KR20070014638A - Plasma display device and driving method thereof - Google Patents

Abstract

A plasma display device and a driving method thereof are provided to stabilize the operation of the plasma display device by using a protective circuit, which reliably operates, even when too many sustain pulses are applied. A plasma display device includes a PDP(Plasma Display Panel,100), a scan driver(300), a sustain driver(400), an address driver(200), a power supply(600), and a controller(500). The PDP includes plural scan and sustain electrodes, plural address electrodes, and plural discharge cells. The sustain driver applies a driving signal on the sustain electrode. The address driver applies the driving signal on the address electrode. The scan driver applies the driving signal on the scan electrode. The power supply supplies voltages to the scan, sustain, and address drivers and the controller. The controller supplies control signals to the scan, sustain, and address drivers, and controls the scan control signal, when an output current amount from the power supply exceeds a reference current amount to repress sustain discharge in the discharge cell.

Description

Plasma display device and driving method thereof {PLASMA DISPLAY DEVICE AND DRIVING METHOD THEREOF}

1 is a configuration diagram of a plasma display device according to a first embodiment of the present invention.

2 illustrates a configuration of a power supply unit of a plasma display device according to a first embodiment of the present invention.

3 is a driving waveform diagram applied to the plasma display panel when the amount of generated current of the power supply unit is less than the reference current amount in the plasma display device according to the first embodiment of the present invention.

FIG. 4 is a driving waveform diagram applied to the plasma display panel when the generated current amount of the power supply unit is greater than or equal to the reference current amount in the plasma display device according to the first embodiment of the present invention.

5 is a flowchart of a method of driving a plasma display device according to a second embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device and a driving method thereof, and more particularly, to a plasma display device and a driving method thereof for preventing an overload of a plasma display device.

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

Meanwhile, the plasma display device includes a switching mode power supply (hereinafter, also referred to as “SMPS”) for generating a voltage for gas discharge. However, when a video signal in which noise is mixed suddenly is input to the plasma display device or an abnormal signal that the entire screen becomes bright is input, a situation may occur in which the power supply unit supplies an excessive current exceeding a rated current. The power supply can overheat or break if this happens.

In order to prevent this, the power supply unit of the plasma display device includes a protection circuit that stops supply of a voltage when a current above a rated current flows. However, when the protection circuit is operated, there is a problem that the entire plasma display device does not operate.

Therefore, there is a need for a method of adjusting the amount of current supplied to the plasma display device before the protection circuit is operated.

An object of the present invention is to provide a plasma display device that controls the amount of current supplied to a plasma display device before an operation of a protection circuit.

In addition, the present invention is to provide a plasma display device driving method for controlling the amount of current supplied to the plasma display device before the operation of the protection circuit.

In order to solve the above technical problem, a plasma display device according to an aspect of the present invention may include a plurality of scan electrodes and a plurality of sustain electrodes, scan electrodes, and a plurality of address electrodes arranged to intersect the sustain electrodes. And a plasma display panel including a plurality of discharge cells, a scan driver for applying a drive signal to the scan electrode, a sustain driver for applying a drive signal to the sustain electrode, an address driver for applying a drive signal to the address electrode, a scan driver, and a sustain driver And a power supply unit for supplying a plurality of voltages to the address driver and the controller, and a scan control signal, a sustain control signal, and an address control signal, respectively, to the scan driver, the sustain driver, and the address driver, wherein the output current amount of the power supply Discharge by controlling the scan control signal when the amount of current is more than In a controller for suppressing the sustain discharge.

According to another aspect of the present invention, there is provided a method of driving a plasma display device, the method comprising: measuring a current amount generated from a power supply, comparing a measured current amount with a reference current amount, and when the measured current amount is equal to or greater than a reference current amount, the plurality of subfields Suppressing sustain discharge in the discharge cell by changing a waveform applied to the scan electrode in the sustain period of some subfields.

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.

Hereinafter, a plasma display device according to a first embodiment of the present invention will be described with reference to FIG. 1.

1 shows a plasma display device according to a first embodiment of the present invention.

The plasma display device according to the first exemplary embodiment of the present invention includes a plasma display panel 100, an address driver 200, a scan driver 300, a sustain driver 400, a controller 500, and a power supply 600. do.

The plasma display panel 100 includes a plurality of discharge cells, and the plurality of discharge cells are driven by the address driver 200, the scan driver 300, and the sustain driver 400 to display an image.

The plasma display panel 100 includes a plurality of address electrodes (hereinafter referred to as "A electrodes") A1-Am and A electrodes A1-Am arranged in one direction. Scan electrodes (hereinafter referred to as "Y electrodes") (Y1-Yn) and a plurality of sustain electrodes (hereinafter referred to as "X electrodes") (X1-Xn) are included. 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 address driver 200 receives an address control signal from the controller 500 and applies a display data signal for selecting discharge cells to be displayed to each of the A electrodes A1-Am.

The scan driver 300 and the sustain driver 400 receive a scan control signal and a sustain control signal from the control unit 500, respectively, and output a scan drive signal and a sustain drive signal corresponding to the scan control signal and the sustain control signal from the Y electrode ( Y1-Yn) and X electrodes (X1-Xn), respectively.

The controller 500 receives an image signal from the outside, generates an address control signal, a scan control signal, and a sustain control signal, and transmits the image control signal, the scan control signal, and the sustain control signal to the address driver 200, the scan driver 300, and the sustain driver 400, respectively.

Specifically, the controller 500 divides one frame into a plurality of subfields having respective luminance weights, and converts the image signal into data corresponding to each subfield (hereinafter referred to as "subfield data"). The controller 500 generates an address drive control signal, a scan drive control signal, and a sustain drive control signal for controlling the driving of the plasma display panel 100 according to the converted data. In this case, the scan driving control signal may include a first scan driving control signal for controlling the scan driving unit 300 to be driven according to the generated subfield data when the generated current amount of the power supply unit is less than a predetermined reference current amount; and the generated current amount of the power supply unit. In the case where the predetermined reference current amount is equal to or greater than the predetermined reference current amount, the second scan driving control signal controls the scan driver 300 so that an image is not displayed in the predetermined partial subfield.

The power supply unit 600 supplies a plurality of predetermined voltages required to drive the plasma display device. Specifically, a plurality of powers required by the address driver 200, the scan driver 300, the sustain driver 400, and the controller 500 are supplied using an external AC power source.

Hereinafter, the power supply unit 600 of the plasma display device according to the first exemplary embodiment of the present invention will be described in detail.

2 is a schematic block diagram of a power supply unit 600 of a plasma display device according to a first embodiment of the present invention.

As shown in FIG. 2, the power supply unit 600 of the plasma display device according to the first embodiment of the present invention includes a voltage supply circuit unit 610, a protection circuit unit 620, and a current detection circuit unit 630.

The voltage supply circuit unit 610 outputs voltages for the address driver 200, the scan driver 300, the sustain driver 400, the controller 500, and other parts by using an external AC power source.

The protection circuit unit 620 sets a predetermined current amount as the operation current amount, and when the current amount equal to or greater than the operating current amount flows from the voltage supply circuit unit 610, the protection operation of stopping the supply of voltage such as suppressing the operation of the voltage supply circuit unit 610. Do this.

The current detection circuit unit 630 measures the amount of current supplied from the voltage supply circuit unit 610. In addition, the current detection circuit unit 630 sets a current amount corresponding to a predetermined ratio of the operating current amount of the protection circuit unit 620 as a reference current amount, and determines whether the measured current amount corresponds to the reference current amount. In this case, when the measured current amount is less than the reference current amount, a normal signal (low signal) is output to the controller 500, and when the measured current amount is greater than or equal to the reference current amount, an abnormal signal (high signal) is output to the controller 500. do. For example, a low level signal may be used as a normal signal, and a high level signal may be used as a higher signal. Herein, the predetermined ratio with respect to the amount of operating current may be appropriately selected according to the purpose of the present invention. In the first embodiment of the present invention, the predetermined ratio for setting the reference current amount is set to 95% of the amount of the operating current of the protection circuit unit 620. Level was set.

In the first embodiment of the present invention, the control unit 500 outputs a first scan drive control signal in response to the normal signal of the current detection circuit unit 630, and the scan driver 300 is connected to the first scan drive control signal. Therefore, the Y electrode is normally driven. The controller 500 outputs a second scan driving control signal in response to the abnormal signal of the current detection circuit unit 630, and the scan driver 300 displays an image in some subfields according to the second scan driving control signal. Drive the Y electrode so that it is not displayed.

In this case, as a scan electrode driving method for preventing an image from being displayed in some subfields, the scan driver 300 may prevent the sustain discharge pulse from being applied to the Y electrode during the sustain period of the some subfields. The some subfields may be subfields (hereinafter, referred to as "last subfields") that are located last in time among the plurality of subfields. In general, since the last subfield is a subfield having the highest luminance weight, if the sustain discharge does not occur in the last subfield, the amount of current supplied from the voltage supply circuit unit 610 may be reduced.

Hereinafter, the operation of the plasma display device according to the first embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

3 is a view showing a normal driving waveform of the plasma display device according to the first embodiment of the present invention. That is, the driving waveform of FIG. 3 is a case where the first scan driving control signal is output from the controller 500.

As shown in Fig. 3, in the plasma display device according to the first embodiment of the present invention, each subfield includes a reset period, an address period, and a sustain period.

Specifically, in the rising period of the reset period, the X electrodes X1 to Xn and the A electrodes A1 to Am are held at the Y electrodes Y1 to Yn while maintaining the reference voltage (assuming 0 V in FIG. 3). Apply a voltage that slowly rises from Vp voltage to Vr voltage. Then, a weak reset discharge is generated from the Y electrodes Y1 to Yn to the A electrodes A1 to Am and the X electrodes X1 to Xn, respectively, and a negative wall charge is applied to the Y electrodes Y1 to Yn. (+) Wall charges are formed on the A electrodes A1 to Am and the X electrodes X1 to Xn. When the voltage of the electrode is gradually changed as shown in FIG. 3, a weak discharge occurs in the cell, and wall charge is formed so that the sum of the voltage applied from the outside and the wall voltage of the cell maintains the discharge start voltage state. This principle is disclosed in US Pat. No. 5,745,086 to Weber. In the reset period, since the states of all cells must be initialized, the Vr voltage is high enough to cause discharge in the cells of all conditions. In addition, the voltage Vp is generally higher than the voltage Vs which is the voltage applied to the Y electrodes Y1 to Yn in the sustain period, and is higher than the discharge start voltage between the Y electrodes Y1 to Yn and the X electrodes X1 to Xn. Low voltage.

In the falling period of the reset period, a voltage gently falling from the Vq voltage to the Vn voltage is applied to the Y electrodes Y1 to Yn. At this time, the reference voltage 0V is applied to the A electrodes A1 to Am, and the Vh voltage is applied to the X electrodes X1 to Xn. Then, while the voltages of the Y electrodes Y1 to Yn are decreasing, they are weak between the Y electrodes Y1 to Yn and the X electrodes X1 to Xn, and between the Y electrodes Y1 to Yn and the A electrodes A1 to Am. As the reset discharge occurs, the negative wall charges formed on the Y electrodes Y1 to Yn and the positive wall charges formed on the X electrodes X1 to Xn and the A electrodes A1 to Am are erased. In FIG. 3, the voltage Vn is represented as a reference voltage (0V), but the voltage level may be set to a voltage lower than the reference voltage (0V). In general, the magnitudes of the Vn voltage and the Vh voltage are set such that the wall voltage between the Y electrodes Y1 to Yn and the X electrodes X1 to Xn becomes almost 0 V, so that cells in which the address discharge has not occurred in the address period are held in the sustain period. Misdischarge can be prevented. Since the A electrodes A1 to Am are maintained at the reference voltage, the wall voltage between the Y electrodes Y1 to Yn and the A electrodes A1 to Am is determined by the level of the Vn voltage.

Next, in the address period, in order to select a discharge cell, scan pulses having a Vsc voltage are sequentially applied to the Y electrodes Y1 to Yn, and the Y electrode to which the Vsc voltage is not applied is biased to the Vm voltage. At this time, the Vsc voltage is called a scan voltage, and the Vm voltage is also called a non-scan voltage. The address pulse having the voltage Vw is applied to the A electrode passing through the discharge cell to be selected among the plurality of discharge cells formed by the Y electrode to which the Vsc voltage is applied, and the unselected A electrode is biased to the reference voltage. Then, an address discharge occurs in the discharge cell formed by the A electrode to which the Vw voltage is applied and the Y electrode to which the Vsc voltage is applied, so that a positive wall charge is formed at the Y electrode and a negative wall charge is formed at the X electrode. Is formed.

In the sustain period, the sustain discharge pulse voltage Vs is alternately applied to the Y electrodes Y1 to Yn and the X electrodes X1 to Xn to sustain discharge the discharge cells selected in the address period.

In the first embodiment of the present invention, the sustain discharge pulse voltage Vs is a voltage applied alternately to the Y electrode and the X electrode, and the Y electrode or the X electrode to which the sustain discharge pulse voltage Vs is applied and the reference voltage (0 V) are applied. When the voltage between the X electrode and the Y electrode biased together with the wall voltage of the discharge cell is set to a voltage at which the discharge cell is maintained at a discharge start voltage or more.

4 is a diagram illustrating driving waveforms when the plasma display device according to the first embodiment of the present invention is overloaded. That is, the driving waveform of FIG. 4 is a case where the second scan driving control signal is output from the controller 500.

The driving waveforms of FIG. 4 are the same except for the driving waveforms and the sustain period of FIG. Therefore, since the description of the reset period and the address period in the driving waveform of FIG. 4 is the same as the description of the reset period and the address period of the driving waveform of FIG. 3, it is omitted in the specification of the present invention.

As shown in FIG. 4, when the driving waveform is examined during the sustain period, the reference voltage 0V lower than the sustain discharge pulse voltage Vs is applied to the scan electrode. Then, the Y electrode is bias-maintained at 0V, and since only the Vs voltage is periodically applied to the X electrode, the voltage between the Y electrode and the X electrode becomes less than the discharge start voltage, so that no discharge occurs in the discharge cell.

In FIG. 4, the scan driver 300 teaches to output the reference voltage (0V) during the sustain period. However, the voltage output from the scan driver 300 is sufficiently lower than the sustain discharge pulse voltage (Vs) voltage. Any voltage can be used as long as it does not cause sustain discharge in the cell.

On the other hand, as a method for preventing sustain discharge during the sustain period, a method of floating without applying a voltage to the Y electrode during the sustain period may be considered. In this case, too, the voltage between the X electrode and the Y electrode becomes less than the discharge start voltage during the sustain period, so that discharge does not occur.

Hereinafter, a driving method of the plasma display device according to the second embodiment of the present invention will be described with reference to FIG. 5.

In the method of driving the plasma display device according to the second embodiment of the present invention, the current amount is measured from the power supply of the plasma display device so that the sustain discharge is not performed during the sustain period when the measured current amount is equal to or greater than the predetermined current amount. The voltage of the scan driving signal applied to the Y electrode is adjusted. Therefore, since sustain discharge does not occur in the discharge cell during the sustain period, the amount of current flowing through the plasma display device is adjusted to be low.

5 is a flowchart illustrating a method of driving a plasma display device according to a second embodiment of the present invention.

The plasma display device used in the method of driving the plasma display device according to the second embodiment of the present invention may be the plasma display device according to the first embodiment of the present invention. Therefore, in the second embodiment of the present invention, a detailed description of the plasma display device to be used is omitted.

First, a protection circuit operating current amount and a predetermined reference current amount for a protection circuit of a power supply unit of a plasma display device are set (s100). The protection circuit operating current amount is a current amount for stopping the supply of voltage to the power supply unit when the current amount is higher than that, and the reference current amount is a current amount for adjusting the voltage of the scan driving signal. It can be set to the amount of current corresponding to the ratio of. The protection circuit operating current amount and the reference current amount can be appropriately set according to the characteristics or the purpose of the plasma display device in which the present driving method is used.

Next, the amount of current generated from the power supply unit is measured in real time (s200).

The measured current amount is compared with the preset reference current amount (s300).

When the measured current amount is less than the reference current amount, the normal signal (a control signal for outputting the first driving signal) is transmitted to the scan driver (S400 and S500).

The scan driver outputs the first driving signal to the Y electrode in response to the normal signal (S600). The first driving signal includes a reset period, an address period, and a sustain period, and the voltage during the sustain period includes the sustain discharge pulse voltage Vs.

On the other hand, when the measured current amount is greater than or equal to the reference current amount, the abnormality signal (control signal for outputting the second driving signal) is transmitted to the scan driver (S400 and S700).

The scan driver outputs the second driving signal to the Y electrode in response to the abnormal signal (S800). The second driving signal includes a signal of a reset period and an address period and a sustain period, wherein the reset period and the address period are the same as the first drive signal, and the voltage during the sustain period is lower than the sustain discharge pulse voltage Vs. It consists of voltage.

When the reference current amount is set too low, abnormal signals are transmitted to the scan driver too frequently, which may degrade the image quality displayed on the plasma display panel. On the other hand, when the reference current amount is set too high, the protection circuit may operate before the current amount is reduced by adjusting the voltage of the drive signal waveform output from the scan driver to fail to achieve the effect of the present invention.

As described above, in the driving method of the plasma display device according to the second embodiment of the present invention, when the abnormal signal is applied to the scan driver, the sustain discharge pulse voltage Vs is maintained during the sustain period of the last subfield of the current video signal. The second driving signal configured with the low voltage is output. However, the driving method of the plasma display device according to the second exemplary embodiment of the present invention may be implemented by a method of controlling the output of the scan driver in another subfield instead of the last subfield of the current image signal.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to

The power supply unit that generates power in the plasma display device includes a protection circuit that operates when the amount of current exceeds a predetermined value to stop the operation of the power supply unit. However, the protection circuit may be operated when a large number of sustain pulses are applied during processing of a specific image signal, thereby causing the current to be more than a predetermined value to stop the entire operation of the plasma display device.

In the plasma display device of the present invention, before the amount of current reaches the protection circuit operation value, the generation of the sustain discharge pulse can be suppressed to reduce the amount of current to prevent the operation of the protection circuit. Therefore, it is possible to prevent an abnormal operation of the entire plasma display device with respect to a specific image signal.

Claims (6)

A plasma display panel including a plurality of scan electrodes and a plurality of sustain electrodes, a plurality of address electrodes and a plurality of discharge cells arranged to intersect the scan electrodes and the sustain electrodes; A scan driver for applying a driving signal to the scan electrode; A sustain driver for applying a drive signal to the sustain electrode; An address driver which applies a driving signal to the address electrode; A power supply unit supplying a plurality of voltages to the scan driver, the sustain driver, the address driver, and the controller, respectively; And The scan control signal, the sustain control signal, and the address control signal are respectively applied to the scan driver, the sustain driver, and the address driver, and the scan control signal is controlled when the output current amount of the power supply is equal to or greater than a reference current amount. And a control unit for suppressing sustain discharge in the discharge cell. The method of claim 1, The controller divides one frame into a plurality of subfields having respective weights. When the output current amount of the power supply unit is equal to or greater than a reference current amount, the scan driver applies a predetermined voltage to the scan electrode in the sustain period of some subfields of the plurality of subfields so that the voltage between the scan electrode and the sustain electrode is increased. A plasma display device which is controlled to be less than a discharge start voltage. The method of claim 1, The controller divides one frame into a plurality of subfields having respective weights. And the scan driver floats the scan electrode in a sustain period of some of the subfields of the plurality of subfields when the output current amount of the power supply is equal to or greater than a reference current amount. A plasma display device comprising a plurality of scan electrodes, a plurality of sustain electrodes, a plurality of address electrodes, a driver for driving the scan electrodes, the sustain electrodes and the address electrodes, a plurality of discharge cells, and a power supply unit for supplying voltage to the driver. In the method of driving by dividing a frame into a plurality of subfields having respective weights, Measuring an amount of current generated from the power supply; Comparing the measured current amount with a predetermined reference current amount; If the measured current amount is greater than or equal to the reference current amount, changing the waveform applied to the scan electrode in the sustain period of some subfields of the plurality of subfields, thereby suppressing sustain discharge in the discharge cells; Driving method. The method of claim 4, wherein And wherein the changed waveform is a waveform for biasing the scan electrode to a predetermined voltage during the sustain period. The method of claim 5, And wherein the changed waveform is a waveform such that the voltage between the scan electrode and the sustain electrode becomes less than the discharge start voltage during the sustain period.

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