KR100999164B1 - Power Supply And Liquid Crystal Display Device Having The Same - Google Patents

Abstract

The power supply of the liquid crystal display according to the present invention includes a lamp lighting detection unit for detecting a signal proportional to the lamp current, the initial lighting period and the pulse width modulation dimming of the lamp lighting detection signal applied from the lamp lighting detection sensor. And a sensing signal controller for causing a high level to appear in a low level interval between pulses, an inverter controller operating according to a signal from the sensing signal controller, and an inverter driving a lamp according to a control signal of the inverter controller. do. With this configuration, the inverter can be operated effectively so as to recognize the lamp initial lighting section or the low level section between the pulses according to the pulse width modulation dimming as the lamp is not lit, thereby avoiding the error of turning off all lamps. have.

Description

Power Supply and Liquid Crystal Display Device Having The Same

1 is a block diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a structure of a direct type backlight installed in the liquid crystal display of FIG. 1.

3 is a block diagram illustrating a sensing signal controller constituting a liquid crystal display according to a first exemplary embodiment of the present invention.

4 is an example in which the sensing signal controller of FIG. 3 is configured as an actual circuit.

5 is a timing diagram illustrating each sub-waveform of the sensing signal controller of FIG. 3.

6 is a block diagram illustrating a sensing signal controller constituting a liquid crystal display according to a second exemplary embodiment of the present invention.

FIG. 7 illustrates an example in which the sensing signal controller of FIG. 6 is configured as an actual circuit.

FIG. 8 is a timing diagram illustrating a lamp lighting detection signal and a signal lighting the lamp lighting detection signal through the low pass filter of FIG. 6.

9 is a timing diagram showing a lamp current waveform when a lamp is turned on in accordance with a lamp on signal in a conventional liquid crystal display.

The present invention relates to a power supply and a liquid crystal display having the same, and more particularly, to a power supply for controlling a lamp lighting detection signal and a liquid crystal display having the same.

In general, the liquid crystal display includes a liquid crystal module including a liquid crystal panel, a data driver, and a gate driver, and a backlight.

In a liquid crystal display device, the liquid crystal panel itself is non-luminous and thus cannot be used where there is no light. Therefore, a lamp is used as a backlight for transmitting light evenly to the entire liquid crystal panel from the rear of the liquid crystal panel.

The power supply of the liquid crystal display device includes an inverter circuit for driving the lamp.

The backlight is classified into a direct type and an edge type according to the lamp arrangement. The direct type method is a method of directly dimming the front surface of the panel by arranging a plurality of lamps on the bottom of the liquid crystal panel, which can increase the luminance and widen the light emitting surface than the edge method.

In the case of a large liquid crystal display, it is common to drive the plurality of lamps in parallel with one inverter by employing the direct type lamp arrangement.

However, in the case of the parallel driving method, when only one lamp of the plurality of lamps fails, all lamps connected to the inverter are turned off in consideration of the safety of the inverter and the lamp. Therefore, a sensor for checking whether the lamp is defective is attached to each lamp.

9 is a timing diagram showing a lamp current waveform when a lamp is turned on in accordance with a lamp on signal in a conventional liquid crystal display.

As shown in Fig. 9, when the lamp is initially turned on by applying the lamp on signal, the lamp is normally turned on after several hundred ms, and thus has a lamp transient period before that.

During the lamp transient period, the inverter receiving the lamp lighting detection signal from the sensor has a problem of generating an error of turning off all the lamps by determining that the lamp is abnormal.

In addition, when the lamp brightness is controlled by pulse dimming (PWM Dimming), it is recognized that the lamp is turned off instantaneously in the low level section between pulses according to the lamp lighting detection signal corresponding to the pulse width modulation dimming signal. And turning off all lamps could cause an error.

The technical problem to be achieved by the present invention is to recognize that the lamp is not turned on in the initial lighting period of the lamp or the low level period between the pulses according to the pulse width modulation dimming so as not to make an error to turn off all the lamps. It is to provide a power supply.                         

Another technical problem to be solved by the present invention is to recognize that the lamp is not lit in the initial lighting period of the lamp or the low level period between the pulses according to the pulse width modulation dimming so as not to make an error of turning off all the lamps. It is to provide a liquid crystal display device.

The power supply device according to the present invention for achieving the above technical problem, the lamp lighting detection unit for detecting a signal proportional to the lamp current, the initial period of the lighting of the lamp lighting detection signal applied from the lamp lighting detection sensor and A sensing signal controller for displaying a high level in a low level section between pulses according to pulse width modulation dimming, an inverter controller operating according to a signal from the sensing signal controller, and driving a lamp according to a control signal of the inverter controller It includes an inverter.

The sensing signal controller may be configured to receive a constant high level in response to a first multi-vibrator circuit part and a lamp lighting detection signal applied to the first multi-vibrator circuit unit for outputting a high level according to a rising edge trigger of a ramp-on signal. And a logic operation unit for providing a signal to the inverter controller that the lamp is normally turned on when at least one of the second multi-vibrator circuit unit for maintaining and at least one of the outputs of the first and second multi-vibrator circuit units is at a high level. have.

The second multivibrator circuit may include a multivibrator configured to maintain a constant high level of a pulse signal according to a rising edge trigger of the lamp lighting detection signal, and one input may be grounded and the other may be sensed by the other input. It is preferable to include a 1st logic circuit which receives a sustain signal, and a 2nd logic circuit which takes as an input the output of the said multivibrator and said 1st logic circuit.

The sensing signal controller may further include: a first multi-vibrator circuit unit configured to maintain an output of a high level for a predetermined period in response to a rising edge trigger of a ramp-on signal; When the lamp lighting detection signal is applied and at least one of the output of the low pass filter unit, the first multi-vibrator circuit unit, or the low pass filter unit to maintain a constant high level in the case of a pulse waveform, the lamp is It may include a logic operation unit for providing a signal that is normally turned on to the inverter controller.

In this case, the first multi-vibrator circuit unit, the output is preferably configured to maintain a high level for a time of 280mS to 320mS according to the rising edge trigger of the applied ramp-on signal.

According to another aspect of the present invention, a liquid crystal display device includes a liquid crystal panel including a liquid crystal panel, a gate driver transferring a scan signal to the liquid crystal panel, and a data driver transferring an image signal; A timing controller for providing an image signal, a timing signal for controlling the display of the liquid crystal module, a timing controller for providing a lamp on signal, a lamp for transmitting predetermined light to the liquid crystal panel, and a lamp lighting sensor for detecting a signal proportional to the lamp current. A detection signal controller for causing a high level to appear in an initial period of lighting of a lamp lighting detection signal applied from the lamp lighting detection sensor and a low level section between pulses according to pulse width modulation dimming, and a signal from the sensing signal controller Inverter controller operating in accordance with, and the inverter control Of an inverter for driving the lamp in accordance with the control signal.

Here, the lamp is a direct type arrangement structure in which a plurality of lamps are arranged side by side in the vertical direction, it is preferable to be driven in parallel with one or less than the number of lamps.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

1 is a view for explaining a liquid crystal display according to an exemplary embodiment of the present invention.

As illustrated in FIG. 1, the liquid crystal display according to the exemplary embodiments may include a timing controller 100, a gate driver 200, a data driver 300, a liquid crystal panel 400, a lamp 500, and the like. And a power supply device 900 for driving the lamp 500.

The timing controller 100 receives the image signals R, G, and B, the vertical synchronizing signal Vsync, the horizontal synchronizing signal Hsync, the main clock MCLK, and the data of each RGB from an external graphic controller (not shown). The first to third timing signals are received based on the vertical synchronization signal Vsync and the horizontal synchronization signal Hsync that receive the enable signal DE and the like and control the display of the image signals R, G, and B. C1, C2, C3). The generated first timing signal C1 is input to the gate driver 200, and the generated second timing signal C2 is input to the data driver 300 together with the image signals R, G, and B. The third timing signal C3 is input to the sensing signal controller 700.

The first timing signal C1 may include a gate selection signal CPV for controlling the output of the gate on / off signal, a vertical synchronization start signal STV for selecting the first gate line, and an output enable signal OE. Include.

In addition, the second timing signal C2 may be a load signal TP for starting output to the data driver IC after the completion of the transmission of the image signals R, G, and B, a horizontal synchronization start signal STH for notifying the start of the gate lines, It includes a data selection signal HCLK.

The third timing signal C3 includes a ramp on off signal.

The gate driver 200 receives a gate selection signal CPV and a vertical synchronization start signal STV provided from the timing controller 100 to receive a plurality of gate on / off signals G1, G2,..., Gn. It is sequentially applied to the plurality of gate lines configured in the liquid crystal panel 400.

The data driver 300 receives image signals R, G, and B provided from the timing controller 100, stores them in a shift register (not shown), and then applies a horizontal synchronization start signal STH. Is converted into a voltage corresponding to the image signals R, G, and B and applied to a plurality of data lines configured in the liquid crystal panel 400, and the horizontal synchronization start signal STH corresponding to the last gate line from the first gate line. When is input, the image signal R, G, and B are transmitted to the liquid crystal panel 400.

The liquid crystal panel 400 includes a plurality of pixel electrodes composed of m × n matrix types, and the gate on / off signals G1, G2,... Gn provided from the gate driver 200 are applied to the pixels. Accordingly, in response to the data voltages D1, D2,... Dn supplied from the data driver 300, the corresponding pixel electrode is driven to display an image.

The lamp 500 provides predetermined light to the back of the liquid crystal panel, and a Cold Cathod Fluorescence Lamp (CCFL) or an External Electrode Fluorescence Lamp (EEFL) is generally used.

FIG. 2 is a schematic diagram illustrating a structure of a direct type backlight installed in the liquid crystal display of FIG. 1.

In the case of the EEFL, parallel driving is easy, and as shown in FIG. 2, the lamp 500 is disposed in a direct type method, and a parallel driving method of driving a plurality of lamps with one inverter 600 is preferable.

Referring back to FIG. 1, the power supply device 900 includes a power supply unit 910, a lamp lighting detection sensor unit 920, a detection signal control unit 700, an inverter controller 800, and an inverter 600. do.

Here, the power supply unit 910 applies a DC voltage of a predetermined level to the detection signal controller 700.

The lamp lighting detection sensor 920 is formed of a respective sensing sensor formed at a lower end of each of the plurality of lamps, and the sensing sensor provides a lamp lighting detection signal proportional to a lamp current to the detection signal controller 700. .

Here, the lamp lighting sensor unit 920 may detect a lighting state of each lamp so that all lamps are turned off when a failure that does not light even one lamp occurs.

The sensing signal controller 700 controls a lamp on signal from the timing controller 100 and a signal applied from the lamp lighting sensor 920 to be applied to the inverter controller 800.

In this case, the lamp on signal may be a signal applied from the outside of the timing controller 100.

Meanwhile, when the lamp lighting detection signal is a waveform according to pulse width dimming, the detection signal controller 700 may turn off the lamp in the inverter controller 800 for a low level period between pulses and a transient time of the lamp lighting initial stage. As a structure to improve the malfunction of not lit, a detailed description will be described later.

The inverter controller 800 operates according to the signal received from the detection signal controller 700 to apply a control signal to the inverter 600.

The inverter 600 drives the lamp 500 according to the control signal of the inverter controller 800. The inverter 600 converts the applied DC voltage into an AC voltage and applies it to the lamp 500.

Next, the sensing signal controller 700 constituting the liquid crystal display according to the first exemplary embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

3 is a block diagram of the sensing signal controller 700, and FIG. 4 is an example in which the sensing signal controller of FIG. 3 is configured as an actual circuit.

As shown in FIGS. 3 and 4, the sensing signal controller 700 includes first and second multivibrator circuits 710 and 720 and a logic calculator 730.

The first multi-vibrator circuit 710 is configured to receive the ramp-on signal to the rising edge trigger terminal of the first multi-vibrator 711 and provide an output signal A to the logic operation unit 730. In this case, the first multivibrator 711 is a monostable multivibrator circuit.

The second multivibrator circuit unit 720 includes a second multivibrator 721 and first to third logic NOR circuits 722, 723, and 724.

The second multivibrator 721 receives a lamp lighting detection signal from the lamp lighting detection sensor 920 as a rising edge trigger terminal, and an output signal thereof is provided to the second logic NOR circuit 723. In this case, the second multivibrator 721 is a monostable multivibrator circuit.

The first logic NOR circuit 722 receives a lamp lighting detection signal from the lamp lighting detection sensor 920 as one input terminal, the other input is grounded, and the output signal is the second logic NOR circuit. 723 is provided.                     

The second logic NOR circuit 723 receives an output signal of the second multivibrator 721 and an output signal of the first logic NOR circuit 722, and outputs an output value obtained by performing a NOR operation on the third signal. To the logic NOR circuit 724.

The third logic NOR circuit 724 receives the output signal of the second logic NOR circuit 724 to two input terminals, and provides the output signal B accordingly to the logic operation unit 730.

The logic operation unit 730 is composed of a logic OR circuit 731, and receives the output signals of the first multi-vibrator circuit unit 710 and the second multi-vibrator circuit unit 720 to the two input terminals, respectively, The output value C from which the OR operation is performed is applied to the inverter controller 800.

Meanwhile, in the embodiment of the present invention, the logical operation unit 730 is configured as a logical OR circuit, but may be reconfigured using a logical NOR circuit. In addition, the logic NOR circuit of the second multivibrator circuit unit 720 may also be reconfigured as a logic OR circuit, a NOT circuit, or the like.

Next, an operation of the detection signal controller 700 will be described in detail with reference to FIGS. 5 and 3 and 4, which illustrate respective sub-waveforms of the detection signal controller 700.

As illustrated in FIG. 5, the waveform of the lamp lighting detection signal is configured as a pulse waveform according to the pulse width modulation dimming signal PWM dimming.

At this time, in the initial stage of lighting according to the lamp on signal (Lamp ON), there is a period (T1) that the lamp on detection signal does not reach the threshold that is determined that the lamp is lit.

Therefore, the inverter controller 800 receiving the detection signal from the lamp lighting detection sensor unit 920 may make an error of recognizing that the lamp is not turned on.

Further, even after that, the inverter may make an error of recognizing that the lamp is not turned on even in a low level section between pulses according to the pulse width modulation dimming signal.

Accordingly, in the first embodiment of the present invention, when the lamp lighting detection signal is applied to the inverter controller 800, to solve the problem of error recognition that the lamp is turned off in the low-level period between the initial lighting or the pulse, The lamp lighting detection signal applied to the inverter controller 800 is processed through the detection signal control unit 700 of the present invention, and the output signal is provided so that the operation of detecting whether the lamp is lit is normally performed.

Specifically, the pulse-shaped lamp lighting detection signal is input to the rising edge trigger terminal of the second multivibrator 721, so that a short pulse continuous by the monostable multivibrator characteristic maintains a long pulse output.

Meanwhile, when the lamp lighting detection signal is a waveform according to a 100% dimming signal having no rising edge portion, the output of the second multivibrator 721 is at a low level. Therefore, the lamp lighting detection signal is applied to the second signal so that the lamp lighting detection signal may be applied even when the rising edge portion does not exist (for example, a signal for maintaining an inverted output by a 100% dimming signal). A single input is also input to the grounded first logic NOR circuit 722 while being input to the multivibrator 721.

Accordingly, the second logic NOR circuit 723 outputs a low level when at least one of the output of the second multivibrator 721 or the output of the first logic NOR circuit 722 is a high level. .

The third logic NOR circuit 724 inverts the signal of the second logic NOR circuit 723 so that when the lamp is properly turned on, the output node B of the second multi-vibrator circuit unit 720 is high. The level is applied.

On the other hand, the first multi-vibrator circuit unit 710 receives the rising edge trigger signal when the lamp is turned on in response to the lamp on signal (Lamp ON), the output (A) of the first multi-vibrator 711 to 280mS to Maintain a high level of 320mS. That is, it is preferable that the output signal A of the first multi-vibrator 711 is maintained at a high level for a time longer than the lamp transient time at the initial lamp on time.

The output signal C of the logic calculator 730 is at least one of an output signal B of the second multivibrator circuit unit 720 and an output signal A of the first multivibrator circuit unit 710. If it is a level, it outputs a high level.

Therefore, according to the first embodiment of the present invention, first, through the first multi-vibrator circuit unit 710, to maintain a high level output in the initial lamp lighting period. Next, the second multi-vibrator circuit unit 720 maintains a high level output of a waveform having a low level section between pulses according to a pulse width modulation signal. Next, the OR operation for the two cases is performed through the logic operation unit 730, thereby improving a misjudgment problem in a low level section between an initial lamp lighting section and a pulse that can determine that the lamp is abnormal. can do.

Next, the sensing signal controller 700 constituting the liquid crystal display according to the second exemplary embodiment of the present invention will be described in detail with reference to FIGS. 6 and 7.

6 is a block diagram of the sensing signal controller 700, and FIG. 7 is an example in which the sensing signal controller of FIG.

As illustrated in FIGS. 6 and 7, the sensing signal controller 700 includes a first multi-vibrator circuit 710, a low pass filter 720, and a logic calculator 730.

The sensing signal controller 700 constituting the liquid crystal display according to the second exemplary embodiment of the present invention has all configurations except for replacing the second multi-vibrator circuit with a low pass filter in the first exemplary embodiment of the present invention. This is the same as in the first embodiment of the present invention.

The low pass filter unit 720 is composed of a resistor (R1, R2) and a capacitor (C).

Since the lamp lighting detection signal according to the pulse width modulation dimming is a signal including a pulse width modulation frequency, the component is removed by the low pass filter unit 720.

8 is a timing diagram illustrating a lamp lighting detection signal and a signal lighting the lamp lighting detection signal through the low pass filter unit 720 of FIG. 7.

As shown in FIG. 8, the low pass section of the lamp lighting detection signal maintains the high level relatively longer than the period of the pulse width modulation signal.

Thus, the second embodiment of the present invention has an effect similar to that of the first embodiment of the present invention.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above embodiments and can be variously modified and implemented by those skilled in the art without departing from the technical scope of the present invention.

According to the present invention, the lamp initial lighting section or the low level section between the pulses according to the pulse width modulation dimming is maintained at a high level, so that the lamp is recognized as not lit so that all lamps are turned off. The inverter can be operated effectively so as not to.

Claims (11)

delete delete delete delete delete A liquid crystal module including a liquid crystal panel, a gate driver transferring a scan signal to the liquid crystal panel, and a data driver transferring an image signal; A timing controller for providing the image signal input from an external device, a timing signal for controlling a display of the liquid crystal module, and a lamp on signal; A lamp for transmitting predetermined light to the liquid crystal panel; Lamp lighting detection unit for detecting a signal proportional to the current of the lamp; A detection signal controller configured to output a high level signal in a low level period between an initial lighting period of a lamp lighting detection signal applied from the lamp lighting detection sensor and a pulse according to pulse width modulation dimming; An inverter controller operating according to a signal from the sensing signal controller; And And an inverter for driving a lamp according to a control signal of the inverter controller. In claim 6, The lamp is a direct type arrangement structure in which a plurality of lamps are arranged side by side in a vertical direction, and the LCD is driven in parallel with one or less inverters. In claim 6, The detection signal controller, A first multi-vibrator circuit portion for causing the output to maintain a high level for a predetermined period according to the rising edge trigger of the ramp-on signal; A second multi-vibrator circuit unit receiving the lamp lighting detection signal to maintain a constant high level in the case of a pulse waveform; And And at least one of the outputs of the first and second multivibrator circuits is at a high level, a liquid crystal display for providing a signal to the inverter controller that a lamp is normally turned on. In claim 8, The second multi vibrator circuit unit, A multivibrator configured to maintain a constant high level of a pulse signal according to a rising edge trigger of the lamp lighting detection signal; A first logic circuit having one input grounded and receiving the lamp lighting detection signal to the other input; And And a second logic circuit for inputting the output of the multivibrator and the first logic circuit. In claim 6, The detection signal controller, A first multi-vibrator circuit portion for causing the output to maintain a high level for a predetermined period according to the rising edge trigger of the ramp-on signal; A low pass filter unit receiving the lamp lighting detection signal to maintain a constant high level in the case of a pulse waveform; And And at least one of the output of the first multi-vibrator circuit portion or the low-pass filter portion has a high level, and includes a logic calculating portion for providing a signal to the inverter controller that a lamp is normally turned on. The method of claim 8 or 10, The first multi-vibrator circuit portion, And the output is configured to maintain a high level for a time period of 280mS to 320mS according to the rising edge trigger of the applied lamp on signal.

Images