KR20080092600A - Circuit for protecting lamp drive inverter - Google Patents

Circuit for protecting lamp drive inverter Download PDF

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Publication number
KR20080092600A
KR20080092600A KR1020070036117A KR20070036117A KR20080092600A KR 20080092600 A KR20080092600 A KR 20080092600A KR 1020070036117 A KR1020070036117 A KR 1020070036117A KR 20070036117 A KR20070036117 A KR 20070036117A KR 20080092600 A KR20080092600 A KR 20080092600A
Authority
KR
South Korea
Prior art keywords
capacitor
protection circuit
transformer
inverter protection
voltage follower
Prior art date
Application number
KR1020070036117A
Other languages
Korean (ko)
Inventor
한재현
Original Assignee
엘지이노텍 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 엘지이노텍 주식회사 filed Critical 엘지이노텍 주식회사
Priority to KR1020070036117A priority Critical patent/KR20080092600A/en
Publication of KR20080092600A publication Critical patent/KR20080092600A/en

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Classifications

    • 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
    • H05B41/14—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
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • 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
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions

Abstract

A lamp driving inverter protection circuit is provided to reinforce feedback impedance by transmitting a feedback current using a voltage follower. A lamp driving inverter protection circuit includes a transformer(T1), a detection resistor(Rs), a voltage follower(110), a first capacitor(C1), a second capacitor(C2). The transformer supplies power to a load terminal. The detection resistor detects a feedback current outputted from the load terminal. The voltage follower transmits a feedback current signal detected through the detection resistor to a drive for controlling an operation of the lamp driving inverter protection circuit. A side of the first capacitor is coupled to a second side of the transformer. The other side of the first capacitor is coupled to the load terminal. A side of the second capacitor is coupled between a second side of the transformer and the first capacitor. The other side of the second capacitor is coupled to a ground.

Description

Lamp driving inverter protection circuit {Circuit for protecting lamp drive inverter}

1 is a view showing a conventional lamp driving inverter protection circuit.

2 is a view showing a lamp driving inverter protection circuit according to an embodiment of the present invention.

3 is a view showing a voltage follower according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

110 voltage follower 120 half or full bridge

130 Drive IC OP1 OP Amplifier

Rs sense resistor CN2 load

T1 Transformer C1 First Capacitor

C2 second capacitor

The present invention relates to a protection circuit of a lamp driving inverter.

In general, liquid crystal displays (hereinafter, referred to as "LCDs") have tended to be increasingly wider in application due to light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment, audio / video equipment, and the like. On the other hand, the LCD is controlled to display the desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form.

Since the LCD is not a self-luminous display device, a light source such as a back light is required. These LCD backlights are classified into direct type and edge type according to the arrangement of the lamps, and cold cathode tube lamps (CCFL) and external electrode fluorescent lamps (EEFL) according to the lamp type. ) Can be divided into

The lamp drive inverter circuit must satisfy the safety standard in consideration of the safety of the user, and a function to detect the lamp drive inverter by detecting it when an abnormal situation such as peak current occurs.

1 is a view showing a conventional lamp driving inverter protection circuit.

In FIG. 1, the conventional lamp driving inverter protection circuit senses a feedback current (Isense) from a sense resistor (Rsense) connected to a load, and the feedback current signal is directly transmitted to the IC 10. The IC 10 receives the feedback current signal and activates the circuit protection function if there is an abnormality in the circuit.

As shown in FIG. 1, in the conventional lamp driving inverter protection circuit, the feedback current signal Isense sensed by the sensing resistor Rsense is transmitted to the IC 10 through a long pattern. Therefore, there is a high possibility that external noise is introduced while the feedback current signal Isense is transmitted to the IC 10 through a long pattern, and an error may occur in the transmission of the feedback current signal Isense.

The present invention is to enable the stable feedback current signal transmission in the backlighting inverter protection circuit.

The present invention provides a transformer for supplying power to a load stage, a sense resistor for sensing a feedback current output from the load stage, and a feedback current signal sensed through the sense resistor in a drive controlling an operation of a lamp driving inverter protection circuit. And a voltage follower for delivering the voltage follower.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 is a view showing a lamp driving inverter protection circuit according to an embodiment of the present invention. In FIG. 2, a half-bridge or full-bridge 120 is used for the lamp driving inverter protection circuit. The load terminal CN2 includes a high terminal 1 and a low terminal 2, and a lamp such as a Cold Cathode Fluorescent Lamp (CCFL) or an External Electrode Fluorescent Lighting (EEFL) may be connected to the load terminal CN2.

As shown in FIG. 2, the lamp driving inverter protection circuit of the present invention includes a transformer T1, a sensing resistor Rs, and a voltage follower 110.

The transformer T1 has a primary side connected to the half or full bridge stage 120 and a secondary side connected to the load stage CN2, and serves to supply power to the load stage CN2.

The sensing resistor Rs is connected to one end of the load terminal CN2 and the other end of the sensing resistor Rs to sense a feedback current output from the load terminal CN2.

The voltage follower 110 delivers a feedback current signal Is sensed through the sensing resistor Rs to the drive IC 130 that controls the operation of the lamp driving inverter protection circuit. In the embodiment of FIG. 2, the voltage follower 110 is configured as an OP amplifier OP1. Detailed description of the voltage follower 110 will be described later.

One side of the first capacitor C1 is connected to the secondary side of the transformer T1, and the other side thereof is connected to the load terminal CN2.

One side of the second capacitor C2 is connected between the secondary side of the transformer T1 and the first capacitor C1 and the other side is connected to the ground.

In the present invention, the first capacitor C1 and the second capacitor C2 may be used to set the resonance frequency of the circuit.

In the embodiment of Figure 2, the voltage follower 110 is composed of an OP amplifier (OP1), OP amplifier OP1 is a non-inverting terminal is connected between the load terminal CN2 and the sense resistor (Rs), the inverting terminal It is connected to the output terminal, the output terminal is connected to the drive IC (130).

3 is a diagram illustrating a voltage follower 130 according to an embodiment of the present invention.

As shown in FIG. 3, the voltage follower 110 is a non-inverting amplifier having a voltage gain of 1, and the input voltage is output as it is. This amplifier circuit has no input resistance or feedback resistance and is configured by connecting the output directly to the inverting input terminal.

In FIG. 3, the input resistance is the same as the high input resistance of the OP amplifier OP1, and the output resistance has a very low value. Therefore, the circuit has a high input impedance close to ∞, and the output impedance close to zero. Has a value. Therefore, the output voltage Vo becomes Vo = Vi + (1+ (output resistance / input resistance)) = Vi. That is, the output voltage Vo in the voltage follower 130 has the same value as the input voltage Vi. For example, in FIG. 2, the voltage applied to the sensing resistor Rs is input to the non-inverting terminal of the OP amplifier OP1, and this voltage is output from the output terminal as it is.

Due to the characteristics of the voltage follower 130, the lamp driving inverter protection circuit of the present invention can transmit the electrical signal in one direction without affecting the other device, it is possible to enhance the resistance to high frequency noise.

While the invention has been described using some preferred embodiments, these embodiments are illustrative and not restrictive. Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the invention and the scope of the rights set forth in the appended claims.

As described above, according to the present invention, by transmitting a feedback current using a voltage follower in the lamp driving inverter protection circuit, the feedback impedance is strengthened, immunity to external noise is enhanced, and a more stable feedback current signal can be transmitted. It is effective.

Claims (4)

A transformer for supplying power to the load stage; A sensing resistor for sensing a feedback current output from the load stage; Voltage follower for delivering feedback current signal sensed through the sense resistor to the drive controlling the operation of the lamp drive inverter protection circuit Lamp drive inverter protection circuit comprising a. The method of claim 1, And the voltage follower comprises a non-inverting terminal connected between the load terminal and the sense resistor, an inverting terminal connected to an output terminal, and an output amplifier connected to the drive. The method according to claim 1 or 2, One side is connected to the secondary side of the transformer and the other side lamp driving inverter protection circuit further comprises a first capacitor connected to the load end. The method of claim 3, One side is connected between the secondary side of the transformer and the first capacitor and the other side lamp driving inverter protection circuit further comprises a second capacitor connected to the ground.
KR1020070036117A 2007-04-12 2007-04-12 Circuit for protecting lamp drive inverter KR20080092600A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020070036117A KR20080092600A (en) 2007-04-12 2007-04-12 Circuit for protecting lamp drive inverter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020070036117A KR20080092600A (en) 2007-04-12 2007-04-12 Circuit for protecting lamp drive inverter

Publications (1)

Publication Number Publication Date
KR20080092600A true KR20080092600A (en) 2008-10-16

Family

ID=40153543

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020070036117A KR20080092600A (en) 2007-04-12 2007-04-12 Circuit for protecting lamp drive inverter

Country Status (1)

Country Link
KR (1) KR20080092600A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103941699A (en) * 2014-04-28 2014-07-23 浙江艾罗电源有限公司 Inverter for energy-storage type photovoltaic grid-connected system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103941699A (en) * 2014-04-28 2014-07-23 浙江艾罗电源有限公司 Inverter for energy-storage type photovoltaic grid-connected system
CN103941699B (en) * 2014-04-28 2016-06-08 浙江艾罗电源有限公司 Inverter for accumulation energy type photovoltaic parallel in system

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