KR100660169B1 - Aging inverter for ccfl and eefl - Google Patents

Abstract

An aging inverter for a CCFL and an EEFL is provided to perform a stable aging process on the CCFL and the EEFL by synchronizing output frequencies and phases of the lamps with each other. An aging inverter for a CCFL(Cold Cathode Fluorescent Lamp) and an EEFL(External Electrode Fluorescent Lamp) includes a PWM(Pulse Width Modulation) controller(10), to which a first current amplifier circuit(11) is connected. The inverter(20) includes an inverter protecting unit(21), a second current amplifier circuit(22), a switching unit(23), and a transformer(24). A lamp(30) is connected to the inverter. Output voltages, which are varied according to charge/discharge of a capacitor, are linked with the PWM controller such that output frequencies of the multi-channel inverter are synchronized with each other.

Description

Aging inverter for cold cathode fluorescent lamp or external electrode fluorescent lamp {Aging Inverter for CCFL and EEFL}

1 is an exemplary view of the use of a conventional CCFL / EEFL aging inverter.

2 is an output waveform diagram generated in a conventional aging inverter.

3 is a circuit diagram of an aging inverter according to the present invention.

4 is an output waveform diagram generated in the aging inverter according to the present invention.

<Description of the major reference numerals>

10: PWM control unit 11: first current amplifier circuit

20: inverter 23: switching unit

24: transformer 30: lamp

The present invention relates to an inverter used for aging of a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL). A CCFL / EEFL Aging Inverter capable of synchronizing output frequency and phase.

CCFL / EEFL is widely used as backlight in TFT LCD applications because of its high brightness, low heat generation and long life.

The CCFL / EEFL employs an inverter to generate a high voltage to provide the current required for the lamp.

In general, as shown in FIG. 1, a CCFL / EEFL manufacturing process includes an aging in which one lamp is connected to one aging inverter per channel and an initial lighting is performed by densely arranging a plurality of channels to improve productivity. .

However, when aging is performed in the same manner as in FIG. 1 using a conventional aging inverter, leakage current is generated due to mutual induced voltage due to the characteristics of CCFL / EEFL, and the amount of leakage current also varies between channels. Phenomenon occurs. Figure 2 shows the unstable output waveform of the inverter due to the interference between the channels, the process of making the waveform distortion by the interference between the channels as shown in the graph (graph 1).

<Graph 1>

No matter how the aging inverter supplies the same current, the interference between channels causes the amount of current consumed in each lamp to be changed, resulting in a stable current supply.

This not only guarantees a uniform quality of the lamp, but also impedes the output generating circuit of the inverter, resulting in shortening the lifetime of the inverter.

The present invention is to solve the above problems of the conventional aging inverter, and to provide a stable current supply to the lamp by providing an inverter that can prevent the interference between channels.

In order to achieve the above technical problem, the present invention includes a switching circuit and a transformer in an inverter for aging a cold cathode fluorescent lamp or an external electrode fluorescent lamp, which is connected to a PWM controller and a PWM controller output terminal of the frequency synchronization circuit Including a first current amplifier circuit and n inverters are connected in parallel to the output terminal of the first current amplifier circuit, thereby amplifying the current output from the PWM control through the first current amplifier circuit to the n inverters at the same time It provides a cold cathode fluorescent lamp or an external electrode fluorescent lamp aging inverter characterized in that the supply.

Hereinafter, the technical spirit of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 3, the inverter according to the present invention adopts a PWM control unit 10 and a first current amplifier circuit 11 is connected thereto, and the inverter 20 connected thereto is an inverter protection unit. 21, a second current amplifier circuit 22, a switching unit 23 and a transformer unit 24, the lamp 20 is mounted to the inverter 20.

As shown in the graph below (graph 2), the PWM control unit 10 is a CT value is a voltage value that changes according to the charge / discharge of the capacitor (Capacitor), RT Source is set to a reference voltage (Reference-Volt.) In other words, when the CT value changes, it is triggered based on the RT value to create pulse-wave.

By linking the C-T sources of several PWM controllers, it is possible to synchronize the inverter output frequencies of multiple channels.

<Graph 2>

However, since the PWM control unit is a frequency synchronization circuit, as shown in the graph below (graph 3), the problem of distorting the phase of another channel due to the inverse channel waveform may remain.

<Graph 3>

Therefore, the objective of the present invention can be achieved only by synchronizing the phase as well as the output frequency. As a solution for this, as shown in FIG. One integrated PWM controller is installed to provide the same source.

However, in general, since the amount of current of the gate-source supplied from the PWM control unit 10 is small enough to drive one inverter, sufficient current is supplied to each inverter by using the first current amplifier circuit 11. Therefore, it is desirable to prevent deformation from external noise which may be generated during line transmission.

The inverter 20 is a circuit for amplifying a voltage and a current based on a gate-source, which is a current transmitted from the PWM control unit 10, and supplying the voltage to the lamp 30. Is connected in parallel to the PWM control unit 10.

In this case, when the first current amplifier circuit 11 is adopted, n inverters are actually connected to the first current amplifier circuit in parallel. However, the first current amplifier circuit is separately generated according to the development of the PWM controller. As a dependent means that the design of N may be unnecessary, it can be considered that n inverters are connected in parallel to one PWM controller.

The inverter 20 may include an inverter protection unit 21 for each channel, which is a circuit that prevents damage and failure of the inverter by controlling the gate-source when a problem occurs in each inverter.

If there is an inverter protection unit 21, the inverter protection unit 21 is further included through the second current amplifier circuit 22 to restore the gate-source, which may be lost or deformed, and to amplify the current of the gate-source. Can be.

The generated gate-source is transferred to the switching unit 23, which is a switching circuit. The switching unit 23 amplifies voltage and current based on four gate-sources to generate a waveform having the most similar waveform to the sine-wave. It is desirable to generate a full-bridge switching circuit.

The output voltage and current generated by the switching unit 23 are finally transferred to the lamp 30 by the transformer unit 24 which is a transformer.

As a result of testing the inverter according to the present invention, as shown in FIG. 4, it was possible to obtain a stable output waveform of the inverter without mutual interference between channels.

In the above description, specific limitations are inevitable in describing the technical idea of the present invention. However, differences due to substitution or change at a level apparent to those skilled in the art will belong to the technical scope of the present invention as long as the technical spirit of the present invention is adopted. .

According to the present invention, the inverter output frequency and phase are synchronized to enable stable lamp aging without being concerned with the phenomenon of mutual interference between the lamps.

Therefore, the economic effect of reducing the loss in the lamp aging process, significantly increasing the quality of the lamp with uniform output, and preventing the breakage of the inverter can reduce the cost and maintenance cost.

In addition, the gap between lamps, which had to be maintained at least due to the interference in the lamp aging process, can be greatly reduced, which can increase production by 2 ~ 3 times in the same space, which is expected to contribute greatly to productivity improvement.

Claims (4)

An inverter for aging a cold cathode fluorescent lamp or an external electrode fluorescent lamp including a switching circuit and a transformer, the inverter comprising: a PWM controller as a frequency synchronization circuit and a first current amplifier circuit connected to the PWM controller output terminal; N inverters are connected in parallel to the output terminals of the amplification circuit, thereby amplifying the current output from the PWM control unit through the first current amplifier circuit and simultaneously supplying to the n inverters. Electrode Fluorescent Lamp Aging Inverter. 2. The pulse controller of claim 1, wherein the PWM controller is triggered based on a value set as a reference voltage when the voltage changes due to the charging and discharging of the capacitor. Cold cathode fluorescent lamp or external electrode fluorescent lamp aging inverter, characterized in that to synchronize the frequency by generating a). 2. The cold cathode fluorescent lamp or the external electrode fluorescent lamp of claim 1, wherein the switching circuit installed in each of the n inverters is a full-bridge switching circuit for amplifying voltage and current based on four gate sources. Aging inverter. The inverter protection unit of claim 1 or 3, wherein each of the n inverters is controlled by an inverter protection unit capable of controlling a gate-source input to the inverter from an output terminal of the first current amplification circuit, and is lost or modified in the inverter protection unit. The cold cathode fluorescent lamp or the external electrode fluorescent lamp aging inverter further comprises a second current amplifier circuit for restoring the current.

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