KR20070027331A - Inverter for mutichannel lamp - Google Patents

Inverter for mutichannel lamp Download PDF

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Publication number
KR20070027331A
KR20070027331A KR1020050082815A KR20050082815A KR20070027331A KR 20070027331 A KR20070027331 A KR 20070027331A KR 1020050082815 A KR1020050082815 A KR 1020050082815A KR 20050082815 A KR20050082815 A KR 20050082815A KR 20070027331 A KR20070027331 A KR 20070027331A
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South Korea
Prior art keywords
voltage
current
lamps
transformer
feedback
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KR1020050082815A
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Korean (ko)
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김현식
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엘지이노텍 주식회사
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Priority to KR1020050082815A priority Critical patent/KR20070027331A/en
Publication of KR20070027331A publication Critical patent/KR20070027331A/en

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    • 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
    • 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
    • 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
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • 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
    • H05B41/02—Details
    • H05B41/04—Starting switches
    • 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
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

A multi-channel inverter is provided to accurately control brightness by having a plurality of lamps coupled to one transformer to reduce distributed voltage in case of low current. In a multi-channel inverter, a transformer(T) generates high voltage AC power by controlling current flowing in coils wound around one steel core according to control of a controller. A plurality of lamps for LCD(Liquid Crystal Display) backlight are lighted by an output of the transformer(T). A sensor senses current flowing in the lamps for LCD backlight. A rectifier supplies the feedback current to a feedback terminal of the controller by rectifying a voltage applied to the sensor. A Schottky diode(SD32,SD34) rectifies the voltage applied to the sensor.

Description

다채널 인버터{inverter for mutichannel lamp}Multichannel Inverter {inverter for mutichannel lamp}

도 1은 종래의 백라이트 램프를 구동시키는 전원회로를 설명하기 위한 회로도이다.1 is a circuit diagram for explaining a power supply circuit for driving a conventional backlight lamp.

도 2는 도 1에 사용되는 다이오드D2의 전압, 전류 특성을 나타내는 그래프이다.FIG. 2 is a graph illustrating voltage and current characteristics of the diode D2 used in FIG. 1.

도 3은 본 발명의 일실시예를 설명하기 위한 전체 회로도이다.3 is an overall circuit diagram for explaining an embodiment of the present invention.

도 4는 본 발명에 적용되는 쇼트키 다이오드의 특성을 나타내기 위한 그래프이다.4 is a graph showing the characteristics of the Schottky diode applied to the present invention.

*도면부호에 대한 설명** Description of the drawing symbols *

10: 제어부 T: 트랜스포머 SD32, SD34 : 쇼트키 다이오드10: control unit T: transformer SD 32 , SD 34 : Schottky diode

본 발명은 하나의 트랜스 포머로 여러개의 램프를 구동시키는 다채널 인버터에 관한 것이다.The present invention relates to a multichannel inverter for driving several lamps with one transformer.

대형화된 LCD 패널에는 LCD 패널의 특정 부분에 빛이 편중되게 조사되지 않 도록 하기 위하여 백라이트 램프들이 복수로 설치하지지만, 이러한 램프들을 구동시키는 전원장치의 트랜스포머는 설치공간 및 재료비등을 고려하여 하나만 설치하여 공용으로 사용하는 다채널 인버터를 구성하는 것이 통상적이라 할 수 있다.In the large LCD panel, a plurality of backlight lamps are installed to prevent light from being irradiated to a specific part of the LCD panel, but only one transformer of the power supply unit for driving such lamps is installed in consideration of installation space and material cost. It can be said that it is common to configure a multi-channel inverter to be used in common.

도 1은 종래의 백라이트 램프를 구동시키는 전원회로를 설명하기 위한 회로도이다.1 is a circuit diagram for explaining a power supply circuit for driving a conventional backlight lamp.

스위칭 소자들(Q1), (Q2), (Q3), (Q4)은 제어부(10)로부터 스위칭 소자의 게이트에 공급되는 펄스신호(S1), (S2), (S3), (S4)들에 의하여 스위칭되게 된다. 스위칭 소자 (Q1)의 드레인에는 직류전압(VDC)이 공급되고, 스위칭 소자 (Q1)의 소오스는 스위칭 소자(Q2)의 드레인에 연결되며, 스위칭 소자(Q2)의 소오스는 접지된다. 이때, 스위칭 소자 (Q1)의 소오스와 스위칭 소자(Q2)의 드레인의 접속점과 트랜스의 1차 코일의 입력단간에는 콘덴서(C1)가 직렬연결된다. 또한, 스위칭 소자 (Q3)의 드레인에는 직류전압(VDC)가 공급되고, 스위칭 소자 (Q3)의 소오스는 스위칭 소자(Q4)의 드레인에 연결되며, 스위칭 소자(Q4)의 소오스는 접지된다. 이때, 스위칭 소자 (Q3)의 소오스와 스위칭 소자(Q4)의 드레인의 접속점은 트랜스(T)의 1차 코일의 출력단에 연결된다.The switching elements Q 1 , Q 2 , Q 3 , and Q 4 are pulse signals S 1 , S 2 , and S 3 supplied from the controller 10 to the gate of the switching element. ), (S 4 ) to be switched. The drain of the switching element (Q 1), the DC voltage (V DC) is supplied, a source of the switching device (Q 1) is connected to the drain of the switching element (Q 2), a source of the switching element (Q 2) is ground do. At this time, the switching element source and a switching element between the input capacitor of the primary coil of the transformer and the connection point of the drains of the (Q 2) (C 1) of the (Q 1) are connected in series. The drain of the switching element (Q 3), the DC voltage (V DC) is supplied, a source of the switching device (Q 3) is connected to the drain of the switching element (Q 4), a source of the switching element (Q 4) Is grounded. At this time, the connection point of the drain of the source and the switching element (Q 4) of the switching device (Q 3) is connected to the primary coil of the transformer (T) outputs.

또한, 트랜스(T)의 2차코일의 입력단과 접지간에는 콘덴서(C2), 냉음극 형광램프(Cold Cathode Fluorescent Lamp: CCFL), 전압검출저항(R1)이 직렬연결되고, 전압검출저항(R1)과 CCFL의 출력단의 접속점에는 다이오드(D2)와 저항(R3)가 직렬연결되어 제어부의 피드백단자에 연결된다. 또한, 저항(R1)과 다이오드(D2)의 접속점과 접지간에는 다이오드(D1)이 역방향으로 연결되고, 다이오드(D2)와 저항(R3)의 접속점과 접지간에는 저항(R2)가 연결된다.In addition, a capacitor (C 2 ), a cold cathode fluorescent lamp (CCFL), and a voltage detection resistor (R1) are connected in series between the input terminal and the ground of the secondary coil of the transformer (T), and the voltage detection resistor (R1) is connected. ) Is connected in series with the output terminal of the CCFL and the diode D2 and the resistor R3 are connected to the feedback terminal of the controller. In addition, the diode D1 is connected in the reverse direction between the connection point of the resistor R1 and the diode D2 and the ground, and the resistor R2 is connected between the connection point of the diode D2 and the resistor R3 and the ground.

상기의 구성으로 이루어진 인버터는 제어부(10)의 스위칭 신호(S1), (S2), (S4)에 의하여 스위칭 소자(Q1), (Q2), (Q3), (Q4)가 동작되고, 이러한 스위칭 동작에 의하여 직류Vdc는 고압의 교류로 변화되어 CCFL을 점등시킨다.In the inverter having the above configuration, the switching elements Q1, Q2, Q3, and Q4 are operated by the switching signals S1, S2, and S4 of the control unit 10. By operation, the direct current Vdc is changed to a high voltage alternating current to light the CCFL.

CCFL의 출력단에 연결된 저항(R1)에는 CCFL에 흐르는 전류에 의하여 전압이 인가되게 되고, 이 전압은 정류용 다이오드(D2)와 전류제한용 저항(R3)를 거쳐 제어부(10)의 피드백 단자에 입력되게 된다. 제어부(10)에서는 피드백 단자에 입력되는 전류의 크기에 따라서 스위칭 신호의 펄스의 듀티비를 조정하여 스위칭 소자에 인가하도록 함으로써 항상 균일한 전류가 CCFL에 흐르도록 한다.A voltage is applied to the resistor R1 connected to the output terminal of the CCFL by the current flowing through the CCFL, and the voltage is input to the feedback terminal of the controller 10 through the rectifying diode D2 and the current limiting resistor R3. Will be. The controller 10 adjusts the duty ratio of the pulse of the switching signal according to the magnitude of the current input to the feedback terminal to apply the current to the switching element so that a uniform current always flows to the CCFL.

이때, 미설명 부호 다이오드D1, 저항R2는 접지로 흐르는 전류를 방지하기 위한 것이다.At this time, the description diode D1 and the resistor R2 are for preventing a current flowing to the ground.

도 2는 도 1에 사용되는 다이오드D2의 전압, 전류 특성을 나타내는 그래프이다.FIG. 2 is a graph illustrating voltage and current characteristics of the diode D2 used in FIG. 1.

일반 정류용 다이오드(D2)는 피드백되는 전류량에 따라서 전압강하(Vab)의 크기가 다르게 되고, 온도변화, 제품종류마다 전압강하가 다르게 나타날 수 있다.In the general rectifier diode D2, the magnitude of the voltage drop Vab varies according to the amount of current fed back, and the voltage drop may vary depending on temperature change and product types.

그래프에 도시된 바와 같이, 온도가 증가함에 따라서 다이오드의 특성은 A, B, C, D의 그래프 특성을 갖게된다. 피드백 전류가 1mA 이상으로 큰 경우에는 전압 강하(Vab)는 온도변화에 관계없이 균일하지만, 낮은 피드백전류에 대하여는 큰 산포값을 갖게 된다. 0.01mA의 피드백 전류가 흐를 때 다이오드 자체에서 강하되는 전압은 각각의 온도에서 0.3V, 0.5V, 0.6V, 0.7V 다양하게 산포된다. 이와 같이, 흐르는 전류가 약할 때는 전압산포가 크게 되어 피드백단자에 입력되는 전류량이 변화되게 됨으로써 제어부(10)에서는 원하는 듀티조정이 어렵게 된다.As shown in the graph, as the temperature increases, the characteristics of the diode have the graph characteristics of A, B, C, and D. When the feedback current is larger than 1mA, the voltage drop Vab is uniform regardless of the temperature change, but has a large dispersion value for the low feedback current. When a 0.01mA feedback current flows, the voltage drop across the diode itself is varied over 0.3V, 0.5V, 0.6V, and 0.7V at each temperature. As described above, when the flowing current is weak, the voltage distribution is increased so that the amount of current input to the feedback terminal is changed, so that the desired duty adjustment is difficult in the controller 10.

이와 같은 일반 정류용 다이오드(D2)를 사용하는 경우에는 도 1에 도시된 바와 같이 하나의 램프만을 구동시키는 회로에서 피드백 전류는 비교적 1mA 이상의 큰 값을 유지하기 때문에 다이오드(D2)의 전압 산포문제는 크지 않지만 두 대이상의 램프를 구동시키고, 이들 각각의 램프에서 발생되는 피드백 전류가 감소되기 때문에 많은 산포값을 갖게 되어 정확한 제어가 이루어지지 않게 된다.In the case of using such a general rectifying diode (D2), as shown in Figure 1 in the circuit for driving only one lamp, since the feedback current maintains a relatively large value of more than 1mA, the voltage distribution problem of the diode (D2) is It is not large but drives more than two lamps, and the feedback current generated in each of these lamps is reduced, resulting in a large dispersion value and thus inaccurate control.

본 발명은 두 대이상의 CCFL을 점등시키는 멀티 채널의 인버터에서 상기의 문제점을 해결하기 위한 것으로, 저 전류에서도 산포값이 매우 작은 쇼트키 다이오드를 사용하여 피드백 전류를 정류하도록 함으로써 정밀한 듀티비 제어를 이루도록 함으로써 CCFL을 균일하게 점등시키도록 하기 위한 것이다. The present invention is to solve the above problems in a multi-channel inverter that turns on two or more CCFLs, to achieve a precise duty ratio control by rectifying the feedback current using a Schottky diode having a very small dispersion value even at low current This is to make the CCFL light up uniformly.

상기 목적을 달성하기 위한 본 발명의 구성의 특징은 제어부의 제어에 따라 하나의 철심에 권선된 코일들에 흐르는 전류를 제어하여 고압의 교류전원을 발생시키는 전압변환부, 상기 전압변환부의 출력에 의하여 점등되는 복수의 LCD 백라이트용 램프들, 상기 LCD 백라이트 램프들에 흐르는 전류를 감지하기 위한 감지부; 상 기 감지부에 인가되는 전압을 정류하여 상기 제어부의 피드백 단자에 피드백전류를 공급하는 정류부를 포함하는 다채널 인버터에 있어서: 상기 감지부에 인가되는 전압의 정류는 쇼트키 다이오드(Schottky Diode)에 의하여 이루어지는 것이다.Features of the present invention for achieving the above object is a voltage conversion unit for generating a high-voltage AC power by controlling the current flowing in the coils wound on one iron core under the control of the control unit, by the output of the voltage conversion unit A plurality of LCD backlight lamps which are turned on, and a sensing unit for sensing a current flowing in the LCD backlight lamps; In the multi-channel inverter comprising a rectifier for rectifying the voltage applied to the sensing unit to supply a feedback current to the feedback terminal of the control unit: Rectification of the voltage applied to the sensing unit to a Schottky diode It is done by.

이하, 첨부된 도면에 따라서 본 발명을 상세히 설명하기로 한다.Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

도 3은 본 발명의 일실시예를 설명하기 위한 전체 회로도이다.3 is an overall circuit diagram for explaining an embodiment of the present invention.

도 3에 도시된 회로는 단순히 두 개의 CCFL을 점등시킨 것을 도시하고 있으나, 이러한 구성은 두 개 이상의 CCFL을 점등시키기 위한 회로에도 적용할 수 있음은 주지의 사실이다.Although the circuit shown in FIG. 3 simply shows two CCFLs turned on, it is well known that such a configuration can be applied to a circuit for turning on two or more CCFLs.

스위칭 소자들(Q1), (Q2), (Q3), (Q4)은 제어부(10)로부터 스위칭 소자의 게이트에 공급되는 펄스신호(S1), (S2), (S3), (S4)들에 의하여 스위칭되게 된다. 스위칭 소자 (Q1)의 드레인에는 직류전압(VDC)이 공급되고, 스위칭 소자 (Q1)의 소오스는 스위칭 소자(Q2)의 드레인에 연결되며, 스위칭 소자(Q2)의 소오스는 접지된다. 이때, 스위칭 소자 (Q1)의 소오스와 스위칭 소자(Q2)의 드레인의 접속점과 트랜스의 1차 코일의 입력단간에는 콘덴서(C31)가 직렬연결된다. 또한, 스위칭 소자 (Q3)의 드레인에는 직류전압(VDC)가 공급되고, 스위칭 소자 (Q3)의 소오스는 스위칭 소자(Q4)의 드레인에 연결되며, 스위칭 소자(Q4)의 소오스는 접지된다. 이때, 스위칭 소자 (Q3)의 소오스와 스위칭 소자(Q4)의 드레인의 접속점은 트랜스(T)의 1차 코일의 출력단에 연결된다.The switching elements Q 1 , Q 2 , Q 3 , and Q 4 are pulse signals S 1 , S 2 , and S 3 supplied from the controller 10 to the gate of the switching element. ), (S 4 ) to be switched. The drain of the switching element (Q 1), the DC voltage (V DC) is supplied, a source of the switching device (Q 1) is connected to the drain of the switching element (Q 2), a source of the switching element (Q 2) is ground do. At this time, the switching element source and a switching element (Q 2) junction and a capacitor (C 31) between the input terminal of the primary coil of the transformer of the drain of the (Q 1) are connected in series. The drain of the switching element (Q 3), the DC voltage (V DC) is supplied, a source of the switching device (Q 3) is connected to the drain of the switching element (Q 4), a source of the switching element (Q 4) Is grounded. At this time, the connection point of the drain of the source and the switching element (Q 4) of the switching device (Q 3) is connected to the primary coil of the transformer (T) outputs.

또한, 트랜스(T)의 2차측에는 두 개의 코일(N2), (N3)가 권선되어 있고, 코일(N2)에 유기된 전압은 콘덴서(C32)를 통하여 CCFL(20)을 점등시키고, 코일(N3)에 유기된 전압은 콘덴서(C33)를 통하여 CCFL(30)을 점등시킨다. In addition, two coils N2 and N3 are wound on the secondary side of the transformer T. The voltage induced in the coil N2 turns on the CCFL 20 through the capacitor C 32 , and the coil The voltage induced at N3 turns on the CCFL 30 through the capacitor C 33 .

CCFL(20)의 출력단과 접지사이에는 저항(R31)이 연결되어 CCFL(20)에 흐르는 전류에 의하여 전압이 검출된다. 또한, CCFL(20)의 출력단과 저항(R31)의 접속점에는 쇼트키 다이오드(Schottky Diode:SD32)가 연결된다.A resistor R 31 is connected between the output terminal of the CCFL 20 and the ground to detect a voltage by a current flowing in the CCFL 20. In addition, a Schottky diode SD 32 is connected to a connection point of the output terminal of the CCFL 20 and the resistor R 31 .

CCFL(30)의 출력단과 접지사이에는 저항(R34)이 연결되어 CCFL(30)에 흐르는 전류에 의하여 전압이 검출된다. 또한, CCFL(30)의 출력단과 저항(R34)의 접속점에는 쇼트키 다이오드(SD34)가 연결되고, 쇼트키 다이오드(SD32), (SD34)의 캐소오드들은 서로 연결되어 저항(R36)을 통하여 제어부(10)의 피드백단자(FB)에 연결된다.A resistor R 34 is connected between the output terminal of the CCFL 30 and the ground to detect a voltage by a current flowing in the CCFL 30. In addition, the Schottky diode SD 34 is connected to the output terminal of the CCFL 30 and the resistor R 34 , and the cathodes of the Schottky diodes SD 32 and SD 34 are connected to each other so that the resistor R is connected. It is connected to the feedback terminal FB of the control unit 10 through 36 ).

미설명 부호R32, R35, D31, D33 은 피드백 전류가 접지로 흐르는 것을 방지하기 위한 것이다.Reference numerals R 32 , R 35 , D 31 and D 33 are for preventing the feedback current from flowing to ground.

이하, 상기 회로 구성의 동작과정을 설명하기로 한다.Hereinafter, an operation process of the circuit configuration will be described.

제어부(10)에 의하여 듀티비가 조정되는 펄스신호(S1), (S2), (S3), (S4)에 의하여 동작되는 스위칭 소자들(Q1), (Q2), (Q3), (Q4)에 의하여 입력되는 직류전원 (VDC)은 트랜스 포머의 2차측 코일(N2), (N3)에 고압의 교류전원을 유기시킨다. 코일(N2), (N3)에 유기된 전압에 의하여 CCFL(20), (30)은 점등되게 되고, CCFL의 출력단에 연결되는 저항(R31), (R34)에서 전압강하가 발생되고, 저항(R31), (R34)에 인가되는 전압에 의하여 쇼트키 다이오드(SD32), (SD34)를 통과하는 전류는 쇼트키 다이오드에서 정류되고 결국 합해져 저항(R36)을 통하여 제어부(10)의 피드백 단자에 입력되게 된다. Switching elements Q 1 , Q 2 , and Q operated by pulse signals S 1 , S 2 , S 3 , and S 4 whose duty ratio is adjusted by the controller 10. 3 ), DC power input (V DC ) input by (Q 4 ) induces high voltage AC power to the secondary coils (N2), (N3) of the transformer. The CCFLs 20 and 30 are turned on by the voltage induced in the coils N2 and N3, and a voltage drop is generated at the resistors R 31 and R 34 connected to the output terminal of the CCFL. The currents passing through the Schottky diodes SD 32 and SD 34 by the voltages applied to the resistors R 31 and R 34 are rectified in the Schottky diodes and eventually summed to form a control unit through the resistor R 36 . Input to the feedback terminal of 10).

도 4는 본 발명에 적용되는 쇼트키 다이오드의 특성을 나타내기 위한 그래프이다.4 is a graph showing the characteristics of the Schottky diode applied to the present invention.

도 4에 도시된 바와 쇼트키 다이오드는 0.0mA로 전류가 미세하게 흐를 때에도 그 산포값이 0.1V로 작게 나타나므로 제어부(10)에 입력되는 전류는 온도변화에 따라서 유동되지 않게된다. 따라서, 쇼트키 다이오드를 사용하게 되면 복수의 램프를 구동함에 따라서 각각의 램프를 구동시키는 구동전류가 미약하게 되어도 정확한 제어를 수행함으로써 정확한 듀티제어를 이룰 수 있다.As shown in FIG. 4, the Schottky diode has a small dispersion value of 0.1 V even when the current flows in a small amount of 0.0 mA, so that the current input to the controller 10 does not flow in accordance with the temperature change. Therefore, when the Schottky diode is used, accurate duty control can be achieved by performing accurate control even when the driving current for driving each lamp is weak as the plurality of lamps are driven.

상기의 목적과 구성을 갖는 본 발명에 따르면, 하나의 트랜스에 결합되는 램프가 복수로 되어 램프에 흐르는 전류량이 작게 되는 경우에 산포되는 전압을 감소시켜 정확한 밝기 제어를 이룰 수 있다.According to the present invention having the above object and configuration, when the number of lamps coupled to one transformer is plural and the amount of current flowing through the lamp is reduced, the scattered voltage can be reduced to achieve accurate brightness control.

Claims (1)

제어부의 제어에 따라 하나의 철심에 권선된 코일들에 흐르는 전류를 제어하여 고압의 교류전원을 발생시키는 전압변환부, 상기 전압변환부의 출력에 의하여 점등되는 복수의 LCD 백라이트용 램프들, 상기 LCD 백라이트 램프들에 흐르는 전류를 감지하기 위한 감지부; 상기 감지부에 인가되는 전압을 정류하여 상기 제어부의 피드백 단자에 피드백전류를 공급하는 정류부를 포함하는 다채널 인버터에 있어서:A voltage conversion unit for generating a high-voltage AC power by controlling the current flowing through the coils wound on one iron core under the control of the control unit, a plurality of LCD backlight lamps that are lit by the output of the voltage conversion unit, the LCD backlight A sensing unit for sensing current flowing through the lamps; In the multi-channel inverter comprising a rectifier for rectifying the voltage applied to the sensing unit to supply a feedback current to the feedback terminal of the control unit: 상기 감지부에 인가되는 전압의 정류는 쇼트키 다이오드(Schottky Diode)에 의하여 이루어지는 것을 특징으로 하는 다채널 인버터.Rectification of the voltage applied to the sensing unit is a multi-channel inverter, characterized in that the Schottky diode (Schottky Diode).
KR1020050082815A 2005-09-06 2005-09-06 Inverter for mutichannel lamp KR20070027331A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100978119B1 (en) * 2008-06-18 2010-08-25 샬롬엔지니어링 주식회사 EL inverter with brightness control function
KR101053408B1 (en) * 2010-02-23 2011-08-01 삼성전기주식회사 Driver for back light unit
KR20210154858A (en) * 2019-05-31 2021-12-21 엘지전자 주식회사 display device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100978119B1 (en) * 2008-06-18 2010-08-25 샬롬엔지니어링 주식회사 EL inverter with brightness control function
KR101053408B1 (en) * 2010-02-23 2011-08-01 삼성전기주식회사 Driver for back light unit
KR20210154858A (en) * 2019-05-31 2021-12-21 엘지전자 주식회사 display device

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