Display, display driving device, and driving method thereof

The present invention relates to a display, a driving device, and a driving method thereof, and in particular, to a display, a display driving device, and a driving method thereof that are capable of reducing noise.

Among various consumer electronics, display technologies including display panels have been widely applied to mobile phones, notebook computers, tablet computers, and the like. In recent years, touch function begin to be integrated into all display panels, allowing users to directly tap and slide on a screen with fingers or styluses to control the electronic product.

However, when a display panel is driving a plurality of data lines with a plurality of pixel data of a picture, noise is easily generated during or between the transmission of these pixel data, and furthermore, excessive noise affects the touch function.

For example, data signals in the pixel data are provided by a data driving circuit, and can be alternately provided to different data lines through a demultiplexer. When the data driving circuit outputs the data signals to these data lines, charge sharing occurs due to different voltage levels during switching between different data lines if data signals are different from each other. Noise caused by charge sharing often leads to malfunction of touch operation. Therefore, to propose a driving method capable of reducing panel noise is one of the main issues in the technical field.

A display driving device and a driving method thereof of the present invention can reduce noise generated during the driving of a display panel.

The display driving device of the present invention includes a first data line, a first switch, a first storage unit, and a data output unit. The first switch is electrically connected between the first data line and the data output unit, and the data output unit is further electrically connected to the first storage unit.

In a first closing period of the first switch, the data output unit outputs a first data signal to the first data line through the first switch, and the first storage unit stores the first data signal received from the data output unit.

After the first closing period and before a second closing period of the first switch, the first storage unit charges the data output unit with the first data signal so that the data output unit and the first data line are at the same voltage level.

The driving method of the present invention is applicable to the foregoing driving device, and the driving method includes:

in the first closing period of the first switch, outputting, by the data output unit, the first data signal to the first data line through the first switch, and outputting the first data signal to the first storage unit;

in the second closing period of the first switch, outputting, by the data output unit, a third data signal to the first data line through the first switch, and outputting the third data signal to the first storage unit; and

before the step of outputting the third signal, charging, by the first storage unit, the data output unit with the first data signal so that the data output unit and the first data line are at the same voltage level.

A display of the present invention includes a data driver, a plurality of data lines, a multiplexing unit, a data output unit, and a plurality of storage units. An output pin of the data driver is configured to output a data signal, and the data output unit and the multiplexing unit are connected between the data driver and the data lines. The data output unit is electrically connected between the multiplexing unit and the data driver, and the data output unit outputs the data signal from the data driver to the multiplexing unit. The multiplexing unit includes a plurality of first switches, each first switch including a first input end, a first output end, and a first control end, the first output end being connected to a data line.

The first control ends of these first switches connect the first input end and the first output end according to a selection signal, and the data output unit outputs, the data signal from the data driver through the first switch to the data line to which the closed first switch is connected.

Each storage unit is electrically connected to the data output unit, and is connected to one of the first switches. The storage unit includes a second switch, a third switch, and a capacitor. The second switch including a second input end, a second output end, and a second control end. The second input end is electrically connected to the data output unit and the first switch. The selection signal for closing the first switch also serves to close the second switch through the second control end. The third switch includes a third input end, a third output end, and a third control end. The third input end is electrically connected to the second output end of the second switch, and the third output end is electrically connected to the data output unit. The third control end electrically connects the third input end and the third output end according to a horizontal enable signal. The capacitor is electrically connected to the second output end and the third input end.

When the second switch is closed according to the selection signal, the capacitor stores the data signal; when the third switch is closed according to the horizontal enable signal, the capacitor charges the data output unit.

As described above, the display driving device and the driving method thereof of the present invention can be used to store a data signal transmitted to a data line using the storage unit, and charge the data output unit with the stored data signal when the signal is to be transmitted to the same data line next time. Noise is reduced by reducing the voltage level difference between elements. A display including the display driving device of the present invention also has low noise.

In order to further the understanding of the present disclosure, reference is made to the following detailed description illustrating the embodiments and examples of the present disclosure. The description is for illustrative purpose only and is not intended to limit the scope of the claim.

FIG. 1 is a functional diagram illustrating a display according to a first embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of a display panel and a driving device according to a first embodiment of the present invention;

FIG. 3 is a schematic circuit diagram of a driving device according to a first embodiment of the present invention;

FIG. 4 is a schematic signal diagram of a driving device according to a first embodiment of the present invention.

A display driving device and a driving method provided in the present invention can be applied to a liquid crystal display (LCD). Preferably, the display driving device and the driving method provided in the present invention can be applied to a multiplexer (MUX) driven LCD.

Referring to FIG. 1 , a display 50 according to a first embodiment of the present invention includes a display panel 51 and a driving device 100 . In this embodiment, the display device 50 is an LCD, and the display panel 51 is a liquid crystal panel. The driving device 100 includes a driving control circuit 102 , a scan control circuit (Scan driver) 101 , a multiplexing unit 130 , an output storage circuit 120 , a data driving circuit (Data driver) 110 , a timing control circuit 104 (timing controller, T con), and a voltage source conversion circuit 103 .

The display panel 51 includes a plurality of pixel electrodes, a plurality of scan lines and a plurality of data lines (not shown) connected to the pixel electrodes. The scan control circuit 101 is connected to these scan lines to output scan signals, and the data driving circuit 110 is connected to these data lines through the output storage circuit 120 and the multiplexing unit 130 to output data signals. The timing control circuit 104 converts a video signal provided to the display 50 into a data signal for the data driving circuit 110 , and controls the time for driving the data line of the display panel 51 . The voltage source conversion circuit 103 generates a voltage source required for each circuit from an external power source. The above is merely exemplified to illustrate the technical features of the present invention, but the present invention is not limited to the foregoing layout. A person skilled in the art can replace the aforementioned components according to actual needs to achieve the same function. Detailed features of the driving device 100 proposed in the present invention is further described below with reference to specific drawings, and in order to describe the detailed features and the connections, some components are omitted in the drawings, which are not intended to limit the present invention.

It should be understood that, although terms such as “first,” “second,” and “third,” are used in the following description to describe various components; however, these components should not be limited by these terms. These terms are merely used to distinguish one component from another. Therefore, “first component”, for example, can also be referred to as “second component” without departing from the teachings herein.

Referring to FIG. 2 , the display panel 51 has a plurality of scan lines S 1 -S 4 and data lines D 1 -D 12 . The data driving circuit 110 includes an output pin (not shown), and the data signal is outputted via the output pin through the output storage circuit 120 and the multiplexing unit 130 to the data lines D 1 -D 12 . The driving device 100 connected to the data line D 1 is used as an example. The driving device 100 includes a first switch M 1 , a data output unit 121 , and a first storage unit 122 A. When the first switch M 1 is closed during a first closing period, the data driving circuit 110 outputs a data signal to the data line D 1 through the data output unit 121 , and the storage unit 122 A receives the data signal from the data driving circuit 110 and stores the data signal. After the first closing period, the storage unit 122 A stores the voltage level of the data line D 1 .

The storage unit 122 A of this embodiment enables the voltage level of the data output unit 121 to return to the voltage level of the data line D 1 during the first closing period when the data driving circuit 110 provides a data signal to the data line D 1 next time. When the data driving circuit 110 is to provide the data signal to the data line D 1 again after the first closing period of the first switch M 1 , the first switch M 1 is closed during a second closing period. Before the second closing period, the first storage unit 122 A charges the data output unit 121 with the data signal during the first closing period so that the voltage level of the data output unit 121 is at the same voltage level with the data line D 1 . In this way, charge sharing is avoided or reduced when the first switch M 1 is closed during the second closing period. The first switch M 1 may be a transistor, and the connection between the data line D 1 and the data output unit 121 is controlled a gate signal.

For the data line D 3 that also receives, the data signal from the data driving circuit 110 through the foregoing data output unit 121 and the second switch M 2 , a storage unit 122 B of the driving device 100 can store the data signal thereof so that the next time a data signal is outputted to the data line D 3 , the data output unit 121 may be charged by the storage unit 122 B in a manner such that the voltage level of the data line D 3 is the same as the voltage level of the data output unit 121 . The second switch M 2 may be a transistor, and the connection between the data line D 3 and the data output unit 121 is controlled via a gate signal.

When the driving device 100 of this embodiment provides data signals to the data lines D 1 and D 3 through the data output unit 121 , with the storage units 122 A and 122 B, the first switch M 1 is closed when the data line D 1 and the data output unit 121 are at the same voltage level, and the second switch M 2 is closed when the data line D 3 and the data output unit 121 are at the same voltage level, thereby reducing or even avoiding charge sharing.

For example, when the first switch M 1 and the second switch M 2 are provided by the demultiplexer 131 in the multiplexing unit 130 , when the data driving circuit 110 sequentially allocates data signals to the data lines D 1 and D 3 through the demultiplexer 131 , the storage unit 122 A stores the voltage level of the data line D 1 after the data line D 1 receives the data signal, and the storage unit 122 B stores the voltage level of the data line D 3 after the data line D 3 receives the data signal. Before the demultiplexer 131 switches between the data lines D 1 and D 3 , the voltage level of the data output unit 121 can be charged by the storage unit 122 A before a data signal is to be transmitted to the data line D 1 next time, and charged by the storage unit 122 B before a data signal is to be transmitted to the data line D 3 next time, so that when the first switch M 1 or the second switch M 2 is closed, the voltage level of the data output unit 121 can be the same as the voltage level of the data line D 1 or the data line D 3 .

This embodiment is exemplified using demultiplexers 131 of two data output ends, but the present invention is not limited to the setting of the multiplexer or the demultiplexer in the multiplexing unit 130 , nor is it limited to a number of input ends or output ends in these assemblies. A person with ordinary skill in the technical field of the present invention may reduce noise generated by the multiplexing unit 130 during switching of these data lines D 1 to D 12 using the technical solutions proposed by the present invention.

In particular, referring to FIG. 3 , the storage unit 122 A of this embodiment includes a third switch 123 A, a first capacitor C 1 , and a fourth switch 125 A. The third switch 123 A is connected to the fourth switch 125 A, and the first capacitor C 1 is connected to a point where the third switch 123 A and the fourth switch 125 A are connected to each other.

In this embodiment, the first switch M 1 is enabled during the first closing period, so that the data signal can be transmitted to the data line D 1 and a display capacitor P 1 . During the first closing period in which the first switch M 1 is closed, the third switch 123 A is also switched on. During this period, the first capacitor C 1 can store the data signal from the data driving circuit 110 through the third switch 123 A. After the first closing period ends, the data signal stored in the first capacitor C 1 includes the voltage level of the data line D 1 and the data output unit 121 during the first closing period.

After the first switch M 1 is disabled, the data output unit 121 provides another data signal to the data line D 3 , wherein the voltage level of the data signal provided to the data line D 3 is different from that of the data signal provided to the data line D 1 . After the data signal is provided to the data line D 3 , the fourth switch 125 A is switched on before the first switch M 1 is closed again, so that the data output unit 121 can be charged with the voltage level during the first closing period using the first capacitor C 1 , and the voltage level of the data output unit 121 when the first switch M 1 is closed again during the second closing period can be the same as the voltage level of the data line D 1 .

In another aspect, the second storage unit 122 B of this embodiment includes a fifth switch 123 B, a second capacitor C 2 , and a sixth switch 125 B. The fifth switch 123 B is connected to the sixth switch 125 B, and the second capacitor C 2 is connected to a point at which the fifth switch 123 B and the sixth switch 125 B are connected to each other.

In this embodiment, the second switch M 2 is enabled during the second closing period, so that the data signal can be transmitted to the data line D 3 and a display capacitor P 3 . After the first closing period of the first switch M 1 , the sixth switch 125 B is first switched on before the second switch M 2 is closed, so that the second capacitor C 2 charges the data output unit 121 with a data signal stored last time, and the voltage level of the data output unit 121 is the same as that of the data line D 3 when the second switch M 2 is closed.

When the second switch M 2 is closed, the fifth switch 123 B is also switched on, and the data signal that is outputted from the data driving circuit 110 can be transmitted to the data line D 3 and the second capacitor C 2 . The second capacitor C 2 receives the data signal through the fifth switch 123 B during a closing period of the second switch M 2 , and the second capacitor C 2 stores the data signal, so that the fifth switch 123 B and the sixth switch 125 B can maintain at the same voltage level same as that of the data line D 3 .

After the second switch M 2 is disabled, the voltage level of the data output unit 121 after the second closing period of the first switch M 1 is the same as the voltage level of the data line D 1 , but is different from the voltage level of the data line D 3 . The second capacitor C 2 charges the data output unit 121 by switching on the sixth switch 125 B, so that the voltage level of the data output unit 121 returns to the same as that of the data line D 3 .

The driving method for the driving device of the present invention is further described below from the perspective of driving signals. Referring first to FIG. 3 , the first switch M 1 and the third switch 123 A are controlled using a signal MUX 1 , the second switch M 2 and the fifth switch 123 B are controlled using a signal MUX 2 , the fourth switch 125 A is controlled using a horizontal enable signal S 1 , and the sixth switch 125 B is controlled using horizontal enable signal S 2 .

Referring to FIG. 4 , the signals MUX 1 and MUX 2 are used to sequentially close the foregoing switches M 1 and 123 A and the switches M 2 and 123 B in one cycle of a timing signal CLK. The first closing period of the first switch M 1 starts, at time t 1 . At this time, with the output of the data signal, the voltage level (signal S 3 ) of the data output unit 121 changes the voltage level of the data line D 1 and a voltage level of the first capacitor C 1 . After the first closing period ends and before a time t 3 of the second switch M 2 starts, the sixth switch 125 B is switched on at time t 2 so that the second capacitor C 2 can charge the data output unit 121 , thereby enabling the voltage level (signal S 3 ) of the data output unit 121 to be the same as the voltage level of the second capacitor C 2 .

After the second switch M 2 is closed by the signal MUX 2 , signal S 1 switches on the fourth switch 125 A at time t 4 , so that the voltage level (the signal S 3 ) of the data output unit 121 is again the same as the voltage level of the first capacitor C 1 . The voltage levels (signal S 3 ) of the data output unit 121 after time t 4 and after time t 1 are the same, and are also the same as the voltage level of the data line D 1 .

After the first switch M 1 is closed by the signal MUX 1 , the signal S 2 is switches on the sixth switch 125 B at time t 6 , so that the voltage level (signal S 3 ) of the data output unit 121 is again the same as the voltage level of the second capacitor C 2 . The voltage levels (signal S 3 ) of the data output unit 121 after the time t 6 and after the time t 3 are the same, and are also the same as the voltage level of the data line D 3 .

In summary, in the driving method for the display driving device proposed in the present invention, during each driving of a data line, with the help of the first storage unit, the data output unit can return to a voltage level before outputting a data signal to a data line, wherein the voltage level is that of the data output unit and the data line after the last time the data output unit outputs a data signal to the data line, so that both the data output unit and the data line can start receiving a data signal at the same voltage level, thereby reducing charge sharing to reduce noise. Since the driving device included in the display device proposed in the present invention includes the first storage unit, the voltage level at which each time the data line of the display panel in the display receives a data signal is the same as the voltage level of the data output unit of the driving device, so that overall noise can be reduced.

The descriptions illustrated supra set forth simply the embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.