a, the fifth switch sw5 is turned off, and the sixth switch sw6 is turned on; in the second phase t1b, the fifth switch sw5 is in an open state and the sixth switch sw6 is in a closed state. In fig. 8B, only three sub-periods are taken as an example, and the number of sub-periods in the driving period T is not limited in practice.
The detailed operation of the sensing circuit s of the third embodiment is described in detail below. Referring to fig. 9A, a schematic diagram of a sensing circuit during a reset period is shown. In the reset period, only the fifth switch sw5 is in an open state, and the first to fourth switches sw1 to sw4 and the sixth switch sw6 are in a closed state. Therefore, the feedback capacitance Cf is short-circuited with both ends of the mutual capacitance Cs, and thus the charge amount is 0. The operational amplifier 800 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 9B, a schematic diagram of the sensing circuit for the first phase T1a of the first sub-period T1 in the driving period T is shown. As can be seen from fig. 8B, in the first phase t1a of the first sub-period t1, the first switch sw1, the fourth switch sw4 and the fifth switch sw5 are turned off, and the second switch sw2, the third switch sw3 and the sixth switch sw6 are turned on. At this time, the voltage on the feedback capacitor Cf is
The operational amplifier 800 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 9C, a schematic diagram of the sensing circuit for the second phase T1b of the first sub-period T1 in the driving period T is shown. As can be seen from fig. 8B, in the second phase t1B of the first sub-period t1, the first switch sw1, the fourth switch sw4 and the fifth switch sw5 are in the open state, and the second switch sw2, the third switch sw3 and the sixth switch sw6 are in the closed state. At this time, the voltage at the output terminal of the operational amplifier 800
While the voltage on the mutual capacitance is alsoAnd V1. Therefore, the charge stored on the mutual capacitance Cs is Cs × V1, and the charge stored on the feedback capacitance Cf is Cf × V1.
Referring to FIG. 9D, a schematic diagram of the sensing circuit in the first phase T2a of the second sub-period T2 of the driving period T is shown. As can be seen from fig. 8B, in the first phase t2a of the second sub-period t2, the first switch sw1, the fourth switch sw4 and the fifth switch sw5 are turned off, and the second switch sw2, the third switch sw3 and the sixth switch sw6 are turned on. At this time, it is assumed that the voltage of the feedback capacitance Cf changes to V2. Therefore, (Cf + Cs) × V1 ═ (V2-Vy) × Cs + V2 × Cf,the operational amplifier 800 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 9E, a schematic diagram of the sensing circuit for the second phase T2b of the second sub-period T2 in the driving period T is shown. As can be seen from fig. 8B, in the second phase t2B of the second sub-period t2, the first switch sw1, the fourth switch sw4 and the fifth switch sw5 are in the open state, and the second switch sw2, the third switch sw3 and the sixth switch sw6 are in the closed state. At this time, the voltage at the output terminal of the operational amplifier 800While the voltage on the mutual capacitance is also V2. Therefore, the charge stored on the mutual capacitance Cs is Cs × V2; and the charge stored on the feedback capacitance Cf is Cf × V2.
Referring to FIG. 9F, a schematic diagram of the sensing circuit in the first phase T3a of the third sub-period T3 of the driving period T is shown. As can be seen from fig. 8B, in the first phase t3a of the third sub-period t3, the first switch sw1, the fourth switch sw4 and the fifth switch sw5 are turned off, and the second switch sw2, the third switch sw3 and the sixth switch sw6 are turned on. At this time, it is assumed that the voltage of the feedback capacitance Cf changes to V3. Therefore, (Cf + Cs) × V2 ═ (V3-Vy) × Cs + V3 × Cf,
the operational amplifier 800 is connected as a unity gain amplifier, so that the voltage of the output Vo is 0.
Referring to FIG. 9G, a schematic diagram of the sensing circuit for the second phase T3b of the third sub-period T3 in the driving period T is shown. As can be seen from fig. 8B, in the second phase t3B of the third sub-period t3, the first switch sw1, the fourth switch sw4 and the fifth switch sw5 are in the open state, and the second switch sw2, the third switch sw3 and the sixth switch sw6 are in the closed state. At this time, the voltage at the output terminal of the operational amplifier 800
While the voltage on the mutual capacitance is also V3.
In the third embodiment of the present invention, when the number of sub-periods in the driving period T is N, charges are accumulated in the feedback capacitor Cf in the first phase. In the second phase of the Nth pulse, the output voltage available at the output Vo of the sensing circuit s is
Therefore, the subsequent circuit can be judged according to the output voltage.
According to the embodiment of the invention, during the driving period, the voltage generated at the output terminal of the sensing circuit s is increased, so that the subsequent circuits can easily distinguish the voltage variation when there is a contact point and when there is no contact point, and determine the correct position of the contact point, thereby improving the sensitivity (sensitivity) of the touch panel.
The present invention is advantageous in that a sensing circuit of a capacitive touch panel is provided, which can generate a large voltage variation at an output end, thereby improving a signal-to-noise ratio (SNR), and a subsequent circuit can easily calculate a position of a contact point according to an output voltage of the sensing circuit, thereby greatly improving a sensing capability of the touch panel.
In summary, although the present invention has been described with reference to the preferred embodiments, it should be understood that the invention is not limited thereto, and that various changes and modifications can be made by one skilled in the art without departing from the spirit and scope of the invention.
Claims (13)
1. A sensing circuit is suitable for a capacitive touch panel, the sensing circuit is connected to a receiving electrode of the capacitive touch panel, a mutual capacitance is arranged between a driving electrode and the receiving electrode of the capacitive touch panel, the driving electrode is used for receiving a driving signal, and the sensing circuit comprises:
a first switch having a first end for connecting to the receiving electrode;
a second switch having a first end for connecting to the receiving electrode;
a third switch having a first end connected to a second end of the first switch;
a feedback capacitor having a first end for connecting to the second end of the first switch;
a fourth switch having a first end connected to a second end of the feedback capacitor; and
an operational amplifier having a positive input terminal for connecting to a ground terminal, a negative input terminal for connecting to the first terminal of the fourth switch, and an output terminal for connecting to a second terminal of the second switch, a second terminal of the third switch, and a second terminal of the fourth switch,
the driving signal generates N sub-periods in a driving period, wherein N is a positive integer, when a high level in the N sub-periods is reached, the first switch and the fourth switch are in an off state, the second switch and the third switch are in an open state, when a low level in the N sub-periods is reached, the first switch and the fourth switch are in the open state, and the second switch and the third switch are in the off state, so that the output end of the operational amplifier generates an output voltage when the low level in the N sub-period is reached.
2. The sensing circuit of claim 1, wherein the driving signal comprises the driving period and a reset period.
3. The sensing circuit as claimed in claim 2, wherein during the reset period, the first switch, the second switch, the third switch, and the fourth switch are controlled to be in the off state, such that the charges on the feedback capacitor and the mutual capacitor are 0.
4. The sensing circuit of claim 1, wherein the output voltage isWherein the capacitance value of the mutual capacitanceCs, the capacitance of the feedback capacitor is Cf, and the amplitudes of the N pulses are Vy, respectively.
5. The sensing circuit of claim 4, wherein the output voltage at the low level in the Nth sub-period is N times the output voltage at the low level in the first sub-period.
6. A sensing circuit is suitable for a capacitance touch panel, the sensing circuit is connected to a receiving electrode of the capacitance touch panel, a mutual capacitance is arranged between a driving electrode and the receiving electrode of the capacitance touch panel, the driving electrode can receive a driving signal, and the sensing circuit comprises:
a first switch having a first end for connecting to the receiving electrode;
a second switch having a first end for connecting to the receiving electrode;
a third switch having a first end connected to a second end of the first switch;
a feedback capacitor having a first end for connecting to the second end of the first switch;
a fourth switch having a first end connected to a second end of the feedback capacitor; and
an operational amplifier having a positive input terminal for connecting to a ground terminal, a negative input terminal for connecting to the first terminal of the fourth switch, and an output terminal for connecting to a second terminal of the second switch, a second terminal of the third switch, and a second terminal of the fourth switch,
wherein the driving signal has N sub-periods in a driving period, N is a positive integer, the N sub-periods respectively include a first phase, a second phase, a third phase and a fourth phase, when the driving signal is in the first phase, the driving signal is in a floating state, the first switch and the second switch are in an open state, the third switch and the fourth switch are in a closed state, when the driving signal is in the second phase, the driving signal is in a low level, the first switch and the fourth switch are in the closed state, the second switch and the third switch are in the open state, when the driving signal is in the third phase, the driving signal is in a high level, the first switch and the fourth switch are in the closed state, the second switch and the third switch are in the open state, and when the driving signal is in the fourth phase, the driving signal is in the low level, the first switch and the fourth switch are in the open state, the second switch and the third switch are in the off state, so that the output end of the operational amplifier generates an output voltage when the fourth phase is in the nth sub-period.
7. The sensing circuit of claim 6, wherein the driving signal comprises the driving period and a reset period.
8. The sensing circuit as claimed in claim 7, wherein during the reset period, the first switch, the second switch, the third switch, and the fourth switch are controlled to be in the off state, such that the charges on the feedback capacitor and the mutual capacitor are 0.
9. The sensing circuit of claim 6, wherein the driving electrode is connected to a first terminal of a fifth switch and a first terminal of a sixth switch, a second terminal of the fifth switch receives the high level, a second terminal of the sixth switch receives the low level, the fifth switch and the sixth switch are in the open state when in the first phase, the sixth switch is in the closed state when in the second phase, the fifth switch is in the open state, the fifth switch is in the closed state when in the third phase, the sixth switch is in the open state, and the sixth switch is in the closed state and the fifth switch is in the open state when in the fourth phase.
10. The sensing circuit of claim 6, wherein the output voltage isAmong them, in the case of a high-frequency, the capacitance value of the mutual capacitance is Cs, the capacitance value of the feedback capacitance is Cf, and the high level is Vy.
11. A sensing circuit is suitable for a capacitance touch panel, the sensing circuit is connected with a receiving electrode of the capacitance touch panel, a mutual capacitance is arranged between a driving electrode and the receiving electrode of the capacitance touch panel, the driving electrode is connected with a grounding terminal, and the sensing circuit comprises:
a first switch having a first end for connecting to the receiving electrode;
a second switch having a first end for connecting to the receiving electrode;
a third switch having a first end connected to a second end of the first switch;
a feedback capacitor having a first end for connecting to the second end of the first switch;
a fourth switch;
an operational amplifier having a positive input terminal for connecting to the ground terminal, a negative input terminal connected to a first terminal of the fourth switch, and an output terminal connected to a second terminal of the second switch, a second terminal of the third switch, and a second terminal of the fourth switch;
a fifth switch having a first end for connecting to a voltage source and a second end connected to a second end of the feedback capacitor; and
a sixth switch having a first end connected to the second end of the feedback capacitor, a second end connected to the first end of the fourth switch,
the first switch, the fourth switch and the fifth switch are in an open state, the second switch, the third switch and the sixth switch are in a closed state, and when the second phase is in the second phase, the first switch, the fourth switch and the fifth switch are in the open state, the second switch, the third switch and the sixth switch are in the closed state, so that the output end of the operational amplifier generates an output voltage when the second phase is in the nth sub-period.
12. The sensing circuit as claimed in claim 11, further comprising a reset period for controlling the first switch, the second switch, the third switch, the fourth switch, and the sixth switch to be in an off state, and the fifth switch to be in an open state, such that the charges on the feedback capacitor and the mutual capacitor are 0.
13. The sensing circuit of claim 11, wherein the output voltage isThe capacitance of the mutual capacitor is Cs, the capacitance of the feedback capacitor is Cf, and the voltage of the voltage source is Vy.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010100020986A CN101751193B (en) | 2010-01-11 | 2010-01-11 | Sensing circuit of capacitance type touch panel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010100020986A CN101751193B (en) | 2010-01-11 | 2010-01-11 | Sensing circuit of capacitance type touch panel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101751193A true CN101751193A (en) | 2010-06-23 |
| CN101751193B CN101751193B (en) | 2011-06-22 |
Family
ID=42478230
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010100020986A Active CN101751193B (en) | 2010-01-11 | 2010-01-11 | Sensing circuit of capacitance type touch panel |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101751193B (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102566817A (en) * | 2010-11-29 | 2012-07-11 | 群康科技(深圳)有限公司 | Sensing methods for touch sensing devices |
| CN103885655A (en) * | 2012-12-21 | 2014-06-25 | 乐金显示有限公司 | Display device and driving method thereof |
| CN103902123A (en) * | 2014-01-30 | 2014-07-02 | 敦泰科技有限公司 | Self-capacitance touch sensing device capable of reducing substrate capacitance |
| EP2638459A4 (en) * | 2010-11-12 | 2015-07-22 | Sharp Kk | Linear system coefficient estimating method, linear device column value estimating method, capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| US9146632B2 (en) | 2011-06-29 | 2015-09-29 | Sharp Kabushiki Kaisha | Linear device value estimating method, capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| US9354757B2 (en) | 2011-06-27 | 2016-05-31 | Sharp Kabushiki Kaisha | Touch sensor system, and electronic device |
| US9830026B2 (en) | 2011-06-29 | 2017-11-28 | Sharp Kabushiki Kaisha | Touch sensor system and electronic device |
| CN109798923A (en) * | 2017-11-17 | 2019-05-24 | 艾普凌科有限公司 | Sensor device |
| CN110262686A (en) * | 2016-10-24 | 2019-09-20 | 瑞鼎科技股份有限公司 | Mutual capacitance touch control sensing circuit |
| CN110895293A (en) * | 2019-12-12 | 2020-03-20 | 深圳芯启航科技有限公司 | Differential mutual capacitance detection circuit, method, chip and device |
-
2010
- 2010-01-11 CN CN2010100020986A patent/CN101751193B/en active Active
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9501451B2 (en) | 2010-11-12 | 2016-11-22 | Sharp Kabushiki Kaisha | Linear system coefficient estimating method, linear device column value estimating method, capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| EP2638459A4 (en) * | 2010-11-12 | 2015-07-22 | Sharp Kk | Linear system coefficient estimating method, linear device column value estimating method, capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| EP3012724A1 (en) * | 2010-11-12 | 2016-04-27 | Sharp Kabushiki Kaisha | Linear system coefficient estimating method, linear device column value estimating method, capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| US9563323B1 (en) | 2010-11-12 | 2017-02-07 | Sharp Kabushiki Kaisha | Capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| CN102566817B (en) * | 2010-11-29 | 2014-10-01 | 群康科技(深圳)有限公司 | Sensing methods for touch sensing devices |
| CN102566817A (en) * | 2010-11-29 | 2012-07-11 | 群康科技(深圳)有限公司 | Sensing methods for touch sensing devices |
| US9354757B2 (en) | 2011-06-27 | 2016-05-31 | Sharp Kabushiki Kaisha | Touch sensor system, and electronic device |
| US9830026B2 (en) | 2011-06-29 | 2017-11-28 | Sharp Kabushiki Kaisha | Touch sensor system and electronic device |
| US9146632B2 (en) | 2011-06-29 | 2015-09-29 | Sharp Kabushiki Kaisha | Linear device value estimating method, capacitance detecting method, integrated circuit, touch sensor system, and electronic device |
| CN103885655B (en) * | 2012-12-21 | 2018-08-17 | 乐金显示有限公司 | Display device and its driving method |
| CN103885655A (en) * | 2012-12-21 | 2014-06-25 | 乐金显示有限公司 | Display device and driving method thereof |
| CN103902123B (en) * | 2014-01-30 | 2017-04-19 | 敦泰科技有限公司 | Self-capacitance touch sensing device capable of reducing substrate capacitance |
| CN103902123A (en) * | 2014-01-30 | 2014-07-02 | 敦泰科技有限公司 | Self-capacitance touch sensing device capable of reducing substrate capacitance |
| CN110262686A (en) * | 2016-10-24 | 2019-09-20 | 瑞鼎科技股份有限公司 | Mutual capacitance touch control sensing circuit |
| CN109798923A (en) * | 2017-11-17 | 2019-05-24 | 艾普凌科有限公司 | Sensor device |
| CN109798923B (en) * | 2017-11-17 | 2022-02-18 | 艾普凌科有限公司 | Sensor device |
| CN110895293A (en) * | 2019-12-12 | 2020-03-20 | 深圳芯启航科技有限公司 | Differential mutual capacitance detection circuit, method, chip and device |
| CN110895293B (en) * | 2019-12-12 | 2025-05-06 | 深圳芯启航科技有限公司 | Differential mutual capacitance detection circuit, method, chip and device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101751193B (en) | 2011-06-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101751193B (en) | Sensing circuit of capacitance type touch panel | |
| US8681110B2 (en) | Sensing circuit for use with capacitive touch panel | |
| TWI401599B (en) | Sensing circuit applied to capacitive touch panel | |
| US7973542B2 (en) | Methods and systems for guarding a charge transfer capacitance sensor for proximity detection | |
| US8174273B2 (en) | Capacitance measurement circuit with dynamic feedback | |
| CN104679372B (en) | Capacitive sensing interface for proximity test | |
| CN104317462B (en) | Touch controller, the display driver circuit with it, display equipment and system | |
| JP5324297B2 (en) | Coordinate input device and display device including the same | |
| CN110045856B (en) | Touch display device, touch driving circuit and method of sensing touch | |
| US8547113B2 (en) | Capacitive touch panel | |
| KR20190015436A (en) | Multi-step incremental switching scheme | |
| CN101702109B (en) | Sensing circuit of capacitive touch panel | |
| CN102200869A (en) | Capacitive touch device and sensing device thereof | |
| CN102375625B (en) | Sensing circuit and method for capacitive touch panel | |
| US8547117B2 (en) | Capacitive touch panel | |
| US20170293376A1 (en) | Hover sensor | |
| CN112965641B (en) | Capacitance detection circuit, related method, module, device and equipment | |
| CN102193694B (en) | Electronics for Compensating Capacitance Deviations | |
| KR20160119294A (en) | Touch Detection Apparatus and Touch Display Device with the same | |
| TWI407358B (en) | Sensing Circuit and Method of Capacitive Touchpad | |
| JP5642847B2 (en) | Coordinate input device | |
| CN118068988B (en) | Self-capacitance touch detection circuit and detection method | |
| KR20130072537A (en) | Touch signal processing circuit and touch signal detection system including the circuit | |
| JPH10149250A (en) | Charge current detecting circuit and coordinate input device utilizing the same | |
| CN111045554B (en) | Capacitance sensing sampling circuit and its sensing sampling method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |