KR102514046B1 - Touch screen controller, touch sensing device, and touch sensing method - Google Patents

Abstract

A touch screen controller according to the present disclosure is connected to a touch screen panel including a first channel and a second channel crossing the first channel through a sensing node and configured to remove an offset capacitance of the touch screen panel. A charge amplifier including an amplifier having a first input terminal connected to the node and a second input terminal to which an input voltage is applied and generating a sensing voltage from a sensing signal output from a touch screen panel, and a self-capacitance sensing mode for a first channel includes a channel driver providing a driving voltage equal to or greater than the input voltage to the second channel.

Description

Touch screen controller, touch sensing device, and touch sensing method

The technical idea of the present disclosure relates to a touch sensing device, and more particularly, to a touch screen controller, a touch sensing device including the touch screen controller, and a touch sensing method.

A touch sensing device is a type of input device that allows a user to transmit a user's input using an object such as a hand or a touch pen in response to content displayed on a screen of a display device or the like. The touch sensing device may be provided on the front surface of the display device and may convert a touch position of a user's hand or an object such as a touch pen on the front surface into an electrical signal. Electronic devices such as mobile phones, laptop computers, desktop computers, PDAs, etc., in which a display device is installed, can recognize the touched position based on the converted electrical signal, and interpret the touched position to perform an operation according to the user's input. can be done As a method of sensing a touch by a touch sensing device, a resistive method, an optical sensing method, a capacitive method, and the like are known. In particular, the capacitive type may convert a touch position into an electrical signal based on capacitance formed between an object such as a user's hand or a touch pen and a conductive electrode of a touch sensing device.

An object to be solved by the technical spirit of the present disclosure is to provide a touch screen controller, a touch sensing device, and a touch sensing method capable of improving touch sensitivity and reducing a chip size.

A touch screen controller according to the technical idea of the present disclosure is connected to a touch screen panel including a first channel and a second channel crossing the first channel through a sensing node to remove an offset capacitance of the touch screen panel. A charge amplifier including an offset cancellation circuit, an amplifier having a first input terminal connected to the sensing node and a second input terminal to which an input voltage is applied, and generating a sensing voltage from a sensing signal output from the touch screen panel. amplifier), and a channel driver providing a driving voltage equal to or greater than the input voltage to the second channel in a self capacitance sensing mode for the first channel.

In addition, a touch sensing device according to another technical idea of the present disclosure includes a touch screen panel including a first channel for sensing a touch input and a second channel crossing the first channel, and a control for the first channel. and a touch screen controller configured to provide a driving voltage to the second channel in a self capacitance sensing mode and detect a change in capacitance of the first channel by the touch input.

In addition, a touch sensing method according to another technical idea of the present disclosure is a touch sensing method for a touch screen panel including a first channel and a second channel crossing the first channel, wherein the self capacitance for the first channel In a sensing mode, setting a voltage of a sensing node connected to the first channel as an input voltage, and applying a driving voltage equal to or greater than the input voltage to the second channel in the self capacitance sensing mode for the first channel. , and generating a sensing voltage from a sensing signal of the sensing node according to a change in capacitance of the first channel due to a touch input.

According to the technical idea of the present disclosure, a dynamic range of a sensing signal may be increased by removing an offset capacitance of a touch screen panel. In addition, the size of an offset elimination circuit for removing offset capacitance of the touch screen panel can be reduced, and accordingly, the touch sensing device can be miniaturized by reducing the size of a chip in which a touch screen controller including the offset elimination circuit is implemented. can Furthermore, touch sensitivity may be improved due to an increase in a sensing signal output in the self capacitance sensing mode.

1 is a block diagram schematically illustrating a touch sensing device according to an exemplary embodiment of the present disclosure.
2 is a block diagram illustrating a touch sensing device according to an embodiment of the present disclosure in more detail.
3A is a diagram for explaining a change in capacitance due to a touch input in a mutual capacitance sensing mode.
3B is a graph showing an ideal amount of change in capacitance due to a touch input in a mutual capacitance sensing mode.
4A is a diagram for explaining a capacitance change due to a touch input in a self capacitance sensing mode.
4B is a graph showing an ideal change in capacitance due to a touch input in a self capacitance sensing mode.
5 is a graph showing an actual amount of change in capacitance according to an offset mutual capacitance in a self capacitance sensing mode.
6A and 6B illustrate driving methods of a touch screen panel in a self capacitance sensing mode according to an embodiment of the present disclosure.
7 is a circuit diagram specifically illustrating a sensing signal receiver according to an embodiment of the present disclosure.
8A is a graph illustrating an example of an input voltage applied to the charge amplifier of FIG. 7 .
FIG. 8B is a graph showing an example of an offset cancellation voltage applied to the offset cancellation circuit of FIG. 7 .
8C is a graph showing an example of a driving voltage applied to the touch screen panel of FIG. 7 .
9A to 9C are graphs illustrating various examples of driving voltages according to an embodiment of the present disclosure.
10 is a graph showing a change amount of capacitance in a self capacitance sensing mode according to an embodiment of the present disclosure.
11 is a block diagram illustrating an example of a sensing signal receiver according to an embodiment of the present disclosure.
12 is a flowchart illustrating a touch sensing method according to an embodiment of the present disclosure.
13 is a flowchart illustrating a touch sensing method according to an embodiment of the present disclosure.
14 is a diagram illustrating a touch panel and a display panel included in a touch sensing device according to an embodiment of the present disclosure.
15 is a block diagram illustrating a touch screen system according to an exemplary embodiment of the present disclosure.
16 is a diagram illustrating a touch screen module including a touch sensing device according to an embodiment of the present disclosure.
17A and 17B are diagrams illustrating the structure of a touch screen module when a touch panel and a display panel are integrated according to an embodiment of the present disclosure.
18 is a diagram illustrating application examples of various electronic products in which a touch sensing device according to an embodiment of the present disclosure is mounted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Since the present invention can have various changes and various forms, specific embodiments are illustrated in the drawings and described in detail. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numbers are used for like elements. In the accompanying drawings, the dimensions of the structures are shown enlarged or reduced than actual for clarity of the present invention.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Also, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms may be used for the purpose of distinguishing one component from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of the present invention.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this application, it should not be interpreted in an ideal or excessively formal meaning. don't

1 is a schematic block diagram of a touch sensing device 10 according to an embodiment of the present disclosure.

Referring to FIG. 1 , the touch sensing device 10 includes a touch screen controller 100 and a touch screen panel 200 . The touch sensing device 10 may be an electronic device having an image display function, and specifically, may mean a PC or a mobile device, but is not limited thereto. Mobile devices include laptop computers, mobile phones, smart phones, tablet PCs, personal digital assistants (PDAs), enterprise digital assistants (EDAs), digital still cameras, digital A digital video camera, a portable multimedia player (PMP), a personal navigation device or portable navigation device (PND), a handheld game console, a mobile internet device (MID), a wearable computer, It may be implemented as an internet of things (IoT) device, an internet of everything (IoE) device, a drone, or an e-book, but is not limited thereto.

The touch screen panel 200 may generate a sensing signal corresponding to the touch input in response to a touch input, and may provide the generated sensing signal to the touch screen controller 100 . In this case, the touch input includes not only a direct contact of a conductive object such as a finger on the touch screen panel 200 but also a proximity of the conductive object to the touch screen panel 200 . Hereinafter, an object through which a user can apply a touch input to the touch screen panel 200 will be defined as an “object”. For example, the object may be a conductive object such as a finger, palm, touch pen, or stylus pen, but is not limited thereto.

The touch screen panel 200 may include row channels R1 to Rn arranged in a first direction and column channels C1 to Cm arranged in a second direction crossing the first direction. For example, the first direction may be substantially perpendicular to the second direction. Each of the row channels R1 to Rn and the column channels C1 to Cm may include a plurality of sensing units (SU) electrically connected to each other. In one embodiment, the plurality of row channels R1 to Rn and the plurality of column channels C1 to Cm may be formed on different layers. In one embodiment, the plurality of row channels R1 to Rn and the plurality of column channels C1 to Cm may be formed on the same layer.

In this embodiment, the plurality of sensing units SU may be capacitive touch sensors, and thus, the touch screen panel 200 may be referred to as a capacitive touch screen panel. The touch screen panel 200 may generate a sensing signal using a mutual capacitance sensing method, that is, a mutual capacitance sensing method or a self capacitance sensing method, that is, a self capacitance sensing method. there is. The mutual capacitance sensing method and the self capacitance sensing method will be described in detail with reference to FIGS. 3A to 4B hereinafter.

The touch screen controller 100 can detect whether or not a touch input has occurred on the touch screen panel 200 and a location where the touch input is applied. In this embodiment, the touch screen controller 100 may sense a touch input using a self capacitance sensing method. However, the present disclosure is not limited thereto, and in some embodiments, the touch screen controller 100 may sense a touch input using a self capacitance sensing method and a mutual capacitance sensing method. In one embodiment, the touch screen controller 100 may sense a touch input by alternately applying a self capacitance sensing method and a mutual capacitance sensing method.

Specifically, in the self capacitance sensing mode, the touch screen controller 100 applies an input voltage for driving to the first channel, receives a sensing signal from the first channel, and whether or not there is a touch input based on the received sensing signal. And the position of the touch input can be detected. In this case, the input signal may be implemented as a voltage signal that swings based on a specific voltage, such as a square wave. In this specification, the first channel may mean a channel to be subjected to self capacitance sensing.

Also, the touch screen controller 100 may provide a driving signal to a second channel crossing the first channel in the self capacitance sensing mode. In this case, the driving signal may be implemented as a voltage signal that swings based on a specific voltage, such as a square wave. In this specification, the second channel may refer to a channel that is not a self capacitance sensing target.

In an embodiment, the first channel may be one of the plurality of row channels R1 to Rn, and the second channel may be one of the plurality of column channels C1 to Cm. Also, in one embodiment, the first channel may be one of the plurality of column channels C1 to Cm, and the second channel may be one of the plurality of row channels R1 to Rn.

Also, the touch screen controller 100 may remove offset capacitance from the sensing signal received from the touch screen panel 200 . Accordingly, the dynamic range of the sensing signal may be increased. Here, the offset capacitance may refer to a parasitic capacitance component generated by one or more sensing units SU. Even when a touch input is not applied to the touch screen panel 200, a sensing signal may be output by the offset capacitance.

2 is a block diagram illustrating a touch sensing device 10a according to an exemplary embodiment in more detail.

Referring to FIG. 2 , the touch sensing device 10a includes a touch screen controller 100a and a touch screen panel 200 . The touch sensing device 10a may correspond to one embodiment of the touch sensing device 10 of FIG. 1 , and the touch screen panel 200 may correspond to the touch screen panel 200 of FIG. 1 . Therefore, the above description with reference to FIG. 1 can be applied to the present embodiment, and redundant description will be omitted. Hereinafter, the touch screen controller 100a will be mainly described.

The touch screen controller 100a may include a channel driver 110 , a sensing signal receiver 120 , a controller 130 and a processor 140 . In this embodiment, the touch screen controller 100a may sense a touch input using a self capacitance sensing method. Specifically, the touch screen controller 100a may detect a touch input by sensing a sensing signal Ssen corresponding to a change in capacitance of the first channel caused by the touch input. Here, the first channel may be a channel that is sensed in the self capacitance sensing mode. For example, the first channel may be one of the row channels R1 to Rn, but the present invention is not limited thereto, and the first channel may be one of the column channels C1 to Cm.

The channel driver 110 may provide a driving signal Sdrv to a second channel crossing the first channel. Here, the second channel may be a channel that is not sensed in the self capacitance sensing mode. When the first channel is one of the row channels R1 to Rn, the second channel may be one of the column channels C1 to Cm. Meanwhile, when the first channel is one of the column channels C1 to Cm, the second channel may be one of the row channels R1 to Rn. The number of driving signals Sdrv may be determined according to the number of second channels formed in the touch screen panel 200 . In one embodiment, a plurality of driving signals Sdrv may be sequentially applied to corresponding second channels.

The sensing signal receiver 120 may receive the sensing signal Ssen from the first channel. In this embodiment, when using the self capacitance sensing method, the sensing signal receiver 120 may apply an input signal to the first channel and also receive the sensing signal Ssen from the first channel. In other words, in the self capacitance sensing mode, the sensing signal receiver 120 may serve as both a driving unit and a receiving unit. Meanwhile, in the case of using the mutual capacitance sensing method, the sensing signal receiver 120 may only receive the sensing signal Ssen from the first channel without applying an input signal to the first channel. In other words, in the mutual capacitance sensing mode, the sensing signal receiver 120 can only serve as a receiver.

In this embodiment, the sensing sensing signal receiver 120 may include an offset cancellation circuit 121 and a charge amplifier 122 . The offset removal circuit 121 may remove offset capacitance from the sensing signal Ssen. The charge amplifier 122 may generate a sensing voltage from the sensing signal Ssen. A detailed operation of the sensing signal receiver 120 will be described later with reference to FIG. 7 .

The controller 130 may control the channel driver 110 and the sensing signal receiver 120 . Specifically, the controller 130 may determine the frequency or amplitude of the drive signal Sdrv and provide a control signal according to the determined frequency or amplitude to the channel driver 110 . In addition, the controller 130 may determine the frequency or amplitude of the voltages applied to the offset cancellation circuit 121 and the charge amplifier 122, and provide a control signal according to the determined frequency or amplitude to the sensing signal receiver 120. can

The processor 140 may calculate touch coordinates based on touch data received from the sensing signal receiver 120 and provide the calculated touch coordinates to the host HOST. At this time, the processor 140 may calculate the touch coordinates by applying various algorithms. In one embodiment, the processor 140 may calculate touch coordinates according to a single touch input. In one embodiment, the processor 140 may calculate touch coordinates according to multi-touch input.

3A is a diagram for explaining a change in capacitance due to a touch input in a mutual capacitance sensing mode.

Referring to FIG. 3A, the mutual capacitance sensing method applies a constant voltage pulse to a drive electrode, and collects charges corresponding to the voltage pulse at a receive electrode (or referred to as a sensing electrode). charge). At this time, when the object OBJ is placed between the driving electrode and the receiving electrode, the electric field indicated by the dotted line changes, and the change in strength of the electric field causes a change in capacitance.

As such, the capacitance is changed through a change in the electric field between the driving electrode and the receiving electrode, and through this, a touch input can be sensed. Although FIG. 3A shows a case of a contact touch, a change in the electric field may be caused similarly in the case of a proximity touch. In addition, although FIG. 3A shows a case where the object OBJ is a finger, a change in electric field may be caused similarly in the case of a touch by another conductor such as a touch pen.

Referring to FIGS. 1 and 3A together, in an embodiment, row channels R1 to Rn of FIG. 1 may be driving channels, and column channels C1 to Cm may be sensing channels. The driving channel may include a plurality of driving electrodes electrically connected to each other, and the sensing channel may include a plurality of sensing electrodes electrically connected to each other. In this case, the driving electrode and the sensing electrode may be referred to as a sensing unit. A capacitor may be formed between the driving electrode and the sensing electrode, and the capacitance of the capacitor may be changed in response to a touch input. In this case, the capacitance of the capacitor formed between the driving electrode and the sensing electrode may be referred to as mutual capacitance.

3B is a graph showing an ideal amount of change in capacitance due to a touch input in a mutual capacitance sensing mode.

Referring to FIG. 3B , the X-axis represents time, and the Y-axis represents capacitance. Each sensing unit (eg, SU in FIG. 1 ) basically has an offset mutual capacitance (Cm) corresponding to a parasitic component, and the capacitance of each sensing unit may change due to the proximity or contact of the object OBJ. there is. Specifically, section A is a state in which the object OBJ is not in contact, and at this time, the capacitance of the sensing unit may correspond to the offset mutual capacitance Cm. For example, the offset mutual capacitance (Cm) may be several picofarads (pF).

Meanwhile, section B is a state in which the object OBJ is in contact with the sensing unit, and at this time, the signal capacitance of the sensing unit is a value reduced by the amount of change in mutual capacitance (ΔCm) by the object (OBJ) from the offset mutual capacitance (Cm) (i.e., Cm-ΔCm). For example, the signal capacitance in section B may be several tens of femtofarads (fF).

4A is a diagram for explaining a capacitance change due to a touch input in a self capacitance sensing mode.

Referring to FIG. 4A , in the self capacitance sensing method, a constant voltage pulse is applied to an electrode, and a voltage or charge corresponding to the voltage pulse is collected from the electrode. The electrodes form capacitors with surrounding conductors (such as ground nodes). In this case, when the object OBJ contacts or approaches the electrode, the capacitance of the capacitor may increase. In this way, a change in capacitance is sensed through the electrode, and a touch can be sensed through this.

Referring to FIGS. 1 and 4A together, in an embodiment, each of the row channels R1 to Rn and the column channels C1 to Cm may be a driving channel and a sensing channel. Each of the electrodes included in the row channels R1 to Rn and the column channels C1 to Cm forms a capacitor (eg, a floating capacitor) with respect to a nearby conductive object, and the capacitance of the capacitor in response to a touch input is It can change. In this case, capacitance of a capacitor formed between electrodes included in the row channels R1 to Rn and column channels C1 to Cm and a nearby conductive object may be referred to as self capacitance.

4B is a graph showing an ideal change in capacitance due to a touch input in a self capacitance sensing mode.

Referring to FIG. 4B , the X axis represents time, and the Y axis represents capacitance. Each sensing unit (eg, SU in FIG. 1 ) basically has an offset self capacitance (Cs) corresponding to a parasitic component, and the capacitance of each sensing unit may change due to the proximity or contact of the object OBJ. . Specifically, section A is a state in which the object OBJ is not in contact, and at this time, the capacitance of the sensing unit may correspond to the offset self capacitance Cs. For example, the offset self capacitance (Cs) may be several tens of picofarads (pF). The offset self capacitance (Cs) may be greater than the offset mutual capacitance (Cm).

Meanwhile, section B is a state in which the object OBJ is in contact with the sensing unit, and at this time, the signal capacitance of the sensing unit corresponds to a value increased by the amount of change in self capacitance ΔCs by the object OBJ in the offset self capacitance Cs. (i.e., Cs+ΔCs). For example, the signal capacitance in section B may be several tens of femtofarads (fF). In the self-capacitance sensing method, the offset self-capacitance (Cs) may have a considerably larger value than the signal capacitance. Accordingly, since the signal capacitance may not be properly sensed unless the offset capacitance is removed, the offset capacitance may greatly affect the sensitivity of the capacitive touch screen.

5 is a graph showing an actual amount of change in capacitance according to an offset mutual capacitance in a self capacitance sensing mode.

Referring to FIG. 5 , the X axis represents time, and the Y axis represents capacitance. In a self capacitance sensing mode for detecting a change in self capacitance of the first channel, a ground voltage may be applied to a second channel crossing the first channel. The capacitance in section A in which the object OBJ does not contact the electrode may correspond to the sum of the offset self capacitance Cs and the offset mutual capacitance Cm (ie, Cs+Cm). Compared to the graph of FIG. 4B , the capacitance in section A is greater than the offset mutual capacitance (Cm) between the second channel and the first channel connected to the ground voltage.

On the other hand, the amount of change in capacitance in section B where the object OBJ contacts the electrode corresponds to the difference between the amount of change in self capacitance (ΔCs) and the amount of change in mutual capacitance (ΔCm) (ie, ΔCs-ΔCm). Compared to the graph of FIG. 4B , the change in capacitance in section B is smaller by the amount of change in mutual capacitance (ΔCm), and thus, the touch sensitivity is lowered due to the decrease in the sensing signal.

6A and 6B show driving methods of the touch screen panel 200 in a self capacitance sensing mode according to an embodiment of the present disclosure.

Referring to FIG. 6A , in the self capacitance sensing mode for the column channels C1 to Cm, the sensing signal receiver 120 may be connected to the column channels C1 to Cm. The sensing signal receiver 120 may include a plurality of receivers RX respectively connected to the column channels C1 to Cm. Specifically, the receivers RX connected to the first column C1 , the second column C2 , and the m-th column Cm respectively receive the first sensing signal X[1], the second sensing signal X[ 2]) and the m th sensing signal X[m] may be respectively received.

In the self capacitance sensing mode for the column channels C1 to Cm, the driving signal Sdrv may be applied to the row channels R1 to Rn. Specifically, the first drive signal Y[1], the second drive signal Y[2], and the n-th drive signal are applied to the first row R1, the second row R2, and the n-th row Rn. (Y[n]) may be applied respectively. In an embodiment, the driving signal Sdrv may be provided as a driving voltage implemented in the form of a square wave.

Referring to FIG. 6B , in the self capacitance sensing mode for the low channels R1 to Rn, the sensing signal receiver 120 may be connected to the low channels R1 to Rn. The sensing signal receiver 120 may include a plurality of receivers RX respectively connected to the row channels R1 to Rn. Specifically, the receivers RX connected to the first row R1 , the second row R2 , and the n-th row Rm respectively receive the first sensing signal Y[1] and the second sensing signal Y[ 2]) and the nth sensing signal Y[n] may be respectively received.

In the self capacitance sensing mode for the row channels R1 to Rn, the driving signal Sdrv may be applied to the column channels C1 to Cm. Specifically, the first driving signal X[1], the second driving signal X[2], and the mth driving signal are included in the first column C1, the second column C2, and the mth column Cm. (X[m]) may be applied respectively. In an embodiment, the driving signal Sdrv may be provided as a driving voltage implemented in the form of a square wave.

7 is a circuit diagram specifically illustrating the sensing signal receiver 120a according to an embodiment of the present disclosure.

Referring to FIG. 7 , the sensing signal receiver 120a may include an offset cancellation circuit 121a and a charge amplifier 122a. The sensing signal receiver 120a may receive the sensing signal Ssen from the touch screen panel 200 through the sensing node SN. In this case, the sensing signal Ssen may be a signal received through the sensing node SN in the self capacitance sensing mode for the first channel. The sensing signal receiving unit 120a shown in FIG. 7 may correspond to an example of the receiver RX included in the sensing signal receiving unit 120 of FIG. 6B .

The charge amplifier 122a may be connected to the sensing node SN to generate the sensing voltage Vout from the sensing signal Ssen. In one embodiment, the charge amplifier 122a may convert a sensing signal Ssen, which is a current signal output from the touch screen panel 200, into a sensing voltage Vout, which is a voltage signal. Accordingly, the charge amplifier 122a may also be referred to as a Q-V converter or a capacitance-voltage converter.

In this embodiment, the charge amplifier 122a may include an amplifier AMP and a feedback capacitor Cf. The amplifier AMP has a first input terminal connected to the sensing node SN (hereinafter referred to as 'inverting input terminal') and a second input terminal receiving the input voltage Vin (hereinafter referred to as 'non-inverting input terminal'). , and an output terminal for outputting the sensing voltage Vout. In one embodiment, the input voltage Vin applied to the non-inverting input terminal of the amplifier AMP may be implemented in the form of a square wave. For example, the input voltage Vin may be implemented as shown in FIG. 8A. The feedback capacitor Cf may be connected between the inverting input terminal and the output terminal of the amplifier AMP.

In some embodiments, the charge amplifier 122a may further include a switch connected in parallel with the feedback capacitor Cf, and the switch may be turned on/off by a controller (eg, 130 in FIG. 2 ). . At this time, the switch may discharge the feedback capacitor (Cf). Also, in some embodiments, the charge amplifier 122a may further include a resistor connected in parallel with the feedback capacitor Cf.

The offset removal circuit 121a may be connected to the sensing node SN to remove offset capacitance of the touch screen panel 200 . In this embodiment, the offset cancellation circuit 121a may include an offset cancellation capacitor 1211, and the offset cancellation capacitor 1211 has a first terminal connected to the sensing node SN and a second terminal to which an offset cancellation voltage is applied. can have terminals. In this embodiment, the offset cancellation voltage may be higher than the input voltage Vin applied to the non-inverting input terminal of the amplifier AMP. In one embodiment, the offset cancellation voltage may correspond to twice the input voltage (Vin) (ie, 2Vin), and hereinafter, the case where the offset cancellation voltage is 2Vin will be described in detail. For example, the offset cancellation voltage may be implemented as shown in FIG. 8B.

According to the virtual short principle of the amplifier AMP, the voltage level of the inverting input terminal of the amplifier AMP is substantially equal to the voltage level of the non-inverting input terminal. Accordingly, the voltage level of the non-inverting input terminal of the amplifier AMP corresponds to the input voltage Vin, and thus, the voltage level of the sensing node SN may correspond to the input voltage Vin.

In this embodiment, in the self capacitance sensing mode for the first channel, a driving voltage may be applied to a second channel that is not sensed, and the driving voltage may be greater than or equal to the input voltage Vin. In one embodiment, the driving voltage may correspond to k times the input voltage Vin (ie, k*Vin), and k may be an integer greater than 1. For example, the driving voltage may be implemented as shown in FIG. 8C. For example, k may be 1, and the driving voltage may be equal to the input voltage Vin. For another example, k may be 2, and the driving voltage may be twice the input voltage (2Vin).

FIG. 8A is a graph illustrating an example of an input voltage Vin applied to the charge amplifier 122a of FIG. 7 . Referring to FIG. 8A , the X-axis represents time, and the Y-axis represents voltage level. The input voltage Vin may be provided in the form of a square wave having an amplitude of V.

FIG. 8B is a graph showing an example of an offset cancellation voltage applied to the offset cancellation circuit 121a of FIG. 7 . Referring to FIG. 8B , the X-axis represents time, and the Y-axis represents voltage level. The offset cancellation voltage may be provided in the form of a square wave having an amplitude of 2V, and the offset cancellation voltage may correspond to twice the input voltage Vin (ie, 2Vin).

FIG. 8C is a graph showing an example of a driving voltage applied to the touch screen panel 200 of FIG. 7 . Referring to FIG. 8C , the X-axis represents time and the Y-axis represents voltage level. The driving voltage may be provided in the form of a square wave having an amplitude of k*V, and the driving voltage may correspond to k times the input voltage Vin (ie, k*Vin). In this case, k may be an integer greater than or equal to 1.

9A to 9C are graphs illustrating various examples of driving voltages according to an embodiment of the present disclosure.

Referring to FIG. 9A , the driving voltage may be implemented as a ramp voltage. Referring to FIG. 9B , the driving voltage may be implemented as a triangular wave. Referring to FIG. 9C , the driving voltage may be implemented as a sine wave. As such, the driving voltage may be implemented in various forms. In one embodiment, the shape of the driving voltage may be implemented in a form similar to that of the input voltage Vin applied to the charge amplifier 122a of FIG. 7 , and the driving voltage may be greater than or equal to the input voltage Vin.

10 is a graph showing a change amount of capacitance in a self capacitance sensing mode according to an embodiment of the present disclosure.

Referring to FIG. 10 , the X-axis represents time, and the Y-axis represents capacitance. Cs represents the offset self capacitance of the offset self capacitor 211, and Cm represents the offset mutual capacitance of the offset mutual capacitor 212. ΔCs represents the amount of change in self capacitance by touch input, and ΔCm represents the amount of change in mutual capacitance by touch input. As described above with reference to FIGS. 3A and 3B, the touch input reduces the mutual capacitance by ΔCm, and as described above with reference to FIGS. 4A and 4B, the touch input increases the self capacitance by ΔCs. do.

Hereinafter, a specific operation of the sensing signal receiver 120a according to a touch input will be described in detail with reference to FIGS. 7 and 10 . First, an operation of the sensing signal receiver 120a in section A where a touch input is not applied will be described, and then an operation of the sensing signal receiver 120a in section B where a touch input is applied will be described.

In section A where there is no touch input, there is no change in self capacitance (ΔCs) and no change in mutual capacitance (ΔCm) (ie, ΔCs=ΔCm=0). At this time, since the voltage of the sensing node SN is the input voltage Vin, the voltage across the offset self capacitor 211 is Vin, and the voltage across the offset mutual capacitor 212 is (Vin-k*Vin), The voltage across the offset cancellation capacitor 1211 is -Vin. Therefore, the amount of charge Qs charged in the offset self capacitor 211 corresponds to Cs*Vin (ie, Qs=Cs*Vin), and the amount of charge Qm charged in the offset mutual capacitor 212 corresponds to Cm*( Vin-k*Vin), and the amount of charge Qoff charged in the offset cancellation capacitor 1211 may correspond to Coff*(-Vin). Here, Coff represents the offset capacitance of the offset cancellation capacitor 1211.

Since the sum of the charge amount Qs charged in the offset self capacitor 211, the charge amount Qm charged in the offset mutual capacitor 212, and the charge amount Qoff charged in the offset cancellation capacitor 2122 is 0 ( That is, Qs+Qm+Qoff=0), the offset cancellation capacitance Coff of the offset cancellation capacitor 1211 can be expressed as in Equation 1 below.

[Equation 1]

Coff=Cs-(k-1)*Cm

In this embodiment, since k is greater than or equal to 1, the offset cancellation capacitance Coff may be a value lower than the offset self capacitance Cs by (k−1)*Cm. Therefore, since the offset capacitance of the touch screen panel 200 is reduced compared to the offset capacitance of FIG. 5 (ie, Cs+Cm), the size of the offset cancellation capacitor 1211 may be reduced compared to the prior art.

As such, according to the present embodiment, the offset mutual capacitance (Cm) can remove a part of the offset self capacitance (Cs). That is, since both the offset mutual capacitance (Cm) and the offset cancellation capacitance (Coff) serve to remove the offset self capacitance (Cs), the offset cancellation capacitance (Coff) is reduced compared to the prior art. Accordingly, the size of the offset elimination circuit 121a may be reduced, and the size of a chip in which the touch screen controller (eg, 100a of FIG. 2 ) including the offset elimination circuit 121a may be implemented. Accordingly, the touch sensing device may be miniaturized.

Meanwhile, in section B where a touch input is applied, the self capacitance increases by the change amount (ΔCs) in the offset self capacitance (Cs), and the mutual capacitance decreases by the change amount (ΔCm) in the offset mutual capacitance (Cm). At this time, since the driving voltage (k*Vin) is applied to the second channel, the capacitance variation (ΔC) of the first channel may correspond to ΔCs+(k−1)*ΔCm. Accordingly, the sensing signal Ssen may be a current signal corresponding to ΔCs+(k−1)*ΔCm.

According to this embodiment, the amount of change in capacitance ΔC of the first channel in section B where a touch input is applied is greater than the amount of change in capacitance shown in FIG. 5 . At this time, since the amount of change in mutual capacitance (ΔCm) serves to increase the capacitance of the first channel, the capacitance of the first channel increases compared to the prior art upon touch input, and thus the sensitivity of the sensing signal Ssen is improved. It can be.

11 is a block diagram illustrating an example 120b of a sensing signal receiving unit according to an embodiment of the present disclosure.

Referring to FIG. 11 , the sensing signal receiver 120b may include an offset cancellation circuit 121, a charge amplifier 122, an integrator 123, and an analog to digital converter (ADC) 124. The sensing signal receiving unit 120b according to the present embodiment is a modified embodiment of the sensing signal receiving unit 120 of FIG. 2, and further includes an integrator 123 and an ADC 124 compared to the sensing signal receiving unit 120 of FIG. can include For the offset cancellation circuit 121 and the charge amplifier 122, the above description with reference to FIGS. 2 and 7 may be applied, and integrator 123 and ADC 124 will be mainly described below.

The integrator 123 may integrate (or accumulate) the sensing voltage Vout output from the charge amplifier 122 . For example, the integrator 123 may perform an integration operation at least twice or more under the control of the controller 130 of FIG. 2 . The ADC 124 may generate a digital output signal OUT by performing an analog-to-digital conversion operation on the output of the integrator 123 . The digital output signal OUT may be provided to the processor 140 of FIG. 2 , and the processor 140 may calculate touch coordinates based on the digital output signal OUT.

12 is a flowchart illustrating a touch sensing method according to an embodiment of the present disclosure.

Referring to FIG. 12 , the touch sensing method according to the present embodiment is an operation of detecting the presence or absence of a touch input and the location of a touch input to a touch screen panel according to a self capacitance sensing method. The touch sensing method according to this embodiment may include steps performed time-sequentially by the touch screen controller 100a of FIG. 2 . Details described above with reference to FIGS. 1 to 11 may also be applied to the present embodiment, and redundant descriptions will be omitted.

In step S110, the voltage of the sensing node connected to the first channel is set as an input voltage. Here, the first channel is a channel to be sensed in the self capacitance sensing mode, and may be, for example, one of the low channels R1 to Rn of FIG. 1 . Taking the sensing signal receiver 120a of FIG. 7 as an example, by applying the input voltage Vin to the non-inverting input terminal of the amplifier AMP, the inverting input terminal may correspond to the input voltage Vin, and thus, the inverting input terminal may correspond to the input voltage Vin. A voltage of the sensing node SN connected to the terminal may be set to the input voltage Vin. For example, the input voltage Vin may be implemented as a square wave.

In step S130, a driving voltage equal to or higher than the input voltage is applied to the second channel. Here, the second channel is a channel that is not a sensing target in the self capacitance sensing mode, and may be a channel crossing the first channel. For example, the second channel may be one of the column channels C1 to Cm of FIG. 1 . The channel driver 110 may apply a driving voltage corresponding to k times the input voltage Vin to the second channel, where k may be an integer greater than or equal to 1. In some embodiments, steps S110 and S130 may be performed substantially concurrently. Also, in some embodiments, step S110 may be performed after step S130.

In step S150, a sensing voltage is generated from a sensing signal according to a change in capacitance of the first channel due to a touch input. For example, the sensing signal Ssen may increase according to the self capacitance variation ΔCs of the first channel. For example, the sensing signal Ssen may be a current signal according to the self capacitance variation ΔCs of the first channel, and the feedback capacitor Cf may be charged by the sensing signal Ssen, and thus, the sensing voltage (Vout).

13 is a flowchart illustrating a touch sensing method according to an embodiment of the present disclosure.

Referring to FIG. 13 , the touch sensing method according to the present embodiment is an operation of detecting the presence or absence of a touch input and the location of a touch input to a touch screen panel according to a self capacitance sensing method. The touch sensing method according to this embodiment is a modified embodiment of the touch sensing method of FIG. 12 and may further include step S120 compared to the touch sensing method of FIG. 12 . Therefore, the above description with reference to FIG. 12 can also be applied to the present embodiment, and redundant description will be omitted.

In step S110, the voltage of the sensing node connected to the first channel is set as an input voltage. In step S120, an offset cancellation voltage higher than the input voltage is applied to the offset cancellation capacitor. For example, the offset cancellation voltage may correspond to twice the input voltage. In some embodiments, steps S110 and S120 may be performed substantially concurrently. Also, in some embodiments, step S110 may be performed after step S120.

In step S130, a driving voltage equal to or higher than the input voltage is applied to the second channel. In some embodiments, steps S110 through S130 may be performed substantially concurrently. Also, in some embodiments, step S110 may be performed after step S130. Also, in some embodiments, step S120 may be performed after step S130. In step S150, a sensing voltage is generated from a sensing signal according to a change in self capacitance of the first channel due to a touch input.

14 is a diagram illustrating a touch panel TP and a display panel DP provided in a touch sensing device TSD according to an embodiment of the present disclosure.

Referring to FIG. 14 , the touch sensing device TSD may include a touch panel TP and a display panel DP. The touch sensing device 100 of FIG. 1 and the touch sensing device 100a of FIG. 2 according to embodiments of the present disclosure may be implemented as the touch sensing device TSD illustrated in FIG. 14 .

The display panel DP may be implemented as a liquid crystal display (LCD), a light emitting diode (LED) display, an organic LED (OLED) display, an active-matrix OLED (AMOLED) display, and a flexible display. It can be implemented with other types of flat panel displays.

For process or price competitiveness, the touch panel TP may be integrated with the display panel DP. 14 illustrates an example in which the touch panel TP is positioned above the display panel DP. However, it is not limited thereto, and the touch panel TP may be positioned below the display panel DP. The touch panel TP may be disposed at a predetermined distance from the display panel DP, or may be disposed attached to the upper plate of the display panel DP.

14 illustrates a case in which the display panel DP is an on-cell type provided as a separate panel or layer from the touch panel TP, but is not limited thereto. In some embodiments, a display pixel used for display and a sensing unit (SU) used for touch sensing may be implemented as an in-cell type formed on the same layer.

15 is a block diagram illustrating a touch screen system 1000 according to an embodiment of the present disclosure.

Referring to FIG. 15 , the touch screen system 1000 includes a touch panel 1110, a display panel 1210, a touch controller 1120, a display driving circuit 1220, a processor 1300, a storage device 1400, an interface 1500 and bus 1600.

The touch panel 1110 is configured to detect touch events occurring at each point. The display panel 1210 may be composed of various types of panels such as LCD, LED, and OLED configured to display an image (video). The touch panel 1110 and the display panel 1210 may be integrally formed to overlap each other.

The touch controller 1120 may control the operation of the touch panel 1110 and transmit an output of the touch panel 1110 to the processor 1300 . The touch controller 1120 may be a touch screen controller ( 100 in FIG. 1 or 100a in FIG. 2 ) according to the above-described embodiment of the present disclosure. In detail, the touch controller 1120 may receive a sensing signal from the first channel in the self capacitance sensing mode, and detect the presence or absence of a touch input and the location of the touch input based on the received sensing signal. Also, the touch controller 1120 may provide a driving signal to a second channel crossing the first channel in the self capacitance sensing mode. Furthermore, the touch controller 1120 may remove offset capacitance from the sensing signal received from the touch panel 11100 .

The display driving circuit 1220 controls the display panel 1210 to display an image on the display panel 1210 . Although not shown, the display driving circuit 1220 may include a source driver, a grayscale voltage generator, a gate driver, a timing controller, a power supply unit, and an in-image interface. Image data to be displayed on the display panel 1210 may be stored in the memory through an image interface and converted into an analog signal using grayscale voltages generated by the grayscale voltage generator. The source driver and the gate driver may drive the display panel 1210 in response to a vertical synchronization signal and a horizontal synchronization signal provided from a timing controller.

The processor 1300 may execute commands and control the overall operation of the touch screen system 1000 . Program coordination or data required by the processor 1300 may be stored in the storage device 1400 . Interface 1500 can communicate with any external device and/or system.

The processor 1300 may include a coordinate mapping unit 1310 . A position on the touch panel 1110 and a position on the display panel 1210 may be mapped to each other, and the coordinate mapping unit 1310 may map the display panel 1210 corresponding to a touch point on the touch panel 1110 where a touch input occurs. ) can extract the corresponding coordinates. Through coordinate mapping between the touch panel 1110 and the touch panel 1210, the user selects and controls an icon, menu item, or image displayed on the display panel 1210, such as a touch operation, dragging, pinching, or stretching. , input actions such as single or multi-touch operations can be performed.

According to some embodiments, the touch screen system 1000 may be a smart home appliance having an image display function. Smart appliances include, for example, televisions, digital video disk (DVD) players, audio systems, refrigerators, air conditioners, vacuum cleaners, ovens, microwave ovens, washing machines, air purifiers, set-top boxes, TV boxes (eg For example, it may include at least one of Samsung HomeSyncTM, Apple TVTM, or Google TVTM), game consoles, electronic dictionaries, electronic keys, camcorders, or electronic picture frames.

According to some embodiments, the touch screen system 1000 may be used for various medical devices (e.g., magnetic resonance angiography (MRA), magnetic resonance imaging (MRI), computed tomography (CT), camera, sonicator, etc.), navigation Devices, global positioning system receivers (GPS), event data recorders (EDRs), flight data recorders (FDRs), automotive infotainment devices, marine electronics (e.g., marine navigation systems and gyrocompasses), avionics (avionics), a security device, a vehicle head unit, an industrial or household robot, an automatic teller's machine (ATM) of a financial institution, or a point of sales (POS) of a store.

According to some embodiments, the touch screen system 1000 is a piece of furniture or building / structure including an image display function, an electronic board, an electronic signature receiving device, a projector ( projector), or at least one of various measuring devices (eg, water, electricity, gas, radio wave measuring devices, etc.). An electronic device including a touch screen system according to various embodiments of the present disclosure may be one or a combination of the various devices described above. Also, the touch screen system may be a flexible device. It is apparent to those skilled in the art that the touch screen system according to various embodiments of the present disclosure is not limited to the above devices.

16 is a diagram illustrating a touch screen module 2000 including a touch sensing device according to an embodiment of the present disclosure.

Referring to FIG. 16 , a touch screen module 2000 may include a window glass 2010, a touch panel 2020, and a display panel 2040. In addition, a polarizer 2030 may be disposed between the touch panel 2020 and the display panel 2040 for optical characteristics.

The window glass 2010 is made of a material such as acrylic or tempered glass, and protects the touch screen module 2000 from external impact or scratches caused by repetitive touches. The touch panel 2020 may be formed by patterning a transparent electrode such as indium tin oxide (ITO) on a glass substrate or a polyethylene terephthlate (PET) film. The touch controller 2021 may be mounted on a flexible printed circuit board (FPCB) in the form of a chip on board (COB), detect a touch occurrence on the touch panel 3400, extract touch coordinates, and provide them to the host controller. there is.

The display panel 2040 is generally formed by bonding two sheets of glass consisting of an upper plate and a lower plate. The display panel 2040 includes a plurality of pixels for displaying a frame. According to one embodiment, the display panel 2040 may be a liquid crystal panel. However, it is not limited thereto, and the display panel 2040 may include various types of display elements. For example, the display panel 2040 may include an Organic Light Emitting Diode (OLED), an Electrochromic Display (ECD), a Digital Mirror Device (DMD), an Actuated Mirror Device (AMD), a Grating Light Value (GLV), a Plasma Display Panel (PDP), It may be one of an Electro Luminescent Display (ELD), a Light Emitting Diode (LED) display, and a Vacuum Fluorescent Display (VFD).

As illustrated, the display driving circuit 2041 may be mounted on a printed circuit board made of a glass material in a COG (Chip On Glass) form. However, this is only an example, and the display driving circuit 2041 may be mounted in various forms such as a chip on film (COF) or a chip on board (COB). In this embodiment, the display driving integrated circuit 3130 is illustrated as a single chip, but this is merely for convenience of illustration and may be mounted as a plurality of chips. Also, the touch controller 2021 and the display driving circuit 2041 may be integrated into one semiconductor chip.

17A and 17B are diagrams illustrating the structure of a touch screen module when a touch panel and a display panel are integrated according to an embodiment of the present disclosure.

17A and 17B are views illustrating the structure of a touch screen module when a touch panel and a display panel are integrated. As shown in FIG. 17A , the touch screen module 2000a may include a window glass 2010, a display panel 2020, and a polarizer 2030. In particular, in implementing the touch panel, the touch panel may not be formed on a separate glass substrate, but may be formed by patterning a transparent electrode on the upper plate of the display panel 2020 . 17A illustrates an example in which a plurality of sensing units SU are formed on the top plate of the display panel 2020. In addition, when the panel structure is formed in this way, the touch controller and the display driving circuit may be integrated into one semiconductor chip 2022 .

When the touch controller and the display driving circuit are integrated in one semiconductor chip 2022, the voltage signal T_sig from the sensing unit SU and the image data I_data from an external host are provided to the semiconductor chip 2022. . In addition, the semiconductor chip 2022 processes the image data I_data to generate grayscale data for driving an actual display device and provides the grayscale data to the display panel 2020 . To this end, the semiconductor chip 2022 may include a pad related to the touch data T_data and a pad related to the image data I_data and grayscale data (not shown). The semiconductor chip 2022 receives the touch data voltage signal T_sig from the sensing unit SU through a conductive line connected to one side of the touch panel. In arranging the pads on the semiconductor chip 2022, placing the pad receiving the touch data voltage signal T_sig adjacent to the conductive line for transmitting the voltage signal T_sig results in data noise. This may be desirable in terms of reduction.

Although not shown in FIG. 17A , when a conductive line for providing grayscale data to the display panel is located on the opposite side of a conductive line for transmitting the touch data voltage signal T_sig, a pad for providing the grayscale data also has the voltage It can be placed on the opposite side of the pad receiving the signal T_sig.

Meanwhile, the touch screen module 2000b of FIG. 17B has a structure substantially similar to that of the touch screen module 2000a of FIG. 17A, and a voltage signal from the sensing unit SU is provided to the semiconductor chip 2022 through the FPCB. Rather, it shows an example of being directly provided to the semiconductor chip 2022 through a conductive line.

18 is a diagram illustrating application examples of various electronic products in which the touch sensing device 3000 according to an embodiment of the present disclosure is mounted.

Referring to FIG. 18 , a touch sensing device 3000 according to embodiments of the present disclosure may be employed in various electronic products. A TV (3100), an ATM (3200) that automatically handles bank cash withdrawals, an elevator (3300), a smart watch (3400), and a tablet PC (3500) ), PMP (3600), e-book (3700) and navigation (3800) can be widely used.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims.

10: touch sensing device, 100, 100a: touch screen controller
200: touch screen panel, 110: channel driver, 120: sensing signal receiver
130: controller, 140: processor
121: offset cancellation circuit, 122: charge amplifier

Claims (20)

an offset cancellation circuit connected to a touch screen panel including a first channel and a second channel crossing the first channel through a sensing node and configured to remove an offset capacitance of the touch screen panel;
an amplifier having a first input terminal connected to the sensing node and a second input terminal to which a first driving voltage is applied in a self capacitance sensing mode for the first channel; sensing from a sensing signal output from the touch screen panel; a charge amplifier that generates a voltage; and
a channel driver configured to provide a second driving voltage higher than the first driving voltage to the second channel in the self capacitance sensing mode for the first channel;
The first driving voltage is provided to the first channel to generate the sensing signal, characterized in that the touch screen controller. According to claim 1,
The touch screen controller of claim 1 , wherein the offset cancellation circuit includes an offset cancellation capacitor having a capacitance less than an offset self capacitance of the first channel. According to claim 2,
The touch screen controller of claim 1 , wherein the offset cancellation capacitor has a first terminal connected to the sensing node and a second terminal to which an offset cancellation voltage higher than the first driving voltage is applied. According to claim 3,
The touch screen controller of claim 1 , wherein the offset cancellation voltage corresponds to twice the first driving voltage. According to claim 4,
The channel driver provides the second driving voltage corresponding to k times the first driving voltage to the second channel in the self capacitance sensing mode for the first channel, where k is an integer greater than 1 Features a touch screen controller. According to claim 5,
The capacitance of the offset cancellation capacitor corresponds to Cs-(k-1)*Cm,
Cs is the offset self capacitance of the first channel, and Cm is an offset mutual capacitance between the first channel and the second channel. According to claim 5,
The sensing signal corresponds to ΔCs + (k-1) * ΔCm,
ΔCs is the amount of change in self capacitance of the first channel, and ΔCm is the amount of change in mutual capacitance between the first channel and the second channel. According to claim 2,
The offset mutual capacitance between the first channel and the second channel eliminates a portion of the offset self capacitance. According to claim 1,
The touch screen controller of claim 1 , wherein the sensing signal is increased by an amount of change in mutual capacitance between the first channel and the second channel. According to claim 1,
The amplifier further includes an output terminal outputting the sensing voltage,
The touch screen controller of claim 1 , wherein the charge amplifier further comprises a feedback capacitor connected between the first input terminal and the output terminal. According to claim 1,
The touch screen controller, characterized in that the second driving voltage has a square wave form. a touch screen panel including a first channel for sensing a touch input and a second channel crossing the first channel; and
In the self capacitance sensing mode for the first channel, a first driving voltage is provided to the first channel, and in the self capacitance sensing mode for the first channel, a voltage higher than the first driving voltage is applied to the second channel. A touch screen controller providing a second driving voltage and detecting a change in capacitance of the first channel by the touch input;
The touch screen controller includes a charge amplifier generating a sensing voltage from a sensing signal output from the touch screen panel;
The charge amplifier includes an amplifier having a first input terminal connected to a sensing node between the touch screen panel and the touch screen controller and a second input terminal to which the first driving voltage is applied in the self capacitance sensing mode;
The first driving voltage is a touch sensing device, characterized in that provided to the first channel to generate the sensing signal. According to claim 12,
The touch screen controller includes an offset cancellation circuit configured to remove an offset capacitance of the touch screen panel;
The touch sensing device of claim 1 , wherein the offset cancellation circuit includes an offset cancellation capacitor having a capacitance less than an offset self capacitance (Cs) of the first channel. delete According to claim 12,
The offset cancellation capacitor has a first terminal connected to the sensing node and a second terminal to which an offset cancellation voltage higher than the first driving voltage is applied. According to claim 12,
The amplifier further includes an output terminal outputting the sensing voltage,
The charge amplifier may further include a feedback capacitor connected between the first input terminal and the output terminal. According to claim 12,
The touch screen controller may further include a channel driver configured to provide the second driving voltage higher than the first driving voltage to the second channel. According to claim 17,
The channel driver provides the second driving voltage corresponding to k times the first driving voltage to the second channel, k is an integer greater than 1;
The touch sensing device of claim 1 , wherein the offset cancellation capacitor has a first terminal connected to the sensing node and a second terminal to which a voltage corresponding to twice the first driving voltage is applied. A first channel, a second channel crossing the first channel, an offset self capacitor having an offset self capacitance when the first driving voltage is applied to the first channel, and the first driving voltage being applied to the first channel a touch screen panel including an offset mutual capacitance having an offset mutual capacitance when the touch screen panel senses a touch input or a proximity input; and
a touch screen controller that senses a change in capacitance of the first channel due to the touch input or proximity input and generates a sensing voltage from a sensing signal output from the touch screen panel;
The touch screen controller includes an offset cancellation capacitor connected to the offset self capacitor and the offset mutual capacitor of the touch screen panel;
The offset mutual capacitor and the offset cancellation capacitor remove at least a portion of the offset self capacitance. The method of claim 19, wherein the touch screen controller,
an amplifier generating the sensing voltage from the sensing signal output from the touch screen panel and having a first input terminal connected to the offset cancellation capacitor and a second input terminal to which the first driving voltage is applied; ; and
and a channel driver configured to provide a second driving voltage higher than the first driving voltage to the second channel.

Images