KR20110095710A - Liquid crystal display and driving method thereof - Google Patents

Abstract

PURPOSE: A liquid crystal display and driving method thereof are provided to selectively implement a normal mode capable of changing a diming curve through a scanning mode and a dimming frequency. CONSTITUTION: In a liquid crystal display and driving method thereof, a backlight unit includes at least two light source blocks. The back light unit radiates light to the liquid crystal display panel. A light source driving circuit(15) comprises at least one multi channel inverter IC. The light source driving circuit supplies a light source driving signal to the backlight unit. The light source control circuit differently generates the light source driving signal according to a mode selection signal. The light source control circuit controls the light source driving circuit through a scanning mode and a normal mode.

Description

Liquid crystal display and its driving method {LIQUID CRYSTAL DISPLAY AND DRIVING METHOD THEREOF}

The present invention relates to a liquid crystal display device and a driving method thereof capable of improving moving picture response time (hereinafter referred to as "MRPT") and adjusting the brightness of a backlight.

An active matrix liquid crystal display device displays a moving image using a thin film transistor (“TFT”) as a switching element. The liquid crystal display device is thinner and higher definition than a cathode ray tube (CRT), and is being applied to a display in portable information equipment, office equipment, and computers, and is also rapidly replacing CRT.

In the liquid crystal display device, MPRT is worse than CRT in terms of driving characteristics. The CRT is driven by an impulse-type that emits phosphors only for an initial very short time of one frame period to display an image, and maintains a non-display state for the rest of one frame period. On the other hand, the liquid crystal display is driven by a hold-type which supplies data to the liquid crystal cell during the scanning period during one frame period and maintains the data for the remaining time during the non-scanning period, which is the remaining time of one frame period. do. As a result, in the LCD, due to the hold type characteristic, a motion blurring phenomenon in which a screen is not clear and blurry in a moving image or a trailing phenomenon in which an afterimage of the previous screen remains on the current screen is displayed. MPRT drops

In order to improve the MPRT, a scanning backlight driving method has been proposed in which the liquid crystal display is driven in a quasi-impulse type by sequentially turning on the backlight in synchronization with video data displayed on the screen.

However, the liquid crystal display device employing the conventional scanning backlight driving method has the following problems.

First, a conventional liquid crystal display requires a plurality of inverter ICs to individually drive a backlight by scanning. As a result, the conventional liquid crystal display device is difficult to slim down the liquid crystal display device due to the large number of inverter ICs, and it is difficult to reduce the manufacturing cost. Accordingly, there is a need for a liquid crystal display capable of realizing a scanning backlight by controlling a plurality of light source blocks with a few inverter ICs.

Second, since the liquid crystal display device employing the conventional scanning backlight driving method performs a dimming operation according to a predetermined dimming frequency (eg, 120 Hz), the brightness curve of the backlight according to the dimming from the outside in the case of the conventional liquid crystal display device. It is impossible to change the following ("dimming curve"). As a result, the set maker has to use only a dimming frequency determined by the liquid crystal module, which has many limitations in design. Accordingly, a liquid crystal capable of selectively implementing a scanning mode for implementing a scanning backlight and a PWM (pulse width modulation) mode (hereinafter, referred to as a “normal mode”) that can change a dimming curve by adjusting a dimming frequency from an external (set maker). A display device is required.

Accordingly, an object of the present invention is to reduce the number of inverter ICs, and to provide a liquid crystal display and a driving method thereof to selectively implement a normal mode for changing a dimming curve by adjusting a scanning mode and dimming frequency for driving a scanning backlight. To provide.

In order to achieve the above object, the liquid crystal display device according to an embodiment of the present invention comprises a liquid crystal display panel; A backlight for irradiating light to the liquid crystal display panel including at least two light source blocks; A light source driving circuit including at least one multi-channel inverter IC and generating a light source driving signal to supply the backlight; And a light source control circuit for generating a light source control signal differently according to a mode selection signal input from the outside to control the light source driving circuit to a scanning mode or a normal mode.

According to an exemplary embodiment of the present invention, a method of driving a liquid crystal display device having a liquid crystal display panel and a backlight for irradiating light to the liquid crystal display panel including at least two light source blocks may be provided according to a mode selection signal input from the outside. Generating a light source control signal differently to control generation of the light source driving signal in a scanning mode or a normal mode (A); And generating (B) and generating the light source driving signal to the backlight by using one multi-channel inverter IC.

The liquid crystal display and the driving method thereof according to the present invention are a small number of multi-channel inverter IC, by selectively implementing a normal mode that can change the dimming curve by adjusting the scanning mode and dimming frequency for driving the scanning backlight, It can slim down, reduce manufacturing costs, and further increase the performance of specifications and products.

1 is a block diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.
FIG. 2 is a block diagram illustrating in detail the light source control circuit of FIG. 1. FIG.
3 is an operation table showing the operation of the switches of FIG.
4 is a block diagram showing in detail the light source driving circuit of FIG.
5 is a view showing a light source connection configuration.
6 is a waveform diagram for explaining the operation of the light source driving circuit in the scanning mode.
7 is a waveform diagram for explaining the operation of the light source driving circuit in the normal mode.
8 is a waveform diagram of a PWM signal when only the dimming frequency is changed while maintaining the same duty ratio.
9 is a diagram illustrating an example in which a dimming curve is changed by adjusting a dimming frequency.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 1 to 9.

1 to 5 show a liquid crystal display according to an embodiment of the present invention.

1, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal display panel 10, a timing controller 11, a data driving circuit 12, a gate driving circuit 13, and a light source control circuit 14. And a light source driving circuit 15 and a backlight unit 16.

In the liquid crystal display panel 10, a liquid crystal layer is formed between two glass substrates. A plurality of data lines DL and a plurality of gate lines GL cross on the lower glass substrate of the liquid crystal display panel 10. The liquid crystal cells Clc are arranged in a matrix form on the liquid crystal display panel 10 due to the cross structure of the data lines DL and the gate lines GL. In addition, a thin film transistor TFT, a pixel electrode 1 of a liquid crystal cell Clc connected to the thin film transistor TFT, a storage capacitor Cst, and the like are formed on a lower glass substrate of the liquid crystal display panel 10.

The black matrix, the color filter, and the common electrode 2 are formed on the upper glass substrate of the liquid crystal display panel 10. The common electrode 2 is formed on the upper glass substrate in a vertical electric field driving method such as twisted nematic (TN) mode and vertical alignment (VA) mode, and has an in plane switching (IPS) mode and a fringe field switching (FFS) mode. In the same horizontal electric field driving method, the pixel electrode 1 is formed on the lower glass substrate. A polarizing plate is attached to each of the upper glass substrate and the lower glass substrate of the liquid crystal display panel 10, and an alignment layer for setting a pretilt angle of the liquid crystal is formed on an inner surface of the liquid crystal display panel 10 in contact with the liquid crystal.

The timing controller 11 receives digital video data RGB, timing signals Vsync, Hsync, DE, DCLK, and a PWM signal input from an external system board. The timing signals Vsync, Hsync, DE, and DCLK include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, a dot clock signal DCLK, and the like. The timing controller 11 includes timing control signals for controlling the operation timing of the data driving circuit 12 and the gate driving circuit 13 based on the timing signals Vsync, Hsync, DE, and DCLK from the system board. DDC, GDC). The timing controller 11 generates a scan control signal SCAN for sequentially controlling the light source blocks of the backlight based on the PWM signal from the system board, and supplies the scan control signal SCAN to the light source control circuit 14. The scan control signal SCAN may be composed of at least two control signals according to the number of light source blocks, in which case the phases of the control signals are generated differently. Here, the dimming frequency of the scan control signal SCAN is fixed to a predetermined predetermined value (eg, 120 Hz).

The data driver circuit 12 includes a plurality of data drive ICs. The data driving circuit 12 latches the digital video data RGB under the control of the timing controller 11. The data driving circuit 12 converts the digital video data RGB into a positive / negative analog data voltage using the positive / negative gamma compensation voltage and supplies the converted data to the data lines DL.

The gate driving circuit 13 includes a plurality of gate drive ICs. The gate driving circuit 13 sequentially outputs gate pulses (or scan pulses) having a pulse width of approximately one horizontal period under the control of the timing controller 11 and supplies them to the gate lines GL.

The light source control circuit 14 generates the light source control signal SS differently according to the mode selection signal SEL input from the system board, thereby bringing the light source driving circuit 15 into the scanning mode MODE_S or the normal mode MODE_N. To control. The light source control signal SS may be composed of at least two control signals so as to correspond to the number of scan control signals SCAN.

As illustrated in FIG. 2, the light source control circuit 14 includes a scanning block 141 and a mode selection block 142, and outputs the first light source control signal SS1 and the second light source control signal to the output nodes No1 and No2. Outputs (SS2). The first and second light source control signals SS1 and SS2 are output in different phases in the scanning mode MODE_S and are output in the same phase in the normal mode MODE_N.

The scanning block 141 may include a first scanning block 141A for generating a first swing signal swinging between a reference voltage VREF level and a base level in response to the first scan control signal SCAN1, and a second scan control. The second scanning block 141B generates a second swing signal swinging between the reference voltage VREF level and the base level in response to the signal SCAN2. The first scanning block 141A includes the first switch SW1 according to the first switch SW1 and the first scan control signal SCAN1 connected between the input terminal of the reference voltage VREF and the first output node No1. A first scanning unit 1411A for controlling the switching operation of the. As shown in FIG. 3, the first scanning unit 1411A turns off the first switch SW1 during the on duty period of the first scan control signal SCAN1 and off duty of the first scan control signal SCAN1. By turning on the first switch SW1 during the period, the first swing signal applied to the first output node No1 is maintained at the reference voltage VREF level only during the off duty period of the first scan control signal SCAN1. do. In addition, the second scanning block 141B includes a second switch according to the second switch SW2 and the second scan control signal SCAN2 connected between the input terminal of the reference voltage VREF and the second output node No2. And a second scanning unit 1411B for controlling the switching operation of SW2. As shown in FIG. 3, the second scanning unit 1411B turns off the second switch SW2 during the on duty period of the second scan control signal SCAN2 and off duty of the second scan control signal SCAN2. By turning on the second switch SW2 during the period, the second swing signal applied to the second output node No2 is maintained at the reference voltage VREF level only during the off duty period of the second scan control signal SCAN2. do.

The mode selection block 142 outputs the first and second swing signals input from the scanning block 141 as the first and second light source control signals SS1 and SS2 according to the mode selection signal SEL, or The third swing signal generated by itself is output as the first and second light source control signals SS1 and SS2 based on the PWM signal from the system board. The mode selection block 142 includes a third switch SW3 connected between the first output node No1 and the first switch SW1 of the first scanning block 141A, the second output node No2 and the first output node No1. The fourth switch SW4 connected between the second switch SW2 of the scanning block 141B, and the fifth switch SW5 having one end connected in common to the first and second output nodes No1 and No2. ), The sixth switch SW6 connected between the second output node No2 and one end of the fifth switch SW5, and the third to sixth switches SW3 to SW6 according to the mode selection signal SEL. And a mode selector 1421 for controlling a switching operation of the control panel and applying a third swing signal to the other end of the fifth switch SW5. The third swing signal is a signal swinging between the reference voltage VREF level and the base level, and is maintained at the reference voltage VREF level only during the off duty period of the PWM signal input from the system board. As illustrated in FIG. 3, the mode selector 1421 turns on the third and fourth switches SW3 and SW4 in the scanning mode MODE_S in which the mode selection signal SEL is maintained at the first logic level. By turning off the fifth and sixth switches SW5 and SW6, the first and second swing signals from the scanning block 141 are output as the first and second light source control signals SS1 and SS2, respectively. Output through nodes No1 and No2. As a result, the first and second light source control signals SS1 and SS2 are output in different phases in the scanning mode MODE_S. Here, since the first and second light source control signals SS1 and SS2 depend on the first and second scan control signals SCAN1 and SCAN2, the dimming frequencies of the light source control signals SS1 and SS2 are preset scan control. The dimming frequency of the signals SCAN1 and SCAN2 is fixed. On the other hand, as shown in FIG. 3, the mode selector 1421 turns off the third and fourth switches SW3 and SW4 in the normal mode MODE_N in which the mode selection signal SEL is maintained at the second logic level. By turning on the fifth and sixth switches SW5 and SW6, the first and second light source control signals SS1, the third swing signal commonly applied to the first and second output nodes No1 and No2 are turned on. Output as SS2). As a result, the first and second light source control signals SS1 and SS2 are output in the same phase in the normal mode MODE_N. Here, since the first and second light source control signals SS1 and SS2 depend on the PWM signal input from the system board, the dimming frequencies of the light source control signals SS1 and SS2 may be adjusted by varying the dimming frequency of the PWM signal. Can be.

The light source driving circuit 15 generates a light source driving signal LDS under the control of the light source control circuit 14 to drive the light sources in the scanning mode MODE_S or the normal mode MODE_N. Under the scanning mode MODE_S, the first light source driving signal Iout1 to be applied to the first light source block BL1 and the second light source driving signal Iout2 to be applied to the second light source block BL2 have different phases. . Under the normal mode MODE_N, the first and second light source driving signals Iout1 and Iout2 have the same phase.

The light source driving circuit 15 controls the output of the first light source driving signal Iout1 to be applied to the first light source block BL1 with reference to the first sensing signal ISEN1 input as shown in FIG. 4. A second output channel for controlling the output of the second light source driving signal Iout2 to be applied to the second light source block BL2 with reference to the first output channel CH1 and the input second sensing signal ISEN2. A multi-channel inverter IC 151 having a CH2). The first output channel CH1 of the multi-channel inverter IC 151 includes a first switching unit 152A for generating a first light source driving signal Iout1 under the control of the multi-channel inverter IC 151, and a first light source driving. The first transformer 153A which boosts the signal Iout1 and applies it to the first light source block BL1 is connected in series. The second output channel CH2 of the multi-channel inverter IC 151 has a second switching unit 152B for generating a second light source driving signal Iout2 under the control of the multi-channel inverter IC 151, and a second light source driving. The second transformer 153B which boosts the signal Iout2 and applies it to the second light source block BL2 is connected in series. The light source driving circuit 15 adds the first feedback signal FB1 fed back from one end of the first transformer 153A and the first light source control signal SS1 input from the light source control circuit 14 to add a first light source. The first adder 154A for generating the sensing signal ISEN1, the second feedback signal FB2 fed back from one end of the second transformer 153B, and the second light source input from the light source control circuit 14. A second adder 154B may be further provided to add the control signal SS2 to generate the second sensing signal ISEN2. The number of multi-channel inverter ICs 151 in the light source driving circuit 15 is proportional to the number of boards. That is, when the mounting board is n (n is a positive integer), n multi-channel inverter ICs 151 are also required. A detailed operation of the light source driving circuit 15 in each driving mode will be described later with reference to FIGS. 6 to 9.

The backlight unit 16 includes a plurality of light sources to irradiate light to the liquid crystal display panel 10. The backlight unit 16 may be implemented as one of a direct type and an edge type. The direct type backlight unit 16 has a structure in which a plurality of optical sheets and a diffusion plate are stacked below the liquid crystal display panel 10 and a plurality of light sources are disposed below the diffusion plate. The edge type backlight unit 16 has a structure in which a plurality of optical sheets and a light guide plate are stacked below the liquid crystal display panel 10 and a plurality of light sources are disposed on the side of the light guide plate. The light sources can be implemented with line light sources such as Cold Cathode Fluorescent Lamps (CCFLs) or External Electrode Fluorescent Lamps (EEFLs), and are similar to Light Emitting Diodes (LEDs). It can be implemented with light sources. Although the light sources are physically divided into three light source blocks BL1 (A), BL2, and BL1 (B), as shown in FIG. 5, the light sources are divided through the balance patterns 162A and 162B formed on the balance board 161. Driven by four light source blocks. This is because the upper and lower light source blocks BL1 (A) and BL1 (B) are electrically connected to each other. Through this, the present invention can reduce the number of output channels of the inverter IC to k compared to the number of 2k-1 (k is a positive integer of 2 or more) physical light source blocks. According to Fig. 5, the backlight scanning effect occurs at three points more than the number of output channels (two) of the inverter IC.

6 shows a control waveform and an output waveform for explaining the operation of the light source driving circuit 15 under the scanning mode MODE_S.

4 and 6, under the scanning mode MODE_S, the first sensing signal ISEN1 is generated at the first level L1 during the off duty period of the first scan control signal SCAN1 and the first scan control. It is generated at the second level L2 lower than the first level L1 during the on duty period of the signal SCAN1 and then input to the multi-channel inverter IC 151. Here, the first level L1 is obtained by adding the first feedback signal FB1 to the reference voltage VREF level of the first light source control signal SS1, and the second level L2 is the first light source control signal. It is obtained by adding the first feedback signal FB1 to the base level of (SS1).

Under the scanning mode MODE_S, the second sensing signal ISEN2 is applied to the first level during the off duty period of the second scan control signal SCAN2 (which has a predetermined phase difference from the off duty period of the first scan control signal SCAN1). L2) and a second level lower than the first level L1 during the on duty period of the second scan control signal SCAN2 (having a predetermined phase difference from the on duty period of the first scan control signal SCAN1). L2) and then input to the multi-channel inverter IC (151). Here, the first level L1 is obtained by adding the second feedback signal FB2 to the reference voltage VREF level of the second light source control signal SS2, and the second level L2 is the second light source control signal. It is obtained by adding the second feedback signal FB2 to the base level of (SS2).

The multi-channel inverter IC 151 compares the preset output control value with the level values of the input first and second sensing signals ISEN1 and ISEN2 to perform the switching operation of the first and second switching units 152A and 152B. By controlling, the on / off timing of the 1st and 2nd light source drive signals Iout1 and Iout2 is adjusted. Specifically, the multi-channel inverter IC 151 is a period in which the first and second sensing signals ISEN1 and ISEN2 are maintained at the first level L1 beyond the output control value (each off duty period of the scan control signals). In the meantime, the first and second light source driving signals Iout1 and Iout2 are controlled to be off. As a result, the light sources are sequentially turned off in blocks. On the other hand, in the multi-channel inverter IC 151 during the period in which the first and second sensing signals ISEN1 and ISEN2 are maintained at the second level L2 below the output control value (each on duty period of the scan control signals), The first and second light source driving signals Iout1 and Iout2 are controlled on. As a result, the light sources are sequentially turned on in block units.

7 shows a control waveform and an output waveform for explaining the operation of the light source driving circuit 15 under the normal mode MODE_N. 8 and 9 illustrate an example in which the dimming curve can be changed by adjusting the dimming frequency.

4 and 7, under the normal mode MODE_N, the first sensing signal ISEN1 is generated at the first level L1 during the off duty period of the PWM signal, and the first level during the on duty period of the PWM signal. It is generated at the second level L2 lower than L1 and then input to the multi-channel inverter IC 151. Here, the first level L1 may be obtained by adding the first feedback signal FB1 to the reference voltage VREF level of the first light source control signal SS1, and the second level L2 may be obtained by adding the first light source. It can be obtained by adding the first feedback signal FB1 to the base level of the control signal SS1.

In the normal mode MODE_N, the second sensing signal ISEN2 in phase with the first sensing signal ISEN1 is generated at the first level L1 during the off duty period of the PWM signal, and is generated during the on duty period of the PWM signal. It is generated at the second level L2 lower than the first level L1 and then input to the multi-channel inverter IC 151. Here, the first level L1 is obtained by adding the second feedback signal FB2 to the reference voltage VREF level of the second light source control signal SS2, and the second level L2 is the second light source control signal. It is obtained by adding the second feedback signal FB2 to the base level of (SS2).

The multi-channel inverter IC 151 compares the preset output control value with the level values of the input first and second sensing signals ISEN1 and ISEN2 to perform the switching operation of the first and second switching units 152A and 152B. By controlling, the on / off timing of the 1st and 2nd light source drive signals Iout1 and Iout2 is adjusted. In detail, the multi-channel inverter IC 151 performs the period (off duty period of the PWM signal) during which the first and second sensing signals ISEN1 and ISEN2 remain at the first level L1 in excess of the output control value. The first and second light source driving signals Iout1 and Iout2 are simultaneously controlled to be off. As a result, the light sources are all turned off. On the other hand, the multi-channel inverter IC 151 may be configured such that the first and second sensing signals ISEN1 and ISEN2 are maintained at a second level L2 below the output control value (on duty period of the PWM signal). And simultaneously control on the second light source driving signals Iout1 and Iout2. As a result, the light sources are all turned on.

Since the lighting period of the light sources under the normal mode MODE_N depends on the PWM signal, increasing the dimming frequency while keeping the duty ratio of the PWM signal constant as shown in FIG. 8 reduces the on duty period of the PWM signal and also the lighting period of the light sources. Will also decrease. This means that the dimming curve can be changed only by adjusting the dimming frequency while maintaining the duty ratio of the PWM signal as shown in FIG. 9. When the backlight brightness is adjusted only by the duty ratio under the normal mode (MODE_N), it is difficult to guarantee the reliability due to the distortion of the driving waveform below a certain duty ratio (eg, 15%). In this case, however, if the dimming frequency is doubled while maintaining the duty ratio at 30%, the backlight brightness can be reduced to 1/2 without distortion of the driving waveform.

As described above, the liquid crystal display and the driving method thereof according to the present invention are a small number of multi-channel inverter IC, selectively implements the normal mode that can change the dimming curve by adjusting the scanning mode and dimming frequency for driving the scanning backlight As a result, the liquid crystal display device can be made slimmer, manufacturing costs can be reduced, and the performance of specifications and products can be greatly improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the present invention should not be limited to the details described in the detailed description, but should be defined by the claims.

10 liquid crystal display panel 11 timing controller
12: data driving circuit 13: gate driving circuit
14 light source control circuit 15 light source driving circuit
16: backlight unit

Claims (18)

A liquid crystal display panel;
A backlight for irradiating light to the liquid crystal display panel including at least two light source blocks;
A light source driving circuit including at least one multi-channel inverter IC and generating a light source driving signal to supply the backlight; And
And a light source control circuit which generates a light source control signal differently according to a mode selection signal input from an external source and controls the light source driving circuit in a scanning mode or a normal mode. The method of claim 1,
And a timing controller which generates at least two scan control signals capable of sequentially controlling the light source blocks and supplies them to the light source control circuit. The method of claim 2,
The light source control circuit,
A first scanning block generating a first swing signal swinging between a reference voltage level and a base level in response to a first scan control signal, and in response to a second scan control signal having a phase different from the first scan control signal; A scanning block including a second scanning block for generating a second swing signal swinging between the reference voltage level and a base level; And
According to the mode selection signal, the first and second swing signals input from the scanning block are output as first and second light source control signals, respectively, or the reference voltage level is based on a PWM signal input from the outside. A mode selection block for generating a third swing signal swinging between the base levels and outputting the third swing signal as the first and second light source control signals;
And the first and second light source control signals are output in different phases in the scanning mode and are output in the same phase in the normal mode. The method of claim 3, wherein
The first scanning block may include a first switch connected between an input terminal of a reference voltage and a first output node and a first scanning unit controlling a switching operation of the first switch according to the first scan control signal. Maintain a first swing signal at the reference voltage level for an off duty period of the first scan control signal;
The second scanning block may include a second switch connected between an input terminal of a reference voltage and a second output node and a second scanning unit controlling a switching operation of the second switch according to the second scan control signal. And a second swing signal at the reference voltage level during an off duty period of the second scan control signal. The method of claim 4, wherein
The mode selection block,
One end of the third switch connected between the first output node and the first switch, the fourth switch connected between the second output node and the second switch, and the first and second output nodes. Controlling a switching operation of the third to sixth switches in accordance with the fifth switch commonly connected, the sixth switch connected between the second output node and the one end of the fifth switch, and the mode selection signal. And a mode selector configured to apply the third swing signal to the other end of the fifth switch, thereby maintaining the third swing signal at the reference voltage level during the off duty period of the PWM signal. Display. The method of claim 3, wherein
The multi-channel inverter IC,
A first output channel for controlling an output of the first light source driving signal to be applied to the first light source block with reference to the first sensing signal input; And
And a second output channel for controlling the output of the second light source driving signal to be applied to the second light source block with reference to the second sensing signal input. The method according to claim 6,
The light source driving circuit,
A first adder configured to add the first feedback signal fed back from the output terminal of the first light source driving signal and the first light source control signal input from the light source control circuit to generate the first sensing signal; And
And a second adder configured to generate the second sensing signal by adding the second feedback signal fed back from the output terminal of the second light source driving signal and the second light source control signal input from the light source control circuit. Liquid crystal display device. The method according to claim 6,
The first and second light source driving signals have different phases under the scanning mode;
And the first and second light source driving signals have the same phase under the normal mode. The method according to claim 6,
The first light source block is disposed above and below the second light source block. The method of claim 3, wherein
The dimming frequency of the first and second light source control signals is
Fixed to a constant value in the scanning mode;
And controlling the dimming frequency of the PWM signal in the normal mode. In the driving method of a liquid crystal display device having a liquid crystal display panel and a backlight for irradiating light to the liquid crystal display panel including at least two light source blocks,
Generating a light source control signal differently according to a mode selection signal input from the outside to control generation of the light source driving signal to a scanning mode or a normal mode; And
And generating (B) the light source driving signal and supplying the light source driving signal to the backlight using one multi-channel inverter IC. The method of claim 11,
And generating (C) at least two scan control signals capable of sequentially controlling the light source blocks. The method of claim 12,
Step (A) is,
Generating a first swing signal swinging between a reference voltage level and a base level in response to the first scan control signal;
Generating a second swing signal swinging between the reference voltage level and a base level in response to a second scan control signal having a phase different from the first scan control signal; And
According to the mode selection signal, the first and second swing signals are output as first and second light source control signals, respectively, or swing between the reference voltage level and the ground level based on a PWM signal input from the outside. Generating a third swing signal and outputting the third swing signal as the first and second light source control signals;
And the first and second light source control signals are output in different phases in the scanning mode and are output in the same phase in the normal mode. The method of claim 13,
The first swing signal is maintained at the reference voltage level during an off duty period of the first scan control signal;
The second swing signal is maintained at the reference voltage level during an off duty period of the second scan control signal;
And the third swing signal is maintained at the reference voltage level during an off duty period of the PWM signal. The method of claim 13,
The multi-channel inverter IC,
A first output channel for controlling the output of the first light source driving signal to be applied to the first light source block with reference to the input first sensing signal;
And a second output channel for controlling the output of the second light source driving signal to be applied to the second light source block with reference to the second sensing signal input. The method of claim 15,
The first sensing signal is obtained by adding the first light source control signal to a first feedback signal fed back from an output terminal of the first light source driving signal;
And the second sensing signal is obtained by adding the second light source control signal to a second feedback signal fed back from an output terminal of the second light source driving signal. The method of claim 15,
The first and second light source driving signals have different phases under the scanning mode;
And the first and second light source driving signals have the same phase under the normal mode. The method of claim 13,
The dimming frequency of the first and second light source control signals is
Fixed to a constant value in the scanning mode;
And controlling the dimming frequency of the PWM signal in the normal mode.

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