KR100920484B1 - Backlight driving system for liquid crystal display device - Google Patents

Abstract

The present invention relates to a backlight driving system of a liquid crystal display device, comprising: a system circuit unit for generating and outputting a dimming signal for controlling a raw backlight; An inverter circuit unit configured to output the raw dimming control dimming signal inputted from the system circuit unit, and to receive a final dimming signal for backlight control to perform light emission control of a backlight; A liquid crystal display backlight driving system including a control circuit unit which receives the raw backlight control dimming signal from the inverter circuit unit and generates the final backlight control dimming signal and outputs the dimming signal to the inverter circuit unit, is identical to a general-purpose liquid crystal display device. While using the system circuit part, DCR driving can improve visibility and reduce power consumption.

Description

Backlight driving system for liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight driving system. In particular, the present invention relates to a backlight driving system for generating a new backlight dimming control signal that can be applied to driving an application for reducing the backlight power consumption and improving the visibility of a display screen. It is about the system.

LCDs have advantages of small size, thinness, and low power consumption, and are being used as notebook computers, office automation devices, and audio / video devices. In particular, an active matrix type liquid crystal display device using a thin film transistor as a switch element is suitable for displaying a dynamic image.

Referring to the block diagram of FIG. 1, such a liquid crystal display device may include a liquid crystal panel 10, a backlight unit 20, a control circuit unit 30, a system circuit unit 40, and an inverter circuit unit 50. Can be configured.

In brief, the liquid crystal panel 10 includes a plurality of liquid crystal pixels to display an image through input of image data, and the backlight unit 20 is an illumination device for supplying light to the liquid crystal panel 10. It includes.

The control circuit unit 30 constitutes a timing controller to perform image display control by supplying image data to the liquid crystal panel 10, and the system circuit unit 40 is configured such as a TV system or a graphic card. As an external interface circuit, the control circuit unit 30 provides image data and a plurality of driving signals.

The inverter circuit unit 50 performs light emission control of the backlight unit 20, and receives a dimming signal for backlight control from the control circuit unit 30 or the system circuit unit 40.

Recently, a liquid crystal display device having such a basic configuration has been proposed a driving method capable of securing visibility while reducing power consumption of the backlight unit 20.

The purpose of the driving method is to increase the contrast by controlling the brightness of the backlight to a minimum in low gradation, in particular black, and in particular, to improve the display quality of a moving image by naturally making the change between gradations in a video. There is an advantage in that the power consumption is reduced. One method of such a driving method may include converting low grayscale image data to increase the grayscale and lowering the average luminance of the backlight.

FIG. 2 is a configuration diagram of a liquid crystal display driving system for explaining a method for improving contrast in a liquid crystal display according to the related art. The control circuit unit 30, the system circuit unit 40, and the inverter circuit unit 50 are illustrated in FIG. 1. ) To illustrate only.

First, as a method of providing a backlight control dimming signal (VBR) from the system circuit unit 40 to the inverter 50 side, a VBR-A method providing only an analog voltage and a VBR that can be selected and provided among a PWM signal and an analog voltage There is a -B method.

The first VBR-B dimming signal VBR-B1 provided from the dual system circuit unit 40 is connected to the connector 42 of the system circuit unit 40 and the connector 34 of the control circuit unit 30. The signal controller CB2 is transferred to the control circuit unit 30, and the timing controller 32 converts the DCR driving enable signal (DCR-EN) from the system circuit unit 40 when the DCR driving enable signal (DCR-EN) is input. According to the image data, a dimming signal (DACOUT) for backlight control of the VBR-B method is separately generated and output.

Accordingly, the first MUX M1 receives one of the first VBR-B dimming signal VBR-B1 provided from the system circuit unit 40 and the dimming signal DACOUT for backlight control separately generated by the timing controller 32. The second VBR-B dimming signal VBR-B2 is transmitted to the system circuit 40 through the second signal cable CB2.

Accordingly, the system circuit 40 may select one of the second VBR-B dimming signal VBR-B2 or the first VBR-B dimming signal VBR-B1 through a second MUX M2. The selected VBR-B dimming signal and the VBR-A dimming signal may include a first signal cable CB1 connecting the connector 44 of the system circuit part 40 and the connector 52 of the inverter circuit part 50. ) Is transferred to the inverter circuit unit 50 and used for backlight dimming control.

In summary, in order to improve the contrast driving, the control circuit unit 30 generates a VBR-B type backlight dimming signal (ie, DACOUT) and VBR-B type dimming input from the system circuit unit 40. One of the signals (ie, VBR-B1) is selected and retransmitted to the system circuit unit 40 (ie, VBR-B2), whereby the system circuit unit 40 receives the VBR received from the control circuit unit 30. Adopt a method of selecting one of the dimming signal (VBR-B2) or the self-generated VBR-A dimming signal (VBR-B1) to provide to the inverter circuit unit 50 as a dimming signal for backlight control. Doing. Of course, the backlight dimming signal of the VBR-A method is also provided to the inverter circuit unit 50 through the first signal cable CB1.

However, the method of providing the dimming signal for controlling the backlight for driving the contrast improvement as described above has a disadvantage in that general use of the system circuit part 40 is difficult due to different circuit part designs for each LCD manufacturer.

For example, the manufacturers of the two connectors 34 and 42 for connecting the second signal cable CB2 electrically connecting the control circuit unit 30 and the system circuit unit 40 to various liquid crystal display manufacturers. The pin-maps are different from each other, and thus it is not easy to realize a signal transmission for driving the contrast improvement. That is, the control circuit unit 30 is configured to transmit the DCR driving enable signal (DCR-EN) signal and the first and second VBR-B dimming signals VBR-B1 and VBR-B2 to improve contrast and drive low power consumption. Although at least three pins are required between the system circuit unit 40 and the system circuit unit 40, since there is no such pin margin in a general system circuit unit for a liquid crystal display, there is a disadvantage in that a pin-map of the system circuit unit must be newly designed and manufactured.

The present invention has been made to solve the above problems, and to provide a backlight driving system of the liquid crystal display device improved to enable the universal use of the system circuit unit (40 of Figure 2) for each liquid crystal display device manufacturer.

To this end, in the present invention, the second cable (CB2 of FIG. 2), which is difficult to apply the same pin-map, is minimized so as to generalize, and the connectors 36 and 54 between the control circuit unit 30 and the inverter circuit unit 50 are used. The use of a third signal cable (CB3 in FIG. 2) provided for connection enables the universal use of the system circuitry 40.

In order to achieve the above object, the present invention includes a system circuit unit for generating and outputting a dimming signal for controlling the raw backlight; An inverter circuit unit configured to output the raw dimming control dimming signal inputted from the system circuit unit, and to receive a final dimming signal for backlight control to perform light emission control of a backlight; The present invention proposes a liquid crystal display backlight driving system including a control circuit unit which receives the source backlight control dimming signal from the inverter circuit unit and generates the final backlight control dimming signal and outputs the dimming signal to the inverter circuit unit.

The liquid crystal display backlight driving system includes: a first signal cable for performing an electrical circuit connection between the system circuit portion and the inverter circuit portion; A second signal cable for performing an electrical circuit connection between the system circuit portion and the control circuit portion; And a third signal cable for performing an electrical circuit connection between the inverter circuit portion and the control circuit portion.

The liquid crystal display backlight driving system is characterized in that the system circuit portion, the inverter circuit portion, and the control circuit portion is characterized in that the connector for performing electrical circuit connection of the first signal cable to the third signal cable, respectively. .

In the liquid crystal display backlight driving system, the system circuit unit generates an enable signal for controlling the method of generating the dimming signal for controlling the last backlight and transmits the enable signal to the control circuit unit through the second signal cable.

The system circuit unit may generate an enable signal for controlling a method of generating the final dimming signal for controlling the last backlight and transmit the enable signal to the control circuit unit through the first signal cable, the inverter circuit unit, and the third signal cable. do.

The third signal cable may include a terminal for outputting the dimming signal for controlling the source backlight from the inverter circuit unit and a terminal for outputting the dimming signal for controlling the last backlight control from the control circuit unit, respectively.

The system circuit unit may be a TV system or a graphic card that provides image data to the control circuit unit.

In the liquid crystal display backlight driving system, the dimming signal for controlling the original backlight and the dimming signal for controlling the last backlight may be PWM signals or analog voltage signals, respectively.

The liquid crystal display backlight driving system, wherein the control circuit unit, the data conversion unit for converting the gray level of the input image data, and the last backlight control for the input dimming signal for the original backlight control corresponding to the grayscale conversion image data A timing controller including a final dimming signal generator for converting the dimming signal into an output signal; A first selection switch for selecting an input terminal to the timing controller according to a type of the dimming signal for controlling the source backlight; And a second selection switch for selecting an output terminal of the timing controller according to the type of the dimming signal for controlling the last backlight.

In the liquid crystal display backlight driving system, the final backlight control dimming signal is a dimming signal converted to lower the emission time or the luminance of the backlight compared to the dimming signal for controlling the original backlight.

The control circuit unit may generate the final dimming signal for controlling the backlight by combining the dimming signal for controlling the original backlight and the dimming signal for controlling the backlight generated by the timing controller.

The control circuit unit may generate one of the dimming signal for controlling the last backlight by selecting one of the dimming signal for controlling the original backlight and the dimming signal for controlling the gray level conversion generated by the timing controller.

On the other hand, the present invention is a liquid crystal panel for displaying an image; A backlight unit for supplying light to the liquid crystal panel; A system circuit unit for generating and outputting a dimming signal for controlling a raw backlight to control the backlight unit; An inverter circuit unit configured to output the raw dimming control dimming signal inputted from the system circuit unit, and to receive a final dimming signal for backlight control to perform light emission control of a backlight; And a control circuit unit configured to receive the raw backlight control dimming signal through the inverter circuit unit and generate the final backlight control dimming signal and output the dimming signal to the inverter circuit unit.

The system circuit unit may generate an enable signal for turning on / off a function of generating the final backlight control dimming signal of the control circuit unit and directly delivering the enable signal to the control circuit unit.

On the other hand, the present invention comprises the steps of generating and outputting a dimming signal for controlling the raw backlight in the system circuit unit; Outputting the raw backlight control dimming signal input from the system circuit unit in an inverter circuit unit, and receiving a final dimming signal for backlight control to perform backlight emission control; The control circuit unit receives the dimming signal for controlling the source backlight from the inverter circuit unit, and generates and outputs the final dimming signal for controlling the backlight.

According to the present invention having the above characteristics, it is possible to improve visibility and reduce power consumption by using contrast and driving low power consumption while using the liquid crystal display device in various system circuits.

In particular, by performing backlight dimming control for improving contrast and driving low power consumption through the cable of the existing configuration, a separate design change is not required for the connection of the system circuit part and the control circuit part, so that it can be easily applied to all liquid crystal display devices. There is an advantage.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a block diagram illustrating a backlight driving system of a liquid crystal display according to a first embodiment of the present invention, and includes a system circuit unit 100, an inverter circuit unit 200, and a control circuit unit 300.

The system circuit unit 100 is a TV system or a graphic card that provides the image data (D), the main clock (CLK), the horizontal / vertical synchronization signal (H / Vsync), and the like to the control circuit unit 300, in particular, a liquid crystal display. In order to control the light emission of the backlight configured in the device, a dimming signal VBR-Bs for controlling the backlight of a selected type of PWM or analog voltage is generated and provided to the control circuit 300 through the inverter circuit 200.

In addition, the user may operate the liquid crystal display in a normal mode or an advanced mode such as contrast and power consumption improvement. For this purpose, the system circuit unit 100 may use the advanced mode enable signal AM-. EN) is generated and transmitted directly to the control circuit unit 300. For example, when the advanced mode enable signal AM-EN is “0” (low, disable), contrast and power consumption improvement driving is turned off, and the control circuit unit 300 performs an operation such as image data gray level conversion. By performing the signal generation operation for backlight emission control without any operation, the liquid crystal display is operated in the normal mode, and when the advanced mode enable signal AM-EN is "1" (high, enable), contrast and power consumption improvement driving are turned on. The control circuit unit 300 is turned on to perform signal generation and image data gray level conversion for backlight emission control, and the liquid crystal display is operated in a contrast and power consumption improvement mode.

The inverter circuit unit 200 mounts an inverter circuit for controlling light emission of the backlight, and controls the light emission of the backlight according to a dimming signal for backlight control provided from the system circuit unit 100 or the control circuit unit 300. Perform In particular, the inverter circuit unit 200 passes the raw backlight control dimming signal (VBR-Bs) input from the system circuit unit 100 to the control circuit unit 300, and the final backlight from the control circuit unit 300. The backlight control is performed by receiving the control dimming signal VBR-Bf.

Referring to FIG. 4, the control circuit unit 300 uses a video controller provided by the system circuit unit 100, a timing controller 310 to control an image display using a liquid crystal panel using a main clock and a vertical / horizontal synchronization signal. In particular, the timing controller 310 includes a data converter 312 for performing gradation conversion of the image data through a method such as data stretching to drive a contrast and power consumption improvement mode. The final dimming signal generation unit 314 is further configured to generate a final dimming signal VBR-Bf for controlling the backlight emission time or the luminance of the backlight to be suitable for driving the contrast and power consumption improvement mode.

At this time, the control circuit unit 300 operates differently according to the advanced mode enable signal AM-EN of the system circuit unit 100. For example, the advanced mode enable signal AM-EN is set to "0" (low). If disabled, the raw backlight control dimming signal (VBR-Bs) is unmodified or synchronized to the timing controller 310 to generate the final backlight control dimming signal (VBR-Bf), and the advanced mode enable signal ( When AM-EN is “1” (high, enable), the final backlight control is modulated by modulating and synthesizing the dimming signal for controlling the raw backlight (VBR-Bs) and the dimming signal for controlling the grayscale conversion backlight generated by the timing controller 310. The dimming signal VBR-Bf is generated. In other words, the control circuit unit 300 contrast and power consumption of the system circuit unit 100 through the advanced mode enable signal AM-EN transmitted directly from the system circuit unit 100 to the control circuit unit 300 by the user's selection. Improvement drive can be controlled.

Meanwhile, the selection control terminal for selecting one of the general mode and the advanced mode may be configured inside the timing controller 310 or may be configured outside the timing controller 310.

In addition, the control circuit unit 300 is provided in the form of an IC chip (IC-chip) in the timing controller 310 in which the input / output terminal of the signal is set, the dimming signal input / output terminal (PWM-) of the PWM or analog voltage type The first selection switch 320 and the second selection switch 330 are further configured to select IN, PWM-OUT, DC-IN, and DC-OUT. In this case, the first selection switch 320 and the second selection switch 330 may each be a switch using a resistance element.

In the first embodiment, the first and second selection switches 320 and 330 are configured externally to the timing controller 310. In another embodiment, the first and second selection switches 320 and 330 are the timing controllers. It may be configured to be integrated into the integrated 310.

In addition, as shown in Figure 3, the system circuit unit 100, the inverter circuit unit 200 and the control circuit unit 300 between the first signal cable (CB1) to the third signal cable (for electrical circuit connection and signal transmission) CB3) is used. In addition, it is natural that the first to sixth connectors CN1 to CN6 for connecting the first and third signal cables CB1 to CB3 are configured.

Although not shown in FIG. 3, the liquid crystal display further includes a liquid crystal panel for displaying an image and a backlight unit for supplying light to the liquid crystal panel in addition to the backlight driving system, and the inverter circuit unit 200 of the backlight driving system includes a backlight unit. Is connected to control the light emission of the backlight, and the control circuit unit 300 of the backlight driving system is connected to the liquid crystal panel of the liquid crystal display to display an image.

The features of the above configuration are proposed for general use of the system circuit unit 100. For example, in the case of a conventional liquid crystal display for driving a contrast and power consumption improvement mode, the system is described as described in the related art. Separate signal transmission such as the advanced mode enable signal AM-EN and the first and second VBR-B dimming signals VBR-B1 and VBR-B2 are required between the circuit unit 100 and the control circuit unit 300. If there is a liquid crystal display device in which the pin-map of the connector between the two circuit units 100 and 300 is not compatible, the first connector CN1 of the control circuit unit 300 side when the backlight driving system of the above concept is applied. And the second connector CN2 of the system circuit unit 100 side of the advanced mode enable signal AM-EN for selecting a driving mode of the liquid crystal display, that is, an advanced mode such as improving contrast and power consumption. Only one transfer pin Additionally needed and this can be applied to the inverter circuit 200 and control circuit 300 according to the first embodiment of the present invention to a liquid crystal display device system circuit portion for which it is possible to use a dummy pin, driving only the normal mode. That is, it is possible to realize advanced mode driving with improved contrast and power consumption, such as DCR (dynamic contrast ratio) or OPC (optimal power control), without designing and manufacturing a new pin-map. There is an advantage that can be applied.

Meanwhile, in the first embodiment, the advanced mode enable signal AM-EN is controlled from the system circuit unit 100 through the first and second connectors CN1 and CN2 and the second signal cable CB2. In another embodiment, the advanced mode enable signal AM-EN is transmitted from the system circuit unit 100 to the inverter circuit unit 200 through the third and fourth connectors CN3 and CN4 and the first signal cable. And may be transferred from the inverter circuit unit 200 to the control circuit unit 300 through the fifth and sixth connectors CN5 and CN6 and the third signal cable CB3.

In this case, the advanced mode enable signal AM-EN is transmitted to the control circuit unit 300 by the inverter circuit unit 200 so that the first connector CN1 of the control circuit unit 300 side and the system circuit unit ( The second connector CN2 on the side 100 has an additional dummy for transmitting the advanced mode enable signal AM-EN for selecting a driving mode of the liquid crystal display, that is, a normal mode or an advanced mode such as contrast and power consumption improvement. No pin is required. Therefore, it is possible to more stably apply the inverter circuit portion and the control circuit portion for the liquid crystal display device capable of driving the advanced mode such as the improvement of the contrast and the power consumption without changing the structure to the system circuit portion for the liquid crystal display device driven only in the normal mode. That is, it is possible to realize advanced mode driving with improved contrast and power consumption, such as DCR (dynamic contrast ratio) or OPC (optimal power control), without designing and manufacturing a new pin-map. There is an advantage that can be applied.

A more specific application example is described below with reference to the second and third embodiments.

5 is a view for explaining a backlight driving system of a liquid crystal display according to a second embodiment of the present invention.

The configuration of the driving system is the same as the case of FIG. 3 described above, in which the backlight control dimming signal input to the inverter circuit unit 200 through the VBR-B method from the system circuit unit 100 is a PWM signal.

First, the user of the backlight driving system operates the first selection switch 320 and the second selection switch 330 of the control circuit unit 300 to respectively use the input / output terminals of the timing controller 310 to PWM-. Applies to IN and PWM-OUT.

Accordingly, the image data D, the main clock CLK, the horizontal / vertical synchronization signal H / Vsync, etc. output from the system circuit unit 100 are controlled through the second signal cable CB2. The system circuit unit 100 generates the advanced mode enable signal AM-EN according to the user's selection of the liquid crystal display device driving mode, and controls the control circuit unit through the second signal cable CB2. Send to 300. For example, when the advanced mode enable signal AM-EN is "0" (low, disable), the contrast and power consumption improvement driving is turned off, and the control circuit unit 300 performs an operation such as image data gradation conversion. By performing the signal generation operation for controlling the backlight emission without performing, the liquid crystal display is operated in the normal mode, and when the advanced mode enable signal AM-EN is "1" (high, enable), driving of contrast and power consumption improvement is performed. When turned on, the control circuit unit 300 performs operations such as signal generation and image data gray level conversion for backlight emission control, and the liquid crystal display is operated in an advanced mode of improving contrast and power consumption.

The dimming signal VBR-Bs for controlling the raw backlight of the PWM method is transferred to the inverter circuit unit 200 through the first signal cable CB1. The timing controller 310 performs gradation conversion of the image data D in order to drive an advanced mode of improving contrast and power consumption in the data converter 312 of FIG. 4.

Thereafter, the inverter circuit unit 200 transmits the source backlight control dimming signal VBR-Bs to the control circuit unit 300 through the third signal cable CB3. That is, the raw backlight control dimming signal VBR-Rs of the system circuit unit 100 is transmitted directly to the control circuit unit 300 by bypassing the inverter circuit unit 200 instead of being directly transmitted to the control circuit unit 300.

The raw backlight control dimming signal VBR-Bs transmitted to the control circuit unit 300 is input to the PWM-IN terminal of the timing controller 310 by the first selection switch 320, and thus the timing controller. Numeral 310 denotes a new backlight control dimming signal VBR-Bf, which is a new backlight control dimming signal corresponding to the gray level conversion of the image data performed by the data converter 312 through the final dimming signal generator 314 of FIG. 4. Create

In this case, the final backlight control dimming signal VBR-Bf generated by the final dimming signal generator 314 is used to control the raw backlight control dimming signal VBR-Bs to improve the contrast and power consumption of the LCD. It is characterized in that it is set to lower the emission time or the luminance of the backlight compared to).

The final backlight control dimming signal VBR-Bf generated by the final dimming signal generator 314 is outputted to the PWM-OUT terminal by the second selection switch 330, and the third signal cable CB3. It is transmitted to the inverter circuit unit 200 through. Accordingly, the inverter circuit unit 200 performs backlight dimming control corresponding to driving the advanced mode of contrast and power consumption by using the final dimming signal VBR-Bf.

When performing backlight dimming control according to the DCR driving using the PWM signal as described above, the backlight dimming control according to the DCR driving may be performed by using the existing third signal cable CB3.

Therefore, it is not necessary to consider the change of the system circuit unit 100 or the pin-map of the connection of the second signal cable CB2 between the system circuit unit 100 and the control circuit unit 300. There is an advantage that the universal use of 100) is possible.

6 illustrates a backlight driving system of a liquid crystal display according to a third exemplary embodiment of the present invention.

The configuration of the driving system is the same as the case of FIG. 3, wherein the dimming signal for backlight control input to the inverter circuit unit 200 from the system circuit unit 100 through the VBR-B method is an analog voltage (DC voltage). .

First, as described above, the user of the backlight driving system operates the first selection switch 320 and the second selection switch 330 of the control circuit unit 300 to use the timing controller 310. Apply input / output terminals as DC-IN and DC-OUT, respectively.

Accordingly, the image data D, the main clock CLK, the horizontal / vertical synchronization signal H / Vsync, etc. output from the system circuit unit 100 are controlled through the second signal cable CB2. The system circuit unit 100 generates the advanced mode enable signal AM-EN according to the user's selection of the liquid crystal display device driving mode, and controls the control circuit unit through the second signal cable CB2. Send to 300. For example, when the advanced mode enable signal AM-EN is "0" (low, disable), the contrast and power consumption improvement driving is turned off so that the control circuit unit 300 generates a signal for controlling backlight emission. Without performing operations such as image data gradation conversion and the like, the LCD device operates in a normal mode, and when the advanced mode enable signal AM-EN is "1" (high, enable), contrast and power consumption improvement driving are turned on. On, the control circuit unit 300 performs operations such as signal generation and image data gray level conversion for backlight emission control, and the liquid crystal display is operated in an advanced mode of improving contrast and power consumption.

In addition, the dimming signal VBR-Bs for controlling the raw backlight of the analog voltage method is transmitted to the inverter circuit unit 200 through the first signal cable CB1. The timing controller 310 performs gradation conversion of the image data D in order to drive an advanced mode of improving contrast and power consumption in the data converter 312 of FIG. 4.

Thereafter, the inverter circuit unit 200 transmits the source backlight control dimming signal VBR-Bs to the control circuit unit 300 through the third signal cable CB3. That is, the dimming signal VBR-Rs for controlling the original backlight of the system circuit unit 100 is not directly transmitted to the control circuit unit 300, but is transmitted to the control circuit unit 300 by bypassing the inverter circuit unit 200.

The source backlight control dimming signal VBR-Bs transmitted to the control circuit unit 300 is input to the DC-IN terminal of the timing controller 310 by the first selection switch 320, and thus the timing controller. The final backlight control dimming signal VBR-Bf is a new backlight control dimming signal corresponding to the gray level conversion of the image data performed by the data converter 312 through the final dimming signal generator 314 of FIG. 4. )

In this case, the final backlight control dimming signal VBR-Bf generated by the final dimming signal generator 314 is used to control the raw backlight control dimming signal VBR-Bs to improve the contrast and power consumption of the LCD. It is characterized in that it is set to lower the emission time or the luminance of the backlight compared to).

The final backlight control dimming signal VBR-Bf generated by the final dimming signal generator 314 is output to the DC-OUT terminal by the second selection switch 330, and the third signal cable CB3. It is transmitted to the inverter circuit unit 200 through. Accordingly, the inverter circuit unit 200 performs backlight dimming control corresponding to driving the advanced mode of contrast and power consumption by using the final dimming signal VBR-Bf.

At this time, the timing controller 310 is for outputting to various transmission formats such as NTSC, PAL, etc. in order to cope with noise generation such as fringes caused by the transmission of the analog voltage signal in backlight dimming control using analog voltage. ) And a (WPWM) terminal for outputting the sync signal, and in this case, the number of transmission lines of the third signal cable CB3 may be increased by about two lines compared to the second embodiment. That is, when the driving frequency of the liquid crystal panel and the driving frequency of the backlight unit are not synchronized, a mottled spot such as a fringe occurs in the image displayed by the liquid crystal display. To prevent this, the control signal of the liquid crystal panel and the control signal of the backlight unit The signal for synchronizing the signal is transferred from the control circuit unit 300 to the inverter circuit unit 200 through the (REFMODE) terminal and the (WPWM) terminal.

Similar to the above-described second embodiment, the third embodiment uses the analog voltage signal to perform the conventionally configured third signal cable CB3 when the backlight dimming control is performed in accordance with the advanced mode driving for improving contrast and power consumption. The backlight dimming control according to the DCR driving can be performed.

Therefore, it is not necessary to consider the change of the system circuit unit 100 or the pin-map of the connection of the second cable CB2 between the system circuit unit 100 and the control circuit unit 300. ), There is an advantage that can be applied universally.

FIG. 7 is a configuration diagram illustrating a backlight driving system of a liquid crystal display according to a fourth exemplary embodiment of the present invention, and includes a system circuit unit 100, an inverter circuit unit 200, and a control circuit unit 300.

The user may operate the liquid crystal display in a normal mode or an advanced mode such as contrast and power consumption improvement. For this purpose, the system circuit unit 100 may use the advanced mode enable signal AM-EN. Is generated and directly transmitted to the control circuit unit 300 through the first and second connectors CN1 and CN2 and the second signal cable CB2. For example, when the advanced mode enable signal AM-EN is "0" (low, disable), the contrast and power consumption improvement driving is turned off, so that the control circuit unit 300 operates an image data gradation conversion operation. By performing the signal generation operation for controlling the backlight emission without performing, the liquid crystal display is operated in the normal mode, and when the advanced mode enable signal AM-EN is "1" (high, enable), driving of contrast and power consumption improvement is performed. When turned on, the control circuit unit 300 performs operations such as signal generation and image data gray level conversion for backlight emission control, and the liquid crystal display is operated in a contrast and power consumption improvement mode.

In addition, the system circuit unit 100 is a TV system or a graphic card that provides the image data (D), the main clock (CLK), a horizontal / vertical synchronization signal (H / Vsync), etc., to the control circuit unit 300. It provides a backlight control dimming signal (VBR) for controlling the light emission of the backlight configured in the liquid crystal display device. The VBR-A method providing only an analog voltage and the VBR-B method providing a selected one of a PWM signal and an analog voltage are provided. have.

Among them, the first VBR-B dimming signal VRB-B1 provided by the system circuit unit 100 is transmitted to the control circuit unit 300 by bypassing the inverter circuit unit 200. Specifically, the first VBR-B dimming signal is provided. The signal VRB-B1 and the VBR-A dimming signal VBR-A are connected to the third and fourth connectors CN3 and CN4 and the first signal cable connecting the system circuit unit 100 and the inverter circuit unit 200. The first and second VBR-B dimming signals VRB-B1 are transmitted to the inverter circuit unit 200 through CB1, and fifth and sixth connectors CN5 connecting the inverter circuit unit 200 and the control circuit unit 300 to each other. Is transmitted to the control circuit unit 300 through the CN6 and the third signal cable CB3.

The timing controller 310 separately generates and outputs a gradation conversion backlight control dimming signal DACOUT in accordance with the converted image data for driving the advanced mode, and outputs the advanced mode enable signal AM-EN of the system circuit unit 100. According to the first MUX (M1) is the first VBR-B dimming signal (VBR-B1) received through the inverter circuit 200 and the gradation conversion backlight control dimming signal (DACOUT) generated separately from the timing controller 310 One of them is transmitted to the inverter circuit unit 200 through the third signal cable CB3 as the second VBR-B dimming signal VBR-B2.

Accordingly, the inverter circuit unit 200 uses the second VBR-B dimming signal VBR-B2 received from the control circuit unit 300 and the VBR-A dimming signal VBR-A received from the system circuit unit 100. Dimming the backlight.

Meanwhile, in another embodiment, the inverter circuit unit 200 may include a second MUX. The second MUX may include the second VBR-B dimming signal VBR-B2 and the system circuit unit 100 transmitted from the control circuit unit 300. ) Selects one of the first VBR-B dimming signal (VBR-B1) received from the above, and the selected VBR-B dimming signal and the VBR-A dimming signal transmitted from the system circuit unit 100 The inverter circuit unit 200 may be used for backlight dimming control.

In summary, in order to improve contrast and power consumption, the control circuit 300 may include a dimming signal DACOUT for controlling grayscale conversion backlight and a first VBR-B dimming signal input from the system circuit 100. One of the VBR-B1s is selected and retransmitted as the second VBR-B dimming signal VBR-B to the inverter circuit unit 200, whereby the inverter circuit unit 200 receives the first received from the control circuit unit 300. The 2VBR-B dimming signal (VBR-B2) is used as a dimming signal for backlight control or transmitted from the second VBR-B dimming signal (VBR-B2) received from the control circuit unit 300 and the system circuit unit 100. One of the received first VBR-A dimming signals VBR-B1 is selected and used as a dimming signal for backlight control. Of course, the VBR-A type backlight dimming signal VBR-A is also provided to the inverter circuit unit 200 through the first signal cable CB1.

The inverter circuit unit 200 mounts an inverter circuit for controlling light emission of the backlight, and controls the light emission of the backlight according to a dimming signal for backlight control provided from the system circuit unit 100 or the control circuit unit 300. Perform In particular, the inverter circuit unit 200 passes the first VBR-B dimming signal VBR-B2 input from the system circuit unit 100 to the control circuit unit 300 and bypasses the control circuit unit 300. The backlight emits light by receiving the second VBR-B dimming signal VBR-B2 or by selecting one of the first and second VBR-B dimming signals VBR-B1 and VBR-B2. Perform control.

In particular, the control circuit unit 300 operates differently according to the advanced mode enable signal AM-EN of the system circuit unit 100. For example, the advanced mode enable signal AM-EN is set to "0" ( low, disable) to generate the second VBR-B dimming signal VBR-B2 by synchronizing the first VBR-B dimming signal VBR-B1 without modification or to the timing controller 310. If the mode enable signal AM-EN is “1” (high, enable), the first VBR-B dimming signal VBR-B1 and the gradation conversion backlight control dimming signal DACOUT generated by the timing controller 310 are generated. One is selected to generate a second VBR-B dimming signal VBR-B2. In other words, the control circuit unit 300 contrast and power consumption of the system circuit unit 100 through the advanced mode enable signal AM-EN transmitted directly from the system circuit unit 100 to the control circuit unit 300 by the user's selection. Improvement drive can be controlled.

Meanwhile, the selection control terminal for selecting one of the general mode and the advanced mode may be configured inside the timing controller 310 or may be configured outside the timing controller 310.

In addition, as shown in FIG. 7, between the system circuit unit 100, the inverter circuit unit 200, and the control circuit unit 300, a first signal cable CB1 to a third signal cable (for electrical circuit connection and signal transmission). CB3) is used. In addition, it is natural that the first to sixth connectors CN1 to CN6 for connecting the first and third signal cables CB1 to CB3 are configured.

Although not shown in FIG. 7, the liquid crystal display further includes a liquid crystal panel for displaying an image and a backlight unit for supplying light to the liquid crystal panel, in addition to the backlight driving system, and the inverter circuit unit 200 of the backlight driving system includes a backlight unit. Is connected to control the light emission of the backlight, and the control circuit unit 300 of the backlight driving system is connected to the liquid crystal panel of the liquid crystal display to display an image.

The features of the above configuration are proposed for general use of the system circuit unit 100. For example, in the case of a conventional liquid crystal display for driving a contrast and power consumption improvement mode, the system is described as described in the related art. Separate signal transmission such as the advanced mode enable signal AM-EN and the first and second VBR-B dimming signals VBR-B1 and VBR-B2 are required between the circuit unit 100 and the control circuit unit 300. If there is a liquid crystal display device in which the pin-map of the connector between the two circuit units 100 and 300 is not compatible, the first connector CN1 of the control circuit unit 300 side when the backlight driving system of the above concept is applied. And the second connector CN2 of the system circuit unit 100 side of the advanced mode enable signal AM-EN for selecting a driving mode of the liquid crystal display, that is, an advanced mode such as improving contrast and power consumption. Only one transfer pin Additionally needed and this can be applied to the inverter circuit 200 and control circuit 300 according to the fourth embodiment of the present invention to a liquid crystal display device system circuit portion for which it is possible to use a dummy pin, driving only the normal mode. That is, it is possible to realize advanced mode driving with improved contrast and power consumption, such as DCR (dynamic contrast ratio) or OPC (optimal power control), without designing and manufacturing a new pin-map. There is an advantage that can be applied.

Meanwhile, in the fourth embodiment, the advanced mode enable signal AM-EN is controlled from the system circuit unit 100 through the first and second connectors CN1 and CN2 and the second signal cable CB2. In another embodiment, the advanced mode enable signal AM-EN is transmitted from the system circuit unit 100 to the inverter circuit unit 200 through the third and fourth connectors CN3 and CN4 and the first signal cable. The inverter may be transferred from the inverter circuit unit 200 to the control circuit unit 300 through the fifth and sixth connectors CN5 and CN6 and the third signal cable CB3.

In this case, the advanced mode enable signal AM-EN is transmitted to the control circuit unit 300 by the inverter circuit unit 200 so that the first connector CN1 of the control circuit unit 300 side and the system circuit unit ( The second connector CN2 at side 100 has an additional mode for transmitting the advanced mode enable signal AM-EN for selecting a driving mode of the liquid crystal display, that is, a general mode or an advanced mode such as contrast and power consumption improvement. No dummy pins are needed. Therefore, it is possible to more stably apply the inverter circuit portion and the control circuit portion for the liquid crystal display device capable of driving the advanced mode such as the improvement of the contrast and the power consumption without changing the structure to the system circuit portion for the liquid crystal display device driven only in the normal mode. That is, it is possible to realize advanced mode driving with improved contrast and power consumption, such as DCR (dynamic contrast ratio) or OPC (optimal power control), without designing and manufacturing a new pin-map. There is an advantage that can be applied.

1 is a block diagram schematically illustrating a configuration of a general liquid crystal display device.

2 is a configuration diagram of a liquid crystal display driving system for explaining a method for driving contrast improvement in a liquid crystal display according to the related art.

3 is a configuration diagram illustrating a concept of a backlight driving system of a liquid crystal display according to a first embodiment of the present invention.

4 is a block diagram showing a detailed configuration of the control circuit unit 300 of the backlight driving system of the liquid crystal display according to the first embodiment of the present invention.

5 is a view for explaining a backlight driving system of a liquid crystal display according to a second embodiment of the present invention.

6 is a view for explaining a backlight driving system of a liquid crystal display according to a third embodiment of the present invention.

7 is a configuration diagram illustrating a backlight driving system of a liquid crystal display according to a fourth embodiment of the present invention.

<Brief description of the main parts of the drawing>

100: system circuit portion 200: inverter circuit portion

300; Control Circuit 310: Timing Controller

312: data converter 314: final dimming signal generator

Claims (15)

A system circuit unit generating and outputting a dimming signal for controlling a raw backlight; An inverter circuit unit which receives the source backlight control dimming signal from the system circuit unit and receives the final backlight control dimming signal and performs light emission control of the backlight; The control circuit unit which receives the raw backlight control dimming signal from the inverter circuit unit generates the final backlight control dimming signal and outputs the dimming signal to the inverter circuit unit. And a dimming signal for controlling the raw backlight, which is output from the system circuit part, and is input to the control circuit part through the inverter circuit part. The method according to claim 1, A first signal cable for performing an electrical circuit connection between the system circuit portion and the inverter circuit portion; A second signal cable for performing an electrical circuit connection between the system circuit portion and the control circuit portion; A third signal cable performing an electrical circuit connection between the inverter circuit portion and the control circuit portion Backlight driving system of the liquid crystal display device comprising a The method according to claim 2, The system circuit unit, the inverter circuit unit, and the control circuit unit is a backlight driving system of the liquid crystal display device, characterized in that the connector for performing electrical circuit connection of the first signal cable to the third signal cable, respectively. The method according to claim 2, The system circuit unit generates an enable signal for controlling the method of generating the dimming signal for controlling the final backlight and transmits the enable signal to the control circuit unit through the second signal cable. The method according to claim 2, The system circuit unit generates an enable signal for controlling the method of generating the dimming signal for the last backlight control and transmits the enable signal to the control circuit unit through the first signal cable, the inverter circuit unit and the third signal cable. Display Backlight Driving System The method according to claim 2, The third signal cable includes a terminal for outputting the dimming signal for controlling the original backlight from the inverter circuit unit and a terminal for outputting the dimming signal for controlling the final backlight control from the control circuit unit, respectively. The method according to claim 1, The system circuit unit is a backlight system for a liquid crystal display device, characterized in that the TV system or graphics card for providing image data to the control circuit unit. The method according to claim 1, The dimming signal for controlling the raw backlight and the dimming signal for controlling the last backlight are PWM signals or analog voltage signals, respectively. The method according to claim 1, The control circuit unit, A data conversion unit for performing gradation conversion of the input image data, and a final dimming signal generation unit for converting the input dimming signal for controlling the original backlight into the final dimming signal for control of the backlight corresponding to the gradation conversion image data and outputting the dimming signal; A timing controller; A first selection switch for selecting an input terminal to the timing controller according to a type of the dimming signal for controlling the source backlight; A second selection switch for selecting an output terminal of the timing controller according to a type of the dimming signal for controlling the last backlight; Backlight driving system of the liquid crystal display device comprising a The method of claim 9, The dimming signal for the final backlight control is a dimming signal converted to lower the emission time or the luminance of the backlight compared to the dimming signal for controlling the original backlight. The method according to claim 1, The control circuit unit generates the final backlight control dimming signal by combining the dimming signal for controlling the source backlight and the dimming signal for controlling the backlight generated by the timing controller to generate the final backlight control dimming signal. The method according to claim 1, The control circuit unit generates the final dimming signal for controlling the backlight by selecting one of the dimming signal for controlling the raw backlight and the dimming signal for controlling the gray level conversion generated by the timing controller. A liquid crystal panel displaying an image; A backlight unit for supplying light to the liquid crystal panel; A system circuit unit for generating and outputting a dimming signal for controlling a raw backlight to control the backlight unit; An inverter circuit unit which receives the source backlight control dimming signal from the system circuit unit and receives the final backlight control dimming signal and performs light emission control of the backlight; The control circuit unit which receives the raw backlight control dimming signal from the inverter circuit unit generates the final backlight control dimming signal and outputs the dimming signal to the inverter circuit unit. And a dimming signal for controlling the raw backlight, which is output from the system circuit part and input to the control circuit part via the inverter circuit part. The method of claim 13, And the system circuit unit generates an enable signal for turning on / off the function of generating the final backlight control dimming signal of the control circuit unit and directly delivers the enable signal to the control circuit unit. Generating and outputting a dimming signal for controlling a raw backlight by the system circuit unit; Receiving an input of the dimming signal for controlling the original backlight from the system circuit unit and receiving a final dimming signal for controlling the backlight from the system circuit unit in the inverter circuit unit to perform light emission control of the backlight; Receiving a dimming signal for controlling the source backlight from the inverter circuit unit in the control circuit unit, and generating and outputting the final dimming signal for controlling the backlight; The dimming signal for controlling the raw backlight is output from the system circuit part and is input to the control circuit part through the inverter circuit part.

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