KR100648724B1 - Plasma display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to a plasma display device for generating a voltage required for screen display using a back pressure circuit.

Screen display in the plasma display device requires various voltages. The plasma display device generates the various DC voltages using several DC-to-DC converters. However, since the DC-to-DC converter is expensive, a plurality of DC-to-DC converters are expensive, and the circuit of the power supply device becomes complicated.

According to the present invention, there is provided a plasma display device having a power supply device in which the number of DC-to-DC converters is reduced by using a back voltage circuit.

Plasma Display, Back Pressure Circuit, SMPS, Transformer, DC-to-DC Converter

Description

Plasma display device {PLASMA DISPLAY DEVICE}

1 is a driving waveform diagram of a plasma display device.

2 is a schematic diagram of a plasma display device according to an embodiment of the present invention.

3 is a circuit diagram illustrating a power supply device according to an embodiment of the present invention.

4 is a waveform diagram used in a power supply device according to an embodiment of the present invention.

5A to 5D illustrate the operation of the circuit shown in FIG. 3.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to a plasma display device for generating a voltage required for screen display using a back pressure circuit.

Recently, flat display devices such as a liquid crystal display (LCD), a field emission display (FED), and a plasma display have been actively developed. Among these flat panel display devices, the plasma display device has advantages of higher luminance and luminous efficiency and a wider viewing angle than other flat panel display devices. Accordingly, the plasma display device is in the spotlight as a display device to replace a conventional cathode ray tube (CRT) in a large display device of 40 inches or more.

Plasma display devices are flat display devices that display characters or images using plasma generated by gas discharge, and dozens to millions or more of pixels are arranged in a matrix form according to their size.

In general, a plasma display device is driven by dividing one field into a plurality of subfields each having a weight, and a gray level is expressed by a sum of weights according to combinations of subfields to be turned on. Each subfield consists of a reset period, an address period, and a sustain period. The reset period serves to initialize the wall charge in order to stably perform the address discharge through the reset discharge. The address period is a period in which a wall charge is accumulated in cells that are turned on by selecting cells that are turned on and cells that are not turned on in the panel. The sustain period is a period in which sustain discharge is performed to actually display an image in the addressed cells.

These reset periods, address periods, and sustain periods require various voltages.

1 is a driving waveform diagram of a plasma display device.

The reset waveform applied to the scan electrode (Y electrode) in the reset period is a waveform that gradually rises to the Vset voltage and then gradually falls to the Vnf voltage. During the reset period, reset discharge occurs in all discharge cells, and a wall is formed on each electrode. The charge builds up enough.

Next, in order to select a cell to be turned on while the X electrode is maintained at the Ve voltage in the address period, a scan pulse having a VscL voltage and an address pulse having a Va voltage are applied to the Y and A electrodes, respectively. The unselected Y electrode biases the VscH voltage higher than the VscL voltage, and applies a reference voltage to the address electrode of the cell that is not turned on.

Next, in the sustain period, a sustain discharge pulse having a voltage of Vs is first applied to the Y electrode, and a reference voltage is applied to the X electrode. At this time, the Vs voltage is a voltage capable of causing a discharge between the Y electrode and the X electrode together with the wall voltage formed between the Y electrode and the X electrode by the address discharge. Then, in the cell in which the discharge occurred in the address period, the discharge occurs between the Y electrode and the X electrode.

Next, a reference voltage is applied to the Y electrode and a sustain discharge pulse of the Vs voltage is applied to the X electrode. At this time, since the wall voltage was formed between the Y electrode and the X electrode by the last sustain discharge, discharge occurs between the Y electrode and the X electrode. As a result, (-) wall charges and (+) wall charges are formed at the Y electrode and the X electrode, respectively, and (+) wall charges are formed at the A electrode.

The screen display in such a plasma display device requires various voltages. The plasma display device has a switching mode power supply (SMPS) for applying the voltage. Conventionally, the power supply has generated the various DC voltages using several DC-to-DC converters. However, since the DC-to-DC converter is expensive, a plurality of DC-to-DC converters are expensive, and the circuit of the power supply device becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a plasma display device having a power supply device having a reduced number of DC-to-DC converters using a back voltage circuit.

In accordance with an aspect of the present invention, a plasma display device includes a plurality of first electrodes and a second electrode arranged alternately in a row direction, a plurality of third electrodes arranged in a column direction, and the In the plasma display device including a switching mode power supply (SMPS) for applying a voltage to the electrode,
The SMPS,
A primary circuit for outputting a predetermined alternating voltage;
A transformer including a primary coil receiving a predetermined alternating voltage output from the primary circuit, and a secondary coil inducing a predetermined voltage corresponding to the primary coil;
A first capacitor having a first end electrically connected to the first end of the secondary coil;
A first diode having a cathode electrically connected to the second end of the first capacitor and an anode electrically connected to the second end of the secondary coil;
A second diode in which an anode is electrically connected to the cathode of the first diode; And
And a second capacitor electrically connected to a cathode of the second diode and a second capacitor electrically connected to the anode of the first diode.

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DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Now, a plasma display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 2.

2 is a schematic diagram of a plasma display device according to an embodiment of the present invention. The plasma display device includes a plasma panel 100, an address driver 200, a scan / hold driver 300, a controller 400, and a switching mode power supply (SMPS) 500.

The plasma panel 100 includes a plurality of electrodes. The electrodes are arranged in a matrix of m × n, specifically, address electrodes (hereinafter referred to as A electrodes) A1-Am are arranged in a column direction, and n rows of scan electrodes (hereinafter referred to as Y electrodes) in a row direction. (Y1-Yn) and sustain electrodes (hereinafter referred to as X electrodes) X1-Xn are arranged in a zigzag. Here, the discharge space at the intersection of the A electrodes A1-Am and the X and Y electrodes X1-Xn and Y1-Yn forms a discharge cell.

The SMPS 500 supplies a voltage required to drive the plasma display device. That is, at least one DC-to-DC converter generates and supplies voltages for driving the plurality of electrodes of the plasma panel with an external AC power source.

Since the SMPS 500 according to the embodiment of the present invention generates voltages for driving the plurality of electrodes using a back voltage circuit, the number of DC-to-DC converters mounted in comparison with the conventional SMPS is reduced. And the circuit is simplified.

The controller 400 receives R, G, and B image signals and a synchronization signal from the outside, divides one frame into several subfields, and divides each subfield into a reset period, an address period, and a sustain period to drive the plasma display device. Generate a control signal.

The address driver 200 receives a control signal from the controller 400, selects a discharge cell to be displayed, and applies an address pulse to each address electrode A1-Am.

The scan and sustain driver 300 receives a control signal from the controller 400 and alternately applies the sustain discharge pulse voltage Vs to the scan electrodes Y1-Yn and the sustain electrodes X1-Xn to the selected discharge cells. Perform sustain discharge.

3 is a circuit diagram illustrating an internal SMPS of a plasma display device according to an exemplary embodiment of the present invention.

The back pressure circuit includes a primary circuit 510 for supplying power, a transformer 520 including a primary coil L1 and a secondary coil L2, and a secondary circuit 530 capable of outputting a back pressure. ). The primary circuit 510 receives a voltage from an AC terminal and inputs +100 V and -100 V to terminals T1 and T2 of the primary coil L1 of the transformer 520 as shown in FIG. 4. Apply voltage alternately. In the exemplary embodiment of the present invention, a square wave in which a positive voltage and a negative voltage are alternately applied is illustrated, but the waveform may be any waveform if the positive and negative voltages having the same numerical value are alternately applied.

Here, two black spots visible on the upper side of the primary side and the lower side of the secondary side have a negative voltage induced at T3 of the secondary coil L2 when a positive voltage is applied to T1 of the primary coil L1. It is an indication that it is. Since the primary circuit 510 is easily configurable to those skilled in the art, description thereof will be omitted.

The secondary circuit 530 of the back pressure circuit is a quadruple back pressure circuit. The first capacitor C1 and the first diode D1 are sequentially connected between the terminals T3 and T4 of the secondary coil L2. In detail, the first capacitor C1 of the secondary circuit L1 is One end is connected to one end T3 of the secondary coil of the transformer, the other end of the first capacitor C1 is connected to the cathode side of the first diode D1, and the first diode D1. The anode side of is connected to the other end T (4) of the secondary coil.

The second diode D2 and the second capacitor C2 are sequentially connected between the contact point n2 of the first diode D1 and the contact point n4 of the other end, in detail, the second diode ( The anode side of D2) is connected with the cathode side of the first diode D1, the cathode side of the second diode D2 is connected with one end of the second capacitor C2, and the second capacitor C2 The other end of is connected to the anode side of the first diode D1.

A third capacitor C3 and a third diode D3 are sequentially connected between the contact point n2 of the second diode D2 and the contact point n5 of the other end, in detail, the third diode D3. ) Is connected to the cathode side of the second diode (D2), the cathode side of the third diode (D3) is connected to one end of the third capacitor (C3), the other end of the third capacitor (C3) Is connected to the anode side of the second diode D2.

The fourth diode D4 and the fourth capacitor C4 are sequentially connected between the contact point n3 of the third diode D3 and the contact point n5 of the other end thereof, in detail, the fourth diode D4. ) Is connected to the cathode side of the third diode (D3), the cathode side of the fourth diode (D4) is connected to one end of the fourth capacitor (C4), the other end of the fourth capacitor (C4) Is connected to the anode side of the third diode D3.

Here, a predetermined voltage is applied between the contact n1 and the contact n2, between the contact n4 and the contact n5, between the contact n1 and the contact n3, and between the contact n4 and the contact n6, respectively. Is output, and a DC-to-DC converter (not shown) may be located between these contacts as needed.

Next, the operation of the power supply apparatus according to the embodiment of the present invention will be described with reference to FIGS. 5A to 5C.

The ratio of the voltage applied to the primary coil and the voltage output from the secondary coil is determined by the ratio of the number of turns of the primary coil L1 and the secondary coil L2. In the embodiment of the present invention, the ratio of the number of turns of the primary coil L1 and the secondary coil L2 is set to 10 to 1, but the present invention is not limited thereto.

Referring to FIG. 5A, when a voltage of +100 V is first applied to the primary coil L1 side, a voltage of +10 V is induced on the secondary coil L2 side of the transformer. Accordingly, the first current I1 flows along the path of the first diode D1 and the first capacitor C1, and the potential difference between the contact n2 and the contact n4 is in the first capacitor C1. The 10V voltage is charged to be 10V (except the voltage applied to the diode).
Referring next to FIG. 5B, when a voltage of -100 V is applied to the primary coil L1 side, a voltage of -10 V is induced on the secondary coil L2 side of the transformer. Then, the second current I2 flows along the path of the first capacitor C1, the second diode D2, and the second capacitor C2 in a direction opposite to the first current I1. The capacitor C2 is charged with 20V so that the potential difference between the contact n2 and the contact n5 becomes -10V.

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Next, referring to FIG. 5C, when a voltage of +100 V is applied to the primary coil L1 side, a voltage of +10 V is induced on the secondary coil L2 side of the transformer. Then, the third current I3 flows along the path of the second capacitor C2, the diode D3, the third capacitor C3, and the first capacitor C1, and the third capacitor C3 The voltage of 20V is charged so that the potential difference between the contact n5 and the contact n3 becomes 10V.
Finally, referring to FIG. 5D, when a voltage of −100 V is applied to the primary coil L1 side, a voltage of −10 V is induced on the secondary coil L2 side of the transformer. Then, the fourth current flows along the paths of the first capacitor C1, the third capacitor C3, the fourth diode D4, the fourth capacitor C4, and the second capacitor C2. Accordingly, the fourth capacitor is charged with a 20V voltage such that the potential difference between the contact n3 and the contact 6 becomes -10V.
As such, when the voltage of FIG. 4 is applied to the primary coil L1 of the transformer, a voltage of 10 V is charged in the first capacitor C1, and a voltage of 20 V is supplied to the second to fourth capacitors C2-C4. The voltage is charged. Thereby, the voltage of the multiple of the output of the secondary coil L2 side of a transformer is output between the contact n1 and the contact n2, and similarly, the secondary coil L2 is provided between the contact n4 and the contact n5. Outputs twice the voltage of the side output, and outputs three times the voltage of the secondary coil L2 side output between the contact n1 and the contact n3, and between the contact n4 and the contact n6. Outputs a voltage four times the output of the secondary coil L2 side.

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In the embodiment of the present invention, the voltage applied to the primary coil L1 side of the transformer is ± 100 V and the output of the secondary coil L2 side is ± 10 V, but the present invention is not limited thereto. For example, when the output of the secondary coil L2 is set to 1/2 of the Vs voltage, which is one of the voltages applied to the electrodes of the plasma panel, the voltage of Vs and the voltage of about twice the Vs voltage It is possible to output the voltage of Vset with V without using a DC-to-DC converter.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the present invention, the number of DC-to-DC converters is simplified by using a back pressure circuit in the plasma display device, thereby simplifying the circuit and reducing the manufacturing cost of the plasma display device.

Claims (3)

A plurality of first and second electrodes arranged alternately in a row direction, a plurality of third electrodes arranged in a column direction, and a switching mode power supply (SMPS) for applying a voltage to the electrodes A plasma display device comprising: The SMPS, A primary circuit for outputting a predetermined alternating voltage; A transformer including a primary coil receiving a predetermined alternating voltage output from the primary circuit, and a secondary coil inducing a predetermined voltage corresponding to the primary coil; A first capacitor having a first end electrically connected to the first end of the secondary coil; A first diode having a cathode electrically connected to the second end of the first capacitor and an anode electrically connected to the second end of the secondary coil; A second diode in which an anode is electrically connected to the cathode of the first diode; And And a second capacitor electrically connected to a cathode of the second diode and a second capacitor electrically connected to an anode of the first diode. The method of claim 1, When a first voltage is induced at a first end and a second end of the secondary coil, a first voltage is charged at the first end and the second end of the first capacitor, When a first voltage is induced at the second end and the first end of the secondary coil of the transformer, a second voltage greater than the first voltage is charged at the second end and the first end of the second capacitor. Wherein the first voltage and the second voltage are used as voltages that double each other among voltages used to drive the plasma display device. The method of claim 2, A third capacitor having one end connected to an anode of the second diode, A third diode having a cathode connected to the other end of the third capacitor and an anode connected to a cathode of the third diode and a contact of the second capacitor; A fourth capacitor having one end connected to the cathode of the third diode; And a fourth diode having a cathode connected to the other end of the third capacitor and an anode connected to the cathode of the third diode and the contact of the third capacitor.

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