KR20120137113A - Driving apparatus for liquid crystal display and method thereof - Google Patents

Driving apparatus for liquid crystal display and method thereof Download PDF

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Publication number
KR20120137113A
KR20120137113A KR1020110056447A KR20110056447A KR20120137113A KR 20120137113 A KR20120137113 A KR 20120137113A KR 1020110056447 A KR1020110056447 A KR 1020110056447A KR 20110056447 A KR20110056447 A KR 20110056447A KR 20120137113 A KR20120137113 A KR 20120137113A
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KR
South Korea
Prior art keywords
voltage
boosted
control signal
boosting
liquid crystal
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Application number
KR1020110056447A
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Korean (ko)
Inventor
나영선
김현호
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엘지전자 주식회사
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Priority to KR1020110056447A priority Critical patent/KR20120137113A/en
Publication of KR20120137113A publication Critical patent/KR20120137113A/en

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/12—Regulating voltage or current wherein the variable actually regulated by the final control device is ac
    • G05F1/24—Regulating voltage or current wherein the variable actually regulated by the final control device is ac using bucking or boosting transformers as final control devices
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3696—Generation of voltages supplied to electrode drivers
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0819—Several active elements per pixel in active matrix panels used for counteracting undesired variations, e.g. feedback or autozeroing

Abstract

PURPOSE: A driving apparatus of a liquid crystal display device and a method thereof are provided to constantly maintain an output voltage as a predetermined reference voltage regardless of load change by controlling a boosted voltage. CONSTITUTION: A controller(110) generates a control signal. The control signal boosts an input voltage with different boost multiples. A booster(120) generates a voltage for turning a thin film transistor on or off by boosting the input voltage with different boost multiples. A comparator generates a control signal for controlling the boosted voltage. [Reference numerals] (110) Controller; (120) Booster; (130) Reference clock generator

Description

Driving device of liquid crystal display and its method {DRIVING APPARATUS FOR LIQUID CRYSTAL DISPLAY AND METHOD THEREOF}

The present specification relates to a driving device of a liquid crystal display and a method thereof.

In general, a liquid crystal display (LCD) requires a voltage higher than an input power supply voltage to display an image, and a driving device applied to the liquid crystal display includes a boosting circuit for generating a high voltage. .

An object of the present disclosure is to provide a driving apparatus and a method of a liquid crystal display device capable of generating a high and stable output voltage required by the liquid crystal display device.

In the present specification, when the boosted voltage applied to the liquid crystal display is higher than the preset reference voltage, the boosted voltage can be controlled to maintain the output voltage at a predetermined reference voltage regardless of load variation on the liquid crystal display. Another object of the present invention is to provide a driving apparatus and a method of the liquid crystal display.

According to embodiments of the present disclosure, a driving device of a liquid crystal display device includes: a controller configured to generate a control signal for boosting an input voltage to a different boost multiple according to an image display period or an image non-display period; The booster may include a booster configured to generate a voltage for turning on or off the thin film transistor of the liquid crystal display by boosting the input voltage based on the control signal.

As an example related to the present disclosure, the control unit may generate a control signal for boosting the input voltage to a first preset step-up multiple during the image display period, and increase the input voltage during a second non-display period during the image display period. A control signal for boosting to a multiple may be generated, and the first preset boosted drain may be different from the second preset boosted drain.

As an example related to the present disclosure, the first preset boosted drain may be higher than the second preset boosted drain.

As an example related to the present disclosure, the booster may increase a voltage for turning on the thin film transistor and a voltage for turning off the thin film transistor by boosting the input voltage by a first predetermined boost multiplier during the image display period. And a voltage for turning on the thin film transistor and a voltage for turning off the thin film transistor by boosting the input voltage by a second preset voltage boost multiple during the non-display period of the image.

As an example related to the present invention, the control unit further includes a comparator configured to generate a control signal for controlling the boosted voltage when the boosted voltage and the reference voltage are different from each other. The controlled voltage can be controlled.

As an example related to the present invention, the comparator compares the boosted voltage and the reference voltage with each other, and controls a control signal for maintaining the boosted voltage at a predetermined voltage when the boosted voltage is higher than the reference voltage. It may be applied to the boosting unit.

As an example related to the present invention, the comparison unit compares the boosted voltage and the reference voltage with each other, and boosts the input voltage to the preset voltage when the boosted voltage is lower than or equal to the reference voltage. The control signal may be applied to the booster.

As an example related to the present invention, the comparing unit may further include feedback resistors connected to the line of the boosted voltage to distribute the boosted voltage, and compare the voltage divided by the feedback resistors with the reference voltage. have.

A driving method of a liquid crystal display according to embodiments of the present disclosure includes generating a control signal for boosting an input voltage to a different boost multiple according to an image display period or an image non-display period; The method may include generating a voltage for turning on or off the thin film transistor of the liquid crystal display by boosting the input voltage based on the control signal.

The driving apparatus and method of the liquid crystal display according to the embodiments of the present invention, when the input voltage is boosted to a voltage for turning on or off the thin film transistor of the liquid crystal display device image display section Alternatively, the step-up may be performed by different boosting factors according to the non-display period, thereby generating a high and stable output voltage required by the high resolution liquid crystal display without changing the manufacturing process for increasing the rated voltage of the liquid crystal display.

An apparatus and method for driving a liquid crystal display according to embodiments of the present invention are directed to controlling a boosted voltage when the boosted voltage applied to the liquid crystal display is higher than a preset reference voltage. Irrespective of the above, the boosted voltage may be maintained at a predetermined reference voltage.

1 is a configuration diagram illustrating a driving device of a liquid crystal display according to a first embodiment of the present invention.
2 is a flowchart illustrating an operation of the driving apparatus 100 of the liquid crystal display according to the first embodiment of the present invention.
3 is an exemplary diagram illustrating a control signal and an output voltage difference (VGH-VGL) for boosting an input voltage by the same (fixed) boost multiplier.
4 is an exemplary diagram illustrating a control signal and an output voltage difference VGH-VGL for boosting the input voltage VIN to different boost multiples.
5 is a configuration diagram illustrating a driving device of a liquid crystal display according to a second exemplary embodiment of the present invention.
6 is a flowchart illustrating an operation of the driving apparatus 100 of the liquid crystal display according to the second embodiment of the present invention.
7 is an exemplary diagram illustrating a specific circuit of a comparator applied to a driving device of a liquid crystal display according to a second exemplary embodiment of the present invention.

It is to be noted that the technical terms used herein are merely used to describe particular embodiments, and are not intended to limit the present invention. It is also to be understood that the technical terms used herein are to be interpreted in a sense generally understood by a person skilled in the art to which the present invention belongs, Should not be construed to mean, or be interpreted in an excessively reduced sense. In addition, when the technical terms used herein are incorrect technical terms that do not accurately express the spirit of the present invention, they should be replaced with technical terms that can be understood correctly by those skilled in the art. In addition, the general terms used in the present invention should be interpreted according to a predefined or prior context, and should not be construed as being excessively reduced.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In the present application, the term "comprising" or "comprising" or the like should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps.

Furthermore, terms including ordinals such as first, second, etc. used in this specification can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or similar elements throughout the several views, and redundant description thereof will be omitted.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be noted that the accompanying drawings are only for the purpose of facilitating understanding of the present invention, and should not be construed as limiting the scope of the present invention with reference to the accompanying drawings.

Hereinafter, a driving apparatus and a method of a liquid crystal display (LCD) (for example, a thin film transistor liquid crystal display, TFT LCD) according to a first embodiment of the present invention will be described with reference to FIGS. It demonstrates with reference. The driving apparatus according to embodiments of the present invention may be applied to a driving apparatus for driving an organic light emitting diode (OLED) and various flat panel displays as well as a liquid crystal display.

1 is a configuration diagram illustrating a driving device of a liquid crystal display according to a first embodiment of the present invention.

As shown in FIG. 1, the driving apparatus 100 of the liquid crystal display according to the first exemplary embodiment of the present invention may convert an input voltage VIN into an image display area or a non-display area. A control unit 110 for generating a control signal for boosting to a different boosting power factor depending on the area; A voltage for turning on or off the thin film transistor of the liquid crystal display is generated by boosting the input voltage by the different boosting factor based on the control signal, and the generated voltage is applied to the liquid crystal display 200. It consists of a boosting unit 120 to be applied.

For example, the driving device 100 of the liquid crystal display according to the first embodiment of the present invention includes a reference clock generator 130 for generating a reference clock; When the thin film transistor of the liquid crystal display is boosted to a voltage for turning on or off according to the reference clock, the input voltage VIN is boosted to a different boost factor according to an image display section or an image non-display section. A control unit 110 for generating a control signal (a control signal for controlling the boost multiplier differently according to the image display section and the image non-display section); According to the control signal, a voltage for turning on the thin film transistor (thin film transistor turn-on voltage VGH) and a voltage for turning off the thin film transistor by boosting the input voltage VIN to a different boost multiple The booster 120 generates a thin film transistor turn-off voltage VGL and applies the thin film transistor turn-on voltage VGH and the thin film transistor turn-off voltage VGL to the liquid crystal display 200. It may be configured as.

The control unit 110 generates a control signal for boosting the input voltage VIN to a first preset voltage boost multiple (for example, four times the input voltage) during the image display period, and the image non-display period. In this case, a control signal is generated to boost the input voltage VIN to a second preset boost multiple (for example, three times the input voltage). Here, the first preset boosted drain may be higher than the second preset boosted drain, and the different boosted drains are not limited to three or four times, and the input voltage may be boosted to various boosted drains.

The control signal boosts the input voltage to voltages VGH and VGL for turning on or off the thin film transistor of the liquid crystal display 200, and the input voltage is displayed in an image display section or an image non-display section. As a result it may be a signal for boosting to different boost multiples.

The booster 120 turns the thin film transistor by boosting the input voltage VIN to a first predetermined boost multiplier (eg, four times the input voltage) during the image display period according to the control signal. A voltage for turning on (thin film transistor turn-on voltage, VGH) and a voltage for turning off thin film transistor (thin film transistor turn-off voltage, VGL), and according to the control signal during the non-display period A thin film transistor (voltage thin film transistor turn-on voltage, VGH) and a voltage for turning on the thin film transistor by boosting the input voltage VIN to a second predetermined boost voltage multiple (for example, three times the input voltage). Generates a voltage for turning off (thin film transistor turn-off voltage, VGL).

The driving device 100 controls the thin film transistor connected to the pixel of the liquid crystal display so that the liquid crystal display 200 may display an image. For example, the driving device 100 generates a voltage VGH for turning on the thin film transistor and a voltage VGL for turning off the thin film transistor, and generates the generated voltages VGH and VGL. It is applied to the display device 200. Here, since the method of generating the voltage VGH for turning on the thin film transistor and the voltage VGL for turning off the thin film transistor is already known, a detailed description thereof will be omitted.

The driving device 100 may generate other analog data signals in addition to the voltages VGH and VGL, but the voltages VGH and VGL according to the present invention may be different from each other according to an image display period and an image non-display period. The method of boosting by boosted drainage will be described.

Hereinafter, an operation of the driving apparatus 100 of the liquid crystal display according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

2 is a flowchart illustrating an operation of the driving apparatus 100 of the liquid crystal display according to the first embodiment of the present invention.

First, the reference clock generator 130 generates a reference clock and outputs the reference clock to the controller 110.

The control unit 110 generates a control signal for generating a boosted voltage VGH for turning on the thin film transistor of the liquid crystal display 200 and a boost for turning off the thin film transistor according to the reference clock. A control signal for generating the voltage VGL is generated. In this case, the controller 110 generates a control signal for boosting the input voltage VIN to a first preset voltage boost multiple (for example, four times the input voltage) during the image display period, and the image is not displayed. During the period, a control signal for boosting the input voltage VIN to a second preset boost multiple (for example, three times the input voltage) is generated (S11). Here, the first preset boosted drainage may be higher than the second preset boosted drainage.

The booster 120 receives an input voltage VIN from the outside (S12), boosts the input voltage VIN by a different boost multiple according to the control signal (S13), and the boosted voltage VGH, VGL) is applied to the liquid crystal display 200 (S14). For example, the booster 120 boosts the input voltage VIN to a different boosting factor according to the control signal to turn on the thin film transistor (thin film transistor turn-on voltage VGH) and the thin film. A voltage (thin film transistor turn-off voltage, VGL) for turning off the transistor is generated.

The booster 120 outputs the output voltages VGH and VGL higher than the input voltage VIN by connecting a plurality of capacitors (for example, three to four) in parallel or in series through a switching element (not shown). ) May occur. For example, the booster 120 charges the input voltage VIN to the plurality of capacitors by switching the plurality of capacitors in parallel during a charging phase period of the control signal (or the reference clock). During the boosting phase of the control signal, the plurality of capacitors are switched in series to output a boosted voltage higher than the input voltage VIN (for example, 3 to 4 times the input voltage). . The boost multiplier may be adjusted in various ways by increasing or decreasing the number of the capacitors.

The booster 120 may boost the input voltage VIN by a charge pumping method, but the present invention is not limited thereto. The maximum output voltage of the booster 120 may be set lower than the rated voltage of the semiconductor device in order to prevent damage to the semiconductor device used in the driving device 100 for driving the liquid crystal display 200.

3 is an exemplary diagram illustrating a control signal and an output voltage difference (VGH-VGL) for boosting an input voltage by the same (fixed) boost multiplier.

As shown in FIG. 3, in general, a video signal is divided in time into an image display section and an image non-display section. The image display area is a period in which the thin film transistor of the liquid crystal display is activated according to a predetermined timing, and the power consumption of the liquid crystal display is increased rather than the image non-display period. Accordingly, a phenomenon in which the output voltages VGH and VGL boosted by the booster 120 is actually lowered due to power consumption of the liquid crystal display (load) occurs. On the other hand, the non-display area is a period in which the power consumption of the liquid crystal display device is lower than the power consumption of the liquid crystal display device during the image display period, and is equal to the image display period and the image non-display period. The booster 120 outputs the output voltages VGH and VGL boosted by the booster 120 by the control signal 3-3 to boost to a boosted multiple during the non-display area. This causes the phenomenon of rising or exceeding to the allowed manufacturing rated voltage 3-1 of the drive device. In general, the output voltage of the boosting unit varies depending on the load (image display section or image non-display section of the liquid crystal display).

In fact, the voltage required by the driving device 100 in the liquid crystal display is a voltage in the image display section considering the load loading effect, which is the minimum voltage 3-2 of the liquid crystal display capable of displaying a normal image.

In order to generate the minimum voltage 3-2 in the image display section, the driving device 100 generates (generates) high voltages VGH and VGL when there is no load (liquid crystal display). It is possible to supply the voltage reflecting the load loading effect to the liquid crystal display 200. However, when there is no load at the same step-up drain (not shown section), there is a risk of damage to the drive as it may exceed the permitted manufacturing rated voltage of the drive as described above.

As the resolution of the liquid crystal display 200 increases, the power consumption of the liquid crystal display 200 increases, so that the difference between the output voltage in the image display section and the output voltage in the non-image display section also increases. That is, the difference in the output voltage (VGH-VGL) due to the load variation of the liquid crystal display increases in two sections.

Accordingly, the controller 110 may reduce the difference (variation width) (VGH-VGL) of the output voltage according to the load variation so that the high-resolution liquid crystal display device requires no change in the manufacturing process for increasing the rated voltage of the driving device. In order to generate (generate) a stable output voltage, the input voltage VIN is boosted by the first preset step-up multiple (eg, 4 times) during the video display period, and the first during the video non-display period. The input voltage VIN is boosted by the second preset boost multiplier (e.g., three times) lower than the preset boost multiplier.

4 is an exemplary diagram illustrating a control signal and an output voltage difference VGH-VGL for boosting the input voltage VIN to different boost multiples.

As shown in FIG. 4, in response to the control signal 3-4, the input voltage VIN is boosted by a first preset step-up multiple (for example, 4 times) during the image display period, and the control signal is applied to the control signal. Accordingly, the output voltage difference VGH-VGL of FIG. 4 is increased by boosting the input voltage VIN to a second preset boosted multiple (eg, 3 times) lower than the first preset boosted multiple during the image non-display period. It can be seen that it is significantly lower than the output voltage difference (VGH-VGL) of FIG. That is, when the input voltage VIN is boosted to a voltage for turning on or off the thin film transistor of the liquid crystal display 200, the input voltage is boosted by a low boost multiple during the non-display period. The input voltage is boosted by a high boost multiple during the image display period, thereby generating a high and stable output voltage required by a high resolution liquid crystal display. At this time, during the image display period, the input voltage is boosted to a predetermined high boost multiple (for example, 4 times) to generate output voltages VGH and VGL, and the output voltages VGH and VGL are converted to the liquid crystal display. Since the output voltages VGH and VGL are lowered due to power consumption in the liquid crystal display 200 even when applied to the device 200, the driving device 100 may not exceed the rated voltage to generate a stable output voltage. Can be implemented. In addition, since the output voltage is generated at a low boost multiplier in the image non-display period, the power consumption of the driving device is reduced.

Accordingly, the driving apparatus and method of the liquid crystal display according to the first embodiment of the present invention, when the input voltage is boosted to a voltage for turning on or off the thin film transistor of the liquid crystal display device By boosting the voltage by different boosting times according to the image display section or the non-display section, the high and stable output voltage required by the high resolution liquid crystal display is required without additional manufacturing process change to increase the rated voltage of the driving device 100 of the liquid crystal display. Can be generated.

Hereinafter, a driving apparatus and a method of a liquid crystal display (LCD) according to a second embodiment of the present invention will be described with reference to FIGS. 5 to 7.

5 is a configuration diagram illustrating a driving device of a liquid crystal display according to a second exemplary embodiment of the present invention.

As shown in FIG. 5, the driving apparatus 100 of the liquid crystal display according to the second exemplary embodiment of the present invention may convert the input voltage VIN into an image display area or a non-display area. A control unit 110 for generating a control signal for boosting to a different boosting power factor depending on the area; The voltage (output voltages) VGH and VGL for turning on or off the thin film transistor of the liquid crystal display is generated by boosting the input voltage by the different boosting factor based on the control signal, and the generated voltage. A boosting unit (120) for applying (VGH, VGL) to the liquid crystal display (200); Comparison to generate a control signal for controlling the voltage (VGH, VGL) when the voltage (VGH, VGL) and the reference voltage is different from each other to maintain the voltage (VGH, VGL) to a predetermined output voltage constant It is composed of a portion 140.

The booster 120 controls the output voltages VGH and VGL based on the control signal of the comparator 140. For example, the booster 120 may maintain the output voltages VGH and VGL at the predetermined output voltage based on the control signal of the comparator 140. The step-up may be suspended until the and reference voltages are equal to or less than each other.

The driving apparatus 100 of the liquid crystal display according to the second exemplary embodiment of the present invention includes a reference clock generator 130 for generating a reference clock; When the thin film transistor of the liquid crystal display 200 is boosted to a voltage for turning on or off in accordance with the reference clock, the input voltage VIN is increased by different boosting times according to an image display section or an image non-display section. A control unit 110 for generating a control signal for boosting (a control signal for differently controlling the boost multiple according to the image display section and the non-image display section); According to the control signal, the voltage for turning on the thin film transistor (thin film transistor turn-on voltage, VGH) and the voltage for turning off the thin film transistor (thin film) by boosting the input voltage VIN by different boosting multiples. A booster 120 generating a transistor turn-off voltage VGL and applying the thin film transistor turn-on voltage VGH and the thin film transistor turn-off voltage VGL to the liquid crystal display 200. ; In order to keep the boosted voltages VGH and VGL constant at a preset output voltage regardless of a load variation (for example, a liquid crystal display), the boosted voltages (output voltages) VGH and VGL may be referenced to each other. The comparison unit 140 may be configured to compare voltages (preset reference voltages) with each other and generate a control signal for controlling the boosted voltages when the boosted voltages VGH and VGL are different from each other. have. The booster 120 maintains the output voltages VGH and VGL constant at the preset output voltage based on the control signal of the comparator 140.

The control unit 110 generates a control signal for boosting the input voltage VIN to a first preset voltage boost multiple (for example, four times the input voltage) during the image display period, and the image non-display period. In this case, a control signal is generated to boost the input voltage VIN to a second preset boost multiple (for example, three times the input voltage). Here, the first preset boosted drainage may be higher than the second preset boosted drainage.

Hereinafter, an operation of the driving apparatus 100 of the liquid crystal display according to the second exemplary embodiment of the present invention will be described with reference to FIG. 6.

6 is a flowchart illustrating an operation of the driving apparatus 100 of the liquid crystal display according to the second embodiment of the present invention.

First, the reference clock generator 130 generates a reference clock and outputs the reference clock to the controller 110.

The control unit 110 generates a control signal for generating a boosted voltage VGH for turning on the thin film transistor of the liquid crystal display 200 and a boost for turning off the thin film transistor according to the reference clock. A control signal for generating the voltage VGL is generated. In this case, the controller 110 generates a control signal for boosting the input voltage VIN to a first preset voltage boost multiple (for example, four times the input voltage) during the image display period, and the image is not displayed. During the interval, a control signal for boosting the input voltage VIN to a second preset boost multiple (eg, three times the input voltage) is generated (S21).

The booster 120 receives an input voltage VIN from an external power supply (S22), boosts the input voltage VIN to a different boost multiple according to the control signal (S23), and boosts the voltage VGH. , VGL) is applied to the liquid crystal display 200 (S24). For example, the booster 120 boosts the input voltage VIN to a different boosting factor according to the control signal to turn on the thin film transistor (thin film transistor turn-on voltage VGH) and the thin film. A voltage (thin film transistor turn-off voltage, VGL) for turning off the transistor is generated.

The booster 120 outputs the output voltages VGH and VGL higher than the input voltage VIN by connecting a plurality of capacitors (for example, three to four) in parallel or in series through a switching element (not shown). ) May occur. For example, the booster 120 switches the plurality of capacitors in parallel during the charging phase period of the control signal to charge the plurality of capacitors with the input voltage VIN, and During the boosting phase, the plurality of capacitors are switched in series to output a boosted voltage higher than the input voltage VIN (for example, 3 to 4 times the input voltage). The boost multiplier may be variously selected (determined) by increasing or decreasing the number of capacitors or adjusting the switching transition differently.

The comparison unit 140 compares the output voltages VGH and VGL applied to the liquid crystal display 200 with a reference voltage to maintain the output voltages VGH and VGL at a predetermined output voltage. When the output voltages VGH and VGL are different from each other, a control signal for controlling the output voltage is generated and the control signal is output to the switch 150 (S25). For example, the comparison unit 140 compares the output voltage VGH and the first reference voltage applied to the liquid crystal display 200, and when the output voltage VGH is higher than the first reference voltage. A control signal for controlling the output voltage is output to the boosting unit 120.

On the other hand, the comparator 140 compares the output voltage VGL and the second reference voltage applied to the liquid crystal display 200, and if the output voltage VGL is higher than the second reference voltage, the output. A control signal for controlling the voltage is generated, and the control signal is output to the boosting unit 120. When the output voltage VGL is a negative voltage, the comparator 140 generates a control signal for controlling the output voltage when the output voltage VGL is lower than the second reference voltage. The first and second reference voltages may be voltages required by the liquid crystal display (or a voltage optimized for the liquid crystal display), and may be adjusted by a user.

The comparison unit 140 controls a control signal to boost the input voltage VIN to the predetermined boost multiple when the output voltages VGH and VGL applied to the liquid crystal display 200 are equal to or lower than the reference voltage. Is generated, and the control signal is applied to the switch 150.

Hereinafter, a detailed circuit of the comparison unit 140 will be described with reference to FIG. 7.

7 is an exemplary diagram illustrating a specific circuit of a comparator applied to a driving device of a liquid crystal display according to a second exemplary embodiment of the present invention. Specific circuits of the comparison unit illustrated in FIG. 7 are examples for describing embodiments of the present invention, and the present invention is not limited thereto.

As illustrated in FIG. 7, the comparator 140 applied to the driving device 100 of the liquid crystal display according to the second exemplary embodiment of the present invention may output the output voltage VGH and the first reference voltage Vref1. A first comparator (141) for comparing and generating a first high signal when the output voltage (VGH) is higher than the first reference voltage (Vref1); A second comparator 142 which compares the output voltage VGL and the second reference voltage Vref2 and generates a second high signal when the output voltage VGL is higher than the second reference voltage Vref2; ; Logic circuits (eg, OR gates) for generating a control signal (flag) for maintaining the output voltage (VGH or VGL) constant at a predetermined output voltage when the first high signal or the second high signal is received. OR gate) 143.

The logic circuit 143 boosts the control signal for boosting the input voltage by a predetermined boost multiplier when the output voltage VGH or VGL is lower than or equal to the reference voltage Vref1 or Vref2. Output to. The comparator 140 generates a second high signal when the output voltage VGL is lower than the second reference voltage Vref2 when the output voltage VGL is a negative voltage.

The comparison unit 140 may include feedback resistors (for example, R1, R2, R3, and R4) connected to a line of the output voltages VGH and VGL to distribute the output voltages VGH and VGL. ), And the voltages V1 and V2 distributed by the feedback resistors may be compared with the reference voltages Vref1 and Vref2, respectively. First and second feedback resistors (eg, R1 and R2) may be connected in parallel to the output voltage line VGH to distribute the output voltage VGH, and the output voltage VGL may be distributed. Third and fourth feedback resistors (eg, R3 and R4) may be connected in parallel to the output voltage line VGL.

The booster 120 controls the output voltage to maintain the output voltages VGH and VGL at a predetermined output voltage according to the control signal of the comparator 140 (S26).

Therefore, the driving apparatus and method of the liquid crystal display according to the second embodiment of the present invention, when the input voltage is boosted to a voltage for turning on or off the thin film transistor of the liquid crystal display device By boosting the voltage by different boosting times according to the image display section or the non-display section, it is possible to generate the high and stable output voltage required by the high resolution liquid crystal display without changing the manufacturing process for increasing the rated voltage of the liquid crystal display. By controlling the output voltage when the boosted voltage is higher than the reference voltage, the output voltages VGH and VGL may be kept constant at a preset reference voltage regardless of load variation on the liquid crystal display.

As described above, the driving apparatus and method of the liquid crystal display according to the embodiments of the present invention, when the input voltage is boosted to a voltage for turning on or off the thin film transistor of the liquid crystal display By boosting the input voltage to different voltage multipliers according to the image display period or the non-display period, it is possible to generate the high and stable output voltage required by the high resolution liquid crystal display without changing the manufacturing process for increasing the rated voltage of the liquid crystal display. .

The driving apparatus and method of the liquid crystal display according to the embodiments of the present invention, when the input voltage is boosted to a voltage for turning on or off the thin film transistor of the liquid crystal display device image display section Alternatively, the step-up may be performed by different step-up multiples according to the image non-display period, thereby generating a high and stable output voltage required by the high resolution liquid crystal display without changing the manufacturing process for increasing the rated voltage of the liquid crystal display. By controlling the boosted voltage when the voltage is higher than the reference voltage, the output voltages VGH and VGL may be kept constant at a preset reference voltage regardless of the load variation on the liquid crystal display.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

110: control unit 120: boosting unit
130: reference clock generator

Claims (16)

A control unit for generating a control signal for boosting the input voltage by different boosting times according to an image display section or an image non-display section;
And driving the liquid crystal display to generate a voltage for turning on or off the thin film transistor of the liquid crystal display by boosting the input voltage to the different boost multiples based on the control signal. Device. The apparatus of claim 1,
Generating a control signal for boosting the input voltage to a first predetermined boosted multiple during the video display period, generating a control signal for boosting the input voltage to a second preset boosted multiple during the non-display period; And a first preset boosted drainage different from the second preset boosted drainage different from each other. 3. The driving apparatus of claim 2, wherein the first preset boosted multiple is higher than the second preset boosted multiple. The method of claim 1, wherein the boosting unit,
The voltage for turning on the thin film transistor and the voltage for turning off the thin film transistor are generated by boosting the input voltage by a first predetermined boosting factor during the image display period, and the input during the image non-display period. Driving a voltage to turn on the thin film transistor and to turn off the thin film transistor by boosting a voltage to a second predetermined boost voltage multiple. The method of claim 1,
And a comparator configured to generate a control signal for controlling the boosted voltage when the boosted voltage and the reference voltage are different from each other, wherein the booster controls the boosted voltage according to a control signal of the comparator. A drive device for a liquid crystal display device. The method of claim 5, wherein the comparison unit,
And comparing the boosted voltage and the reference voltage with each other and applying a control signal to the booster to maintain the boosted voltage at a predetermined voltage when the boosted voltage is higher than the reference voltage. Drive device for display device. The method of claim 5, wherein the comparison unit,
And comparing the boosted voltage with the reference voltage and applying a control signal to the booster to boost the input voltage to the predetermined voltage when the boosted voltage is lower than or equal to the reference voltage. A drive device for a liquid crystal display device. The method of claim 5, wherein the comparison unit,
And a feedback resistor connected to the line of the boosted voltage to distribute the boosted voltage, comparing the voltage distributed by the feedback resistors with the reference voltage. Generating a control signal for boosting the input voltage to different boost multiples according to an image display period or an image non-display period;
Generating a voltage for turning on or off the thin film transistor of the liquid crystal display by boosting the input voltage to the different boost multiples based on the control signal. Way. The method of claim 9, wherein generating the control signal comprises:
Generating a control signal for boosting the input voltage to a first preset boost multiple during the video display period;
And generating a control signal for boosting the input voltage to a second preset boosted multiple during the non-display period, wherein the first preset boosted multiple and the second preset boosted multiple are different from each other. A method of driving a liquid crystal display device. The driving method of claim 10, wherein the first preset boosted multiple is higher than the second preset boosted multiple. The method of claim 9, wherein generating the voltage comprises:
Generating a voltage for turning on the thin film transistor and a voltage for turning off the thin film transistor by boosting the input voltage by a first predetermined boost voltage during the image display period;
Generating a voltage for turning on the thin film transistor and a voltage for turning off the thin film transistor by boosting the input voltage by a second predetermined boosting factor during the non-display period. Driving method of liquid crystal display device. 10. The method of claim 9,
Generating a control signal for controlling the boosted voltage when the boosted voltage and the reference voltage are different from each other;
And controlling the boosted voltage based on a control signal for controlling the boosted voltage. The method of claim 13, wherein controlling the boosted voltage comprises:
Comparing the boosted voltage and the reference voltage with each other;
And maintaining the boosted voltage at a predetermined voltage when the boosted voltage is higher than the reference voltage as a result of the comparison. The method of claim 13, wherein controlling the boosted voltage comprises:
Comparing the boosted voltage and the reference voltage with each other;
And as a result of the step of boosting the input voltage to the predetermined voltage when the boosted voltage is lower than or equal to the reference voltage. The method of claim 13, wherein comparing the boosted voltage with the reference voltage comprises:
Distributing the boosted voltage through feedback resistors coupled to the line of boosted voltage;
And comparing the voltage divided by the feedback resistors with the reference voltage.
KR1020110056447A 2011-06-10 2011-06-10 Driving apparatus for liquid crystal display and method thereof KR20120137113A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9818364B2 (en) 2014-08-27 2017-11-14 Samsung Display Co., Ltd. Display apparatus and method of driving display panel using the same
US20240062703A1 (en) * 2022-08-22 2024-02-22 Himax Technologies Limited Display system and a voltage controller thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9818364B2 (en) 2014-08-27 2017-11-14 Samsung Display Co., Ltd. Display apparatus and method of driving display panel using the same
US10438556B2 (en) 2014-08-27 2019-10-08 Samsung Display Co., Ltd. Display apparatus and method of driving display panel using the same
US20240062703A1 (en) * 2022-08-22 2024-02-22 Himax Technologies Limited Display system and a voltage controller thereof

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