KR20210068657A - Touch sensing device controlling bias current - Google Patents

Abstract

One embodiment of the present invention relates to a touch sensing device for controlling a bias current. By controlling a bias current of a driver according to the distance between the touch sensing device and a touch electrode on a channel, unnecessary power consumption due to the bias current can be reduced. The touch sensing device includes: a driver for outputting a driving voltage to the touch electrode using the bias current to sense proximity or touch of an external object; a sensing unit receiving a response signal corresponding to the driving voltage and generating a sensing voltage; and a bias control unit for supplying the bias current to a driving unit.

Description

A touch sensing device that controls the bias current {TOUCH SENSING DEVICE CONTROLLING BIAS CURRENT}

The present embodiment relates to a touch sensing device for controlling a bias current and a display device including the same.

A technology for recognizing an external object that approaches or touches a touch panel is called a touch sensing technology. The touch panel is placed on the same position as the display panel on a plane. Accordingly, users can input a user operation signal to the touch panel while viewing an image of the display panel. This user manipulation signal generating method provides surprising user intuition compared to the previous other user manipulation signal input methods - for example, a mouse input method or a keyboard input method.

According to these advantages, touch sensing technology is applied to various electronic devices including display panels. The touch sensing device may sense a touch or proximity of an external object with respect to the touch panel by supplying a driving signal to a touch electrode disposed on the touch panel and receiving a reaction signal formed on the sensing electrode.

Meanwhile, the touch sensing device may include a plurality of circuits for each functional unit, and the plurality of circuits may include a plurality of amplifiers for sensing. These amplifiers serve to supply a drive signal or receive a response signal. The amplifier operates by the bias current. In particular, the supply of the driving signal of the amplifier and the modulation of the response signal may vary depending on the strength of the bias current.

Although the intensity of the bias current may affect the characteristics and operation of the amplifier, the bias current is generally not controlled and all touch electrodes of the touch panel have been operated by receiving the bias current of the same intensity uniformly. Such an operation method of the amplifier may increase power consumption due to the bias current.

For example, while the touch sensing device senses the driving electrodes, the touch sensing device may drive all the touch electrodes using a bias current of the same strength. The intensity is set based on the farthest touch electrode, and the bias current of the set intensity may be used for all touch electrodes of one channel. However, even if the touch electrode located close to the touch sensing device does not use the bias current of the strength set for the farthest touch electrode as it is, the sensing voltage is effectively generated and the sensing of the touch electrode can be effectively completed. Nevertheless, if the bias current of the intensity set based on the farthest touch electrode is uniformly applied to all touch electrodes, power consumption of the touch sensing device may increase.

In addition, as the display device is actively applied to mobile or portable electronic devices, the battery performance of the electronic device may occupy an important part in the overall device performance. In particular, it is important that the battery consumes less. For this, not only an increase in battery capacity itself but also a reduction in power consumption may be required. A reduction in power consumption due to the bias current may contribute to a reduction in power consumption of the entire display device.

In this regard, the present embodiment intends to provide a technique for improving current consumption and power consumption in the touch sensing device by dynamically adjusting the bias current for the amplifier of the touch sensing device.

Against this background, an object of the present embodiment is to provide a technique for differentiating the bias current strength of the driving unit (internal amplifier) of the touch sensing device according to the position of the touch electrode on one channel or the distance between the touch sensing device and the touch electrode will do

Another object of the present embodiment is to provide a technique for adjusting the bias current of the driving unit (internal amplifier) of the touch sensing device so that sensing voltages for each touch electrode on one channel are formed at a time within a preset similar range.

In order to achieve the above object, an embodiment includes a driving unit that outputs a driving voltage to a touch electrode using a bias current to detect proximity or touch of an external object; a sensing unit for receiving a response signal corresponding to the driving voltage and generating a sensing voltage; and a bias control unit supplying a bias current to the driving unit, wherein the bias control unit adjusts the intensity of the bias current according to the position of the touch electrode, and supplies the bias current of the adjusted strength to the driving unit A touch sensing device is provided.

In the touch sensing device, the touch electrode includes a first touch electrode included in one channel and a second touch electrode included in the one channel and positioned farther than the first touch electrode, and the driver includes: The first touch electrode is driven using one bias current, the second touch electrode is driven using the second bias current, and the bias control unit determines the strength of the second bias current as the strength of the first bias current. By adjusting more strongly, it can be supplied to the driving unit.

In the touch sensing device, a time for forming a first sensing voltage for the first touch electrode and a time for forming a second sensing voltage for the second touch electrode may be within a preset similarity range.

In the touch sensing device, the bias control unit may adjust the bias current so that the intensity gradually increases as the position of the touch electrode increases.

In the touch sensing device, the bias control unit may receive a bias control signal including timing data for adjusting the intensity of the bias current.

In the touch sensing device, the bias control unit may receive a bias control signal including timing data for adjusting the intensity of the bias current.

In another embodiment, an M (M is a natural number greater than or equal to 1)-th touch electrode included in one channel is driven using an M-th driving voltage and an M-th bias current, and an M+1th touch electrode having the same magnitude as the M-th driving voltage driving the M+1-th touch electrode included in the one channel using a driving voltage and an M+1-th bias current greater than the M-th bias current, and consuming M-th power generated by the M-th bias current; , a driving unit that is generated by the M+1th bias current and consumes more M+1th power than the Mth power; and a bias control unit for generating the Mth bias current and the M+1th bias current and supplying them to the driving unit.

In the touch sensing device, the M+1 th touch electrode may be located farther than the M th touch electrode on the one channel.

In the touch sensing device, the driver may output the Mth driving voltage using the Mth bias current and output the M+1th driving voltage using the M+1th bias current; or , in which the Mth driving voltage and the M+1th driving voltage are output using a bias current of the same strength.

Another embodiment provides a driving unit that outputs a driving voltage to a plurality of touch electrodes included in one channel by using a bias current to detect proximity or touch of an external object; a generator configured to receive a response signal corresponding to the driving voltage and generate a sensing voltage; and a bias control unit supplying the bias current to the driving unit, wherein the plurality of touch electrodes include a plurality of touch electrodes of a first group and a plurality of touch electrodes of a second group, wherein the bias control unit comprises: Adjusting the intensity of the bias current to a first intensity for the first group, adjusting the intensity of the bias current to a second intensity for the second group, and supplying the bias current having the adjusted intensity to the driver A touch sensing device is provided.

In the touch sensing device, the second group may be located farther than the first group on the one channel, and the bias control unit may adjust the second intensity to be greater than the first intensity.

In the touch sensing device, a time for forming a plurality of sensing voltages for the first group and a time for forming a plurality of sensing voltages for the second group may be within a preset similarity range.

In the touch sensing device, the bias control unit may receive a bias control signal including position data of each touch electrode for adjusting the intensity of the bias current.

In the touch sensing device, the bias control unit may receive a bias control signal including timing data for adjusting the intensity of the bias current.

In another embodiment, an M (M is a natural number greater than or equal to 1)-th touch electrode included in one channel is driven using an M-th driving voltage and an M-th bias current, and an N-th (M)-th touch electrode having the same magnitude as the M-th driving voltage N is a natural number greater than M+1) a driving voltage and an N-th bias current greater than the M-th bias current to drive the N-th touch electrode included in the one channel, and the N-th touch electrode generated by the M-th bias current a driving unit consuming M power, generated by the Nth bias current and consuming more Nth power than the Mth power; and a bias control unit for generating the Mth bias current and the Nth bias current and supplying them to the driving unit.

As described above, according to the present embodiment, power consumption of the entire display device can be reduced by minimizing unnecessary power consumption due to the bias current.

And, according to this embodiment, it is possible to dynamically and adaptively control the bias current according to the position of the touch electrode of the channel or the distance from the touch sensing device.

And, according to the present embodiment, it is possible to more efficiently and simply provide the bias current control of the touch sensing device driver.

1 is a block diagram of a display device according to an exemplary embodiment.
2 is a diagram schematically illustrating a touch sensing system according to an embodiment.
3A is a first exemplary configuration diagram of a touch sensing device according to an embodiment.
3B is a second exemplary configuration diagram of a touch sensing device according to an embodiment.
4 is a diagram illustrating a touch sensing system according to an embodiment.
5 is a diagram showing the intensity of bias currents used in a plurality of touch electrodes included in one channel according to distance.
6 is a diagram illustrating power consumption by bias currents used for a plurality of touch electrodes included in one channel.
7 is a diagram illustrating the intensity of bias currents used in a plurality of touch electrodes included in one channel according to a distance according to an exemplary embodiment.
8 is a diagram illustrating power consumption by bias currents used in a plurality of touch electrodes included in one channel according to an exemplary embodiment.
9 is an exemplary diagram of adjusting a bias current to drive a plurality of touch electrodes according to another exemplary embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same components are given the same reference numerals as much as possible even though they are indicated on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and the essence, order, or order of the components are not limited by the terms. When a component is described as being “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but another component is between each component. It should be understood that elements may be “connected,” “coupled,” or “connected.”

1 is a block diagram of a display device according to an exemplary embodiment.

Referring to FIG. 1 , the display device 100 includes a panel 110 , a data driving device 120 , a gate driving device 130 , and a touch sensing device 140 .

A plurality of data lines DL connected to the data driver 120 may be formed on the panel 110 , and a plurality of gate lines GL connected to the gate driver 130 may be formed on the panel 110 . In addition, a plurality of pixels P corresponding to intersections of the plurality of data lines DL and the plurality of gate lines GL may be defined in the panel 110 .

In each of these pixels P, a first electrode (eg, a source electrode or a drain electrode) is connected to the data line DL, a gate electrode is connected to the gate line GL, and a second electrode (eg, a second electrode) is connected to the gate line GL. , a drain electrode or a source electrode) may be formed with a transistor connected to the display electrode.

In addition, a plurality of touch electrodes TE may be further formed on the panel 110 to be spaced apart from each other. One pixel P may be located or a plurality of pixels P may be located in the region where the touch electrode TE is located.

The panel 110 may include a display panel and a touch screen panel (TSP), where the display panel and the touch panel may share some components with each other. For example, the plurality of touch electrodes TE may be one component of the display panel (eg, a common electrode to which a common voltage is applied) and at the same time may be one component of the touch panel (touch electrodes for sensing a touch). have. Since some components of the display panel and the touch panel are shared with each other, the panel 110 is also called an integrated panel, but the present invention is not limited thereto. In addition, although an in-cell type panel is known as a form in which some components of the display panel and the touch panel are shared with each other, this is only an example of the aforementioned panel 110 and the panel to which the present invention is applied is such an in-cell panel. It is not limited to an (In-Cell) type panel.

The data driving device 120 supplies a data signal to the data line DL to display an image in each pixel P of the panel 110 .

The data driver 120 may include at least one data driver integrated circuit. The at least one data driver integrated circuit may include a Tape Automated Bonding (TAB) method or a Chip on Glass (COG) method. It may be connected to a bonding pad of the panel 110 by a chip on glass method, or may be formed directly on the panel 110 , or may be formed by being integrated in the panel 110 in some cases. In addition, the data driving device 120 may be implemented in a chip on film (COF) method.

The gate driving device 130 sequentially supplies a scan signal to the gate line GL to turn on or off the transistor located in each pixel P.

The gate driving device 130 may be positioned on only one side of the panel 110 as shown in this figure, or divided into two and positioned on both sides of the panel 110 according to a driving method.

In addition, the gate driver 130 may include at least one gate driver integrated circuit, and the at least one gate driver integrated circuit may be formed using a tape automated bonding (TAB) method or a chip-on-glass (COG) method. It may be directly formed on the panel 110 by being connected to the bonding pad of the panel 110 or embodied in a GIP (Gate In Panel) type, or may be formed by being integrated in the panel 110 in some cases. In addition, the gate driving device 130 may be implemented in a chip on film (COF) method.

The touch sensing device 140 applies a driving signal to all or a part of the plurality of touch electrodes TE connected to the sensing line SL.

As shown in this figure, the touch sensing device 140 is a configuration separate from the data driving device 120 and the gate driving device 130 , and is external to the data driving device 120 and the gate driving device 130 . However, depending on the implementation method, it may be implemented as an internal configuration of another separate driver integrated circuit including at least one of the data driving device 120 and the gate driving device 130, or the data driving device ( 120) or the internal configuration of the gate driving device 130 may be implemented.

Accordingly, when the touch sensing device 140 applies the driving signal to all or a part of the plurality of touch electrodes TE, a separate driver integrated circuit including the touch sensing device 140 operates the plurality of touch electrodes TE. It can also be seen that the driving signal is applied in whole or in part. In addition, depending on the design method, the data driving device 120 or the gate driving device 130 including the touch sensing device 140 can be regarded as applying the driving signal to all or part of the plurality of touch electrodes TE. may be

The touch sensing device 140 is not limited to the implementation and design method, and if only the performance function described in this specification is the same or similar, it may be a different configuration itself or a configuration located inside or outside the other configuration. have.

Also, although one touch sensing device 140 is illustrated as being positioned on the display device 100 in this drawing, the display device 100 may include two or more touch sensing devices 140 .

Meanwhile, in order for the touch sensing device 140 to apply the driving signal to all or part of the plurality of touch electrodes TE, sensing lines SL connected to each of the plurality of touch electrodes TE are required. Accordingly, the sensing line SL, which is connected to each of the plurality of touch electrodes TE and transmits a driving signal, is connected to the panel 110 in the first direction (eg, vertical direction) or in the second direction (eg, horizontal direction). can be formed.

Meanwhile, the display device 100 may employ a capacitive touch method for recognizing proximity or touch of an object by sensing a change in capacitance through the touch electrode TE.

Such a capacitive touch method may be divided into, for example, a mutual capacitive touch method and a self-capacitive touch method.

In the mutual capacitive touch method, which is a type of the capacitive touch method, a driving signal is applied to one touch electrode (Tx electrode) and the other touch electrode (Rx electrode) coupled to the Tx electrode is sensed. In this mutual capacitive touch method, the value sensed by the Rx electrode varies according to proximity or touch of an object such as a finger or pen. In the mutual capacitance touch method, the presence or absence of touch and touch coordinates using the sensing value of the Rx electrode detect etc.

In the self-capacitance touch method, which is another type of the capacitive touch method, a driving signal is applied to one touch electrode TE and then the touch electrode TE is sensed again. In this self-capacitive touch method, the value sensed by the corresponding one touch electrode TE varies according to proximity or touch of an object such as a finger or pen. coordinates, etc. In this self-capacitive touch method, since the touch electrode TE for applying the driving signal and the touch electrode TE for sensing are the same, there is no distinction between the Tx electrode and the Rx electrode.

The display device 100 may employ one of the above-described two capacitive touch methods (mutual capacitive touch method and self-capacitive touch method). However, in this specification, for convenience of description, it is assumed that the self-capacitive touch method is employed and the embodiment will be described.

Meanwhile, the display device 100 may drive the touch electrode TE by dividing the display section and the touch section. As an example, the touch sensing device 140 of the display device 100 may not apply the driving signal to all or part of the touch electrode TE during the period in which the data signal is supplied.

Also, the display device 100 may drive the touch electrode TE without distinguishing between the display section and the touch section. As an example, the touch sensing device 140 of the display device 100 may apply a driving signal to all or a part of the touch electrode TE in a section for supplying a data signal.

2 is a diagram schematically illustrating a touch sensing system according to an embodiment.

Referring to FIG. 2 , the touch sensing system 200 may include a panel 110 and a touch sensing device 140 .

A plurality of touch electrodes TE may be disposed on the panel 110 .

The touch sensing device 140 may supply the driving signal STX to the touch electrode TE. The driving signal STX may be a voltage or current type signal, and the voltage type driving signal STX may be defined as a driving voltage. The driving signal may include one driving period including the first period and the second period.

The touch sensing device 140 receives the response signal SRX to the driving signal STX from the touch electrode TE, and demodulates the response signal SRX to touch or close the object 10 to the panel 110 . can be sensed. The response signal RXS may be a signal in the form of current or voltage.

3A is a first exemplary configuration diagram of a touch sensing device according to an embodiment.

Referring to FIG. 3A , in the first example, the panel 110 includes an electrode capacitor (C _{te ) formed by the touch electrode and an object capacitor (Cob} ) formed while an object contacts or approaches the panel 110 . have.

Normally, the electrode capacitor C _te is formed on the panel 110 , but when a touch by an object occurs, an object capacitor C _ob may be added. In this case, the touch sensing device 140 may detect a change in capacitance due to the addition of the _{object capacitor C ob .} If there is a change in capacitance, the touch sensing device 140 may generate data indicating that there was a touch.

Meanwhile, the touch sensing device 140 may include the driving unit 310a-1 and the sensing unit 310a-2 as separate components. The driver 310a - 1 may output a driving voltage to the touch electrode using a bias current BC to detect proximity or touch of an external object. The driving unit 310a - 1 may include an amplifier Amp to output a driving voltage. The sensing unit 310a - 2 may generate a sensing voltage by receiving a response signal corresponding to the driving voltage. Here, the sensing unit 310a-2 may also be referred to as an analog-front-end (AFE).

Also, the touch sensing device 140 may include a sample-and-hold (S&H) unit 320 and an analog-digital-convert unit (ADC) 330 .

When the driving unit 310a-1 outputs the driving voltage Vdrv to the touch electrode, the sensing unit 310a-2 may sense a response signal corresponding to the driving voltage Vdrv. A response signal representing a change in capacitance in response to the driving voltage Vdrv may be generated at the touch electrode of the panel 110 and transmitted to the sensing unit 310a - 2 .

The sensing unit 310a-2 may pre-process an analog signal transmitted to an input terminal, for example, a voltage or a current. The analog signal may include a response signal.

The sensing unit 310a - 2 may include an integrator 301 .

The integrator 301 includes an amplifier (Amp), a capacitor (Ci) connected between one input terminal - for example, a negative input terminal - and an output terminal of the amplifier (Amp), and a reset switch connected in parallel with the capacitor (Ci) (SWr) and the like.

The integrator 301 may generate a sensing signal by modulating an analog signal (eg, a response signal) from the touch electrode of the panel 110 . The integrator 301 may integrate an analog signal for modulation. The sensing signal may be in the form of a voltage, and the sensing voltage Vout may include a value obtained by integrating the response signal by the integrator 301 through the capacitor Ci. The value integrated by the capacitor Ci may be previously reset by the reset switch SWr before the next integration is performed. The integrator 301 may transfer the sensing voltage Vout to the sample and hold unit 320 .

The sample and hold unit 320 may maintain the signal output from the sensing unit 310a - 2 - for example, the sensing voltage Vout - for a predetermined time. The sample and hold unit 320 may output the signal to the analog-to-digital conversion unit 330 after a predetermined time has elapsed.

The analog-to-digital conversion unit 330 may convert the signal output from the sample and hold unit 320 into digital data.

In addition, the touch sensing device 140 may further include a bias control unit 311 .

The bias controller 311 may supply a bias current BC to the driver 310a - 1 included in the touch sensing device 140 .

For example, the driver 310a - 1 of the touch sensing device 140 may include an amplifier Amp. The bias control unit 311 may supply a bias current BC to the driving unit 310a - 1 .

The bias controller 311 may adjust the intensity of the bias current BC. The bias controller 311 may adjust the intensity of the bias current BC according to the position of the touch electrode, and may supply the bias current BC having the adjusted intensity to the driver 310a - 1 . The driver 310a - 1 may drive the corresponding touch electrode using the bias current BC of the adjusted intensity.

For example, the bias control unit 311 generates and supplies a bias current BC having a relatively high intensity for a touch electrode located far from the touch sensing device 140 among a plurality of touch electrodes included in one channel. In addition, a bias current BC having a relatively weak intensity may be generated and supplied to the touch electrode located close to the touch sensing device 140 .

And, in order to drive the touch electrode, the bias control unit 311 is the same as the first mode of providing bias currents BC of different intensities to the driving unit 310a-1 individually or in groups in consideration of the position regardless of the position. It may operate in the second mode in which the bias current BC of the intensity is provided to the driving unit 310a - 1 .

3B is a second exemplary configuration diagram of a touch sensing device according to an embodiment.

Referring to FIG. 3B , in the second example, the touch sensing device 140 may include a sensing circuit 310b in which a driving unit and a sensing unit are combined. The sensing circuit 310b outputs a driving voltage* to the touch electrode using a bias current BC to detect proximity or touch of an external object, receives a response signal corresponding to the driving voltage, and receives the sensing voltage can create Here, the sensing circuit 310b may also be referred to as an analog-front-end (AFE).

And in the second example, the touch sensing device 140 may include a sample-and-hold (S&H: sample-and-hold, 320) and an analog-digital-convert (ADC: analog-digital-convert, 330).

The sensing circuit 310b of the touch sensing device 140 may output the driving voltage Vdrv to the touch electrode. A response signal representing a change in capacitance in response to the driving voltage Vdrv may be generated at the sensor electrode of the panel 110 and transmitted to the sensing circuit 310b.

The sensing circuit 310b may pre-process an analog signal (eg, voltage or current) transmitted to the input terminal. The analog signal may include a response signal.

The sensing circuit 310b may include an integrator 301 .

The integrator 301 includes an amplifier (Amp), a capacitor (Ci) connected between one input terminal - for example, a negative input terminal - and an output terminal of the amplifier (Amp), and a reset switch connected in parallel with the capacitor (Ci) (SWr) and the like. A driving voltage Vdrv may be applied to the positive input terminal of the amplifier Amp. The driving voltage Vdrv may have a waveform of a square wave.

The integrator 301 may generate a sensing signal by modulating an analog signal (eg, a response signal) from the touch electrode of the panel 110 . The integrator 301 may integrate an analog signal for modulation. The sensing signal may be in the form of a voltage, and the sensing voltage Vout may include a value obtained by integrating the response signal by the integrator 301 through the capacitor Ci. The value integrated by the capacitor Ci may be previously reset by the reset switch SWr before the next integration is performed. The integrator 301 may transfer the sensing voltage Vout to the sample and hold unit 320 .

In addition, the touch sensing device 140 may further include a bias control unit 311 .

The bias controller 311 may supply a bias current BC to the amplifier Amp included in the sensing circuit 310b of the touch sensing device 140 .

For example, the sensing circuit 310b of the touch sensing device 140 may include an integrator 301 as shown in this figure, and the integrator 301 may further include an amplifier Amp therein. The bias controller 311 may supply a bias current BC to the amplifier Amp of the integrator 301 .

The bias controller 311 may adjust the intensity of the bias current BC. The bias controller 311 may adjust the intensity of the bias current BC according to the position of the touch electrode, and may supply the bias current BC having the adjusted intensity to the amplifier Amp. The amplifier Amp may drive the corresponding touch electrode using the adjusted bias current BC.

For example, the bias control unit 311 generates and supplies a bias current BC having a relatively high intensity for a touch electrode located far from the touch sensing device 140 among a plurality of touch electrodes included in one channel. In addition, a bias current BC having a relatively weak intensity may be generated and supplied to the touch electrode located close to the touch sensing device 140 .

And in order to drive the touch electrode, the bias control unit 311 provides the bias current BC of different intensity to the amplifier Amp individually or in groups in consideration of the position and the same intensity regardless of the position. It may operate in the second mode in which the bias current BC is provided to the amplifier Amp.

4 is a diagram illustrating a touch sensing system according to an embodiment.

Referring to FIG. 4 , a plurality of touch electrodes TE may be disposed on the panel 110 . The arrangement of the plurality of touch electrodes TE may have a matrix shape including rows and columns. In this drawing, for convenience of description, the arrangement of the plurality of touch electrodes TE in a 4Х8 configuration may be exemplified, but the present invention is not limited thereto. Hereinafter, a target to which the bias control unit 311 supplies a bias current may be an amplifier included in the driver or an amplifier included in the sensing circuit.

The touch sensing device 140 may be connected to the panel 110 and drive a plurality of touch electrodes TE to sense a touch of the panel 110 . The touch sensing device 140 may be driven by grouping a plurality of touch electrodes TE, and one group may be referred to as a channel. The touch sensing device 140 includes a MUX that selects one of the plurality of touch electrodes TE included in one channel and an analog front end that demodulates response signals from the plurality of touch electrodes TE of the one channel. (AFE) may be included. The touch sensing device 140 includes a plurality of analog front ends AFE, and each analog front end AFE may be in charge of each channel. In the example of this figure, there are eight analog front ends AFE and eight channels, and each analog front end AFE may be in charge of four touch electrodes TE included in one channel.

In addition, the touch sensing device 140 includes a MUX that selects one of the demodulated response signals from the plurality of analog front end units (AFE) and an analog-to-digital converter (ADC) that converts the selected demodulated response signal into a digital signal. may include

The touch sensing device 140 senses a plurality of touch electrodes TE included in any one channel, but the position or distance of each touch electrode TE may be considered. The touch sensing device 140 may adjust the intensity of the bias current BC according to the position of the touch electrode, and may supply the bias current BC having the adjusted intensity to the amplifier Amp. The amplifier Amp may drive the corresponding touch electrode using the adjusted bias current BC.

For example, the touch sensing device 140 has a first bias current BIAS_1 having the lowest intensity in the touch electrode TE closest to the touch sensing device 140 among the four touch electrodes TE included in one channel. is available. In addition, the touch sensing device 140 uses the fourth bias current BIAS_4 having the highest intensity to the touch electrode TE furthest from the touch sensing device 140 among the four touch electrodes TE included in one channel. can In addition, the touch sensing device 140 has a higher than the first bias current BIAS_1 and a fourth touch electrode TE located at an intermediate point from the touch sensing device 140 among the four touch electrodes TE included in one channel. The second and third bias currents BIAS_2 and BIAS_3 that are weaker than the bias current BIAS_4 may be used.

The touch sensing device 140 may recognize the panel 110 including the plurality of touch electrodes TE as a load. The load may increase as the touch electrode TE is farther from the touch sensing device 140 and decrease as it approaches the touch sensing device 140 . That is, the load recognized by the touch sensing device 140 may vary according to the positions of the plurality of touch electrodes TE or the distance from the touch sensing device 140 . The touch sensing device 140 may transmit the bias current of the adjusted intensity to the plurality of touch electrodes TE by adjusting the intensity of the bias current. Through this, the touch sensing device 140 efficiently drives the load (the plurality of touch electrodes TE).

5 is a diagram showing the intensity of bias currents used in a plurality of touch electrodes included in one channel according to distance.

Referring to FIG. 5 , a plurality of touch electrodes included in one channel and a bias current corresponding to each touch electrode are illustrated. Conventionally, the amplifier of the touch sensing device 140 may drive the touch electrode through the bias current of the same strength regardless of the position of each touch electrode on the channel. Therefore, the amplifier of the driving unit or the amplifier of the sensing circuit may transmit each driving voltage to the touch electrode close to the touch sensing device 140 or the touch electrode far away from the touch sensing device 140 through the bias current of the same strength. .

For example, the amplifier may transmit the driving voltage to the plurality of touch electrodes TE_1 to TE_10 included in one channel by using the same bias current. Accordingly, the first bias current BIAS_1 for the first touch electrode TE_1, the fifth bias current BIAS_5 for the fifth touch electrode TE_5, and the tenth bias current BIAS_10 for the tenth touch electrode TE_10 ) can all have the same intensity. In this figure, the strength of the bias current STRENGTH may be the same according to the position of each touch electrode, that is, the distance DISTANCE.

6 is a diagram illustrating power consumption by bias currents used for a plurality of touch electrodes included in one channel.

Referring to FIG. 6 , power consumption by a plurality of touch electrodes included in one channel and a bias current corresponding to each touch electrode is illustrated. Conventionally, the amplifier can drive each touch electrode using the same bias current regardless of the position of each touch electrode on the channel. Accordingly, the amplifier may consume the same power when driving a touch electrode close to the touch sensing device 140 or driving a touch electrode far away from the touch sensing device 140 .

For example, the power consumed by the amplifier due to the bias current for driving the plurality of touch electrodes TE_1 to TE_10 may be the same regardless of the positions of the respective touch electrodes TE_1 to TE_10 . Accordingly, the first power consumed by the amplifier due to the bias current for driving the first touch electrode TE_1, the fifth power consumed by the amplifier due to the bias current for driving the fifth touch electrode TE_5, and the tenth touch electrode TE_10 All of the tenth power consumed due to the bias current for driving may be the same.

In addition, the total power consumed by the amplifier in one channel due to the bias current may be the same as the sum of the first to ten powers. In this figure, the power consumption POWER by each bias current may be the same according to the position of each touch electrode, that is, the distance DISTANCE.

7 is a diagram illustrating the intensity of bias currents used in a plurality of touch electrodes included in one channel according to a distance according to an exemplary embodiment.

Referring to FIG. 7 , a plurality of touch electrodes connected on one channel and a bias current corresponding to each touch electrode are illustrated according to an exemplary embodiment. The amplifier may drive each touch electrode through a bias current having different intensities in consideration of the position of each touch electrode on the channel. Therefore, the amplifier transmits a driving voltage to the touch electrode close to the touch sensing device 140 by using a weak bias current, and outputs a data voltage to the touch electrode far away from the touch sensing device 140 by using the strong bias current. have.

For example, the amplifier may transmit the driving voltage to the plurality of touch electrodes TE_1 to TE_10 included in one channel using bias currents having different intensities. In more detail, the amplifier may transmit the driving voltage using a bias current that increases from the first touch electrode TE_1 to the tenth touch electrode TE_10 . Accordingly, the first bias current BIAS_1 for the first touch electrode TE_1 is the weakest, the tenth bias current BIAS_10 for the ten touch electrode TE_10 is the highest, and the fifth touch electrode TE_5 has the second bias current BIAS_5. The fifth bias current BIAS_5 may be stronger than the first bias current BIAS_1 and weaker than the tenth bias current BIAS_10 .

Meanwhile, the bias control unit of the touch sensing device 140 may receive the bias control signal including the position data of each touch electrode to determine the position of the target touch electrode. The bias control unit may adjust the bias current to a specific intensity for the touch electrode at the determined position and supply it to the amplifier. The bias control unit may receive the timing data instead of the position data of the touch electrode to determine the position of the touch electrode.

Meanwhile, when the amplifier of the touch sensing device 140 uses the differentially adjusted bias current, power consumption due to the bias current can be reduced.

For example, the amplifier may drive the first touch electrode TE_1 using a relatively weak first bias current. Since the amplifier uses a weak first bias current, the power consumed by the amplifier may also be reduced accordingly. Even if the amplifier uses a strong bias current for the tenth touch electrode TE_10, the closer the position of the touch electrode is to the touch sensing device 140, the more the amplifier uses a weak bias current, the overall power consumption of the amplifier can be reduced. have.

8 is a diagram illustrating power consumption by bias currents used in a plurality of touch electrodes included in one channel according to an exemplary embodiment.

Referring to FIG. 6 , power consumption by a plurality of touch electrodes included in one channel and a bias current corresponding to each touch electrode is illustrated according to an exemplary embodiment. The amplifier may drive each touch electrode by using bias currents having different strengths in consideration of the position of each touch electrode on the channel. Accordingly, the amplifier may consume less power when driving a touch electrode close to the touch sensing device 140 , and consume a lot of power when driving a touch electrode far away from the touch sensing device 140 .

For example, power consumed by the amplifier due to a bias current for driving the plurality of touch electrodes TE_1 to TE_10 may vary depending on the position of each touch electrode. Preferably, the power consumed by the amplifier may increase as the touch electrode located farther from the touch sensing device 140 is driven. The amplifier consumes the least power when driving the first touch electrode TE_1 located closest to the touch sensing device 140 , and drives the tenth touch electrode TE_10 located farthest from the touch sensing device 140 . when it can consume the most power.

Accordingly, the first power consumed by the amplifier by the first bias current BIAS_1 to drive the first touch electrode TE_1 and the first power consumed by the fifth bias current BIAS_5 to drive the fifth touch electrode TE_5 The second power and the tenth power consumed by the tenth bias current BIAS_10 for driving the tenth touch electrode TE_10 are different amounts, but the first power is the smallest and the tenth power is the largest in the amounts. have.

_{In addition, the total power (P T} ) consumed by the amplifier through one channel due to the bias current may be the same as the sum of the first to tenth powers.

In FIG. 6 , when the amplifier uses a bias current of the same strength to drive the plurality of touch electrodes TE_1 to TE_10 , power consumption by the bias current in the amplifier may increase. When the bias current of the same strength is used, the total power P _T may be represented by a rectangular area.

On the other hand, if the amplifier uses the differentially adjusted bias current to drive the plurality of touch electrodes TE_1 to TE_10 as shown in this figure, power consumption by the bias current in the amplifier may be reduced. When a bias current that continuously increases according to the position of the touch electrode is used, the total power P _T may be a right-angled triangle region.

Comparing the widths of the regions for the two cases, the total power P _T according to an exemplary embodiment may be reduced by about 1/2.

9 is an exemplary diagram of adjusting a bias current to drive a plurality of touch electrodes according to another exemplary embodiment.

Referring to FIG. 9 , the amplifier of the touch sensing device 140 according to another embodiment may sense a plurality of touch electrodes TE included in one channel using a bias current. Here, the amplifier may classify the plurality of touch electrodes TE for each group and differentially use a bias current for each group. The amplifier may use a bias current of the same strength to drive and sense the plurality of touch electrodes TE included in a group. Also in this method, the amplifier may receive a bias current corresponding to each touch electrode from the bias control unit of the touch sensing device 140 and drive each touch electrode using the bias current. Hereinafter, an example in which the touch sensing device 140 drives the six touch electrodes TE connected to the four sensing lines SL_1 to SL_4 will be described as an example.

Here, a region including one sensing line and a plurality of touch electrodes TE connected to the one sensing line may be referred to as a channel. In this figure, CH1 to CH4 may represent channels, respectively.

Also, the plurality of touch electrodes TE may be located near or far from the touch sensing device 140 . A close position of the touch electrode TE means a position close to the touch sensing device 140 , and a far position of the touch electrode TE means a position away from the touch sensing device 140 . have. In this figure, a point close to the touch sensing device 140 may be shown as NEAR, and a point distant from the touch sensing device 140 may be shown as FAR.

The amplifier may classify the plurality of touch electrodes TE included in one channel for each group, and drive and sense the touch electrodes TE using bias currents of different intensities for each group.

For example, the touch sensing device 140 may divide the six touch electrodes connected to the first sensing line SL_1 into three groups. The touch sensing device 140 may be divided into first to third groups by grouping two in close order. The touch sensing device 140 may use the first to third bias currents BIAS_1 to BIAS_3 to transmit driving voltages to the first to third groups of touch electrodes, respectively.

Here, the first to third bias currents BIAS_1 to BIAS_3 may have different intensities. Preferably, the farther the group is located, the greater its intensity may be. Accordingly, the intensity may increase from the first bias current BIAS_1 to the third bias current BIAS_3. In this figure, the intensity increasing from the first bias current BIAS_1 to the third bias current BIAS_3 may be shown as WEAK and STRONG.

In addition, the touch sensing device 140 uses a bias current of a different intensity for each group, but may use a bias current of the same intensity for the plurality of touch electrodes TE included in one group.

For example, when the touch sensing device 140 drives the two touch electrodes TE of the first group, the first bias current BIAS_1 may be used. The two touch electrodes of the first group may be driven by a bias current of the same strength. However, due to the difference in position or distance, the intensity of the bias current for the two touch electrodes of the first group becomes smaller than the intensity for the touch electrodes of the other group.

The touch sensing device 140 may classify the six touch electrodes TE connected to the second to fourth sensing lines SL_2 to SL_4 by group. The touch sensing device 140 may drive the touch electrode TE using bias currents of different intensities for each group. In addition, the touch sensing device 140 may use a bias current of the same intensity for the plurality of touch electrodes TE included in one group.

Even if the plurality of touch electrodes TE of one channel are divided into groups and driven through bias currents having different intensities, the sensing voltages generated for each touch electrode TE may be within a preset similarity range. That is, the time for the sensing voltage corresponding to each touch electrode TE to be formed at the amplifier output terminal of the touch sensing device 140 may be within a preset similarity range. If the sensing voltage is within the similar range, it may mean that valid touch data is generated from the sensing voltage, and thus a touch or proximity of an external object may be determined.

Meanwhile, the touch electrode TE in which the intensity of the bias current changes may be defined as a boundary touch electrode. When the touch sensing device 140 sequentially drives the touch electrodes TE of one sensing line, the boundary touch electrodes may be driven through a bias current having a different intensity from that of the previous touch electrode. Therefore, one boundary touch electrode may be included in each group. For example, the boundary touch electrode of the second group is the first touch electrode driven through the second bias current BIAS_2 in the second group, and is the fourth touch electrode among the six touch electrodes of the first sensing line SL_1. can

Meanwhile, the bias control unit of the touch sensing device 140 may receive the bias control signal including the position data of each touch electrode to determine the position of the target touch electrode. The bias control unit may adjust the bias current to a specific intensity for the touch electrode at the determined position and supply it to the amplifier. The bias control unit may receive the timing data instead of the position data of the touch electrode to determine the position of the touch electrode.

As described above, when the touch sensing device 120 differentially adjusts the bias current for each group rather than using the bias current of the same intensity for all the touch electrodes TE, power consumption due to the bias current can be reduced.

Claims (15)

a driver for outputting a driving voltage to the touch electrode using a bias current to detect proximity or touch of an external object;
a sensing unit receiving a response signal corresponding to the driving voltage and generating a sensing voltage; and
a bias control unit for supplying a bias current to the driving unit;
The bias control unit adjusts the intensity of the bias current according to the position of the touch electrode, and supplies the bias current of the adjusted intensity to the driving unit. According to claim 1,
The touch electrode includes a first touch electrode included in one channel and a second touch electrode included in the one channel and positioned farther than the first touch electrode,
The driving unit drives the first touch electrode using the first bias current and drives the second touch electrode using the second bias current,
The bias control unit adjusts the intensity of the second bias current to be stronger than the intensity of the first bias current and supplies it to the driving unit. 3. The method of claim 2,
A time for forming a first sensing voltage for the first touch electrode and a time for forming a second sensing voltage for the second touch electrode are within a preset similarity range. According to claim 1,
The bias control unit is a touch sensing device for adjusting the bias current so that the intensity is gradually increased as the position of the touch electrode is further away. According to claim 1,
The bias control unit may be configured to receive a bias control signal including position data of each touch electrode for adjusting the intensity of the bias current. According to claim 1,
The bias control unit is a touch sensing device for receiving a bias control signal including timing data for adjusting the intensity of the bias current. An M (M is a natural number greater than or equal to 1)-th touch electrode included in one channel is driven using the M-th driving voltage and the M-th bias current, and the M+1-th driving voltage and the M-th driving voltage having the same magnitude as the M-th driving voltage and the The M+1th touch electrode included in the one channel is driven using the M+1th bias current higher than the Mth bias current, and Mth power generated by the Mth bias current is consumed, and the M+th touch electrode is used. a driving unit generated by the first bias current and consuming more M+1th power than the Mth power; and
and a bias control unit generating the Mth bias current and the M+1th bias current and supplying them to the driving unit. 8. The method of claim 7,
The M+1 th touch electrode is a touch sensing device positioned farther than the M th touch electrode on the one channel. 8. The method of claim 7,
The driving unit may include a first mode in which the Mth driving voltage is output using the Mth bias current and the M+1th driving voltage is output using the M+1th bias current, or the Mth driving voltage and a touch sensing device operating according to a second mode of outputting the M+1th driving voltage using a bias current of the same strength. a driver for outputting a driving voltage to a plurality of touch electrodes included in one channel using a bias current to detect proximity or touch of an external object;
a generator configured to receive a response signal corresponding to the driving voltage and generate a sensing voltage; and
a bias control unit for supplying the bias current to the driving unit;
The plurality of touch electrodes includes a plurality of touch electrodes of a first group and a plurality of touch electrodes of a second group,
The bias control unit adjusts the intensity of the bias current to a first intensity for the first group, adjusts the intensity of the bias current to a second intensity for the second group, and adjusts the intensity of the bias current to a second intensity for the second group A touch sensing device for supplying a bias current having 11. The method of claim 10,
The second group is located farther than the first group on the one channel,
The bias control unit may be configured to adjust the second intensity to be greater than the first intensity. 11. The method of claim 10,
A time for forming a plurality of sensing voltages for the first group and a time for forming a plurality of sensing voltages for the second group are within a preset similarity range. 11. The method of claim 10,
The bias control unit may be configured to receive a bias control signal including position data of each touch electrode for adjusting the intensity of the bias current. 11. The method of claim 10,
The bias control unit is a touch sensing device for receiving a bias control signal including timing data for adjusting the intensity of the bias current. An M (M is a natural number greater than or equal to 1)-th touch electrode included in one channel is driven using the M-th driving voltage and the M-th bias current, and an N-th (N is greater than M+1)-th touch electrode having the same magnitude as the M-th driving voltage. large natural number) driving the N-th touch electrode included in the one channel using a driving voltage and an N-th bias current greater than the M-th bias current, and consuming M-th power generated by the M-th bias current; a driving unit generated by the Nth bias current and consuming more Nth power than the Mth power; and
and a bias control unit generating the M th bias current and the N th bias current and supplying the M th bias current and the N th bias current to the driving unit.

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