KR100528698B1 - Apparatus and method for driving of lamp - Google Patents

Abstract

The present invention relates to a driving device and a driving method of a lamp to increase the variable brightness range of the lamp and to prevent wave noise.

An apparatus for driving a lamp according to an embodiment of the present invention includes a lamp for generating light and an inverter for supplying a high voltage analog AC waveform to each of the first electrode and the second electrode of the lamp , wherein the inverter is external. An inverter integrated circuit including a switch element for converting driving power supplied from the inverter into an alternating current waveform, and converting the alternating current waveform from the inverter integrated circuit into the high voltage alternating current waveform for driving the lamp, and converting A transformer for supplying a high voltage alternating current waveform to each of the first and second electrodes of the lamp, and a modulation circuit for controlling the magnitude of the high voltage alternating current waveform supplied to the lamp by controlling switching of the switch element. It features.

The present invention can increase the luminance variable range of the analog mode method, and can minimize the wave noise phenomenon generated in the burst mode method. Furthermore, the present invention can reduce power consumption by reducing the current value for driving the lamp to half of the conventional one.

Description

Lamp driving device and driving method {APPARATUS AND METHOD FOR DRIVING OF LAMP}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp driving device and a driving method of a liquid crystal display device, and more particularly, to a driving device and a driving method of a lamp to increase a variable brightness range of a lamp and to prevent wave noise.

In general, liquid crystal displays (hereinafter referred to as "LCDs") have tended to be increasingly wider in application due to features such as 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 unit is required.

As a light source used in the backlight unit, a halogen cathode fluorescent lamp (Halogen Cathode Fluorescent tube) or a cold cathode tube (hereinafter referred to as "CCFL") is used. Among the light sources, CCFL is a light source tube using the cold emission (electron emission caused by a strong electric field applied to the surface of the cathode), and is easy to generate low heat, high brightness, long life, and full color. These CCFLs include a light guide type, a direct type type, a reflecting plate type, and the like, and a light source tube suitable for the type of LCD is adopted.

Such a light source is classified into an internal electrode fluorescent lamp having electrodes formed inside the discharge tube and an external electrode fluorescent lamp having electrodes formed outside the discharge tube. These fluorescent lamps are driven by a high pressure AC waveform. That is, the high-voltage AC waveform for driving the fluorescent lamps is obtained by converting the DC power supplied from the DC power supply unit into an AC waveform by the inverter and then boosting it by the transformer.

Specifically, the lamp driving apparatus according to the prior art drives the lamp 10 by converting the lamp 10 to generate light as shown in FIG. 1 and the voltage from the voltage source Vcc into an AC waveform. Inverter 20 is provided.

The first electrode terminal N1 of the lamp 10 is connected to each of the inverters 20, and the second electrode terminal N2 is connected to the ground voltage source GND. The lamp 10 receives the AC waveform supplied from the inverter 20 to emit light.

The inverter 20 receives a voltage from the voltage source Vcc and converts the signal into an AC waveform. The inverter 20 boosts the converted AC waveform to a high-voltage AC waveform for driving the lamp 10 and supplies the lamp to each of the lamps 10. An electric field is formed in (10) to generate light.

To this end, the inverter 20 is an inverter integrated circuit (hereinafter referred to as " IC ") 2 that receives a voltage from a voltage source Vcc and converts it into an AC waveform using a switching element, and an inverter IC. Transformer 4 for boosting and supplying the AC waveform supplied from (2) to the lamp 10, and Pulse Width Modulation (hereinafter referred to as " PWM ") controller 6 for controlling switching of the switching element. ).

The inverter IC 2 converts the voltage supplied from the voltage source Vcc into an AC waveform by using a switching element switched by the PWM control signal PWM from the PWM controller 6. The AC waveform, which is the output waveform of the inverter IC 2, is supplied to the transformer 4.

The transformer 4 boosts the AC waveform supplied from the inverter IC 2 to an AC waveform of high pressure for driving the lamp 10. For this purpose, the primary winding T1 of the transformer 4 is connected to the inverter IC 2, and the secondary winding T2 is connected to the first electrode terminal N1 of the lamp 10. In the transformer 4, the AC waveform from the inverter IC 2 supplied to the primary winding T1 is boosted by the winding ratio between the primary winding T1 and the secondary winding T2, and thus the secondary winding T2. ) And high voltage AC waveforms induced in the secondary winding T2 are supplied to the first electrode terminal N1 of the lamp 10.

The PWM controller 6 receives feedback of a luminance control signal (not shown) or a tube current flowing through the lamp 10 to control the switching of the switching element of the inverter IC 2.

Such a lamp driving apparatus according to the related art is an analog mode and a burst mode (Burst Mode) according to an AC waveform supply method supplied from the inverter IC 2 to the lamp 10 via the transformer 4. ).

The lamp driving apparatus of the analog mode type continuously supplies an AC waveform to the lamp 10 as shown in FIG. 2. Since the lamp driving apparatus of the analog mode method continuously turns on the lamp 10, there is an advantage that no wave noise occurs during driving. However, in the analog mode type lamp driving device, the brightness of the lamp 10 is varied by adjusting the amplitude Pmax of the AC waveform . As a result, the analog mode lamp driving apparatus has a narrow luminance variable range of about 50%. Therefore, an analog mode lamp driving apparatus has a disadvantage in that the luminance variable range is narrow. In addition, in the analog driving mode lamp driving apparatus, the left side dark phenomenon occurs when the amplitude is changed from the maximum amplitude Pmax to the minimum amplitude Pmax.

On the other hand, the lamp driving apparatus of the burst mode method supplies an alternating current waveform to the lamp 10 repeatedly on and off as shown in FIG. Such a burst mode lamp driving device has a disadvantage in that wave noise occurs during driving because the lamp 10 is turned on and off in a predetermined cycle unit. However, the burst mode lamp driving apparatus may vary the brightness of the lamp 10 by adjusting the on time TON during one cycle T of the AC waveform. That is, the burst mode lamp driving apparatus adjusts the duty ratio of on and off to vary the brightness of the lamp 10. As a result, the burst mode lamp driving apparatus has a wide luminance variable range of about 99%. At this time, the AC waveform supplied to the lamp 10 becomes the AC waveform of the analog mode shown in FIG. 2 when the duty of on-off is adjusted to 100% in the burst mode lamp driving apparatus.

Such a driving device of the lamp according to the prior art can prevent the generation of wave noise when driving in the analog mode method, but there is a problem that the narrow brightness range is narrow, when driving in the burst mode method can obtain a wide brightness variable range However, there is a problem that wave noise occurs.

Accordingly, an object of the present invention is to provide a lamp driving device and a method for driving the lamp to increase the variable brightness range of the lamp and to prevent wave noise.

In order to achieve the above object, a lamp driving apparatus according to an embodiment of the present invention includes a lamp for generating light, and an inverter for supplying a high-voltage AC waveform to each of the first electrode and the second electrode of the lamp; It is characterized by.

In the drive device of the lamp, the inverter includes an inverter integrated circuit including a switch element for converting drive power supplied from the outside into an AC waveform, and the high voltage for driving the lamp with the AC waveform from the inverter integrated circuit. A transformer for converting the AC waveform into the AC waveform, and supplying the converted AC waveform to the first and second electrodes of the lamp, and controlling the switching of the switch element. And a pulse width modulation circuit for controlling the magnitude.

In the driving device of the lamp, the transformer has a primary winding supplied with the AC waveform from the inverter integrated circuit, and a secondary winding in which the high voltage AC waveform is induced by a winding ratio with the primary winding. The secondary winding is characterized by having a secondary first winding connected between the first electrode of the lamp and the ground voltage source and a secondary secondary winding connected between the second electrode of the lamp and the ground voltage source.

The AC waveform of the high voltage supplied to each of the first and second electrodes in the driving device of the lamp is characterized in that the analog form for continuously lighting the lamp.

In the driving device of the lamp, the pulse width modulation circuit may vary the brightness of light emitted from the lamp by varying the amplitude of the high-voltage AC waveform in the analog form.

The AC waveform of the high voltage supplied to each of the first and second electrodes in the driving device of the lamp is characterized in that the burst form for turning on and off the lamp in a predetermined cycle unit.

In the driving device of the lamp, the pulse width modulation circuit may vary the brightness of light emitted from the lamp by varying an on time for one cycle of the burst of the high voltage AC waveform.

According to an aspect of the present invention, there is provided a method of driving a lamp, the method comprising: providing a lamp for generating light, generating a high-pressure AC waveform for driving the lamp, and converting the high-voltage AC waveform into a first electrode of the lamp And supplying to each of the second electrodes.

The generating of the high-voltage AC waveform in the driving method may include converting a driving voltage supplied from the outside into an AC waveform, controlling the magnitude of the AC waveform, and converting the AC waveform into the high-voltage AC waveform. And converting.

In the driving method, the lamp is continuously lit by the high-voltage AC waveform supplied to each of its first and second electrodes.

The controlling of the magnitude of the AC waveform in the driving method may vary the amplitude of the AC waveform.

In the driving method, the lamp is turned on and off by a predetermined cycle unit by the high-voltage AC waveform.

The controlling of the magnitude of the AC waveform in the driving method may vary an on time for turning on the lamp within a predetermined period unit.

Other objects and features of the present invention in addition to the above object will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4 to 7C.

Referring to FIG. 4, the driving apparatus of the lamp according to the embodiment of the present invention receives the voltage from the lamp 110 and the voltage source Vcc and converts the signal into an AC waveform to convert both electrode terminals N1, N2) is provided with an inverter 120 for supplying and driving an AC waveform.

Each of the first electrode terminal N1 and the second electrode terminal N2 of the lamp 110 is connected to the inverter 120. Accordingly, the lamp 110 receives the AC waveform supplied from the inverter 120 to emit light. The lamp 110 includes a fluorescent lamp in which the first and second electrode terminals N1 and N2 are respectively formed inside the discharge tube 112 as shown in FIG. 5A and the first and second electrodes as shown in FIG. 5B. Each of the terminals N1 and N2 is divided into an external electrode fluorescent lamp in which electrodes are formed outside the discharge tube 112.

Inverter 120 receives the voltage from the voltage source (Vcc) to convert into an AC waveform, and boosts the converted AC waveform to a high-voltage AC waveform for driving the lamp 110 to supply to each lamp 110 An electric field is formed in 110 to generate light.

To this end, the inverter 120 is an inverter integrated circuit (hereinafter referred to as "IC") 102, the inverter IC receives a voltage from the voltage source (Vcc) by using a switching element to convert into an AC waveform, and the inverter IC Transformer 104 for boosting and supplying the AC waveform supplied from 102 to lamp 110, and Pulse Width Modulation (hereinafter referred to as " PWM ") controller 106 for controlling switching of switching elements. ).

The inverter IC 102 converts the voltage supplied from the voltage source Vcc into an AC waveform by using a switching element switched by the PWM control signal PWM from the PWM controller 106. The AC waveform, which is the output waveform of the inverter IC 102, is supplied to the transformer 104.

The transformer 104 boosts the AC waveform supplied from the inverter IC 102 to an AC waveform having a high pressure for driving the lamp 110. To this end, the primary winding of the transformer 104 is connected to the inverter IC 102, and the secondary winding is connected to the first electrode terminal N1 and the second electrode terminal N2 of the lamp 110. At this time, the secondary winding of the transformer 104 includes the secondary first winding 2T1 connected between the first electrode terminal N1 of the lamp 110 and the ground voltage source GND, and the first winding of the lamp 110. The secondary second winding 2T2 connected between the two electrode terminal N2 and the ground voltage source GND is provided. In each of the secondary first and second windings 2T1 and 2T2, an AC waveform supplied from the inverter IC 102 is boosted to a high voltage by a winding ratio between the primary winding T1 and the secondary winding T2, thereby inducing organic matter. do. As such, the high-pressure AC wave induced in each of the secondary first and second windings 2T1 and 2T2 is supplied to each of the first and second electrode terminals N1 and N2 of the lamp 110.

The PWM controller 106 receives feedback of a luminance control signal (not shown) or a tube current flowing through the lamp 110 to control switching of the switching element of the inverter IC 102.

As described above, the lamp driving apparatus according to the embodiment of the present invention is an analog mode and a burst mode according to a supply method of an AC waveform supplied from the inverter IC 102 to the lamp 110 via the transformer 104. It is divided into (Burst Mode).

First, an analog mode lamp driving apparatus and driving method according to an exemplary embodiment of the present invention may be applied to the first electrode and the second electrode terminals N1 and N2 of the lamp 110 as shown in FIGS. 6A to 6C. Supply ACwave continuously. The lamp driving apparatus and driving method of the analog mode method has a merit that a wave noise is not generated during driving because the lamp 110 is continuously turned on.

In addition, the analog driving method lamp driving apparatus and driving method according to an embodiment of the present invention is to change the brightness of the lamp 110 by adjusting the amplitude (Pmax) of the AC waveform. Accordingly, the lamp driving apparatus and the driving method of the analog mode method include the first and second electrode terminals N1 and N2 of the lamp 110 from the secondary first and second windings 2T1 and 2T2 of the transformer 104, respectively. Since each of the high-voltage AC waveforms is simultaneously supplied, each has a variable brightness range of about 90%. Therefore, the luminance variable range of the analog mode lamp driving apparatus according to the embodiment of the present invention is increased than the luminance variable range of the analog mode lamp driving apparatus according to the prior art. In other words, the lamp driving apparatus of the analog mode system according to the embodiment of the present invention shows the amplitude P of the AC waveform supplied to the first and second electrode terminals N1 and N2 of the lamp 110 in FIG. 6A. As shown, by changing the intermediate amplitude Pmid as shown in FIG. 6B and the minimum amplitude Pmin as shown in FIG. 6C at the maximum amplitude Pmax, the luminance variable range can be increased more than before.

In addition, the lamp driving apparatus and the driving method of the analog mode method according to an embodiment of the present invention is the first and second electrode terminals (N1, N2) of the lamp 110, that is, the high voltage electrode and the low voltage electrode of the lamp 110, respectively Since an AC waveform of high voltage and low current is applied to the current, power consumption can be reduced by halving the current supplied to the conventional lamp. For example, if the current value of the AC waveform supplied to the lamp in the lamp driving apparatus of the prior art is 4mA in the analog mode lamp driving apparatus according to an embodiment of the present invention the current value of the AC waveform supplied to the lamp is about 2mA. .

In addition, the lamp driving apparatus and the driving method of the analog mode method according to an embodiment of the present invention, the first and second electrode terminals (N1, N2) of the lamp 110, that is, the high voltage electrode and the low pressure electrode of the lamp 110, respectively By supplying the AC waveform to the left side, the dark phenomenon can be prevented.

On the other hand, the lamp driving apparatus and driving method of the burst mode method according to an embodiment of the present invention is turned on each of the first and second electrode terminals (N1, N2) of the lamp 110, as shown in Figure 7a and 7b. It supplies ACwave that repeats off (TON, TOFF). In such a burst mode lamp driving apparatus and driving method, since the lamp 110 is turned on and off by a predetermined period T, wave noise can be minimized during driving.

In addition, the lamp driving apparatus and driving method of the burst mode method according to an embodiment of the present invention is to change the brightness of the lamp 110 by adjusting the on time (TON) during one period (T) of the AC waveform (ACwave). . That is, in the burst mode type lamp driving device and the driving method, the brightness of the lamp 110 is varied by adjusting a duty ratio of on and off. For this reason, the luminance variable range of the burst mode lamp driving apparatus according to the embodiment of the present invention is increased than the luminance variable range of the analog mode lamp driving apparatus according to the prior art. In other words, the lamp driving apparatus of the burst mode method according to an embodiment of the present invention is one period (T) of an AC waveform supplied to each of the first and second electrode terminals N1 and N2 of the lamp 110. By varying the on time (TON) for a time as shown in FIGS. 7A and 7B, the luminance variable range can be increased. At this time, when the on-off duty is adjusted to 100% in the burst mode lamp driving device, the AC waveform supplied to each of the first and second electrode terminals N1 and N2 of the lamp 110 is It becomes the AC waveform of the analog mode system shown in FIG.

The driving device and driving method of the lamp according to the embodiment of the present invention can prevent the generation of wave noise when driving in the analog mode method or the burst mode method, and can increase the luminance variable range than the conventional one, and the wave noise The phenomenon can be minimized.

As described above, the driving apparatus and driving method of the lamp according to the embodiment of the present invention includes an inverter for supplying an AC waveform to each of the first and second electrode terminals of the lamp. Accordingly, the present invention can increase the luminance variable range of the analog mode method, it is possible to minimize the wave noise phenomenon generated in the burst mode method. Furthermore, the present invention can reduce power consumption by reducing the current value for driving the lamp to half of the conventional one.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1 is a block diagram showing a driving device of a conventional lamp.

Fig. 2 is a waveform diagram showing an AC waveform supplied to the lamp shown in Fig. 1 by the analog mode method.

Fig. 3 is a waveform diagram showing an AC waveform supplied to the lamp shown in Fig. 1 by the burst mode method.

Figure 4 is a block diagram showing a driving device of the lamp according to an embodiment of the present invention.

FIG. 5A is a sectional view of the lamp shown in FIG. 1 employing an internal electrode method. FIG.

FIG. 5B is a sectional view of the lamp shown in FIG. 1 employing an external electrode method. FIG.

Fig. 6A is a waveform diagram showing an AC waveform having the maximum amplitude supplied to the lamp shown in Fig. 4 by the analog mode method.

Fig. 6B is a waveform diagram showing an AC waveform having an intermediate amplitude supplied to the lamp shown in Fig. 4 by the analog mode method.

Fig. 6C is a waveform diagram showing an AC waveform having a minimum amplitude supplied to the lamp shown in Fig. 4 by the analog mode method.

7A is a waveform diagram showing an AC waveform having a minimum on time in one cycle unit supplied to the lamp shown in FIG. 4 by the burst mode method.

FIG. 7B is a waveform diagram showing an AC waveform having an intermediate on time in one cycle unit supplied to the lamp shown in FIG. 4 by the analog mode method. FIG.

7C is a waveform diagram showing an AC waveform having a maximum on time in one cycle unit supplied to the lamp shown in FIG. 4 by the analog mode method.

<Description of Symbols for Main Parts of Drawings>

2, 102: inverter IC 4, 104: transformer

6, 106: pulse width modulation controller 10, 110: lamp

20, 120: inverter 112: discharge tube

Claims (13)

A lamp for generating light, An inverter for supplying a high voltage analog AC waveform to each of the first electrode and the second electrode of the lamp , The inverter, An inverter integrated circuit including a switch element for converting driving power supplied from the outside into an AC waveform; A transformer for converting the AC waveform from the inverter integrated circuit into the high voltage AC waveform for driving the lamp and supplying the converted high voltage AC waveform to each of the first and second electrodes of the lamp; And a modulation circuit for controlling the size of the high-voltage AC waveform supplied to the lamp by controlling switching of the switch element. delete The method of claim 1, The transformer, A primary winding to which the AC waveform from the inverter integrated circuit is supplied; It has a secondary winding in which the high-pressure AC waveform is induced by the winding ratio with the primary winding, The secondary winding has a secondary first winding connected between the first electrode of the lamp and a ground voltage source and a secondary secondary winding connected between the second electrode of the lamp and the ground voltage source. Drive of the lamp. The method of claim 1, The high voltage analog AC waveform supplied to each of the first and second electrodes continuously drives the lamp. The method of claim 4, wherein And said modulation circuit changes the brightness of light emitted from said lamp by varying the amplitude of said high voltage analog alternating current waveform in said analog form. A lamp for generating light, An inverter for supplying a high voltage alternating current waveform in the form of a burst to turn on and off the lamp in a predetermined cycle unit to each of the first electrode and the second electrode of the lamp, The inverter, An inverter integrated circuit including a switch element for converting driving power supplied from the outside into an AC waveform; A transformer for converting the AC waveform from the inverter integrated circuit into the high voltage AC waveform for driving the lamp and supplying the converted high voltage AC waveform to each of the first and second electrodes of the lamp; And a modulation circuit for controlling the size of the high-voltage AC waveform supplied to the lamp by controlling switching of the switch element. The method of claim 6, And said modulation circuit changes the brightness of light emitted from said lamp by varying the on time for one period of said high voltage alternating current waveform in the form of said burst. Providing a lamp for generating light, Generating an AC waveform in the form of high voltage for driving the lamp; Supplying the high voltage alternating current waveform to each of the first and second electrodes of the lamp, Generating the AC waveform of the high pressure, Converting the driving voltage supplied from the outside into an AC waveform; Controlling the magnitude of the AC waveform; And converting the AC waveform into the AC waveform of the high voltage. delete The method of claim 8, And the lamp is continuously turned on by the high-voltage alternating current waveform supplied to each of its first and second electrodes. The method of claim 8, Controlling the magnitude of the AC waveform comprises varying the amplitude of the AC waveform. Providing a lamp for generating light, Generating a burst-type high-voltage alternating current waveform in each of the first and second electrodes of the lamp to turn the lamp on and off in a predetermined cycle unit ; Supplying the high voltage alternating current waveform to each of the first and second electrodes of the lamp, Generating the AC waveform of the high pressure, Converting the driving voltage supplied from the outside into an AC waveform; Controlling the magnitude of the AC waveform; And converting the AC waveform into the AC waveform of the high voltage. The method of claim 12, And controlling the magnitude of the AC waveform to vary the on time for turning on the lamp within a predetermined period.