KR100612344B1 - Driving apparatus and method of plasma display panel - Google Patents

Abstract

The present invention relates to a driving apparatus and a driving method of a plasma display panel. The present invention drives a circuit for applying a reset waveform by operation of a reactance element and a switching element, feeds back a reset voltage applied to a panel, and adjusts the slope of the reset waveform according to a result of comparing the voltage with a reference voltage. In this way, the power loss of the circuit is reduced and the slope of the reset waveform can be efficiently adjusted, which is advantageous for weak discharge control.

PDP, electrodes, discharge, reactance, panel capacitors, PWM

Description

DRIVING APPARATUS AND METHOD OF PLASMA DISPLAY PANEL}

1 is a schematic diagram of a plasma display panel according to an exemplary embodiment of the present invention.

2 is a view showing a driving circuit for applying a general falling ramp waveform.

3 is a diagram illustrating a reset driving circuit according to a first embodiment of the present invention using an inductor.

4 is a diagram illustrating a reset waveform formed by the reset driving circuit of FIG. 3.

5 is a diagram illustrating a reset driving circuit according to a second embodiment of the present invention using a transformer.

6 is a diagram illustrating a reset driving circuit according to a third embodiment of the present invention using an inductor.

7 illustrates a reset driving circuit according to a fourth embodiment of the present invention using a transformer.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus and a driving method of a plasma display panel, and more particularly to a driving circuit and a driving method for applying a reset waveform.

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 driving method of an AC plasma display device includes a reset period, an address period, and a sustain period.

On the other hand, the ramp waveform is conventionally applied to the scan electrode as described in US Pat. No. 5,745,086 to set the wall charge in the reset period. That is, a slowly rising ramp waveform was applied to the scan electrode and then a slowly descending ramp waveform was applied. A circuit such as that of FIG. 1 is used to generate this ramp waveform.

1 shows a conventional lamp driving circuit.

As shown in Fig. 1, a conventional lamp driving circuit includes a transistor M1, a capacitor C1, a resistor R1 and a control signal voltage source Vg. In FIG. 1, the Y electrode of the panel capacitor Cp is connected to the drain of the transistor M1 to apply the falling ramp waveform, and the Y electrode of the panel capacitor Cp is connected to the drain of the transistor M1 to apply the rising ramp waveform. Just connect to the source. Here, the panel capacitor Cp represents a capacitive component formed by the Y electrode and the X electrode.

When the signal is applied to the gate of the transistor M1 through the control signal voltage source Vg while the panel capacitor Cp is charged, the transistor M1 is turned on and the voltage charged in the panel capacitor Cp is turned on. Discharge through the drain-source of M1). At this time, the gate-source voltage of the transistor M1 is controlled by the voltage charged in the capacitor C1 so that the voltage of the panel capacitor Cp falls in the form of a lamp.

According to such a lamp driving circuit, since the slope of the ramp waveform is adjusted by adjusting the resistor R1, resistance loss and heat generation problems of the driving circuit occur. In addition, a current generated by the panel voltage change during the sustain period is introduced into the gate of the transistor M1 through the capacitor C1 used to keep the slope constant, which causes the transistor M1 to malfunction or the transistor ( There is a problem of heat generation in M1). In addition, it is not easy to adjust the slope because the resistance (R1) must be manually adjusted whenever the slope of the reset waveform is changed.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a driving apparatus and a driving method of a plasma display panel including a reset driving circuit having a low power loss and automatically adjusting a slope of a reset waveform.

The driving device of the plasma plasma display panel according to an aspect of the present invention for solving this problem is a driving device for applying a reset waveform to the electrode of the plasma display panel,

A first power supply for supplying a first voltage, a current source for generating a current using the voltage and reactance components from the first power supply, and comparing the reset waveform and the reference waveform to control the magnitude of the current generated in the current source It includes a control unit for outputting a signal,

The reset waveform is generated by gradually changing the voltage of the electrode from the first voltage to the second voltage using the current from the current source.

At this time, the current source,

A first transistor having a first end connected to the electrode, a second transistor connected to a second end of the first transistor, and a second end connected to a second power supply for supplying a fourth voltage; An inductor having one end connected to a contact point of the first and second transistors and the other end connected to the first power source,

The voltage of the electrode is changed by causing resonance between the inductor and the electrode through a current path formed by turning on the first transistor.

In addition, the current source,

A transformer having a primary coil connected to the first power supply and a secondary coil connected to the electrode, an inductor connected in parallel with the primary coil, and a first end connected to a contact between the primary coil and the inductor, and a second A stage comprising a transistor connected to a second power supply for supplying a second voltage,

A current is injected into the inductor through a current path formed by turning on the transistor, and the current injected into the inductor is transferred to the secondary coil through the primary coil.

In addition, the control unit,

A waveform applied to the electrode from the current source is input to the inverting terminal and a waveform having the reference slope is input to a non-inverting terminal, and a pulse signal for controlling on / off of the transistor is output, and is input from the comparator. It includes a PWM generator for adjusting the duty ratio of the output pulse signal in accordance with the signal,

When the high level signal is input from the comparator, the duty ratio of the output pulse signal is increased. When the low level signal is input from the comparator, the duty ratio of the output pulse signal is decreased.

A driving method of a plasma display panel according to an aspect of the present invention includes a switching element, and is a driving method for applying a reset waveform to an electrode of a plasma display panel through a current source for supplying current using a reactance.

Applying a reset waveform to the electrode through a current path formed by turning on the switching element, measuring a reset waveform applied to the electrode, the slope of the measured reset waveform and the slope of a preset reference reset waveform Comparing the step of outputting a signal for controlling on / off of the switching element according to the comparison result and turning on the switching element according to the output control signal to adjust the slope of the reset waveform; Include.

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.

First, a plasma display device according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

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

As shown in FIG. 2, the plasma display device according to an exemplary embodiment of the present invention includes a display panel 100, a controller 200, an address driver 300, and a sustain electrode driver (hereinafter referred to as an “X electrode driver”) 400. ) And a scan electrode driver (hereinafter referred to as a 'Y electrode driver') 500.

The display panel 100 includes a plurality of address electrodes A1-Am arranged in the column direction, a plurality of sustain electrodes (hereinafter referred to as "X electrodes") and scan electrodes arranged in the row direction. (Hereinafter referred to as 'Y electrode') (Y1-Yn). The X electrodes X1-Xn are formed corresponding to the respective Y electrodes Y1-Yn, and generally have one end connected in common to each other. The display panel 100 includes a substrate (not shown) on which the X and Y electrodes X 1 -X n and Y 1 -Y n are arranged, and a substrate (not shown) on which the address electrodes A 1 -A m are arranged. The two substrates are disposed to face each other with the discharge space therebetween so that the Y electrodes Y1-Yn and the address electrodes A1-Am and the X electrodes X1-Xn and the address electrodes A1-Am are orthogonal to each other. At this time, the discharge space at the intersection of the address electrodes A1-Am and the X and Y electrodes X1-Xn and Y1-Yn forms a discharge cell.

The controller 200 receives an image signal from the outside and outputs an address driving control signal, an X electrode driving control signal, and a Y electrode driving control signal. The controller 200 divides and drives one frame into a plurality of subfields, and each subfield is composed of a reset period, an address period, and a sustain period.

The address driver 300 receives an address drive control signal from the controller 200 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode A1-Am. The X electrode driver 400 receives the X electrode driving control signal from the controller 200 to apply a driving voltage to the X electrodes X1 to Xn, and the Y electrode driver 500 controls the Y electrode driving from the controller 200. The signal is received and a driving voltage is applied to the Y electrodes Y1-Yn.

An embodiment of the present invention proposes a reset driving circuit which applies a reset waveform by using a reactance current source such as an inductor or a transformer.

Hereinafter, a reset driving circuit according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3 and 4.

3 is a diagram illustrating a reset driving circuit according to a first embodiment of the present invention using an inductor.

As shown in FIG. 3, the reset driving circuit according to the first embodiment of the present invention is connected to the Y electrode of the display panel 100 and has a transistor M21, a transistor M22, an inductor L1, and a diode D1. ). The capacitive component is formed on the display panel 100 by the Y electrode, the X electrode, and the A electrode, and the capacitive component is referred to as a panel capacitor below.

One end of the inductor L1 is connected to the power supply DC, and the other end is connected to the drain of the transistor M21 and the transistor M22. The source of the transistor M21 is connected to the ground terminal, and the source of the transistor M22 is connected to the Y electrode of the display panel 100 through the diode D1. At this time, the diode D1 serves to prevent current backflow from the panel toward the reset driving circuit.

Referring to the operation of the circuit having such a configuration, the transistor M21 is first turned on in the reset period. Then, the initial current I ₀ is applied to the inductor L1 as shown in Equation 1 through the path of the power source DC, the inductor L1, and the transistor M21. As such, when the transistor M21 is turned off and the transistor M22 is turned on while the inductor L1 is boosted, the power source DC-inductor L1-transistor M22-diode D1-display panel 100 ), A resonance occurs between the inductor L1 and the panel capacitor so that a current I _L1 as shown in Equation 2 flows through the inductor L1. That is, the inductor _L1 operates as a current source for generating the current I _L1 of Equation 2. Therefore, due to this current, the voltage Vy of the panel capacitor gradually increases in the form of a sine function as shown in Equation (3). That is, as shown in Fig. 4, a reset waveform in the form of a sine function formed by LC resonance is applied to the Y electrode.

이며,

이다.Here, Vdc is the voltage supplied by the direct current power source (DC), Cp is the capacity of the panel capacitor,

Is,

to be.

In this case, the time taken for the voltage Vy of the Y electrode, which determines the average slope of the reset waveform, to increase from the initial voltage to the final voltage is determined by L1, Cp, and I ₀ as shown in Equations 2 and 3 below. However, since L1 and Cp are fixed values, the average slope of the reset waveform may be adjusted by the amount I ₀ of boosting the inductor L1 before turning on the transistor M22. In addition, the amount I ₀ of boosting current in the inductor L1 may be adjusted by the time for turning on the transistor M21.

5 is a diagram illustrating a reset driving circuit according to a second embodiment of the present invention using a transformer.

As shown in FIG. 5, the reset driving circuit according to the second embodiment of the present invention includes a transistor M3, a transformer Tx, an inductor L2, and a diode D2.

One end of the inductor L2 is connected to the power supply DC, and the other end is connected to the primary coil of the transformer Tx and the drain of the transistor M3. In addition, a diode D2 is connected to the secondary side of the transformer Tx to suppress the flow of current from the panel toward the reset driving circuit.

Referring to the operation of the circuit having such a configuration, the transistor M3 is first turned on in the reset period. Then, the initial current is applied to the inductor L2 through the path of the power source DC, inductor L2, and transistor M3. As such, when the transistor M3 is turned off while the inductor L2 is boosted, a current path is formed between the inductor L2 and the primary coil of the transformer Tx and the current charged in the inductor L2 is transformed into the transformer Tx. The secondary coil is transferred to the secondary coil through the primary coil, and resonance occurs between the secondary coil and the panel capacitor. In other words, the transformer Tx operates as a current source for generating current. Therefore, a reset waveform in the form of a sine function formed by LC resonance is applied to this current.

In this case, the average slope of the reset waveform applied to the display panel is determined by the amount of current flowing through the secondary coil, and the amount of current flowing through the secondary coil is equal to the amount of current flowing through the inductor L2 and the winding ratio of the transformer Tx. Can be adjusted. In addition, the amount of current in the inductor L2 is adjustable by the time for turning on the transistor M3.

As described above, according to the first and second embodiments of the present invention, since the reset waveform applying circuit is driven by the operation of the reactance elements such as the inductor and the transformer, and the switching element, less loss occurs than the conventional circuit. In addition, it is possible to efficiently adjust the slope of the reset waveform by controlling the size of the current source for applying the reset voltage.

Next, a method of controlling the slope of the reset waveform in the reset driving circuits described in the first and second embodiments of the present invention will be described.

In the reset driving circuits according to the first and second embodiments of the present invention, the slope of the reset waveform can be more efficiently controlled by controlling the transistor applying the initial current to the inductor in the PWM (Pulse Width Modulation) method.

FIG. 6 illustrates a reset driving circuit according to a third exemplary embodiment of the present invention including a tilt controller for controlling a slope of a reset waveform in the circuit of FIG. 3.

As shown in FIG. 6, the reset driving circuit according to the third embodiment of the present invention includes a reset waveform generator 610 and a tilt controller 620.

Since the configuration of the reset waveform generation unit 610 is the same as that of the reset driving circuit according to the first embodiment of the present invention shown in FIG.

In addition, the tilt adjusting unit 620 according to the embodiment of the present invention includes a PWM generator 621 and a comparator 622.

The inverting input terminal (-) of the comparator 622 is connected to the output terminal of the reset driver 610 connected to the panel, and a waveform having a reference slope is applied to the non-inverting input terminal (+). In addition, the output of the comparator 622 is input to the PWM generator 621, the PWM generator 621 controls the on-off operation of the transistor M41 in accordance with the output of the comparator 622.

The operation of the reset driving circuit according to the third embodiment of the present invention is as follows.

The comparator 622 senses the reset voltage input to the panel, receives the voltage as the inverting input terminal (-), and compares the voltage with the reference voltage ref input to the non-inverting input terminal (+). As a result of the comparison, if the voltage of the inverting input terminal (-) is less than the voltage of the non-inverting input terminal (+), that is, if the reset voltage input to the panel is less than the reference voltage, a high level signal is output. If the voltage of V is smaller than the voltage of the inverting input terminal, that is, if the reset voltage input to the panel is greater than the reference voltage, a low level signal is output.

The PWM generator 621 outputs a pulse having a constant duty ratio to the gate of the transistor M41, whereby the transistor M41 repeats the on / off operation. That is, the PWM generator 521 increases the duty ratio of the output clock pulse when the high level signal is input from the comparator 622, and increases the duty ratio of the output clock pulse when the low level signal is input from the comparator 622. Decrease. When the duty ratio of the clock pulse increases, the amount of initial current applied to the inductor L3 increases. When the duty ratio of the clock pulse decreases, the amount of the initial current applied to the inductor L3 decreases. As described above, the initial current value of the inductor L3 is adjusted by the switching of the transistor M41, thereby adjusting the magnitude of the output voltage, that is, the slope of the reset waveform.

Meanwhile, FIG. 7 illustrates a reset driving circuit according to a fourth embodiment of the present invention including a tilt controller for controlling the slope of the reset waveform in the circuit of FIG. 5.

As shown in FIG. 7, the reset driving circuit according to the fourth embodiment of the present invention includes a reset waveform generator 710 and a tilt controller 720.

The configuration of the reset waveform generator 710 is the same as that of the reset driving circuit according to the second embodiment of the present invention shown in FIG. 5, and the tilt controller 720 is different from the tilt controller 620 of FIG. 6. The same description is omitted since it is the same.

The output of the comparator 722 is input to the PWM generator 721 and the PWM generator 721 controls the on / off operation of the transistor M5 according to the output of the comparator 722.

The operation of the reset driving circuit according to the fourth embodiment of the present invention is as follows.

The PWM generator 721 outputs a pulse having a constant duty ratio to the gate of the transistor M5, and the transistor M5 repeats the on / off operation by this pulse. That is, the PWM generator 721 increases the duty ratio of the output clock pulse when the high level signal is input from the comparator 722, and increases the duty ratio of the output clock pulse when the low level signal is input from the comparator 722. Decrease. Increasing the duty ratio of the clock pulse increases the amount of current delivered from the primary coil of the transformer to the secondary coil, and decreasing the duty ratio of the clock pulse decreases the amount of current delivered from the primary coil of the transformer to the secondary coil. do. In this way, the amount of current delivered to the secondary coil by the switching of the transistor M5 is adjusted, thereby adjusting the magnitude of the output voltage, that is, the slope of the reset waveform.

In this case, the reset waveform may be more effectively controlled by applying various types of waveforms as reference voltages input to the non-inverting input terminal (+) of the comparator 622 and the comparator 722.

Meanwhile, in the exemplary embodiment of the present invention, one end of the transistor used to apply the initial current to the inductor is connected to the ground terminal, but other power sources other than the ground power source may be used.

In addition, the reset driving circuit according to the exemplary embodiment of the present invention described above has been described taking a circuit for generating a rising reset waveform as an example. In order to generate the falling reset waveform, one end of a transistor used to apply an initial current may be connected to a ground terminal. Instead, it is connected to a power supply for supplying a predetermined voltage, and one end of the inductor is connected to a ground terminal instead of a DC power supply. In this case, the diode connected to the display panel is formed in the opposite direction to the rising reset driving circuit.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various other modifications and changes are possible.

That is, by forming a current source using other reactance elements other than the inductor and the transformer, and controlling the magnitude of the current source, it is possible to configure a reset driving circuit capable of adjusting the inclination.

As described above, according to the present invention, since the reset waveform applying circuit is driven by the operation of the reactance element and the switching element without using a lamp switch, less loss occurs than the conventional circuit. In addition, since the inclination of the reset waveform can be efficiently controlled by controlling the size of the current source for applying the reset voltage, it is advantageous for weak discharge control.

In addition, the reset waveform applied to the panel is fed back, and the slope of the reset waveform is adjusted according to the result of comparing the voltage with the reference voltage, so that the reset waveform can be more effectively controlled.

Claims (14)

A driving apparatus for applying a reset waveform to an electrode of a plasma display panel, A first power supply for supplying a first voltage, A current source for generating current using the voltage and reactance components from the first power source, and Control unit for outputting a signal for controlling the magnitude of the current generated from the current source by comparing the reset waveform and the reference waveform Including; Generating the reset waveform by gradually changing the voltage of the electrode from the first voltage to the second voltage using the current from the current source. Driving device of plasma display panel. The method of claim 1, The current source is A first transistor having a first end connected to the electrode; A second transistor having a first end connected to a second end of the first transistor and a second end connected to a second power supply for supplying a fourth voltage; And An inductor having one end connected to a contact point of the first and second transistors and the other end connected to the first power source Driving apparatus for a plasma display panel comprising a. The method of claim 2, Changing the voltage of the electrode by causing resonance between the inductor and the electrode through a current path formed by turning on the first transistor Driving device of plasma display panel. The method of claim 3, Before turning on the first transistor, a current is injected into the inductor through a current path formed by turning on the second transistor. Driving device of plasma display panel. The method of claim 4, wherein Adjusting the turn-on time of the first transistor to adjust the amount of current injected into the inductor to adjust the slope of the reset waveform Driving device of plasma display panel. The method of claim 1, The current source is A transformer having a primary coil connected to the first power supply and a secondary coil connected to the electrode; An inductor connected in parallel with the primary coil; And A transistor connected to a first terminal of the primary coil and an inductor, and a second terminal of the transistor to a second power supply for supplying a second voltage; Driving apparatus for a plasma display panel comprising a. The method of claim 6, Injecting current into the inductor through a current path formed by turning on the transistor, and transfers the current injected into the inductor through the primary coil to the secondary coil Driving device of plasma display panel. The method of claim 7, wherein Adjusting the turn-on time of the transistor and the turns ratio of the transformer to control the slope of the reset waveform Driving device of plasma display panel. The method of claim 1, The control unit, A comparator for inputting a waveform applied from the current source to the electrode to an inverting terminal and a waveform having the reference slope to a non-inverting terminal; And A PWM generator which outputs a pulse signal for controlling on / off of the transistor and adjusts a duty ratio of the output pulse signal according to a signal input from the comparator Driving apparatus for a plasma display panel comprising a. The method of claim 9, The PWM generation unit, When the high level signal is input from the comparator, the duty ratio of the output pulse signal is increased. When the low level signal is input from the comparator, the duty ratio of the output pulse signal is decreased. Driving apparatus for a plasma display panel comprising a. The method according to any one of claims 1, 2 or 6, And a diode connected between the current source and the electrode to control the direction of the current. Driving device of plasma display panel. A driving method comprising a switching element, and applying a reset waveform to an electrode of a plasma display panel through a current source for supplying current using a reactance, the driving method comprising: a) applying a reset waveform to the electrode through a current path formed by turning on the switching element; b) measuring a reset waveform applied to the electrode; c) comparing the slope of the measured reset waveform with the slope of a preset reference reset waveform; d) outputting a signal for controlling on / off of the switching element according to the comparison result; And e) adjusting the slope of the reset waveform by turning on the switching element according to the output control signal; Method of driving a plasma display panel comprising a. The method of claim 12, Step d), Adjusting and outputting the duty ratio of the pulse signal according to the comparison result A method of driving a plasma display panel. The method of claim 12, Repeating steps a) to e) until the slope of the reset waveform applied to the electrode is substantially equal to the slope of the reference reset waveform. A method of driving a plasma display panel.

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