KR100429649B1 - Driving circuit of plasma display panel - Google Patents

Abstract

PURPOSE: A driving circuit of a plasma display panel is provided to reduce scanning frequencies of horizontal electrode lines by using two or more scanning/sustain drivers. CONSTITUTION: A driving circuit of a plasma display panel includes a microcomputer, sub-frames of Y number, scanning/sustain drivers of X number, a memory, and an address driver. The microcomputer(20) is used for digitalizing analog image data, outputting digital image data, and generating control signals according to the digital image data and external signals. The sub-frames are assigned from sub-frames of X number and sub-frames of Y number according to the control signal of the microcomputer. The scanning/sustain drivers(31,32) are used for sustain pulses to sustain the discharge. The memory(40) is used for storing the digital image data of the microcomputer. The address driver(50) is used for supplying bit values of digital image data M number from the memory to vertical electrode lines of M number.

Description

Driving Circuit of Plasma Display

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and in particular, one frame is divided into X and Y subframes to drive 2 ^{X Y} gray scales on an AC plasma display panel (hereinafter referred to as an AC PDP). A driving circuit of a plasma display device for displaying an image of the present invention.

As the modern society is called an information society, the importance of the image display device is increasing with the development and spread of the information processing system, and the types thereof are gradually diversifying.

CRT (Cathode Ray Tube), which has been used most often as an image display device, has various problems such as large size, high operating voltage, and distortion of display. Recently, research and development of various flat display devices having a matrix structure have been actively conducted.

Among the flat panel display devices, an AC PDP, which is a light emitting device, and displays a moving image or a still image by using a gas discharge phenomenon inside the AC PDP is called a plasma display device.

In general, the AC PDP provided in the plasma display device includes M vertical electrode lines D ₁ , D ₂ ,..., D _M-1 , D _M and N horizontal electrode lines S ₁ , as shown in FIG. ₁ . S ₂ ,..., S _N-1 , S _N ) are arranged at predetermined intervals so that the entire screen is composed of M × N cells in a matrix form. That is, since the intersection of any vertical electrode line and the horizontal electrode line corresponds to one cell, the entire screen is made of M × N cells.

In addition, the AC PDP discharges a corresponding cell by adjusting a voltage applied between an arbitrary vertical electrode line and a horizontal electrode line, and adjusts the discharge holding time of each cell to realize gray scale of an image displayed on each cell. do.

The plasma display device may be driven in various ways, one of which is a subframe method in which one frame is divided into a plurality of subframes.

First, a subframe method is formed in the AC PDP in order to supply digital image data (lowest B ₁ to highest B _{X · Y} ) of X · Y bits for one frame to display 2 ^{X · Y} gradation images on the AC PDP. an N number of the horizontal electrode lines ^{_{(S 1 ~S N) 2 X}} · Y-1: 2 X · Y-2: ... : 2 ¹ : 2 ⁰ X · Y subs consisting of N horizontal electrode lines each divided from the first horizontal electrode line included in each block to the horizontal electrode line immediately preceding each block Construct a frame,

프레임마다 X·Y개 라인씩 순차적으로 소거한 후 스캐닝하면서 현재 스캐닝되는 수평 전극라인에 대응되는 M개 디지털 화상 데이터의 비트값을 상기 M개의 수직 전극라인(D₁∼D_M)에 공급한다.From the first horizontal electrode lines to the last N-th horizontal electrode lines included in each of the X · Y subframe

After erasing and sequentially scanning X and Y lines for each frame, bit values of M digital image data corresponding to the currently scanned horizontal electrode lines are supplied to the M vertical electrode lines D _{1 to} D _M.

In addition, when the horizontal electrode line included in the first subframe is scanned, the least significant bit value B ₁ of M digital image data corresponding to each horizontal electrode line is supplied, and the most significant bit value B in the second subframe. _{X, Y} is the third, fourth,... , Bit values B _{X Y-1} , B _{X Y-2} ,..., In the X-Y-1, X-Y subframe; , B ₃ and B ₂ , respectively.

20 vertical electrode lines D ₁ , D ₂ ,..., D ₁₉ , D ₂₀ and 15 horizontal electrode lines S ₁ , S ₂ ,..., S ₁₄ , S to facilitate understanding of the subframe method described above. A method of displaying 16 (2 ⁴ ) gray scale images by supplying 4-bit digital image data (lowest B ₁ to highest B ₄ ) for one frame to an AC PDP in which ₁₅ is formed will be described as an example.

First, as shown in FIG. 2, one frame is divided into first to fourth subframes SF ₁ , SF ₂ , SF ₃ , and SF ₄ , and from 1 to 15 times in the first subframe SF ₁ . horizontal electrode lines 15 in the order (S ₁ ~S ₁₅₎ the second sub-frame (SF _2), in this order from 9 to 8 to 15 horizontal line electrodes (S ₉ ~S ₈₎ is the third sub- In the frame SF ₃ , 15 horizontal electrode lines S _{13 to} S ₁₂ are arranged in order from 13 to 12, and in the fourth subframe SF ₄ , 15 horizontal electrode lines are arranged in order from 15 to 14. (S ₁₅ ~S ₁₄₎ are contained respectively.

In the above state, the driving circuit of the plasma display device according to the related art for realizing 16 gray levels using a subframe method outputs digital image data by digitizing analog image data as shown in FIG. A microcomputer 120 for outputting various control signals in accordance with image data and external signals;

프레임(이하, 1 수평주기라 함)마다 4개 라인씩 순차적으로 소거한 후 스캐닝하고, 스캐닝 완료된 수평 전극라인에 방전 유지를 위한 서스테인 펄스를 공급하는 스캐닝 및 서스테인 구동부(130)와;From the first horizontal electrode lines included in the four subframes SF ₁ , SF ₂ , SF ₃ , SF ₄ to the last 15th horizontal electrode lines according to the control signal of the microcomputer 120, respectively.

A scanning and sustain driver 130 for sequentially erasing and scanning four lines per frame (hereinafter, referred to as one horizontal cycle), and supplying sustain pulses for sustaining discharge to the scanned horizontal electrode lines;

A memory unit 140 for storing digital image data output from the microcomputer 120 for each frame, color, and bit;

20 vertical electrode lines formed on the AC PDP 10 by receiving bit values of 20 digital image data corresponding to horizontal electrode lines currently scanned by the scanning and sustain driver 130 from the memory unit 140 ( in D ₁ ~D ₂₀₎ is composed of an address driver 150 for supplying respectively.

The driving circuit of the conventional plasma display device constructed as described above operates as follows.

First, the microcomputer 120 digitizes analog image data input from the outside to output 4-bit digital image data B _{1 to} B ₄ , and outputs various control signals according to the digital image data and the external signal.

In this case, the digital image data output from the microcomputer 120 is stored in the memory unit 140 for each frame, color, and bit.

Thereafter, the scanning and sustain driver 130 repeatedly turns on and off the full screen of the AC PDP 10 according to the control signal output from the microcomputer 120 to discharge space of each cell. After the wall charges are formed therein, the first horizontal electrode lines S ₁ , S ₉ , S ₁₃ , and S ₁₅ included in the first to fourth subframes SF ₁ , SF ₂ , SF ₃ , and SF ₄ , respectively. 4 lines are sequentially erased every 1 horizontal period from the last 15 th horizontal electrode lines S ₁₅ , S ₈ , S ₁₂ , and S ₁₄ , and then scanned.

The address driver 150 supplies bit values of 20 digital image data corresponding to the horizontal electrode lines currently scanned by the scanning and sustain driver 130 to the 20 vertical electrode lines D _{1 to} D ₂₀ . The AC PDP 10 displays an image of 16 (2 ⁴ ) gradation.

In this case, the scanning and sustain driver 130 sequentially scans four horizontal electrode lines at predetermined time intervals in each horizontal period.

In addition, the scanning and sustain driver 130 scans the horizontal electrode lines S _{1 to} S ₁₅ , and then supplies a sustain pulse so that the scanning and sustain driving units 130 are among the 20 cells corresponding to the respective horizontal electrode lines S _{1 to} S ₁₅ . A logic " high " signal is supplied through the corresponding vertical electrode line to maintain the discharge and light emission of some cells in which the address discharge has occurred for a predetermined time.

The scanning order of each horizontal electrode line S _{1 to} S ₁₅ described above is summarized in Table 1 below.

TABLE 1

Meanwhile, the address driver 150 of the first sub-frame 15 includes a horizontal electrode lines (SF ₁₎ (S ₁ ~S ₁₅₎ when the scanning of the 20 least significant digital image data corresponding to each bit value B ₁ is supplied to 20 vertical electrode lines D _{1 to} D ₂₀ , and B ₄ , which is the most significant bit value, in the case of 15 horizontal electrode lines S _{9 to} S ₈ included in the second subframe SF ₂ . In the case of the 15 horizontal electrode lines S _{13 to} S ₁₂ included in the third subframe SF ₃ , the third bit value B ₃ is supplied and included in the fourth subframe SF ₄ . In the case of the 15 horizontal electrode lines S _{15 to} S ₁₄ , the second bit value B ₂ is supplied.

Accordingly, referring to the first horizontal electrode line S _{1 as} a bit value of the digital image data supplied to each of the horizontal electrode lines S _{1 to} S ₁₅ during one frame (1 to 15 horizontal periods), The first horizontal electrode line S ₁ is scanned in 1, 2, 4, and 8 horizontal periods, respectively, and 4 bits of digital image data are supplied in bit units. In the 1 horizontal period, B ₁ having a bit weight of 2 ⁰ = ₁ Light emission is maintained for one horizontal period until it is supplied and scanned again in two horizontal periods, and two times until B ₂ with bit weight 2 ¹ = ₂ is supplied and scanned again in four horizontal periods in _two horizontal periods. Light emission is maintained during the horizontal period, and light emission is maintained for four horizontal periods until B ₃ with a bit weight 2 ² = 4 is supplied at 4 horizontal periods and scanned again at 8 horizontal periods, and bit weights at 8 horizontal periods. B ₄ a ball having a 2 ⁴ = 8 Since the discharge is maintained for eight single horizontal period until re-scanned in one horizontal period of the next frame, the 20 cells corresponding to the horizontal electrode lines (S ₁₎ is 1 16-gradation image is displayed.

In addition, the same principle as described above is applied to the horizontal electrode lines S _{2 to} S ₁₅ , respectively, so that 16 grayscale images are displayed in 20 corresponding cells.

Meanwhile, when implementing 2 ⁸ (256) gradations using the subframe method as described above, 8 horizontal electrode lines should be sequentially scanned in one horizontal period, and when performing 2 ¹⁶ (65536) gradations, 1 horizontal period 16 horizontal electrode lines must be scanned one after the other.

That is, as the gray scale to be implemented increases, a large number of horizontal electrode lines must be scanned within one horizontal period, so when the moving image is input from the outside, the scanning frequency of the horizontal electrode line increases as the gray scale to be implemented increases.

As the scanning frequency of the horizontal electrode line increases as described above, the system becomes unstable, and the number of horizontal electrode lines that one scanning and sustain driver can scan within one horizontal period is also limited, so that it is difficult to realize high gradation of 256 or more. There was a difficult problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and includes a driving circuit of a plasma display device which can reduce the scanning frequency of horizontal electrode lines by dividing and assigning subframes to at least two scanning and sustain driving units. The purpose is to provide.

1 is an electrode structure diagram of a typical AC plasma display panel (hereinafter referred to as AC PDP);

2 is a gray scale implementation diagram using a subframe scheme,

3 is a block diagram showing a configuration of a driving circuit of a plasma display device according to the prior art;

4 is a block diagram showing a configuration of a driving circuit of a plasma display device according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: AC PDP 20: Microcomputer

31, 32: first and second scanning and sustain driving unit

40: memory unit 50: address driver

S _{1 to} S ₁₅ : 15 horizontal electrode lines D _{1 to} D ₂₀ : 20 vertical electrode lines

프레임마다 Y개 라인씩 순차적으로 소거한 후 스캐닝하고, 스캐닝 완료된 수평 전극라인에 방전 유지를 위한 서스테인 펄스를 공급하는 X개의 스캐닝 및 서스테인 구동부와; 상기 마이컴에서 출력되는 디지털 화상 데이터를 저장하는 메모리부와; 상기 X개의 스캐닝 및 서스테인 구동부에 의해 현재 스캐닝되는 수평 전극라인에 대응되는 M개 디지털 화상 데이터의 비트값을 상기 메모리부로부터 입력받아 상기 M개의 수직 전극라인에 각각 공급하는 어드레스 구동부로 구성된 것을 특징으로 한다.In order to achieve the above object, the driving circuit of the plasma display device according to the present invention uses one frame to display an image of 2 ^{X Y} gray level on an AC PDP in which M vertical electrode lines and N horizontal electrode lines are formed. In a plasma display device which is dividedly divided into X and Y subframes (where X≥2 is a natural number), analog image data is digitized to output digital image data, and various control signals in accordance with the digital image data and external signals. A microcomputer to output the; From the first horizontal electrode lines to the last N-th horizontal electrode lines included in different Y subframes allocated to each of the X · Y subframes according to the control signal of the microcomputer

X scanning and sustain drivers for sequentially erasing and scanning Y lines per frame and supplying sustain pulses for sustaining discharge to the scanned horizontal electrode lines; A memory unit for storing digital image data output from the microcomputer; And an address driver which receives bit values of M digital image data corresponding to the horizontal electrode lines currently scanned by the X scanning and sustain driving units from the memory unit and supplies the bit values of M digital image data to the M vertical electrode lines, respectively. do.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in more detail.

As shown in FIG. 4, the driving circuit of the plasma display device according to an embodiment of the present invention digitizes analog image data to output digital image data, and outputs various control signals according to the digital image data and external signals. The microcomputer 20;

프레임(이하, 1 수평주기라 함)마다 2개 라인씩 순차적으로 소거한 후 스캐닝하고, 스캐닝 완료된 수평 전극라인에 방전 유지를 위한 서스테인 펄스를 공급하는 제 1 스캐닝 및 서스테인 구동부(31)와;First horizontal electrode lines included in the first and third subframes SF ₁ and SF ₃ of the four subframes SF ₁ , SF ₂ , SF ₃ , and SF ₄ , respectively, according to the control signal of the microcomputer 20. From S ₁ , S ₁₃ to the last 15 th horizontal electrode lines S ₁₅ , S ₁₂

A first scanning and sustain driver 31 for sequentially erasing and scanning two lines per frame (hereinafter, referred to as one horizontal cycle) and supplying a sustain pulse for sustaining discharge to the scanned horizontal electrode line;

First horizontal electrode lines included in the second and fourth subframes SF ₂ and SF ₄ except for the first and third subframes SF ₁ and SF ₃ , respectively, according to the control signal of the microcomputer 20. From (S ₉ , S ₁₅ ) to the last 15 th horizontal electrode lines (S ₈ , S ₁₄ ), two lines are erased sequentially after every 1 horizontal period, and then scanned, and sustained to maintain discharge on the scanned horizontal electrode lines. A second scanning and sustain driver 32 for supplying a pulse;

A memory unit 40 for storing the digital image data output from the microcomputer 20 for each frame, color, and bit;

The bit values of the 20 digital image data corresponding to the horizontal electrode lines currently scanned by the first and second scanning and sustain drivers 31 and 32 are received from the memory unit 40 and are formed in the AC PDP 10. It is composed of 20 vertical line address electrode driver 50 for supplying respectively the _{(D 1, D 2, ...} , D 19, D 20).

The driving circuit of the plasma display device according to the embodiment of the present invention configured as described above operates as follows.

First, as described in the prior art, one frame is divided into first to fourth subframes SF ₁ , SF ₂ , SF ₃ , and SF ₄ , and from 1 to 15 times in the first subframe SF ₁ . horizontal electrode lines 15 in the order (S ₁ ~S ₁₅₎ the second sub-frame (SF _2), in this order from 9 to 8 to 15 horizontal line electrodes (S ₉ ~S ₈₎ is the third sub- In the frame SF ₃ , 15 horizontal electrode lines S _{13 to} S ₁₂ are arranged in order from 13 to 12, and in the fourth subframe SF ₄ , 15 horizontal electrode lines are arranged in order from 15 to 14. (S ₁₅ ~S ₁₄₎ are contained respectively.

In the above state, the microcomputer 20 digitizes the analog image data input from the outside and outputs 4-bit digital image data B _{1 to} B ₄ , and generates various control signals according to the digital image data and the external signal. Output

At this time, the digital image data output from the microcomputer 20 is stored in the memory unit 40 for each frame, color, and bit.

Then, the first and second scanning and sustain drivers 31 and 32 repeatedly turn on and off the full screen of the AC PDP 10 according to the control signal output from the microcomputer 20 to discharge space of each cell. After the wall charges are formed therein, the first scanning and sustain driver 31 may include the first horizontal electrode lines S ₁ and S included in the first and third subframes SF ₁ and SF ₃ assigned thereto. ₁₃ ) sequentially erases two lines every one horizontal period from the last 15 th horizontal electrode lines S ₁₅ and S ₁₂ , and then scans them.

At the same time, the second scanning and sustain driver 32 also lasts from the first horizontal electrode lines S ₉ and S ₁₅ respectively included in the second and fourth subframes SF ₂ and SF ₄ assigned thereto. After the 15th horizontal electrode lines S ₈ and S ₁₄ , two lines are sequentially erased every one horizontal period and then scanned.

In this case, the address driver 50 may determine the bit values of the 20 digital image data corresponding to the horizontal electrode lines currently scanned by the first and second scanning and sustain drivers 31 and 32. _{1 to} D ₂₀ ) to display the image of 16 (2 ⁴ ) gradation on the AC PDP 10.

In the above, since the first and second scanning and sustain drivers 31 and 32 scan two horizontal electrode lines for each horizontal period, four horizontal electrode lines included in different subframes are included in one horizontal period. Scanned. Here, the scanning order of the four horizontal electrode lines scanned in one horizontal period does not affect the gray scale implementation, so it may be set in any order.

In addition, the first and second scanning and sustain drivers 31 and 32 scan the horizontal electrode lines S _{1 to} S ₁₅ and then supply a sustain pulse to each of the horizontal electrode lines S _{1 to} S ₁₅ . A logic " high " signal is supplied through the corresponding vertical electrode line of the corresponding 20 cells to maintain the discharge and light emission of some cells where the address discharge has occurred.

Meanwhile, as described in the related art, the address driver 50 has 20 digital corresponding to each of the ₁₅ horizontal electrode lines S _{1 to} S 15 included in the first subframe SF ₁ . The least significant bit value B ₁ of the image data is supplied to the 20 vertical electrode lines D _{1 to} D ₂₀ and the 15 horizontal electrode lines S _{9 to} S ₈ included in the second subframe SF ₂ are provided. In the case of supplying B ₄ , the most significant bit value, and supplying the third bit value B ₃ in the case of the 15 horizontal electrode lines S _{13 to} S ₁₂ included in the third subframe SF ₃ , the fourth sub In the case of the fifteen horizontal electrode lines S _{15 to} S ₁₄ included in the frame SF ₄ , the second bit value B ₂ is supplied.

Accordingly, one embodiment of the present invention also displays 16 gray scale images in 20 cells corresponding to the horizontal electrode lines S _{1 to} S ₁₅ , as in the related art.

As described above, when the first and second scanning and sustain drivers 31 and 32 divide and drive the first to fourth subframes SF ₁ , SF ₂ , SF ₃ , and SF ₄ by two, the same 16 gray levels as in the prior art may be obtained. While implemented, the scanning frequency is reduced to 1/2 of the prior art.

Meanwhile, as another embodiment of the present invention, two scanning and sustain driving units are provided to divide four subframes into two instead of two to each one, and thus the scanning frequency reduction effect is the same as in the embodiment of the present invention. When four subframes are allocated to each of the four subframes, the scanning frequency is reduced to 1/4 of the prior art.

In addition, by lowering the scanning frequency of the horizontal electrode line with at least two scanning and sustain drivers as in the present invention, high gradation of 256 or more, which was difficult to implement in the prior art, can be easily implemented under a stable system.

As described above, the present invention includes at least two scanning and sustain driving units, each of which drives a plurality of subframes by dividing a plurality of subframes, thereby reducing the scanning frequency of the horizontal electrode line, thereby easily realizing high gray levels of 256 or more under a stable system. It works.

Claims (1)

In order to display an image of 2 ^{X Y} gray levels on an AC plasma display panel (hereinafter referred to as an AC PDP) in which M vertical electrode lines and N horizontal electrode lines are formed, one frame is X Y Y subframes. In a plasma display device which is divided and driven in a manner of being a natural number (where X≥2), A microcomputer that digitizes analog image data, outputs digital image data, and outputs various control signals according to the digital image data and an external signal; From the first horizontal electrode lines to the last N-th horizontal electrode lines included in different Y subframes allocated to each of the X · Y subframes according to the control signal of the microcomputer

X scanning and sustain drivers for sequentially erasing and scanning Y lines per frame and supplying sustain pulses for sustaining discharge to the scanned horizontal electrode lines; A memory unit for storing digital image data output from the microcomputer; And an address driver which receives bit values of M digital image data corresponding to the horizontal electrode lines currently scanned by the X scanning and sustain driving units from the memory unit and supplies the bit values of M digital image data to the M vertical electrode lines, respectively. A driving circuit of the plasma display device.

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