KR101108702B1 - Touch screen device, driving device and driving method of touch panel - Google Patents

Abstract

Disclosed are a touch screen device and a method of driving a touch panel to which bit sequence noise filtering technology is applied.
The touch panel includes a plurality of operation signal lines, a plurality of detection signal lines insulated from the plurality of operation signal lines, and a plurality of node capacitors formed by the corresponding operation signal lines and the corresponding detection signal lines, respectively. In order to drive the touch panel, a driving waveform of a first mode for charging the node capacitor with a positive first voltage or at least one of the plurality of operation signal lines is charged with a negative second voltage. The combination of the driving waveforms of the second mode is applied in a predetermined sequence.
By driving in this manner, it is possible to prevent the touch screen device from malfunctioning due to external noise.

Description

A touch screen device, a driving device and a driving method for a touch panel}

The present invention relates to a touch screen device, a drive device and a driving method of the touch panel, and more particularly, to a touch screen device, a touch device driving device and a driving method for preventing malfunction due to noise.

Display devices such as liquid crystal displays, organic light emitting displays, portable transmission devices, and other information processing devices perform functions using various input devices. Recently, as such an input device, a touch screen device is widely used for a mobile phone, a smart phone, a palm-size PC, an automated teller machine (ATM) device, and the like.

The touch screen device touches a finger or a touch pen (stylus) on the screen to write a character, draw a picture, and execute an icon to execute a desired command.

Since the touch screen device is generally installed on a display device such as a liquid crystal display device and used as an input means of the display device, there is a problem in that the touch screen device malfunctions due to noise generated by an external device or a person such as a display device. .

The present invention is to provide a touch screen device, a drive device of the touch panel and a driving method for preventing a malfunction of the touch screen device due to external noise in order to solve such a problem.

Touch screen device according to a feature of the present invention

A touch panel including a plurality of operation signal lines, a plurality of sensing signal lines insulated from the plurality of operating signal lines, and a plurality of node capacitors respectively formed by corresponding operation signal lines and sensing signal lines; A driving waveform of a first mode or a second negative terminal capacitor configured to charge the node capacitor with a positive first voltage to at least one operation signal line of the plurality of operation signal lines; A driving circuit for applying a combination of driving waveforms of the second mode for charging with a voltage in a predetermined sequence; And a sensing circuit electrically connected to the plurality of sensing signal lines and measuring capacitance of the node capacitor.

Driving device for a touch panel according to a feature of the present invention

A driving device for driving a touch panel including a plurality of operation signal lines, a plurality of sensing signal lines insulated from the plurality of operating signal lines, and a plurality of node capacitors respectively formed by corresponding operation signal lines and sensing signal lines,

A driving waveform of a first mode or a second negative terminal capacitor configured to charge the node capacitor with a positive first voltage to at least one operation signal line of the plurality of operation signal lines; A driving circuit for applying a combination of driving waveforms of the second mode for charging with a voltage in a predetermined sequence; And a sensing circuit electrically connected to the plurality of sensing signal lines and measuring capacitance of the node capacitor.

The driving method of the touch panel according to the characteristics of the present invention

A method of driving a touch panel including a plurality of operation signal lines, a plurality of sensing signal lines insulated from the plurality of operating signal lines, and a plurality of node capacitors respectively formed by corresponding operation signal lines and sensing signal lines,

The on / off operation of a plurality of driving switches electrically connected to the operation signal line or the detection signal line may be performed in a first operation mode for charging a positive first voltage to the node capacitor or a negative second voltage to the node capacitor. Selectively driving to a second operation mode for charging, wherein the first operation mode and the second operation mode is arranged in a first sequence that is not alternately driven.

Here, the driving method of the first operation mode is

Charging the node capacitor to the positive first voltage; Charging a unit charge voltage corresponding to the magnitude of the capacitance of the node capacitor to a reference capacitor electrically connected to the node capacitor; Converting the unit charge voltage charged in the reference capacitor into a digital value; Adding the digital value of the current operation mode converted from the analog-to-digital converter to the cumulative digital value up to the previous operation mode to obtain a cumulative digital value up to the current operation mode; And initializing the unit charge voltage charged in the reference capacitor.

In addition, the driving method of the second operation mode is

Charging the node capacitor to the negative second voltage; Charging a unit charge voltage corresponding to the magnitude of the capacitance of the node capacitor to a reference capacitor electrically connected to the node capacitor; Converting the unit charge voltage charged in the reference capacitor into a digital value; And subtracting the digital value of the current operation mode converted from the analog-to-digital converter to the cumulative digital value up to the previous operation mode to obtain the cumulative digital value up to the current operation mode.

The present invention can prevent the touch screen device from malfunctioning by external noise by operating the driving device of the touch screen device by a sequence of -1 or 1 and then performing the post-processing process in the sensing unit.

1 is a view showing a touch screen device according to an embodiment of the present invention.
2 is a diagram illustrating a driving circuit and a sensing circuit according to an embodiment of the present invention.
3 to 6 are diagrams illustrating a driving method according to a first operation mode.
7 to 10 are diagrams illustrating a driving method according to a second operation mode.
11 to 14 are diagrams illustrating a noise removing effect according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The terms used below are merely for referring to specific embodiments, and are not intended to limit the present invention. Also, the singular forms used below include the plural forms unless the phrases clearly indicate the opposite meanings.

The embodiment of the present invention described below uses a bit sequence noise filtering technique to prevent malfunction due to external noise. A bit sequence is a sequence of only two states, such as 1 and 0 (or -1). Bit sequence noise filtering technology refers to a technology that obtains a noise filtering effect of discrete FIR (Finite Impulse Response) characteristics in the analog stage through post-processing while changing the driving value to bit step. In the embodiment of the present invention, as described later, the driving is operated by a sequence of 1 or -1 and then the sensing unit has a noise filtering effect through its post-processing process.

In general, a touch screen device may be classified into a resistive type and a capacitive type according to a method of sensing a touch.

The resistive touch screen device has a structure in which a resistive material is coated on a glass or transparent plastic plate and a polyester film is covered thereon. The resistive touch screen device detects a touch point by detecting a change in a resistance value that changes when the screen is touched.

The capacitive touch screen device forms electrodes on both sides or one side of glass or transparent plastic, applies a voltage between the two electrodes, and analyzes the amount of capacitance change between two electrodes that changes when an object such as a finger contacts the screen. Detect touch points.

Hereinafter, a capacitive touch screen device will be described as an example of the touch screen device, but the present invention is not limited thereto and may be applied to other touch screen devices. In addition, although the present invention describes a touch screen device as an example, the idea applied to the present invention can be applied to other devices.

1 illustrates a touch screen device according to an embodiment of the present invention.

As shown in FIG. 1, a touch screen device according to an embodiment of the present invention includes a touch panel 100, a driving circuit 200, a sensing circuit 300, and a timing controller 400.

The touch panel 100 includes a plurality of operation signal lines X1, X2, X3, .. Xn and a plurality of sensing signal lines Y1, Y2, Y3,... In FIG. 1, the operation signal lines and the detection signal lines are respectively indicated by lines for convenience, but are actually implemented as electrode patterns. In the present specification, the sensing signal line may be used interchangeably with terms such as sensing line, sensing line, sensing electrode, and the like, and the operation signal line may be mixed with terms such as operating line, operating line, and operating electrode. In addition, in FIG. 1, the plurality of operation signal lines and the plurality of detection signal lines are shown to cross each other by being insulated from each other. However, the present invention is not limited thereto, and the operation signal lines and the detection signal lines may not cross each other.

The sensing node 110 representing the touch point is defined by one sensing signal line and one operation signal line, and each sensing node 110 includes a node capacitor 112. The node capacitor 112 is formed by an operation signal line and a detection signal line that are insulated from and separated from each other. In FIG. 1, the capacitance of the node capacitor 112 formed by the i-th operation signal line and the j-th detection signal line is denoted by Cij.

The driving circuit 200 is electrically connected to the plurality of operation signal lines X1, X2, X3, .. Xn, and applies driving waveforms to the plurality of operation signal lines sequentially or simultaneously. At this time, the driving waveform is made of a combination of a positive power supply voltage (or negative power supply voltage) and ground voltage as described later, the specific drive waveform is determined by the on / off operation sequence of the drive switch of the drive circuit 200. do. The driving circuit 200 according to an embodiment of the present invention uses a plurality of operation signal lines X1, X2, and X3 in a predetermined sequence using two modes of operating waveforms (ie, a driving waveform of the first mode and a driving waveform of the second mode). , .. Xn). In this case, the driving waveform of the first mode is composed of a positive voltage VDD and a ground voltage, and the driving waveform of the second mode is composed of a negative voltage (-VDD) and a ground voltage.

The sensing circuit 300 is electrically connected to the plurality of sensing signal lines Y1, Y2, Y3, ... Ym, and measures the capacitance Cij of the node capacitor 112 corresponding to the sensing signal line to which a driving waveform is applied. do. At this time, the capacitance (Cij) measurement of each node capacitor 112 is implemented by the operation of the sensing switch of the sensing circuit (300).

The timing controller 400 outputs the driving switch control signal Sx and the sensing switch control signal Sy to the driving circuit 200 and the sensing circuit 300, respectively, so that the driving switch and the sensing circuit of the driving circuit 200 ( The on / off operation of the sensing switch of 300 is controlled.

Next, the driving circuit 200 and the sensing circuit 300 according to the exemplary embodiment of the present invention will be described in more detail with reference to FIG. 2.

In FIG. 2, only the driving circuit 200 and the sensing circuit 300 connected to the i-th operation signal line Xi and the j-th detection signal line Yj are shown for convenience, but in practice, n operation signal lines and m detection signal lines are illustrated. The driving circuit 200 and the sensing circuit 300 are electrically connected to each other.

The driving circuit 200 includes a positive power supply voltage VDD, a negative power supply voltage (-VDD), and first to third driving switches S1, S2, and S3, and is an end of the node capacitor 112. The driving waveform of the first mode and the driving waveform of the second mode are output to the signal line Xi in a predetermined sequence.

In FIG. 2, the first driving switch S1 is electrically connected between the positive power supply voltage VDD and the operation signal line Xi which is one end of the node capacitor 112, and the second driving switch S2 is connected to the ground and the node. The third driving switch S3 is electrically connected between one end of the capacitor 112 and the third driving switch S3 is electrically connected between the negative power supply voltage -VDD and one end of the node capacitor 112.

According to the exemplary embodiment of the present invention, the positive power voltage VDD and the ground voltage may be changed according to the on / off operation of the first driving switch S1, the second driving switch S2, and the third driving switch S3. The driving waveform of the first mode composed of the combination or the driving waveform of the second mode composed of the combination of the negative power supply voltage -VDD and the ground voltage is output to the operation signal line Xi.

The sensing circuit 300 includes first and second sensing switches S4 and S5, a reference capacitor 310, a reset switch S6, an analog-to-digital converter 330 (hereinafter referred to as 'ADC'), and a digital signal processor 340. , Hereinafter referred to as 'DSP'.

The first sensing switch S4 is electrically connected between the sensing signal line Yj, which is the other end of the node capacitor 112, and the ground.

The amplifier 320 is a differential amplifier. The inverting terminal is electrically connected to the sensing signal line Yj, which is the other end of the node capacitor, and the non-inverting terminal is grounded. Hereinafter, a typical operational amplifier (OP AMP) will be described as an example of the amplifier 320. However, the present invention is not limited thereto, and other differential amplifiers may be used.

The reference capacitor 310 is electrically connected between the inverting terminal and the output terminal of the operational amplifier 320. That is, the reference capacitor 310 serves to negative feedback the output of the operational amplifier 320 to the input of the operational amplifier 320.

The second sensing switch S5 is electrically connected between the other end of the node capacitor 112 and the reference capacitor 310 (that is, the inverting terminal of the operational amplifier 320), and the voltage charged in the node capacitor 112 is It serves to switch what is delivered to the reference capacitor.

The reset switch S6 is electrically connected between both ends of the reference capacitor 310, and serves to switch the initialization (reset) of the voltage charged in the reference capacitor 310.

The ADC 330 converts the voltage charged in the reference capacitor 310 into a corresponding digital value. At this time, according to an embodiment of the present invention, when the voltage charged in the reference capacitor 310 is a positive voltage, it is converted to a positive digital value, and when the voltage charged in the reference capacitor 310 is a negative voltage Convert to a negative digital value.

The DSP 340 senses a capacitance change amount of the node capacitor 112 based on the accumulated digital value output from the ADC 330.

According to the exemplary embodiment of the present invention, a voltage corresponding to the capacitance Cij of the node capacitor is charged at both ends of the reference capacitor 310 in response to the charge / discharge operation of the node capacitor 112 as described below.

Next, a method of driving a touch screen device according to an embodiment of the present invention will be described with reference to FIGS. 3 to 10.

In the method for driving a touch screen device according to an embodiment of the present invention, the first operation mode or the second operation mode is repeatedly driven a predetermined number of times. As shown in FIGS. 6 and 10, the first operation mode and the second operation mode include a node capacitor charging step, a transfer to a reference capacitor, a reference capacitor reading step, and a reset step of the reference capacitor. 6 and 10, "charge" and "discharge" refer to charging and discharging operations of a node capacitor, respectively, and "delivery" refers to an operation of charging (delivering) unit charging voltage to a reference capacitor.

The first operation mode refers to a mode in which a driving waveform consisting of a positive voltage VDD and a ground voltage is applied to the node capacitor 112, and the second operation mode is a driving waveform consisting of a negative voltage (-VDD) and a ground voltage. Refers to a mode in which the node capacitor 112 is applied.

First, the operation of the first operation mode will be described with reference to FIGS. 3 to 6.

According to the first operation mode, the third operation switch S3 maintains the off state, and the node capacitor 112 is charged or discharged according to the on / off operation of the other switches S1, S2, S4, and S5.

(1) charging stage of node capacitor

First, the charging operation of the node capacitor 112 will be described. The first driving switch S1 and the first sensing switch S4 are turned on, and the second driving switch S2 and the second sensing switch S5 are turned off. . In this case, as shown in FIG. 6, both ends Vx of the node capacitor 112 are charged to the positive power supply voltage VDD.

(2) Transfer to reference capacitor (node capacitor discharge step)

After both ends Vx of the node capacitor 112 are charged to the positive power supply voltage VDD, the discharge operation of the node capacitor 112 is performed. As shown in FIG. 4, the first driving switch S1 and The first sensing switch S4 is turned off and the second driving switch S2 and the second sensing switch S5 are turned on. In this case, both ends Vx of the node capacitor 112 are discharged to the ground potential, and the unit charge voltage Vd is charged (transmitted) at both ends Vy of the reference capacitor 310.

At this time, the unit charge voltage (Vd) is determined by the following equation.

Where Vd is the unit charge voltage, Cij is the capacitance of the node capacitor, Ct is the capacitance of the reference capacitor, and VDD is the supply voltage.

As can be seen from Equation 1, since the magnitude of the unit charging voltage Vd charged across the reference capacitor 310 is proportional to the capacitance of the node capacitor, the amount of change in the capacitance of the node capacitor through the amount of change in the magnitude of the unit charging voltage ( That is, the contact with the sensing node) can be detected.

According to the exemplary embodiment of the present invention, after the charging step of the node capacitor 112 is performed in the first operation mode, the step of transferring to the reference capacitor is performed. Alternatively, the charging step of the node capacitor 112 and the transfer to the reference capacitor are performed. It is also possible to allow step operations to be performed simultaneously.

(3) reference capacitor reading step

After the transfer to the reference capacitor 310, the ADC 330 converts the voltage charged (delivered) to the reference capacitor 310 into a corresponding positive digital value X [n].

Then, the DSP 340 accumulates the digital accumulated up to the current operation mode based on the accumulated digital value up to the previous operation mode and the digital value X [n] converted from the current operation mode as shown in Equation 2 below. Calculate the value Y [n]. At this time, in the embodiment of the present invention, "accumulated digital values" does not mean simply adding up digital values, but adding up the magnitudes (ie, absolute values of digital values) of digital values converted in each operation mode. it means.

Here, Y [n] means the digital value accumulated up to the current operation mode, Y [n-1] means the digital value accumulated up to the previous operation mode, and X [n] is the reference capacitance of the current operation mode. A digital value corresponding to the voltage charged in the.

In this case, according to the first operation mode, the ADC 330 converts the positive digital value (that is, since the voltage charged in the reference capacitor 310 is the positive voltage), and thus the digital value Y accumulated up to the previous operation mode (Y [n-1]) is added to the digital value X [n] converted in the current operation mode to obtain the digital value Y [n] accumulated up to the current operation mode.

(4) Resetting the Reference Capacitor

After reading the reference capacitor, as shown in FIG. 5, the reset switch S6 is turned on to initialize (reset) the voltage charged in the reference capacitor 310.

Next, the operation of the second operation mode will be described with reference to FIGS. 7 to 10.

According to the second operation mode, the first operation switch S1 maintains the off state, and the node capacitor 112 is charged or discharged according to the on / off operation of the other switches S2, S3, S4, and S5.

(5) charging stage of node capacitor

First, the charging operation of the node capacitor 112 will be described. The third driving switch S3 and the first sensing switch S4 are turned on, and the second driving switch S2 and the second sensing switch S5 are turned off. . In this case, as shown in FIG. 10, both ends Vx of the node capacitor 112 are charged to the negative power supply voltage VDD.

(6) Transfer to reference capacitor (node capacitor discharge step)

After both ends (Vx) of the node capacitor 112 is charged to a negative power supply voltage (-VDD), the discharge operation of the node capacitor 112 is performed. As shown in FIG. 8, the third driving switch S3 is performed. And the first sensing switch S4 is turned off and the second driving switch S2 and the second sensing switch S5 are turned on. In this case, both ends Vx of the node capacitor 112 are discharged to the ground potential, and a negative unit charge voltage (-Vd) is charged (transmitted) at both ends Vy of the reference capacitor 310.

According to the exemplary embodiment of the present invention, after the charging step of the node capacitor 112 is performed in the second operation mode, the step of transferring to the reference capacitor is performed. Alternatively, the charging step of the node capacitor 112 and the transfer to the reference capacitor are performed. It is also possible to allow step operations to be performed simultaneously.

(7) reference capacitor reading step

After the transfer to the reference capacitor 310, the ADC 330 converts the voltage charged (delivered) to the reference capacitor 310 into a corresponding negative digital value X [n].

Then, the DSP 340 accumulates the digital value accumulated up to the current operation mode based on the digital value accumulated up to the previous operation mode and the digital value X [n] converted from the current operation mode as shown in Equation 3 below. Calculate (Y [n]).

At this time, according to the second operation mode, unlike the first operation mode, since the ADC 330 converts to a negative digital value (that is, since the voltage charged in the reference capacitor 310 is a negative voltage), the previous operation mode The digital value Y [n-1] accumulated in the current operation mode is subtracted from the accumulated digital value Y [n-1] to obtain the digital value Y [n] accumulated up to the current operation mode.

Since the digital value Y [n] accumulated up to the current operation mode includes information on the capacitance value of the node capacitor 112, according to an embodiment of the present invention, the first operation mode or the second operation mode may be used for a predetermined number of times. For example, 16) it is finally determined whether the sensing node is in contact with each other based on the digital value Y [n] accumulated by repeated driving.

(8) Reset Reference Capacitor

After reading the reference capacitor, the reset switch S6 is turned on to initialize (reset) the voltage charged in the reference capacitor 310.

Since the driving circuit and the sensing circuit according to the embodiment of the present invention use a switched capacitor, the driving circuit and the sensing circuit basically have characteristics of a finite impulse response (FIR) filter. That is, when the touch screen device is driven in the first operation mode or the second operation mode in one circuit, the touch screen device operates as an FIR filter having N taps after N drivings. In this case, the driving circuit and the sensing circuit according to the embodiment of the present invention may operate as a filter having various filtering characteristics according to a predetermined combination or driving frequency N of the first operation mode or the second operation mode.

That is, in the exemplary embodiment of the present invention, the node capacitor 112 is charged with the positive power supply voltage (+ VDD), and then the first operation mode for transmitting the corresponding positive voltage (+ Vd) to the reference capacitor 310 ( Bit value 1) and a second operation mode (bit value -1) that charges the node capacitor 112 with a negative power supply voltage (-VDD) and transfers a corresponding negative voltage (-Vd) to the reference capacitor. By combining the in a predetermined sequence to drive the touch screen device, it is possible to suppress malfunction due to noise from the outside.

11 and 14 illustrate bit sequence noise filtering characteristics according to an embodiment of the present invention. .

FIG. 11 is a diagram illustrating noise filtering characteristics when operating only in the first operation mode (bit value 1). FIG. As shown in FIG. 11, when the touch screen device is driven only in the first operation mode in the embodiment of the present invention, it can be seen that the low pass filter (LPF) plays a role.

FIG. 12 is a diagram illustrating noise filtering characteristics when the first operation mode (bit value 1) and the second operation mode (bit value -1) are operated alternately. FIG. 12 shows a high pass filter when driving in this manner. It can be seen that it performs the role of filter (HPF).

13 and 14 are diagrams illustrating noise filtering characteristics when the first operation mode (bit value 1) and the second operation mode (bit value -1) are operated with a barker sequence and a random code, respectively. . 13 and 14, it can be seen that the frequency filtering characteristic is improved over the entire frequency band.

Therefore, according to an embodiment of the present invention, by properly driving the first operation mode and the second operation mode in a predetermined combination, it is possible to prevent the touch screen device from malfunctioning due to noise generated by an external device such as a display device. .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications, and variations will readily occur to those skilled in the art without departing from the spirit and scope of the invention. Therefore, it should be understood that the disclosed embodiments are to be considered in an illustrative rather than a restrictive sense, and that the true scope of the invention is indicated by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof, .

100: touch panel 200: driving circuit
300: detection circuit 400: timing controller
112: node capacitor 310: reference capacitor
320: operational amplifier S1, S2, S3: drive switch
S4, S5: Detection switch S6: Reset switch

Claims (18)

A driving apparatus for driving a touch panel comprising a plurality of operation signal lines, a plurality of sensing signal lines insulated from the plurality of operating signal lines, and a plurality of node capacitors respectively formed by corresponding operation signal lines and sensing signal lines. ,
A driving waveform of a first mode or a second negative terminal capacitor configured to charge the node capacitor with a positive first voltage to at least one operation signal line of the plurality of operation signal lines; A driving circuit for applying a combination of driving waveforms of the second mode for charging with a voltage in a predetermined sequence; And
And a sensing circuit electrically connected to the plurality of sensing signal lines and measuring capacitance of the node capacitor. The method of claim 1,
And the first voltage and the second voltage have the same magnitude. The method of claim 1,
The driving circuit
A first driving switch electrically connected between one end of the node capacitor and the first voltage;
A second drive switch electrically connected between one end of the node capacitor and a ground voltage, and
And a third driving switch electrically connected between one end of the node capacitor and the second voltage. The method of claim 3,
The sensing circuit
A reference capacitor electrically connected to the other end of the node capacitor to receive and charge a unit charge voltage corresponding to the voltage charged in the node capacitor; And
A first sensing switch electrically connected between the other end of the node capacitor and the reference capacitor and switching the transfer of the unit charge voltage to the reference capacitor;
A reset switch electrically connected to the reference capacitor and initializing the unit charge voltage charged in the reference capacitor;
An analog-digital converter for converting the unit charge voltage charged in the reference capacitor into a digital value; And
And a digital signal processor configured to sense a capacitance change amount of the node capacitor based on a cumulative digital value which is a value obtained by accumulating a digital value output from the analog to digital converter. The method of claim 4, wherein
The sensing circuit
A second sensing switch electrically connected between the other end of the node capacitor and a ground voltage; And
And a differential amplifier having one end and a ground of the reference capacitor connected to a first input terminal and a second input terminal, respectively, and the other end of the reference capacitor connected to an output terminal. The method according to claim 4 or 5,
The first to third driving switches selectively operate in a first operation mode corresponding to the driving waveform of the first mode or a second operation mode corresponding to the driving waveform of the second mode. Drive system. The method of claim 6,
And a combination of the first operation mode or the second operation mode operates in a first sequence which does not alternately operate. The method of claim 7, wherein
The digital signal processor
In the first operation mode, the cumulative digital value up to the current operation mode is obtained by adding the digital value of the current operation mode output from the analog-to-digital converter to the cumulative digital value up to the previous operation mode,
In the second operation mode, a cumulative digital value up to the current operation mode is obtained by subtracting the digital value of the current operation mode output from the analog-to-digital converter to the cumulative digital value up to the previous operation mode. Drive system. The method of claim 8,
And the first sequence is a Barker sequence. A method of driving a touch panel comprising a plurality of operation signal lines, a plurality of detection signal lines insulated from the plurality of operation signal lines, and a plurality of node capacitors respectively formed by corresponding operation signal lines and the detection signal lines.
The on / off operation of a plurality of driving switches electrically connected to the operation signal line or the detection signal line may be performed in a first operation mode for charging a positive first voltage to the node capacitor or a negative second voltage to the node capacitor. And selectively driving to a second operation mode for charging, wherein the first operation mode and the second operation mode are arranged in a first sequence which is not alternately driven. The method of claim 10,
The driving method of the first operation mode is
Charging the node capacitor to the first voltage;
Charging a unit charge voltage corresponding to the magnitude of the capacitance of the node capacitor to a reference capacitor electrically connected to the node capacitor;
Converting the unit charge voltage charged in the reference capacitor into a first digital value;
Calculating the cumulative digital value up to the current operation mode by adding the converted first digital value to the cumulative digital value up to a previous operation mode; And
And initializing the unit charge voltage charged in the reference capacitor. The method of claim 10,
The driving method of the second operation mode is
Charging the node capacitor to the second voltage;
Charging a unit charge voltage corresponding to the magnitude of the capacitance of the node capacitor to a reference capacitor electrically connected to the node capacitor;
Converting the unit charge voltage charged in the reference capacitor into a first digital value;
And subtracting the converted first digital value to a previous operation mode to obtain a cumulative digital value up to a current operation mode. The method according to claim 11 or 12, wherein
And detecting a capacitance change amount of the node capacitor based on the cumulative digital value up to the current operation mode. A touch panel including a plurality of operation signal lines, a plurality of sensing signal lines insulated from the plurality of operating signal lines, and a plurality of node capacitors respectively formed by corresponding operation signal lines and sensing signal lines;
A driving waveform of a first mode or a second negative terminal capacitor configured to charge the node capacitor with a positive first voltage to at least one operation signal line of the plurality of operation signal lines; A driving circuit for applying a combination of driving waveforms of the second mode for charging with a voltage in a predetermined sequence; And
And a sensing circuit electrically connected to the plurality of sensing signal lines and measuring capacitance of the node capacitor. The method of claim 14,
The driving circuit
A first driving switch electrically connected between one end of the node capacitor and the first voltage;
A second drive switch electrically connected between one end of the node capacitor and a ground voltage, and
And a third driving switch electrically connected between one end of the node capacitor and the second voltage. 16. The method of claim 15,
The sensing circuit
A reference capacitor electrically connected to the other end of the node capacitor to receive and charge a unit charge voltage corresponding to the voltage charged in the node capacitor; And
A first sensing switch electrically connected between the other end of the node capacitor and the reference capacitor and switching the transfer of the unit charge voltage to the reference capacitor;
A reset switch electrically connected to the reference capacitor and initializing the unit charge voltage charged in the reference capacitor;
An analog-digital converter for converting the unit charge voltage charged in the reference capacitor into a digital value; And
And a digital signal processor configured to sense a capacitance change amount of the node capacitor based on a cumulative digital value which is a value obtained by accumulating a digital value output from the analog to digital converter. The method according to claim 15 or 16,
Wherein the first to third driving switches selectively operate in a first operation mode corresponding to the driving waveform of the first mode or in a second operation mode corresponding to the driving waveform of the second mode. . The method of claim 17,
The digital signal processor
In the first operation mode, the cumulative digital value up to the current operation mode is obtained by adding the digital value of the current operation mode output from the analog-to-digital converter to the cumulative digital value up to the previous operation mode,
In the case of the second operation mode, the cumulative digital value up to the previous operation mode is subtracted from the digital value of the current operation mode output from the analog-to-digital converter to obtain the cumulative digital value up to the current operation mode. .

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