KR100721170B1 - Current balance curcuit - Google Patents

Abstract

The present invention relates to a current equalization circuit, comprising: a current equalization circuit comprising a plurality of current equalizers, the current equalization circuit comprising: first and second transformers having a primary side and a secondary side; A driving power supply unit connected to the first and second transformers and receiving a feedback signal from a secondary side of the first and second transformers to supply driving power to the primary sides of the first and second transformers; N (N: positive) capacitors each having one end connected to one end of a secondary side of the first and second transformers, respectively; N loads connected to the other ends of the N capacitors, respectively; A feedback unit configured to receive the current flowing through the N loads and transmit a feedback signal for controlling the driving power to the driving power supply unit; And (N / 2-1) current equalizers connected to the N loads to control the same amount of current flowing through the N loads, wherein the plurality of current equalizers respectively include an input terminal. A primary side and a secondary side having an output terminal, wherein the first current equalizer from the load among the plurality of current equalizers has an input terminal of the primary side connected to the first load and an input terminal of the secondary side connected to the third load; The output terminal on the primary side is connected to the second load, the output terminal on the secondary side is connected to the primary input terminal of the second current equalizer, and K (1≤K≤N /) from the load of the plurality of current equalizers. 2-1 (positive) th current equalizer, the primary input terminal is connected to the secondary output terminal of the (K-1) th current equalizer from the load and the secondary input terminal is the (2K + 1) th Connected to the load, the primary output terminal ( 2K) th load and the secondary output terminal is connected to the primary input terminal of the (K + 1) th current equalizer, and the (N / 2-1) th current from the load among the plurality of current equalizers The equalizer has an input terminal on the primary side connected to the secondary output terminal of the (N / 2-2) th current equalizer from the load and a secondary input terminal connected to the (N-1) th load. The secondary output terminal is connected to the (N-2) -th load, and the secondary output terminal is connected to the N-th load.

Cold Cathode Fluorescent Lamps (CCFL), Current Lighting, Uniform Brightness, Current Lighting

Description

Current equalization circuit {CURRENT BALANCE CURCUIT}

1 is a circuit diagram of a current equalization circuit according to the prior art.

2 is a circuit diagram schematically showing a current equalization circuit according to a first embodiment of the present invention.

3 is an explanatory diagram illustrating that the magnitudes of currents flowing through the current equalizer of FIG. 2 are the same;

4 is a circuit diagram schematically showing a current equalization circuit according to a second embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

210: driving power supply unit 220: feedback unit

C ₁ to C ₈ : Capacitor CCFL ₁ to CCFL ₈ : Load

CC ₁ ~ CC ₃ : Current equalizer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current equalization circuit used for a backlight. In parallel lighting of a cold cathode fluorescent lamp, a current equalization circuit capable of uniformizing the magnitude of current flowing through each cold cathode fluorescent lamp with only a small number of current equalizers. It is about.

Today, with the development of display technology, monitors, which are liquid crystal displays (LCDs), are increasingly used in computers or other display devices. Compared with CRT monitors, the LCD monitors have the advantage of slimmer longitudinal sections and reduced flicker. The LCD monitor has a fluorescent lamp driven at high pressure for a backlight system requiring a back-light module.

In addition, an inverter with a driving circuit is used to drive the fluorescent lamp, which has a high voltage transformer, which generates a high AC output voltage with a low AC input voltage, thereby forming an LCD panel. Serves to supply voltage to the lamp.

Meanwhile, as the LCD TV or monitor market matures, the price of backlight unit-related components is falling as sales prices fall.

Therefore, due to the price pressure of the components related to the backlight unit, efforts to reduce the number of parts and the unit price have been continued.

As part of this effort, conventionally, one transformer is used to supply power to one lamp, but recently, a small number of transformers are used to drive an external electrode fluorescent lamp (EEFL) or a cold cathode fluorescent lamp. (CCFL: Cold Cathode Fluorescent Lamps) are connected in parallel to power multiple lamps.

 As described above, it is a recent trend to light several cold cathode fluorescent lamps in parallel, but when the cold cathode fluorescent lamps are connected in parallel, the current flowing through the cold cathode fluorescent lamps is different, so that the brightness of each lamp is uniform. The problem of not doing so arises.

Therefore, continuous research is being conducted on the method of controlling the current deviation of each lamp to make the brightness of each lamp uniform.

Next, a current equalization circuit according to the prior art will be described in detail with reference to the related drawings.

1 is a circuit diagram of a current equalization circuit according to the prior art.

First, as shown in FIG. 1, the current equalization circuit 100 according to the related art includes a driving power supply unit 110, a transformer T, a feedback unit 120, and N (N: positive) capacitors C. ₁ to C _N ), N loads (CCFL ₁ to CCFL _N ), and (N-1) current equalizers (CC ₁ to CC _N-1 ).

Here, the driving power supply unit 110 is connected to the primary side of the transformer T and the feedback unit 120 and receives a feedback signal f from the feedback unit 120 to the transformer T. Control the driving power supply.

The transformer T has a primary side Np connected to the driving power supply 110, a secondary side Ns connected to the plurality of capacitors C ₁ to C _N , and the driving power supply 110. ) And the driving power supplied to the primary side Np is induced to the secondary side Ns.

_One end of each of the plurality of capacitors C ₁ to C _N is connected to the secondary side Ns of the transformer T, and the other end thereof is connected to the plurality of loads CCFL ₁ to CCFL _{N −1} .

In this case, the load (CCFL ₁ ~ CCFL _N) at the other end, the current equalizer _{(CC 1 ~ CC N-1} ) that are connected, the current equalizer _{(CC 1 ~ CC N-1} ) is the load (CCFL ₁ ~ CCFL _N ) is connected to two neighboring loads.

The current equalizers CC ₁ to CC _N-1 include a primary side and a secondary side having input terminals 1 and 3 and output terminals 2 and 4, respectively, and a first current equalizer CC ₁ . The first and second input terminals (1, 3) of the are connected to the first and second load (CCFL ₁ , CCFL ₂ ), the first output terminal (2) is grounded, the second output terminal (4) ) Is connected to the first input terminal 1 of the neighboring second current equalizer (CC ₂ ).

Further, the first input terminal 1 of the K (K: positive) th current equalizer CC _K is the second output terminal 4 of the (K-1) th current equalizer CC _K-1 . And the second input terminal 3 is connected to the (K + 1) th load (CCFL _{K +1} ), the first output terminal 2 is connected to ground, and the second output terminal 4 is connected to (K The first input terminal 1 of the +1) th current equalizer CC _{K +1} is connected.

The second output terminal 4 of the (N-1) th current equalizer CC _N-1 is connected to the feedback unit 120.

The feedback unit 120 is connected to the driving power supply unit 110 and the second output terminal 4 on the secondary side of the (N-1) th current equalizer CC _{n -1} , and the (N− 1) The feedback signal f is outputted by receiving the current In flowing through the _Nth load CCFL _N from the _1st current equalizer CC _{n- 1} .

The driving power supply unit 110 receiving the feedback signal f supplies the predetermined driving power to the primary side Np of the transformer T by controlling the driving power.

In the current equalization circuit 100 having the above structure, the second current I ₂ flowing through the second load CCFL ₂ is driven by the first current equalizer CC ₁ to the first load CCFL _1. ) To have a current value equal to that of the first current I ₁ flowing through the third current I ₁ , and the third current I ₃ flowing through the third load CCFL ₃ also has the second current equalizer CC ₂ . By controlling to have a current value of the same size as the second current (I ₂ ).

Accordingly, the current equalization circuit 100 includes the currents I ₁ to I _N flowing through the plurality of loads CCFL ₁ to CCFL _N by the plurality of current equalizers CC ₁ to CC _N-1 . Since all have the same current value, the luminance of the loads CCFL ₁ to CCFL _N can be maintained uniformly.

However, in order to maintain uniform luminance of the plurality of loads CCFL ₁ to CCFL _{N included in} the current equalization circuit 100, the current equalizers CC ₁ to CC _{N -1} are configured to load the CCCC _1. There is a problem that the size of the circuit increases because it must be composed of one less than the number of ~ CCFL _N ).

In addition, since a large number of current equalizers are required to drive the loads CCFL ₁ to CCFL _N , there is a problem in that a manufacturing cost of a backlight-related component is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to uniformly maintain the luminance of the load by using a small number of current equalizers to equalize the amount of current flowing through each load. It is to provide a current equalization circuit that can reduce the size of the circuit and lower the manufacturing cost.

A current equalizing circuit comprising a plurality of current equalizers, the current equalizing circuit according to the present invention for achieving the above object comprises: first and second transformers having a primary side and a secondary side; A driving power supply unit connected to the first and second transformers and receiving a feedback signal from the secondary sides of the first and second transformers to supply driving power to the primary sides of the first and second transformers; N (N: positive) capacitors each having one end connected to one end of a secondary side of the first and second transformers; N loads connected to the other ends of the N capacitors, respectively; A feedback unit configured to receive the current flowing through the N loads and transmit a feedback signal for controlling the driving power to the driving power supply unit; And (N / 2-1) current equalizers connected to the N loads to control the same amount of current flowing through the N loads, wherein the plurality of current equalizers respectively include an input terminal. A primary side and a secondary side having an output terminal, wherein the first current equalizer from the load among the plurality of current equalizers has an input terminal of the primary side connected to the first load and an input terminal of the secondary side connected to the third load; The output terminal on the primary side is connected to the second load, the output terminal on the secondary side is connected to the primary input terminal of the second current equalizer, and K (1≤K≤N /) from the load of the plurality of current equalizers. 2-1 (positive) th current equalizer, the primary input terminal is connected to the secondary output terminal of the (K-1) th current equalizer from the load and the secondary input terminal is the (2K + 1) th Connected to the load, the primary output terminal ( 2K) th load and the secondary output terminal is connected to the primary input terminal of the (K + 1) th current equalizer, and the (N / 2-1) th current from the load among the plurality of current equalizers The equalizer has an input terminal on the primary side connected to the secondary output terminal of the (N / 2-2) th current equalizer from the load and a secondary input terminal connected to the (N-1) th load. The secondary output terminal is connected to the (N-2) th load and the secondary output terminal is characterized in that it is connected to the Nth load.

Here, the load is a cold cathode fluorescent lamp, characterized in that the current equalizer is a transformer having the same turns ratio of the primary side and the turns ratio of the secondary side.

In addition, in the current equalization circuit according to the present invention, the feedback unit comprises: a first resistor connected to any one of the plurality of current equalizers; A second resistor having one end connected to the first resistor and the other end connected to the ground; A first diode having a cathode connected to the common terminal of the first resistor and the second resistor and an anode connected to the ground; And a second diode having an anode connected to the cathode of the first diode and a cathode connected to the driving power supply.

The above objects, features, and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be.

In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

The current equalization circuit according to the present invention will now be described in detail with reference to the accompanying drawings.

First, the current equalization circuit according to the present invention is connected to the first and second transformers having a primary side and a secondary side, and the first and second transformers, and from the secondary side of the first and second transformers. A driving power supply unit receiving a feedback signal to supply driving power to the primary sides of the first and second transformers, and N (N: positive) dogs having one end connected to one end of the secondary side of the first and second transformers, respectively; A capacitor, N loads connected to the other ends of the N capacitors, respectively, a feedback unit for receiving a current flowing through the N loads and transmitting a feedback signal for controlling the driving power to the driving power supply unit and the N loads And (N / 2-1) current equalizers connected to each other to control the same amount of current flowing through the N loads.

In this case, the plurality of current equalizer includes a primary side and a secondary side having an input terminal and an output terminal, respectively, wherein the first current equalizer from the load among the plurality of current equalizers, the input terminal of the primary side is the first load The input terminal on the secondary side is connected to the third load, the output terminal on the primary side is connected to the second load, and the output terminal on the secondary side is connected to the primary input terminal of the second current equalizer.

Further, the K (1≤K≤N / 2-1: positive) th current equalizer from the load among the plurality of current equalizers has a secondary terminal of the (K-1) th current equalizer from the load at the primary input terminal. The output terminal of the secondary side is connected to the (2K + 1) th load, the output terminal of the primary side is connected to the (2K) th load and the output terminal of the secondary side is connected to the (K + 1) th current equalizer. It is connected to the primary input terminal.

Further, the (N / 2-1) th current equalizer from the load among the plurality of current equalizers, the input terminal of the primary side is connected to the secondary output terminal of the (N / 2-2) th current equalizer from the load. The secondary input terminal is connected to the (N-1) th load, the primary output terminal is connected to the (N-2) th load, and the secondary output terminal is connected to the Nth load.

In the following description, the current equalization circuit including eight loads and three current equalizers (N = 8) will be described in detail with reference to the first and second embodiments in order to more clearly describe the present invention.

Example  One

FIG. 2 is a circuit diagram schematically illustrating a current equalization circuit according to a first embodiment of the present invention, and FIG. 3 is an explanatory diagram illustrating that the magnitudes of currents flowing through the current equalizer of FIG. 2 are the same.

First, as shown in FIG. 2, the current equalization circuit 200 according to the first embodiment of the present invention may include a driving power supply unit 210, first and second transformers T1 and T2, and first through second operations. 8 capacitors (C ₁ ~ C ₈ ), the first to eighth load (CCFL ₁ ~ CCFL ₈ ), the first to third current equalizer (CC ₁ , CC ₂ , CC ₃ ) and the feedback unit 220 do.

The driving power supply unit 210 is connected to the primary sides Np1 and Np2 and the feedback unit 220 of the first and second transformers T1 and T2, and the first to second power supplies 210 to the first to second transformers T1 and T2. The driving power is supplied to the first and second transformers T1 and T2 by receiving a feedback signal f for uniformly controlling the magnitudes of the currents I ₁ to I ₈ flowing through the eighth loads CCFL ₁ to CCFL ₈ . Supply to the primary sides Np1 and Np2.

One end of each of the first, third, fifth and seventh capacitors C ₁ , C ₃ , C ₅ , and C ₇ is connected to _one end of the second side Ns ₁ of the first transformer T1, respectively. , The other end is connected to the first, third, fifth and seventh loads CCFL ₁ , CCFL ₃ , CCFL ₅ , CCFL ₇ .

In addition, one end of the second, fourth, sixth, and eighth capacitors C ₂ , C ₄ , C ₆ , and C ₈ may be connected to one end of the second side Ns ₂ of the second transformer T1. The other end is connected to the second, fourth, sixth and eighth loads CCFL ₂ , CCFL ₄ , CCFL ₆ , and CCFL ₈ . At this time, the other ends of the secondary sides Ns ₁ and Ns _{2 of} the first and second transformers T1 and T2 are grounded.

In particular, the first to eighth loads CCFL ₁ to CCFL ₈ may be configured using a cold cathode fluorescent lamp used in a backlight module.

The first, second and third current equalizers CC ₁ , CC ₂ , and CC _{3 each} have a first input terminal 1 and a first output terminal 2 having a primary side and a second input terminal 3. And a secondary side having a second output terminal 4.

At this time, the first first current equalizer (CC ₁ ) from the load, the first input terminal 1 of the primary side is connected to the other end of the first load (CCFL ₁ ) of the _first side and the second input of the secondary side The terminal 3 is connected to the other end of the third third load CCFL ₃ , and the first output terminal 2 of the primary side is connected to the other end of the second load CCFL ₂ of the second side and of the secondary side. The second output terminal 4 is connected to the first input terminal 1 of the second second current equalizer CC ₂ .

In addition, the second current equalizer (CC ₂ ) of the second load from the load, the first input terminal (1) of the primary side is connected to the second output terminal (4) of the first current equalizer (CC ₁ ) The second input terminal 3 of the secondary side is connected to the other end of the fifth fifth load CCFL ₅ , and the first output terminal 2 of the primary side is the third current equalizer CC _3. Is connected to the first input terminal 1 of the primary side.

In addition, the third third current equalizer (CC ₃ ) from the load portion, the first input terminal (1) of the primary side is connected to the second output terminal (4) of the second current equalizer (CC ₂ ). And the second input terminal 3 on the secondary side is connected to the seventh seventh load CCFL ₇ , and the first output terminal 3 on the primary side is connected to the sixth sixth load CCFL ₆ . The second output terminal 4 of the secondary side is connected to the eighth eighth load CCFL ₈ .

3, when the current I _N1 is applied to the first input terminal 1 of the primary side N1, the first and second current equalizers CC ₁ and CC ₂ are applied. The current I _N1 is induced to the secondary side N2, and finally, the current I _N1 having the same current value as the applied current I _N1 is output through the second output terminal 4.

On the other hand, the primary side (N1) to equalize the magnitude of the current I _N1 output to the first and second output terminals (2, 4) of the primary side (N1) and secondary side (N2) of the current equalizer as described above. The winding ratio of and the winding ratio of the secondary side (N2) should be the same to output the same current I _N1 . Therefore, it is preferable that the primary side and the secondary side of the first, second and third current equalizers CC ₁ , CC ₂ , CC ₃ are wound with the same turns ratio, and the first, second and third currents The equalizers CC ₁ , CC ₂ , CC ₃ preferably use a transformer.

As described above, the current I ₁ flowing in the first load CCFL ₁ is applied to the first input terminal 1 of the first current equalizer CC ₁ , so that the second load CCFL ₂ and first being applied to the input terminal 1, the current (I ₁₎ applied to the first input terminal (1) of the second current equalizer (CC ₂₎ of the second current equalizer (CC ₂₎ is the The fourth load CCFL ₄ and the third current equalizer CC ₃ are applied to the fourth load CCFL ₄ .

In addition, the sixth and eighth currents I ₁ applied to the first input terminal 1 of the third current equalizer CC ₃ are passed through the first and second output terminals 2 and 4. By applying to the load (CCFL ₆ , CCFL ₈ ), the first through eighth load (CCFL ₁ ~ CCFL ₈ ) through the first, second and third current equalizer (CC ₁ , CC ₂ , CC ₃ ) The magnitude of the current flowing in can be controlled uniformly.

Accordingly, the currents I ₁ to I ₈ flowing through the first to eighth loads CCFL ₁ to CCFL ₈ all have current values of the same magnitude, and thus the first to eighth loads CCFL ₁ to CCFL ₈ . Can maintain uniform brightness.

In addition, the feedback unit 220 may include a first resistor R1 connected to any one of the _first , second and third current equalizers CC ₁ , CC ₂ , and CC ₃ ; The second resistor R2 is connected to the other end of the first resistor R1, the first diode D1 and the anode are connected to the other end of the second resistor R2 and the anode is grounded. A second diode (D2) is connected to the common terminal of the second resistor (R2) and the first diode (D1) and the cathode is connected to the driving power supply 210, the first, second and third current A feedback signal f connected to the equalizers CC ₁ , CC ₂ , CC ₃ , and the driving power supply 210 to uniformly maintain current flowing through the first to eighth loads CCFL ₁ to CCFL ₈ . It delivers to the drive power supply 210.

If the current applied through the first resistor R1 is not a reference current for maintaining uniform luminance of the first to eighth loads CCFL ₁ to CCFL ₈ , the first and second resistors ( The feedback signal f divided through R1 and R2 also does not have a preset reference voltage.

In this case, the driving power supply unit 210 receiving the feedback signal f controls the driving power so that the feedback signal f has the same magnitude as that of the reference voltage, thereby controlling the first and second transformers T1. , T2) to the primary sides Np ₁ and Np ₂ .

Accordingly, as summarized in Table 1 below, the current equalization circuit 100 according to the prior art required seven current equalizers to drive eight loads, but the current equalization circuit 200 according to the present invention. ) Can drive eight loads with only three equalizers, reducing the size of the circuit.

Example  2

4 is a circuit diagram schematically showing a current equalization circuit according to a second embodiment of the present invention. However, the description of the same parts as those of the second embodiment of the configuration of the first embodiment will be omitted, and only the configuration that is different from the second embodiment will be described in detail.

As shown in FIG. 4, the current equalization circuit 300 according to the second embodiment of the present invention may drive the _eight loads CCFL ₁ to CCFL ₈ using only one transformer T1. .

In this case, the transformer T1 has a primary side Np1 connected to the driving power supply 310, and one end of the secondary side Ns1 has the first, third, fifth and seventh capacitors C ₁ ,. C ₃ , C ₅ , and C ₇ are connected to one end, and the other end of the second side Ns1 is one end of the second, fourth, sixth, and eighth capacitors C ₂ , C ₄ , C ₆ , and C ₈ . Connected with

Accordingly, the current equalization circuit 300 according to the second embodiment of the present invention maintains the luminance of the first to eighth loads CCFL ₁ to CCFL ₈ uniformly using only one transformer T1. This has the advantage of reducing the size of the circuit.

Meanwhile, the current equalization circuits 200 and 300 according to the first and second embodiments of the present invention are edge light type used in a backlight module of an LCD monitor or TV of 22 inches or less and 20 inches or more. It can be used for both the direct light type used in the backlight module of the LCD TV.

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be appreciated that such substitutions, changes, and the like should be considered to be within the scope of the following claims.

As described above, the current equalization circuit according to the present invention has the effect of uniformly controlling the magnitude of the current flowing through each load by using a small number of current equalizers, thereby maintaining the brightness of the load uniformly. .

In addition, the present invention has the effect of reducing the size of the circuit by using a small number of current equalizer to reduce the manufacturing cost of the backlight-related components.

Claims (6)

In a current equalization circuit comprising a plurality of current equalizers, The current equalization circuit, First and second transformers having a primary side and a secondary side; A driving power supply unit connected to the first and second transformers and receiving a feedback signal from a secondary side of the first and second transformers to supply driving power to the primary sides of the first and second transformers; N (N: positive) capacitors each having one end connected to one end of a secondary side of the first and second transformers, respectively; N loads connected to the other ends of the N capacitors, respectively; A feedback unit configured to receive the current flowing through the N loads and transmit a feedback signal for controlling the driving power to the driving power supply unit; And And (N / 2-1) current equalizers connected to the N loads and controlling the currents flowing through the N loads to have the same magnitude. The plurality of current equalizers include a primary side and a secondary side, each having an input terminal and an output terminal, The first current equalizer from the load of the plurality of current equalizer, The primary input terminal is connected to the first load, the secondary input terminal is connected to the third load, the primary output terminal is connected to the second load, and the secondary output terminal is connected to the second current equalizer. Connected to the secondary input terminal, Among the plurality of current equalizers, a K (1 ≦ K ≦ N / 2-1: positive) th current equalizer from a load includes: The primary input terminal is connected to the secondary output terminal of the (K-1) th current equalizer from the load, the secondary input terminal is connected to the (2K + 1) th load, and the primary output terminal is (2K). ) Is connected to the 1st load and the output terminal of the secondary side is connected to the primary input terminal of the (K + 1) current equalizer, (N / 2-1) th current equalizer from the load among the plurality of current equalizers, The primary input terminal is connected to the secondary output terminal of the (N / 2-2) th current equalizer from the load, the secondary input terminal is connected to the (N-1) th load, and the primary output terminal is ( N-2) current load circuit, characterized in that connected to the second load and the secondary output terminal is connected to the N-th load. In a current equalization circuit comprising a plurality of current equalizers, The current equalization circuit, One transformer having a primary side and a secondary side; A driving power supply unit connected to the transformer and receiving a feedback signal from a secondary side of the transformer to supply driving power to the primary side of the transformer; N (N: positive) capacitors each having one end connected to one end and the other end of the secondary side of the transformer; N loads connected to the other ends of the N capacitors, respectively; A feedback unit configured to receive the current flowing through the N loads and transmit a feedback signal for controlling the driving power to the driving power supply unit; And And (N / 2-1) current equalizers connected to the N loads and controlling the currents flowing through the N loads to have the same magnitude. The plurality of current equalizers include a primary side and a secondary side, each having an input terminal and an output terminal, The first current equalizer from the load of the plurality of current equalizer, The primary input terminal is connected to the first load, the secondary input terminal is connected to the third load, the primary output terminal is connected to the second load, and the secondary output terminal is connected to the primary side of the second current equalizer. Connected to the terminal, Among the plurality of current equalizers, a K (1 ≦ K ≦ N / 2-1: positive) th current equalizer from a load includes: The primary input terminal is connected to the secondary output terminal of the (K-1) th current equalizer from the load, the secondary input terminal is connected to the (2K + 1) th load, and the primary output terminal is (2K). ) Is connected to the 1st load and the output terminal of the secondary side is connected to the primary input terminal of the (K + 1) current equalizer, (N / 2-1) th current equalizer from the load among the plurality of current equalizers, The primary input terminal is connected to the secondary output terminal of the (N / 2-2) th current equalizer from the load, the secondary input terminal is connected to the (N-1) th load, and the primary output terminal is ( N-2) current load circuit, characterized in that connected to the second load and the secondary output terminal is connected to the N-th load. The method according to claim 1 or 2, And said load is a cold cathode fluorescent lamp. The method according to claim 1 or 2, And the current equalizer is a transformer. The method of claim 4, wherein And the primary side and the secondary side of the current equalizer are wound with the same turns ratio. The method according to claim 1 or 2, The feedback unit, A first resistor connected to any one of the plurality of current equalizers; A second resistor having one end connected to the first resistor and the other end connected to the ground; A first diode having a cathode connected to the common terminal of the first resistor and the second resistor and an anode connected to the ground; And A second diode having an anode connected to the cathode of the first diode and a cathode connected to the driving power supply; Current equalization circuit comprising a.

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