KR20080042543A - Brightness control circuit in inverter - Google Patents

Brightness control circuit in inverter Download PDF

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Publication number
KR20080042543A
KR20080042543A KR1020060111129A KR20060111129A KR20080042543A KR 20080042543 A KR20080042543 A KR 20080042543A KR 1020060111129 A KR1020060111129 A KR 1020060111129A KR 20060111129 A KR20060111129 A KR 20060111129A KR 20080042543 A KR20080042543 A KR 20080042543A
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South Korea
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control voltage
brightness control
controller
capacitor
input terminal
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KR1020060111129A
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Korean (ko)
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김현식
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엘지이노텍 주식회사
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Priority to KR1020060111129A priority Critical patent/KR20080042543A/en
Publication of KR20080042543A publication Critical patent/KR20080042543A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • 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
    • G09G3/3406—Control of illumination source
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/24—Circuit arrangements in which the lamp is fed by high frequency ac, or with separate oscillator frequency
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Computer Hardware Design (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Liquid Crystal Display Device Control (AREA)

Abstract

A brightness control circuit in an LCD inverter is provided to stably control duty against noises or in-rush currents by having a capacitor and a varistor of high capacity between a brightness control voltage input terminal and a controller. A transformer(T) changes input voltage and outputs to an LCD panel. An FET(Field Effect Transistor,Q1) switches operation of the transformer. A controller(100) variably outputs a duty of a pulse width modulation signal supplied to the FET according to the level of brightness control voltage(Vbr) supplied from the outside. A capacitor(C1) is installed in parallel between a brightness control voltage input terminal and the controller for removing noises included in the brightness control voltage. A varistor(VT1) is installed between the brightness control voltage input terminal and the controller for removing static electricity components included in the brightness control voltage.

Description

ＬＣＤ용 인버터의 휘도 조정회로{Brightness control circuit in inverter}Brightness control circuit in inverter

도 1은 본 발명의 일 실시예에 따른 LCD용 인버터의 휘도 조정회로도.1 is a luminance control circuit diagram of an LCD inverter according to an embodiment of the present invention.

＜도면의 주요부분에 사용된 부호의 설명＞<Description of the code used in the main part of the drawing>

100: 컨트롤러 T: 트랜스포머100: controller T: transformer

Q1: FET Vbr: 휘도 제어전압Q1: FET Vbr: luminance control voltage

VT1: 바리스터 C1: 커패시터VT1: Varistor C1: Capacitor

본 발명은 LCD에 적용되는 백라이트장치 구동용 인버터에서, 컨트롤러를 이용하여 휘도를 제어할 수 있는 LCD용 인버터의 휘도 조정회로에 관한 것이다.The present invention relates to a brightness adjusting circuit of an LCD inverter capable of controlling brightness using a controller in a backlight device driving inverter applied to an LCD.

일반적으로, LCD(Liquid Crystal Display divice: 액정표시소자)는 CRT(Cathod Ray Tube: 음극선관)과는 달리 자기발광성이 없어서 백라이트(Back-light)라 불리는 후광이 필요하지만, 동작전압이 낮아 소비전력이 적고, 휴대용으 로 쓰일 수 있는 등의 장점이 커 널리 쓰이는 평판 디스플레이 중의 하나이다.In general, liquid crystal display devices (LCDs), unlike CRTs (Cathod Ray Tubes), have no self-luminous property and require a backlight, which is called a backlight, but consumes low power. It is one of the widely used flat panel displays due to its small, portable, and other advantages.

LCD의 백라이트에 전원을 공급하기 위해서는 LCD의 전원공급장치(Power Supply)에서 공급되는 DC 전원을 AC 전원으로 변환하여 트랜스포머에 의해 고전압으로 승압하는 일련의 구성이 필요하다.In order to supply power to the LCD backlight, a series of configurations are required in which the DC power supplied from the LCD's power supply is converted to AC power and boosted by a transformer to a high voltage.

종래에는 휘도를 조정하기 위한 휘도 제어전압(0~3.3V)이 입력되면, 이 휘도 제어전압의 레벨에 따라 컨트롤러에서 출력되는 펄스폭 변조신호의 듀티(40~100%)를 증감시켜 출력함으로써, 트랜스포머를 통해 백라이트장치에 공급되는 전압레벨을 제어하도록 구성되어 있다.Conventionally, when a luminance control voltage (0 to 3.3 V) for adjusting the luminance is input, the duty (40 to 100%) of the pulse width modulated signal output from the controller is increased or decreased according to the level of the luminance control voltage. It is configured to control the voltage level supplied to the backlight device through the transformer.

그러나, 종래에는 입력되는 휘도 제어전압에 노이즈가 포함되거나 혹은 돌입전류(In-rush current) 등으로 인하여 휘도 제어전압이 흔들리게 되는 경우, 컨트롤러는 휘도 제어전압에 포함된 노이즈 혹은 돌입전류에 따라 펄스폭 변조신호의 듀티를 조정하게 되므로, LCD의 화면상에 플리커 현상(깜박거림)이 발생하게 되는 문제점이 있다.However, conventionally, when noise is included in the luminance control voltage input or the luminance control voltage is shaken due to in-rush current, the controller pulses according to the noise or inrush current included in the luminance control voltage. Since the duty of the width modulated signal is adjusted, there is a problem in that flicker occurs on the screen of the LCD.

본 발명은 외부의 노이즈 혹은 돌입전류에 대하여 안정적인 휘도 제어동작을 수행할 수 있는 LCD용 인버터의 휘도 조정회로를 제공함에 있다.The present invention provides a brightness adjustment circuit of an LCD inverter capable of performing a stable brightness control operation against external noise or inrush current.

본 발명은 입력전압을 변압하여 LCD 패널에 출력하는 트랜스포머와; 상기 트 랜스포머의 동작을 스위칭하는 FET와; 외부에서 인가되는 휘도 제어전압의 레벨에 따라 상기 FET에 공급되는 펄스폭 변조신호의 듀티를 가변하여 출력하는 컨트롤러; 및 상기 휘도 제어전압 입력단자와 상기 컨트롤러 사이에 병렬 설치되어, 상기 휘도 제어전압에 포함된 노이즈를 제거하기 위한 커패시터를 포함한다.The present invention provides a transformer for transforming an input voltage to output an LCD panel; A FET for switching the operation of the transformer; A controller for varying and outputting a duty of a pulse width modulation signal supplied to the FET according to a level of a luminance control voltage applied from the outside; And a capacitor disposed in parallel between the luminance control voltage input terminal and the controller to remove noise included in the luminance control voltage.

여기서, 상기 휘도 제어전압 입력단자와 상기 컨트롤러 사이에 설치되어, 상기 휘도 제어전압에 포함된 정전기 성분을 제거하기 위한 바리스터가 더 포함할 수도 있다.Here, a varistor may be further provided between the luminance control voltage input terminal and the controller to remove the electrostatic components included in the luminance control voltage.

또한, 상기 커패시터는, 상기 휘도 제어전압에 포함되는 노이즈 혹은 돌입전류를 충분하게 안정화시킬 수 있을 만큼의 고용량인 것이 바람직하다.In addition, the capacitor is preferably high enough to sufficiently stabilize noise or inrush current included in the luminance control voltage.

이하, 본 발명의 바람직한 실시 예(들)에 대하여 첨부도면을 참조하여 상세히 설명한다. Hereinafter, exemplary embodiment (s) of the present invention will be described in detail with reference to the accompanying drawings.

도 1은 본 발명의 일 실시예에 따른 LCD용 인버터의 휘도 조정회로도이다.1 is a luminance adjustment circuit diagram of an LCD inverter according to an embodiment of the present invention.

도 1을 참조하면, 입력전압(Vin)을 변압하여 LCD 패널에 출력하는 트랜스포머(T)와, 상기 트랜스포머(T)의 1차측에 연결되어 상기 트랜스포머(T)의 동작을 스위칭하는 FET(Q1)와, 상기 FET(Q1)의 게이트에 연결되어 상기 FET(Q1)의 스위칭을 위한 펄스폭 변조신호(PWM 신호)를 출력하는 컨트롤러(100)로 구성된다.Referring to FIG. 1, a transformer T for transforming an input voltage Vin and outputting the same to an LCD panel, and a FET Q1 connected to a primary side of the transformer T to switch the operation of the transformer T. And a controller 100 connected to the gate of the FET Q1 and outputting a pulse width modulation signal (PWM signal) for switching the FET Q1.

여기서, 컨트롤러(100)는 휘도 제어전압(Vbr)이 입력됨에 따라 펄스폭 변조신호의 듀티를 가변하여 출력한다.Here, the controller 100 outputs the duty of the pulse width modulation signal as the luminance control voltage Vbr is input.

또한, 휘도 제어전압(Vbr) 입력단자와 컨트롤러(100) 사이에는 정전기(ESD) 를 제거하기 위한 바리스터(VT1)와, 노이즈 혹은 돌입전류를 제거하기 위한 고용량의 커패시터(C1)가 각각 병렬로 연결되어 있다.In addition, a varistor VT1 for removing static electricity ESD and a high capacitance capacitor C1 for removing noise or inrush current are respectively connected in parallel between the luminance control voltage Vbr input terminal and the controller 100. It is.

즉, 상기와 같은 구성의 본 발명에서, 휘도 제어전압(Vbr)에 노이즈 혹은 돌입전류가 포함되더라도, 고용량의 커패시터(C1)에 의해 안정화된 후 컨트롤러(100)에 입력되므로, 컨트롤러(100)는 안정된 듀티 제어를 실행할 수 있다.That is, in the present invention having the above-described configuration, even if noise or inrush current is included in the luminance control voltage Vbr, the controller 100 is stabilized by the high capacity capacitor C1 and then input to the controller 100. Stable duty control can be performed.

또한, 입력되는 휘도 제어전압(Vbr)이 정전기 등으로 인한 고압이 포함되어 있을 경우에도 바리스터(VT1)를 통해 안정화될 수 있다.In addition, the input luminance control voltage Vbr may be stabilized through the varistor VT1 even when high voltage is included due to static electricity.

이와 같이, 본 발명의 상세한 설명에서는 구체적인 실시 예(들)에 관해 설명하였으나, 본 발명의 범주에서 벗어나지 않는 한도 내에서 여러 가지 변형이 가능함은 물론이다. 그러므로 본 발명의 범위는 설명된 실시 예(들)에 국한되어 정해져서는 안 되며, 후술하는 특허청구범위 뿐만 아니라 이 특허청구범위와 균등한 것들에 의해 정해져야 한다.As described above, in the detailed description of the present invention, specific embodiment (s) have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiment (s), but should be defined by the claims below and equivalents thereof.

본 발명은 휘도 제어전압 입력단자와 컨트롤러 사이에 고용량의 커패시터와 바리스터를 각각 구성함으로써, 노이즈 혹은 돌입전류 등의 위험요소로부터 안정된 듀티 제어가 가능해지는 이점이 있다.According to the present invention, a high capacity capacitor and a varistor are respectively configured between the luminance control voltage input terminal and the controller, whereby stable duty control can be performed from risk factors such as noise or inrush current.

Claims (3)

입력전압을 변압하여 LCD 패널에 출력하는 트랜스포머;A transformer for transforming an input voltage to output the LCD panel; 상기 트랜스포머의 동작을 스위칭하는 FET;A FET for switching the operation of the transformer; 외부에서 인가되는 휘도 제어전압의 레벨에 따라 상기 FET에 공급되는 펄스폭 변조신호의 듀티를 가변하여 출력하는 컨트롤러; 및A controller for varying and outputting a duty of a pulse width modulation signal supplied to the FET according to a level of a luminance control voltage applied from the outside; And 상기 휘도 제어전압 입력단자와 상기 컨트롤러 사이에 병렬 설치되어, 상기 휘도 제어전압에 포함된 노이즈를 제거하기 위한 커패시터를 포함하는 LCD용 인버터의 휘도 조정회로.And a capacitor disposed in parallel between the brightness control voltage input terminal and the controller and including a capacitor for removing noise included in the brightness control voltage. 제 1항에 있어서, 상기 휘도 제어전압 입력단자와 상기 컨트롤러 사이에 설치되어, 상기 휘도 제어전압에 포함된 정전기 성분을 제거하기 위한 바리스터가 더 포함하는 것을 특징으로 하는 LCD용 인버터의 휘도 조정회로.The brightness control circuit of claim 1, further comprising a varistor disposed between the brightness control voltage input terminal and the controller to remove static electricity contained in the brightness control voltage. 제 1항에 있어서, 상기 커패시터는 상기 휘도 제어전압에 포함되는 노이즈 혹은 돌입전류를 충분하게 안정화시킬 수 있을 만큼의 고용량인 것을 특징으로 하는 LCD용 인버터의 휘도 조정회로.The brightness adjustment circuit of claim 1, wherein the capacitor is high enough to sufficiently stabilize noise or inrush current included in the brightness control voltage.
KR1020060111129A 2006-11-10 2006-11-10 Brightness control circuit in inverter KR20080042543A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140083741A (en) * 2012-12-26 2014-07-04 삼성전자주식회사 Display method and apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140083741A (en) * 2012-12-26 2014-07-04 삼성전자주식회사 Display method and apparatus

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