KR100558710B1 - Circuit Of Driving Plasma Display Panel Using High Frequency - Google Patents

Abstract

The present invention relates to a driving circuit of a plasma display panel using a high frequency that can supply a high frequency signal of a constant level at all times regardless of a change in the variable panel impedance.

The driving circuit of the plasma display panel using the high frequency of the present invention is a high frequency generating means for generating a high frequency signal, and a high frequency signal input from the high frequency generating means is corrected to always have a constant level corresponding to the variable impedance of the panel to the panel. And high frequency signal correction means for supplying.

According to the present invention, by detecting, judging and correcting the level of the high frequency signal supplied to the panel, and actively responding to the panel impedance which is varied by the high frequency discharge, it is possible to supply the high frequency signal of stable maximum output to the panel at all times.

Description

Circuit of Driving Plasma Display Panel Using High Frequency             

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing the structure of a discharge cell formed in a conventional three-electrode alternating current surface discharge plasma display panel.

2 is a perspective view showing the structure of a discharge cell formed in a conventional plasma display panel using a high frequency wave.

FIG. 3 is an overall electrode arrangement diagram of a plasma display panel including the discharge cells shown in FIG. 2.

4 is a block diagram showing the configuration of a conventional PDP high frequency driving circuit.

5 is a block diagram illustrating a plasma display panel driving circuit according to an exemplary embodiment of the present invention.

6 is a block diagram illustrating a plasma display panel driving circuit according to another exemplary embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

10, 40: upper substrate 12, 42: lower substrate

14, 46: scanning electrode 16: sustaining electrode

18, 24, 48: dielectric layer 20: protective layer

22, 44: address electrodes 26, 54: phosphor

21: discharge space 28, 56: discharge cell

30, 60: high frequency generator 32: amplifier

34 matching circuit 36 panel

50, 70, high frequency electrode 52: partition wall

62: gain correction 64: peak detector

66: signal determination unit 68: control unit

72, 74: comparator 76: comparator

78: judgment and control

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to a driving circuit of a plasma display panel using a high frequency that can supply a high frequency signal at a constant level regardless of a change in the variable panel impedance.

Recently, research on plasma display panels (hereinafter referred to as PDPs), which are easy to manufacture panels as large-area flat panel displays, has been actively conducted according to the needs of large flat panel displays. The PDP generally uses a gas discharge phenomenon to display an image using visible light generated by vacuum ultraviolet rays generated during gas discharge to emit phosphors.

Referring to FIG. 1, a structure of a discharge cell configured in a PDP of a three-electrode alternating current (AC) surface discharge method which is commonly used is shown.

In the discharge cell 28 of the PDP shown in FIG. 1, an upper substrate 10 and a lower substrate 12, which are display surfaces of an image, are arranged in parallel by partitions not shown, and a sustain electrode on the upper substrate 10 is provided. A pair, that is, the scan / sustain electrode 14 and the sustain electrode 16 are formed side by side with an upper dielectric layer 18 and a protective layer 20 applied thereon. The address electrode 22 is formed on the lower substrate 12 in a direction perpendicular to the sustain electrode pairs 14 and 16, and the lower dielectric layer 24 and the fluorescent layer 26 are sequentially applied thereon. The discharge gas is injected into the discharge space 21 provided by the partition wall.

The discharge cell having such a configuration is selected by the address discharge between the address electrode 22 and the scan / hold electrode 14, and then the vacuum ultraviolet rays generated by the continuous sustain discharge between the sustain electrodes 14 and 16 are discharged from the phosphor 26. By emitting light, visible light is emitted. In this case, by adjusting the sustain discharge period, that is, the number of sustain discharges, a gray scale necessary for displaying an image is realized. Accordingly, the number of sustain discharges is an important factor in determining the brightness and discharge efficiency of the PDP. For this sustain discharge, a step pulse having a duty ratio of 1 is periodically applied to the sustain electrodes 14 and 16 periodically. At this time, the frequency is generally about 200 to 300 kHz and the pulse width is about 10 to 20 kHz. In this case, the sustain discharge occurs only once at an extremely short instant per sustain pulse. The charged particles generated by the sustain discharge move the discharge paths formed between the sustain electrodes according to the polarities of the electrodes, so that wall charges are formed in the discharge space of the cell, and the discharge voltage in the discharge space decreases due to the wall charges. Will stop. As described above, the sustain discharge by the existing sustain pulse is generated only once at a short time per pulse, and most of the other time is consumed in the preparation of the wall charge and the next discharge, so that the discharge efficiency of the PDP is inevitably low.

Recently, in order to solve the low discharge efficiency problem of the PDP, a method of using a high frequency discharge using a high frequency signal as a display discharge has recently emerged. High frequency discharge is usually generated by high frequency signals in the range of tens of MHz to hundreds of MHz. As the electron vibrates by vibrating electric field, it causes continuous ionization and excitation of discharge gas. It can cause continuous discharge. The high frequency discharge has a physical effect such as a positive column having a very high discharge efficiency when the distance between the electrodes is long in the glow discharge. Accordingly, there is an advantage that can significantly improve the discharge efficiency of the PDP when using a high frequency discharge.

Referring to FIG. 2, there is shown a perspective view showing a discharge cell configured in a PDP using a high frequency wave.

The PDP discharge cell shown in FIG. 2 includes a high frequency electrode 50 disposed on the upper substrate 40, an address electrode 44 and a scanning electrode 46 disposed on the lower substrate 42. The upper substrate 40 and the lower substrate 42 are disposed to face each other in parallel, and the address electrode 44 in the vertical direction and the scan electrode 46 in the horizontal direction are formed on the lower substrate 42. A dielectric layer 48 is formed between the address electrode 44 and the scan electrode 46. In the upper substrate 40, a metal electrode to which a high frequency voltage is applied in the same direction as the scan electrode 46, that is, a high frequency electrode 50 is formed. Between the upper substrate 40 and the lower substrate 42, barrier ribs 52 for eliminating optical interference between neighboring discharge cells are formed in a closed block structure. On the surfaces of the top plate 40 and the partition wall 52 on which the high frequency electrode 50 is formed, a phosphor 54 for generating red, green, or blue visible light is coated. Then, the discharge gas is filled in the discharge space therein. In the discharge cell of this structure, a data signal is supplied to the address electrode 44 and a scan signal is supplied to the scan electrode 46 to generate an address discharge. The charged particles generated by the address discharge are high frequency electrodes 50. The ion does not move between the high frequency electrode 50 and the scan electrode 46 due to the high frequency voltage supplied to the oscillator and only the electrons vibrate in a state in which the electrons are not attracted to the two electrodes 46 and 50. These vibrating electrons ionize and excite the discharge gas continuously and emit visible ultraviolet light by emitting vacuum ultraviolet rays while the excited atoms and molecules transition to the ground state.

FIG. 3 shows the overall electrode arrangement structure of the PDP constituting the discharge cell shown in FIG.

In FIG. 3, the PDP includes address electrode lines X1 to Xm disposed corresponding to each column line, and scan electrode lines Y1 arranged side by side corresponding to each row line. Yn) and high frequency electrode lines RF. The discharge cells 56 are provided at the intersections of the address electrode lines X1 to Xm, the scan electrode lines Y1 to Yn, and the high frequency electrode lines RF.

In order to cause high frequency discharge in the PDP having such a structure, a high frequency signal must be supplied with sufficient power to the high frequency electrode of the panel. Accordingly, the high frequency driving circuit for supplying a high frequency signal to the high frequency electrode has a configuration as shown in FIG.

4 is a block diagram showing the configuration of a high frequency driving circuit of a PDP using a high frequency. The PDP high frequency driving circuit of FIG. 4 amplifies a high frequency signal generated by the high frequency signal generator 30 and a high frequency signal from the high frequency generator 30. An amplifier 32 and a matching circuit 34 connected between the amplifier 32 and the panel 36.

In the PDP high frequency driving circuit shown in FIG. 4, the high frequency generator 30 generates a high frequency signal and outputs the high frequency signal to the amplifier 32. The amplifier 32 amplifies the high frequency signal generated by the high frequency generator 30 with sufficient power to cause high frequency discharge and outputs it to the matching circuit 34. The matching circuit 34 matches the impedance of the high frequency signal input from the amplifier 32 with the impedance of the panel 36 so that the high frequency signal of maximum power is supplied to the panel 36. Here, the panel 36 basically has a capacitance. In this case, when the high frequency discharge occurs in the panel 36, a sheath is generated at the high frequency electrode and the scanning electrode that cause the high frequency discharge, and the gap between the two electrodes for determining the capacitance is narrowed, thereby increasing the capacitance of the panel. Will occur. As a result, the impedance of the panel is reduced, so that the high frequency signal applied to the panel 36 is absorbed (passed) in the panel 36 and the voltage (power) of the high frequency signal applied to the panel 36 is reduced.

However, in order for the PDP to drive the matrix, each discharge cell must be driven independently, and a high frequency signal must be supplied to the panel 36 at a constant level at all times. However, when the high frequency signal is reduced by the discharge cell in which the high frequency discharge occurs, a high frequency signal of a sufficient level is not applied to the discharge cell to generate the high frequency discharge, and thus a high frequency discharge does not occur. In order to solve this problem, there is a need to supply a high frequency signal having a stable margin at all times regardless of the impedance of the variable panel.

Accordingly, an object of the present invention is to provide a PDP driving circuit using a high frequency capable of supplying a high frequency signal of a constant level at all times corresponding to the impedance of a variable panel.

In order to achieve the above object, the PDP driving circuit using a high frequency according to the present invention has a high frequency generating means for generating a high frequency signal, and a high frequency signal input from the high frequency generating means always has a constant level corresponding to the variable impedance of the panel. It is characterized in that it comprises a high frequency signal correction means for correcting to supply to the panel.
The high frequency signal correcting means includes a peak value detecting means for detecting a peak level of a high frequency signal input from the high frequency generating means, and compares and determines a peak level of the high frequency signal input from the peak value detecting means with a preset reference voltage to determine an error. A signal judging means for generating a signal, control means for generating a correction signal corresponding to an error signal input from said signal judging means, and a high frequency input from said high frequency generating means in accordance with a correction signal input from said control means; And gain correction means for correcting the level of the signal.
The high frequency signal correcting means judges comparing means for comparing the level of the high frequency signal input from the high frequency generating means with the first and second reference voltages, and determines the polarity of the signal output from the comparing means and based on the determination result. Determination and control means for generating a correction signal, and gain correction means for correcting the level of the high frequency signal input from the high frequency generation means in accordance with the correction signal inputted from the determination and control means. .

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 5 and 6.

5 is a block diagram illustrating a high frequency driving circuit of a PDP according to an embodiment of the present invention. The PDP high frequency driving circuit of FIG. 5 includes a high frequency generator 60 generating a high frequency signal and a high frequency signal from the high frequency generator 60. A gain correction unit 62 for correcting the gain according to the correction signal obtained by the feedback loop and supplying the gain to the high frequency electrode 70 of the panel, a peak detection unit 64 forming the feedback loop with the gain correction unit 62, The signal determination unit 66 and the control unit 68 are provided.

In the high frequency drive circuit of the PDP shown in FIG. 5, the high frequency generator 60 generates a high frequency signal and outputs the high frequency signal to the gain compensator 62. The gain correction unit 62 corrects the gain of the high frequency signal according to the correction signal output from the control unit 68 by a feedback loop composed of the peak detection unit 64, the signal determination unit 66, and the control unit 68. Output to the high frequency electrode 70. The peak detection unit 64 detects the peak value of the high frequency signal output from the gain correction unit 62 and outputs it to the signal determination unit 66. The signal determining unit 66 generates an error signal by comparing and determining the peak value of the high frequency signal output from the peak detecting unit 64 with a reference voltage already set. The controller 68 generates a correction signal corresponding to the error signal generated by the signal determination unit 66 and outputs the correction signal to the gain correction unit 62. Accordingly, the gain compensator 62 corrects the level of the high frequency signal input from the high frequency generator 60 according to the correction signal output from the control unit 68, thereby always outputting a high frequency signal having a constant level. 70).

6 is a circuit diagram showing a configuration of a high frequency driving circuit of a PDP according to another embodiment of the present invention. The PDP high frequency driving circuit of FIG. 6 is a high frequency signal from the high frequency generator 60 according to a correction signal obtained by a feedback loop. A gain compensator 62 for correcting the gain and supplying it to the high frequency electrode 70 of the panel, a comparator 76 forming a feedback loop with the gain compensator 62, and a signal judgment and control unit 78; .

In the PDP high frequency drive circuit shown in FIG. 6, the gain compensator 62 is in accordance with the correction signal output from the signal judgment and the control unit 78 by a feedback loop composed of the comparator 76, the signal determination and the control unit 78. The gain of the high frequency signal is corrected and output to the high frequency electrode 70 of the panel. The comparator 76 is composed of first and second comparators 72 and 74 for inputting a high frequency signal output from the gain compensator 62 and comparing the respective reference voltages. The first comparator 72 compares the first reference voltage Vref1 inputted to its non-inverting terminal (+) and the high frequency signal inputted to the inverting terminal (-) to have a signal having a (-) or (+) polarity. Will occur. Similarly, the second comparator 74 compares the second reference voltage Vref2 inputted to its non-inverting terminal (+) and the high frequency signal inputted to the inverting terminal (-), thereby comparing the (-) or (+) polarity. The branch will generate a signal. Here, the first reference voltage Vref1 is the highest voltage value that the high frequency signal should have, and the second reference voltage Vref2 is the lowest voltage value that the high frequency signal should have. If the high frequency signal is supplied in the stable region, the high frequency signal has a voltage value lower than the first reference voltage Vref1 and higher than the second reference voltage Vref2. In this case, each of the signals output from the first and second comparators 72 and 74 has a negative polarity and a positive polarity. Therefore, when other signals are output from the first and second comparators 72 and 74, that is, the impedance of the panel is varied by the high frequency discharge and the level of the high frequency signal supplied to the high frequency electrode 70 is reduced, thereby reducing the first. And when the signals output from the second comparators 72 and 74 each have a positive polarity and a negative polarity, the signal judgment and the controller 78 determine that the high frequency signal is not supplied in a stable region. Based on the determination result, a correction signal for amplifying or reducing the high frequency signal is generated. The gain compensator 62 increases or decreases the level of the high frequency signal input from the high frequency generator 60 in response to the signal determination and the correction signal input from the control unit 78 to always generate a high frequency signal of a stable level. It is supplied to the electrode 70.

As described above, according to the PDP driving circuit using high frequency according to the present invention, a high frequency signal having a stable maximum output is always obtained by actively responding to a panel impedance that is changed by high frequency discharge by correcting according to the level of the high frequency signal supplied to the panel. It can be supplied to the panel. Accordingly, since the PDP using the high frequency is always supplied with the high frequency signal of maximum output, stable matrix driving can be realized.
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.

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Claims (3)

High frequency generating means for generating a high frequency signal; Detects the level of the high frequency signal inputted from the high frequency generating means, compares it with a predetermined reference voltage, generates a correction signal corresponding to the comparison result, and generates the high frequency signal so that it always has a constant level corresponding to the variable impedance of the panel. And a high frequency signal correction means for correcting according to the correction signal to supply the panel to the panel. The method of claim 1, The high frequency signal correction means Peak value detecting means for detecting a peak level of the high frequency signal inputted from said high frequency generating means; Signal determination means for generating an error signal by comparing and determining the peak level of the high frequency signal input from the peak value detection means with a preset reference voltage; Control means for generating a correction signal corresponding to the error signal input from said signal determining means; And a gain correction means for correcting the level of the high frequency signal input from said high frequency generation means in accordance with the correction signal input from said control means. The method of claim 1, The high frequency signal correction means Comparing means for detecting a level of the high frequency signal input from the high frequency generating means and comparing the first and second reference voltages; Determination and control means for determining the polarity of the signal output from the comparison means and generating a correction signal based on the determination result; And a gain correction means for correcting the level of the high frequency signal inputted from said high frequency generation means in accordance with the correction signal inputted from said determination and control means.

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