KR20180076542A - Touch display device and method for driving the same - Google Patents

Abstract

The present invention relates to a touch display device and a driving method thereof, capable of reducing power consumption. The touch display device includes a timing controller and a plurality of touch/data integrated circuits (ICs). The timing controller is connected with the touch/data ICs through an embedded point-to-point interface (EPI) transfer line. The timing controller includes a transmitter for transmitting display information to each of the touch/data ICs through the EPI transfer line, and each of the touch/data ICs includes a receiver for receiving the display information through the EPI transfer line. The transmitter of the timing controller or the receiver of the touch/data IC is driven with first driving current during a data writing period and driven with second driving current lower the first driving current during a touch driving period.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch display device and a method of driving the touch display device.

The present invention relates to a touch display device capable of reducing power consumption and a driving method thereof.

With the development of multimedia, the importance of flat panel displays is increasing. In response to this, flat panel display devices such as liquid crystal display devices, plasma display devices, and organic light emitting display devices have been commercialized.

Of these, OLED display devices are self-luminous devices that emit organic light-emitting layers by recombination of electrons and holes, and are expected to be a next generation display device because of their high brightness, low driving voltage and thin film.

Each of the plurality of pixels constituting the OLED display device includes an OLED element composed of an organic light emitting layer between the anode and the cathode, and a pixel circuit independently driving the OLED element. The pixel circuit includes a switching thin film transistor (TFT) for supplying a data voltage to the storage capacitor, a driving TFT for controlling the driving current according to the driving voltage charged to the storage capacitor to supply the OLED element to the OLED element, The device generates light proportional to the driving current.

In the liquid crystal display device, two substrates on which electrodes are formed are arranged so as to face each other with the two electrodes facing each other, and a liquid crystal material is injected between the two substrates to form a voltage The liquid crystal molecules are moved by an electric field generated by applying an electric field to the liquid crystal molecules.

An electrical characteristic such as a resistance or a capacitance is changed at a touch point where a hand or a stylus pen touches the flat panel display device as described above to sense the touch point and output information corresponding to the touch point Or touch panels for performing calculations are widely used.

The touch technology applied to the flat panel display device is divided into an add-on type and an in-cell type depending on the position of the touch sensor. The add-on type is an external type in which a touch screen panel is mounted on a display panel, and the in-cell type is a built-in type in which a display panel and a touch screen are integrated by incorporating a touch electrode in a display panel.

In-cell type is developed as an Advanced In-cell Touch (AIT) display device which is further advanced for slimming down a display device and divides a common electrode of the liquid crystal display device into a touch electrode.

The AIT display device is divided into a data writing period (data writing period) in which image data is written into pixels in each frame period and a touch driving period in which a touch driving signal is applied to the touch electrodes and a touch driving period is sensed, .

In this way, the timing controller and the panel driver are connected through an Embedded Point-to-Point Interface (EPI) interface transmission line in order to write image data to the pixels in the time division manner and to sense whether the touch electrodes touch.

During the data writing period, the timing controller transmits display information to each data driving IC of the panel driving unit through the EPI interface transmission line.

Also, during the touch driving period, touch voltage information or the like is transmitted from each data driving IC of the panel driving unit through the MCUfh SPI interface.

In order to transmit the display information and the touch voltage information through the EPI interface transmission line in the time division manner, each of the data driving ICs of the timing controller and the panel driving unit includes a transmission / reception buffer (Tx / Rx buffer).

The transmission / reception buffers Tx and Rx are driven by a constant current during the data writing period and the touch driving period.

FIG. 1 is a waveform diagram of display information (Source output), EPI signal (EPI signal) and driving current (Tx / Rx Current) of a transmitting / receiving buffer during a conventional data writing period.

As described above, in order to transmit the display information through the EPI interface transmission line in a time division manner, the data writing period (display) and the touch driving period (touch) by the touch synchronous signal Tsync ).

Wherein the timing controller transmits the display information to each of the data driving ICs of the panel driving unit during the data writing period and outputs the display information to the panel driving unit during the touch driving period, It is not transmitted to each data driving IC of the driving unit.

Therefore, the EPI signal has a data signal form during the data writing period and has a clock training form during the touch driving period (touch).

However, the driving current (Tx / Rx Current) of the transmission / reception buffer has a default value in both the data writing period (display) and the touch driving period (touch).

Since the EPI signal has a data signal type (Worst case) during the data writing period, the driving current (Tx / Rx Current) of the transmission / reception buffer requires a predetermined value, The EPI signal has a clock training type during the touch driving period and the clock training signal has a shorter number of times of toggling than the data signal type, Because it is long, it can be driven with low current. Nevertheless, there is a problem that power consumption is wasted because the driving current (Tx / Rx Current) of the transmission / reception buffer has a default value even during the touch driving period (touch).

An object of the present invention is to reduce power consumption of a touch display device by driving a transmission / reception buffer with a driving current lower than a predetermined value during a touch driving period.

According to an aspect of the present invention, there is provided a touch display device including a timing controller and a plurality of touch / data ICs, wherein the timing controller and the plurality of touch / data ICs are connected via an EPI interface transmission line Wherein the timing controller comprises a transmitter for transmitting display information to each of the plurality of touch / data ICs via the EPI interface transmission line, wherein each of the plurality of touch / And a receiver for receiving the display information through a transmission line, wherein the transmitter of the timing controller or the receiver of each touch / data IC is driven with a first drive current during a data writing period, 1 < / RTI > drive current. ≪ RTI ID = 0.0 > .

Here, the transmitting unit or the receiving unit may include: a first driving current supplying unit for supplying the first driving current; a second driving current supplying unit for supplying the second driving current; And a transmission buffer or a reception buffer driven by the current selected by the switching unit. The switching unit may include a plurality of switches, do.

The first driving current supplying unit or the second driving current supplying unit may include a first current mirror unit that mirrors a constant voltage to supply a driving current to a transmission buffer or a receiving buffer, and a second current mirror unit that mirrors the reference current source to mirror the first current mirror unit. And a setting unit for setting the driving current supplied from the first current mirror unit to be greater than or equal to the current mirrored by the second current mirror unit.

Wherein the first driving current supply unit and the second driving current supply unit have the same circuit configuration and that the first driving current supply unit outputs a larger current than the second driving current supply unit by the setting unit .

The setting unit may include a plurality of transistors connected in parallel between a node connected to the first current mirror unit and the second current mirror unit and a ground terminal and outputting different current values, And FIG.

According to another aspect of the present invention, there is provided a method of driving a touch display device including a timing controller and a plurality of touch / data ICs, wherein the timing controller and the plurality of touch / And a plurality of touch / data ICs connected to the plurality of touch / data ICs via a transmission line, wherein the timing controller includes a transmitter, and each of the plurality of touch / data ICs includes a receiver, The receiving unit is driven with a first driving current during a data writing period and is driven with a second driving current lower than the first driving current during a touch driving period.

The touch display device and the driving method thereof according to the embodiment of the present invention having the above-described features have the following effects.

That is, power consumption can be reduced because the transmission / reception buffer is driven by the current of the predetermined value during the data writing period, and the transmission / reception buffer is driven by the current lower than the driving current during the data writing period during the touch driving period.

Also, during the data writing period, the transmission / reception buffer is driven by the current of the predetermined value, and during the touch driving period, the transmission / reception buffer is driven by the current lower than the driving current during the data writing period.

The first driving current supply unit supplies a driving current to the transmission buffer or the reception buffer during the data writing period and the second driving current supply unit supplies the driving current to the transmission buffer or the reception buffer during the touch driving period. And the driving current can be set differently through the setting unit, so that various options can be driven.

FIG. 1 is a waveform diagram of display output (source output), EPI signal (EPI signal) and driving current (Tx / Rx Current) of a transmitting / receiving buffer during a conventional data writing period.
2 is a block diagram schematically showing a configuration of a touch display apparatus according to an embodiment of the present invention.
3 is a schematic block diagram of a transmitter Tx of the timing controller or a receiver of each touch / data IC according to the present invention.
4 is a circuit block diagram of the first or second driving current supply unit in Fig.
5 is a circuit block diagram of the transmission buffer or the reception buffer of FIG.
6 is a waveform diagram of display information (Source output), EPI signal (EPI signal), and driving current (Tx / Rx Current) of the transmitting / receiving buffer during the data writing period according to the present invention.
7 is a waveform diagram of a vertical synchronizing signal Vsync, a touch synchronizing signal Tsync, a driving current Tx Current of the transmitting unit Tx and a driving current Rx Current of the receiving unit Rx according to the present invention.
8 is a graph illustrating the relationship between the driving current Txcurrent of the transmitting unit Tx and the driving current of the receiving unit Rx during the data writing period and the touch driving period Rx Current).
9 is a waveform diagram showing a change in a driving current (Tx Current) of the transmission unit Tx during the data writing period and the touch driving period (touch) according to FIG.
10 is a waveform diagram showing a change in a driving current (Rx Current) of the receiving unit Rx during the data writing period (display) and the touch driving period (touch) according to FIG.

A touch display device and a driving method thereof according to preferred embodiments of the present invention having the above features will be described in more detail with reference to the accompanying drawings.

FIG. 2 is a block diagram schematically showing the configuration of a touch display apparatus according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing a schematic configuration of a transmitter Tx of a timing controller or a receiver of each touch / .

2 and 3, the touch display device according to the present invention includes a timing controller TCON and a plurality of touch / data ICs (TD-IC1, TD-IC2, TD- PANEL) and the like.

Each of the plurality of touch / data ICs (TD-IC1 to TD-IC4) is mounted on a circuit film such as a tape carrier package (TCP), a chip on film (COF), or a flexible printed circuit (FPC) And TAB (Tape Automatic Bonding) method on a PCB (not shown) on which the timing controller TCON is mounted, or mounted on a panel 500 in a COG (Chip On Glass) Lt; / RTI >

The display panel (PANEL) has a touch and display function. The display panel displays an image through a pixel array in which pixels are arranged in a matrix, and senses whether or not the touch is performed by a capacitance method using a common electrode and a touch electrode.

The display panel may be an organic light emitting diode display panel or a liquid crystal display panel.

In addition, between the timing controller (TCON) and each of the plurality of touch / data ICs (TD-IC1 to TD-IC4) for writing image data into pixels in a time division manner and sensing whether the touch data is touched by the touch electrodes It is connected through the EPI interface transmission line.

In order to transmit image data to the plurality of touch / data ICs (TD-IC1 to TD-IC4) from the timing controller (TCON) through the EPI interface transmission line, the timing controller (TCON) Tx), and each of the plurality of touch / data ICs (TD-IC1 to TD-IC4) is provided with a receiving unit Rx.

Of course, although not shown in the drawing, during the touch driving period, touch voltage information, etc., are supplied from the respective touch / data ICs (TD-IC1 to TD-IC4) to the timing controller (TCON) through the EPI interface transmission line A plurality of touch / data ICs TD-IC1 to TD-IC4 are provided with a transmitter Tx and a timing controller TCON is provided with a receiver Rx.

The present invention aims at reducing power consumption when transmitting image data from the timing controller TCON to the respective touch / data ICs TD-IC1 to TD-IC4. Therefore, the transmission unit Tx of the timing controller TCON, And a receiver Rx of each touch / data IC.

The transmitter Tx of the timing controller and the receiver of each touch / data IC have the same configuration as shown in FIG.

3, the transmission unit Tx of the timing controller or the reception unit of each touch / data IC includes a first driving current supply unit 1 for supplying a driving current to the transmission buffer or the reception buffer during a data writing period A second driving current supply unit 2 for supplying a driving current to the transmission buffer or the reception buffer during the touch driving period and a second driving current supply unit 2 for supplying a current outputted from the first driving current supply unit 1 A switching unit SW1 or SW2 for selecting one of the currents outputted from the second driving current supply unit 2 and outputting the selected one of the currents outputted from the second driving current supply unit 2 and a transmission buffer or a reception buffer driven by the current selected by the switching units SW1 and SW2; (3).

The first switching device SW1 of the switching units SW1 and SW2 is an N-type switching device and the second switching device SW2 is a P-type switching device. Therefore, the switching units SW1 and SW2 select and output the current output from the first driving current supply unit 1 during the high logic period (data writing period) of the touch synchronous signal Tsync, And selects and outputs the current output from the second driving current supply unit 2 in the row logic section (touch driving period) of the signal Tsync.

In the above, the second driving current supply unit 2 is set to output a lower current than the first driving current supply unit 1. [

The configuration of the first and second driving current supply units is as shown in FIG.

4 is a circuit block diagram of the first or second driving current supply unit in Fig.

The first driving current supply part (1) and the second driving current supply part (2) have the same circuit configuration.

That is, as shown in FIG. 4, the first current mirror unit M2, which is composed of the first and second transistors T1 and T2 and mirrors the constant voltage VCC to supply a driving current to the transmission buffer or the reception buffer 3, A second current mirror part 12 composed of a third transistor T3 and a fourth transistor T4 for controlling the mirroring value of the first current mirror part 11 by mirroring a reference current source, The first to third switches SW1 to SW3 and the fifth to seventh transistors T5, T6 and T7 having different output currents according to the selection of the first to third switches SW1 to SW3 The current (Tx or Rx Current) output to the transmission buffer or the reception buffer 3 through the first current mirror unit 11 is set to be equal to or greater than the mirroring current of the second current mirror unit 12 And a setting unit (13).

Here, the setting unit 13 includes a first switch SW1 and a second switch SW2 between an N-node and the ground GND, to which the first current mirror unit 11 and the second current mirror unit 12 are connected, The fifth switch T5 is connected in series and the second switch SW2 and the sixth transistor T6 are connected in series and the second switch SW3 and the seventh transistor T7 are connected in series, The fifth through seventh transistors T5, T6, and T7 are connected in parallel with each other.

The fifth through seventh transistors T5, T6 and T7 of the setting unit 13 output a lower current than the third and fourth transistors T3 and T4 of the second current mirror unit 12, The fifth transistor T5 outputs the lowest current and the sixth transistor T6 outputs a current that is higher than the fifth transistor T5 and lower than the seventh transistor T7.

For example, assuming that the third and fourth transistors T3 and T4 of the second current mirror section 12 output a current of k value, the fifth transistor T5 supplies a current of k x 0.1 The sixth transistor T6 outputs a current of k × 0.2, and the seventh transistor T7 outputs a current of k × 0.3.

Therefore, when the reference current Iref is 2 mA and the first switch SW1 is turned off and the second and third switches SW2 and SW3 are turned on, A current of 3 mA is supplied to the transmission buffer or the reception buffer 3 (2 + 0.4 + 0.6 = 3).

When the reference current Iref is 2 mA and all the first to third switches SW1, SW2 and SW3 are turned off, the first current mirror unit 11 turns off the transmission buffer or the reception buffer 3 ) Is supplied with a current of 2 mA.

Although the first driving current supply unit 1 and the second driving current supply unit 2 have the same circuit configuration, the first driving current supply unit 1 may be configured such that the reference current Iref is 2 mA , When the first switch SW1 is turned off and the second and third switches SW2 and SW3 are turned on, a current of 3 mA is output.

On the other hand, when the reference current Iref is set to 2 mA, the second driving current supplying unit 2 turns off all of the first to third switches SW1, SW2 and SW3, And outputs a current of 2 mA lower than the supply section (1).

5 is a circuit block diagram of the transmission buffer or the reception buffer of FIG.

5, the currents selected by the switching units SW1 and SW2 may be referred to as eighth and ninth transistors (eighth and ninth transistors) controlled by EPI + and EPI- signals, respectively. And a tenth and eleventh transistors T13 and T14 for mirroring and outputting a current of the eighth transistor T11.

A driving method (operation) of the touch display device according to the present invention having the above-described structure will now be described.

6 is a waveform diagram of display information (Source output), EPI signal (EPI signal), and driving current (Tx / Rx Current) of the transmitting / receiving buffer during the data writing period according to the present invention.

In order to transmit the display information and the touch voltage information through the EPI interface transmission line in a time division manner, the data writing period and the touch driving period (touch) are controlled by a touch synchronous signal (Tsync, not shown) ).

The timing controller TCON transmits the display information to the plurality of touch / data ICs (TD-IC1, TD-IC2, TD-IC3, and TD-IC4) during the data writing period , And does not transmit the display information to the plurality of touch / data ICs (TD-IC1, TD-IC2, TD-IC3, and TD-IC4) during the touch driving period (touch).

Therefore, the EPI signal has a data signal form during the data writing period and has a clock training form during the touch driving period (touch).

The EPI signal has a clock training type during the touch driving period and the clock training signal has a low number of toggling times and a longer cycle than the data signal type, It can be driven by current (Low Current).

Therefore, the driving current (Tx / Rx Current) of the transmission / reception buffer has a lower value during the touch driving period (touch) than during the data writing period (display).

This will be described in detail as follows.

7 is a waveform diagram of a vertical synchronizing signal Vsync, a touch synchronizing signal Tsync, a driving current Tx Current of the transmitting unit Tx and a driving current Rx Current of the receiving unit Rx according to the present invention.

Generally, there are 16 LHB (Long Horizontal Blank, Touch sensing interval) during one frame.

Therefore, as described above, assuming that the first driving current supply unit 1 is set to output a current of 3 mA and the second driving current supply unit 2 is set to output a current of 2 mA, The switching unit SW1 and the switching unit SW2 are controlled by the touch synchronizing signal so that the driving current Tx Current of the transmitting unit Tx and the driving current Rx Current of the receiving unit Rx are controlled by the touch synchronizing signal, Has a current value of 3 mA during the data writing period and has a current value of 2 mA during the touch driving period (touch).

4, when the number of transistors of the setting unit 13 and the reference current Iref are adjusted in accordance with the model and the resolution of the touch display apparatus, various options can be selected during the data writing period and the touch- The driving current TxCurrent of the transmitting unit Tx and the driving current RxCurrent of the receiving unit Rx during a touch can be set.

8 is a graph illustrating the relationship between the driving current Txcurrent of the transmitting unit Tx and the driving current of the receiving unit Rx during the data writing period and the touch driving period 9 is a graph showing the waveform of the driving current (Tx Current) of the transmission section Tx during the data writing period and the touch driving period (touch) according to FIG. 8, 10 is a waveform diagram showing a change in a driving current (Rx Current) of the receiving unit Rx during the data writing period (display) and the touch driving period (touch) according to FIG.

8 to 10, the output current of the first driving current supplying unit 1, which is the driving current of the transmitting unit Tx during the data writing period, is set to 3 mA, and the touch driving period (touch) Which is the driving current of the receiving unit Rx during the data writing period, is set to 2 mA while the output current of the second driving current supplying unit 2, which is the driving current of the transmitting unit Tx, The output current of the supply unit 1 is set to 8 mA and the output current of the second drive current supply unit 2 which is the drive current of the receiver Rx during the touch drive period touch can be set to 7 mA.

The driving current value during the touch driving period (touch) is not an automatic setting, and it is necessary to check and set a minimum value according to an experiment.

Therefore, it is possible to reduce the transmission / reception driving current during the LHB (touch sensing interval). As the number of EPI interface transmission lines increases, the driving speed increases, and the LHB interval increases, the transmission / reception driving current decreases.

For example, the driving current of the transmitting portion is set to be the same as the driving current of the touch driving portion in the case where the driving current during the data writing period and the driving current difference during the touch driving period is 1 mA, the number of EPI interface transmission lines is 16, When the ratio of the period is 2, 8 mW can be reduced (1 mA x 16 x 1 V) / 2 = 8 mW).

The driving current of the receiver is set so that the driving current during the data writing period and the driving current difference during the touch driving period is 1 mA, the number of EPI interface transmission lines is 16, the driving voltage is 1.8 V, (1mA x 16 x 1.8V) / 2 = 14.4mW) can be reduced when the ratio of the power supply voltage to the power supply voltage is 2.

Therefore, the total power consumption of 22.4 mW can be reduced under the above conditions.

The foregoing description is merely illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the spirit of the present invention. Accordingly, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. It is intended that the scope of the invention be interpreted by the claims appended hereto, and that all techniques within the scope of equivalents thereof should be construed as being included within the scope of the present invention.

1: first driving current supply part 2: second driving current supply part
3: transmission or reception buffer 11, 12: current mirror part
13: Setting section

Claims (6)

A touch display device comprising a timing controller and a plurality of touch / data ICs, wherein the timing controller and the plurality of touch / data ICs are connected through an EPI interface transmission line,
Wherein the timing controller includes a transmitter for transmitting display information to each of the plurality of touch / data ICs via the EPI interface transmission line, wherein each of the plurality of touch / data ICs transmits the display information And a reception unit for receiving the reception signal,
Wherein the transmitter of the timing controller or the receiver of each touch / data IC is driven with a first drive current during a data writing period and a second drive current lower than the first drive current during a touch drive period. The method according to claim 1,
The transmitting unit or the receiving unit,
A first driving current supply unit for supplying the first driving current,
A second driving current supply unit for supplying the second driving current,
A switching unit for selecting one of a first driving current of the first driving current supplying unit and a second driving current of the second driving current supplying unit according to a touch synchronous signal,
And a transmission buffer or a reception buffer driven by a current selected by the switching unit. The method of claim 2,
The first driving current supply unit or the second driving current supply unit may include:
A first current mirror unit for mirroring the constant voltage to supply a driving current to the transmission buffer or the reception buffer,
A second current mirror unit for mirroring the reference current source to control the mirroring of the first current mirror unit,
And a setting unit that sets a driving current supplied from the first current mirror unit to be equal to or greater than a current mirrored by the second current mirror unit. The method of claim 3,
Wherein the first driving current supply unit and the second driving current supply unit have the same circuit configuration and the first driving current supply unit supplies a touch display Device. The method of claim 3,
The setting unit may include a plurality of transistors connected in parallel between a node connected to the first current mirror unit and the second current mirror unit and a ground terminal and outputting different current values, And a display device. The timing controller includes a timing controller and a plurality of touch / data ICs. The timing controller and the plurality of touch / data ICs are connected through an EPI interface transmission line. The timing controller includes a transmitter, Each of the ICs comprising a receiving unit,
Wherein the transmitter of the timing controller or the receiver of each touch / data IC is driven with a first driving current during a data writing period and a second driving current lower than the first driving current during a touch driving period Driving method.

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