KR20080044086A - Plasma display and power supply apparatus thereof - Google Patents

Abstract

A plasma display device and a power supply device thereof are provided to suppress a spiking phenomenon by using a photo coupler instead of turning on/off a relay according to a power on/off signal. A power supply unit(621) includes a first switch and supplies power to a second coil in a secondary unit of a transformer according to the operation of the switch. The first switch is coupled with a first coil in a primary unit of the transformer. An output terminal(623) includes a first capacitor, whose first terminal is electrically connected to the second coil, and outputs a voltage across both ends of the first capacitor. A switch controller(622) controls on-time of the first switch according to output load of the output terminal, while a bias voltage is supplied. When a power on signal is applied, a bias voltage supply unit(624) supplies the bias voltage to the switch controller so that the first switch is activated. When a power off signal is applied, the bias voltage supply unit prevents the bias voltage from being supplied to the switch controller so that the first switch is deactivated.

Description

Plasma display device and power supply thereof {PLASMA DISPLAY AND POWER SUPPLY APPARATUS THEREOF}

1 is a view schematically illustrating a configuration of a power supply device of a conventional plasma display device.

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

3 is a diagram illustrating an internal configuration of a power supply unit 600 according to an embodiment of the present invention.

4 illustrates a structure of a DC-DC converter included in a power supply unit according to an exemplary embodiment of the present invention.

The present invention relates to a plasma display device and a power supply thereof.

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.

Plasma display devices require a high voltage and high power power source to generate plasma, and thus the role of the power supply device is just as important.

The power supply used in such a plasma display device requires various power outputs for discharging, and includes a power supply for supplying an image power for operating as a display and a voltage for discharging.

1 is a view schematically illustrating a configuration of a power supply device of a conventional plasma display device.

As shown in FIG. 1, a conventional power supply device includes bridge diodes BD1 and BD2, a relay switch RELAY, capacitors C1 and C2, a power factor correction unit PFC, and a standby unit connected to an AC power source. STB).

The power supply device having such a configuration maintains a state in which the relay switch REALY switch is turned off in the standby state before AC power is applied and image data is output to the panel. Therefore, the AC power input is full-wave rectified through the bridge diode BD2, and this power is charged in the capacitor C2 and input to the standby unit STB. The standby unit STB converts the input power into a DC power source for driving a microcomputer (not shown) of the imaging unit, and the microcomputer of the imaging unit receiving the output signal of the standby unit STB maintains the system in a standby state.

In addition, when a relay on signal is applied from the outside, the relay switch RELAY is turned on. Accordingly, the AC power supplies the AC power rectified through the bridge diode BD1 to the input power of the power factor correction unit PFC. The power factor correction unit PFC converts the input AC power into DC and compensates the power factor and outputs the power factor. The output of the power factor correction unit PFC is input to each unit for supplying power for driving the plasma display device.

In such a conventional power supply, the relay switch RELAY is turned on / off by a remote controller or other power on signal. However, when the relay switch is turned on / off by the remote controller or the power on signal, the contact sound is loud. . In addition, when the relay switch RELAY is repeatedly turned on / off for a long time, there is a problem in that a spike occurs and the contact becomes unstable.

SUMMARY OF THE INVENTION The present invention provides a plasma display device and a power supply thereof capable of preventing contact sound and spikes caused by on / off of a relay switch.

According to a feature of the invention, there is provided a power supply of the plasma display device including a power supply, an output terminal, a switch controller and a bias voltage supply. The power supply unit includes a first switch coupled to the first coil on the primary side of the transformer for converting the input DC voltage, and supplies power to the second coil on the secondary side of the transformer according to the operation of the switch. The output terminal includes a first capacitor having a first end electrically connected to the second coil, and outputs a voltage across both ends of the first capacitor. The switch controller controls the on time of the first switch according to the output load of the output terminal while the bias voltage is supplied. The bias voltage supply unit supplies the bias voltage to the switch controller when the power on signal is input, and operates the first switch. When the power off signal is input, the bias voltage supply unit does not supply the bias voltage to the switch controller to operate the first switch. Do not.

According to another feature of the present invention, a plasma display device including a plasma display panel, a driver, and a power supply is supplied. The plasma display panel includes a plurality of row electrodes and a plurality of column electrodes. The driver applies a driving signal to the row electrode and the column electrode. The power supply unit supplies power to the drive unit. More specifically, the power supply unit includes a first switch coupled to the first coil on the primary side of the transformer for converting the input DC voltage, and supplies power to the second coil on the secondary side of the transformer according to the operation of the switch. A power supply unit and a first capacitor electrically connected to the second coil at a first end, and outputting a voltage across both ends of the first capacitor, in a state in which a bias voltage is supplied, an output load of the output end. A switch controller for controlling the on time of the first switch according to the present invention, and when a power on signal is input, a bias voltage is supplied to the switch controller to operate the first switch, and when a power off signal is input, a bias voltage is supplied to the switch controller. And a bias voltage supply that does not operate the first switch and does not operate the first switch.

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. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification. In addition, when any part of the specification "includes" a certain component, this means that it may further include other components, without excluding other components unless otherwise stated.

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

As shown in FIG. 2, a plasma display device according to an exemplary embodiment of the present invention includes a plasma display panel 100, a controller 200, an address electrode driver 300, a scan electrode driver 400, a sustain electrode driver 500, and the like. And a power supply unit 600.

The plasma display panel 100 includes a plurality of address electrodes A1 to Am extending in the column direction, and a plurality of sustain electrodes X1 to Xn and scan electrodes Y1 to Yn extending in pairs in the row direction. Include. The sustain electrodes X1 to Xn are formed corresponding to the scan electrodes Y1 to Yn, and the display electrodes X1 to Xn and the scan electrodes Y1 to Yn perform display operations for displaying images in the sustain period. To perform. The address electrodes A1 to Am are disposed to be orthogonal to the sustain electrodes X1 to Xn and the scan electrodes Y1 to Yn. At this time, the discharge space at the intersection of the address electrodes A1 to Am, the scan electrodes Y1 to Yn, and the sustain electrodes X1 to Xn forms the cell 12. The structure of the plasma display panel 100 is an example, and a panel having another structure to which the driving method described below may be applied may also be applied to the present invention.

The controller 200 receives an image signal from the outside and outputs an address electrode driving control signal, a sustain electrode driving control signal, and a scan electrode driving control signal. The controller 200 divides and drives one frame into a plurality of subfields. At this time, each subfield is composed of a reset period, an address period, and a sustain period when expressed as a temporal operation change.

The address driver 300 receives an address electrode driving control signal from the controller 200 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode.

The scan electrode driver 400 receives a scan electrode driving control signal from the controller 200 and applies a driving voltage to the scan electrode.

The sustain electrode driver 500 receives the sustain electrode driving control signal from the controller 200 and applies a driving voltage to the sustain electrode.

The power supply unit 600 supplies voltages and currents of a predetermined size to each of the driving units 300, 400, and 500, the control unit 200, and the plasma display panel 100.

3 is a block diagram schematically illustrating an internal configuration of a power supply unit 600 according to an embodiment of the present invention.

As shown in FIG. 3, the power supply unit 600 according to the embodiment of the present invention includes a bridge diode BD3 and BD4, capacitors C3 and C4, a power factor correction unit (PFC) 620, a voltage generator 640, and the like. A standby unit (STB) 660 is included.

The input AC power is full-wave rectified through the bridge diode BD3, and this power is charged in the capacitor C3 and input to the power factor correction unit 620. The power factor correction unit 620 compensates for the power factor of the input voltage and outputs the compensated power factor to the voltage generator 640. The voltage generator 640 includes a plurality of DC-DC converters. The voltage generator 640 receives a voltage output from the power factor correction unit 620 and uses a plurality of DC voltages Vs, which are used in the plasma display device. Va, 15V, and 5V are generated and supplied to each of the driving units 300, 400, and 500. The standby unit 660 receives the voltage charged in the capacitor C4 and generates and outputs standby voltages 5V and 9V.

Meanwhile, the power factor correction unit 620, the voltage generator 640, and the standby unit 660 each include a switch and a switch width controller (Pulse Width Modulator Integrated Circuit, PWM IC) to generate and supply a predetermined voltage. . Here, the switch control unit (PWM IC) according to an embodiment of the present invention is not fixed to the switching frequency, but varies depending on the output load (load).

Hereinafter, for convenience, one DC-DC converter included in the power factor correction unit 620 will be described as an example, and it can be applied to the voltage generator 640 and the standby unit 660 as well. The configuration and operation of the DC-DC converter included in the power supply unit 600 according to the embodiment of the present invention will be described in detail with reference to FIG. 4.

4 is a diagram illustrating an internal configuration of a DC-DC converter included in the power supply unit 600 according to an embodiment of the present invention.

As shown in FIG. 4, the DC-DC converter according to the embodiment of the present invention includes a power supply unit 621, a switch control unit 622, an output terminal 623, and a bias voltage supply unit 624. Although FIG. 4 shows that one coil is formed on the secondary side of the transformer TX, more DC voltages can be output by adding a coil to the secondary side.

The power supply unit 621 includes a primary coil L1 of a transformer TX having one end connected to the capacitor C3 and a switch Q connected to the primary coil L1. The power supply unit 621 supplies power to the secondary side of the transformer, that is, the output terminal 623 according to the on time Duty of the switch Q.

The switch control unit 622 may be generally implemented through an IC, and controls the on time Duty of the switch Q of the power supply unit 621 according to the output load of the output terminal 623. At this time, in order for the switch controller 622 to operate, the bias voltage Vcc must be supplied from the bias voltage supply unit 624. That is, when the output load of the output terminal 623 increases while the bias voltage Vcc is supplied from the bias voltage supply unit 624, the switch controller 622 indicates that the output voltage Vo is decreased by the output load. To compensate, increase the on time of switch Q. On the contrary, when the output load of the output terminal 623 decreases while the bias voltage Vcc is supplied, the switch controller 622 sets the on time of the switch Q to prevent the output voltage Vo from increasing. Decrease.

The output terminal 623 includes a diode D1 having an anode connected to the secondary coil L2 of the transformer and a secondary coil L2 of the transformer, and a capacitor C5 connected between the cathode of the diode D2 and ground. Include. At this time, the voltage charged in the capacitor C5 is the output voltage Vo of the output terminal 623.

The bias voltage supply unit 624 includes a capacitor C6, a photo coupler PC, and a photo coupler controller 50 (hereinafter, referred to as a “PC controller”).

The capacitor C6 is charged with the bias voltage Vcc. Here, the bias voltage Vcc may be charged in the capacitor C6 in various ways. For example, the bias voltage Vcc may be charged to the capacitor C6 by using a standby voltage (not shown) generated in the standby state before the power ON signal is input. Also, by adding a secondary coil corresponding to the primary coil of the power supply unit 621 (not shown), the bias voltage Vcc may be charged to the capacitor C6 using a voltage derived from the added secondary coil. Can be.

The photo coupler PC includes a light emitting diode D2 having one end connected to the PC controller, and a light receiving transistor Q2 having one end connected to a contact point of the capacitor C6 and the switch controller 50. When a voltage is applied to the light emitting diode D2, light is generated, and the generated light is introduced into the light receiving transistor Q2 to turn on the light receiving transistor Q2. On the contrary, since no light is generated when no voltage is applied to the light emitting diode D2, the light receiving transistor Q2 is turned off.

The PC controller 50 does not apply a voltage to the light emitting diode D2 of the photo coupler PC when a power ON signal is input from a remote controller or other means. On the contrary, when a power OFF signal is input, a voltage is applied to the light emitting diode D2 of the photo coupler PC.

Looking at the operation of the DC-DC converter according to an embodiment of the present invention having such a configuration, when a power on signal (power ON signal) is applied from a remote control or other means (PC) controller 50 is a light emitting diode of the photo coupler (PC) No voltage is applied to (D2). As a result, no light is generated in the light emitting diode D2 and the light receiving transistor Q2 is turned off. When the light receiving transistor Q2 is turned off, the bias voltage Vcc charged in the capacitor C6 is supplied to the switch controller 622. Accordingly, the switch controller 622 regulates the output voltage Vo of the output terminal 623 to a predetermined voltage by adjusting the on time Duty of the switch Q1 according to the output load of the output terminal 623.

On the contrary, when a power OFF signal is applied from the remote controller or other means, the PC controller 50 applies a voltage to the light emitting diode D2 of the photo coupler PC. Then, light is generated in the light emitting diode D2 and the light receiving transistor Q2 is turned on. When light receiving transistor Q2 is turned on, a current path is formed from capacitor C6 to light receiving transistor Q2. By this current path, the bias voltage Vcc that has been charged in the capacitor C6 is discharged. Therefore, since the bias voltage Vcc is not supplied to the switch controller 622, the switch controller 622 cannot operate the switch Q1. Since the switch Q1 does not operate, no power is supplied to the secondary coil L2 of the transformer TX, and no voltage is output to the output terminal 623.

Conventionally, an AC voltage AC is generated according to a power ON / OFF signal by using a relay (shown in FIG. 1) located between the AC voltage AC and the bridge diode BD3. Supply to the power factor correction unit 620 is mechanically connected or blocked. At this time, the AC voltage (AC) is a high voltage of about 220V, the relay (RELAY) by blocking or supplying a high voltage, the contact sound when the relay (RELAY) on / off loud or spike phenomenon occurred.

However, according to the exemplary embodiment of the present invention, the voltage is charged to the capacitor C3 through the bridge diode BD3 before the power ON / OFF signal is input. Then, the photocoupler PC is operated by the bias voltage supply unit 624 to connect or block the supply of the bias voltage Vcc to the switch controller 622 according to the power on / off signal. That is, in the present invention, by controlling the operation of the switch Q1 by connecting or disconnecting the bias voltage supplied to the switch controller 622, the voltage of the power supply unit 621 is induced or interrupted to the output terminal 623.

Here, the voltage for operating the photo coupler PC when the power-on signal is input is a low voltage of approximately 5V, which is a considerably lower voltage than the relay RELAY. Therefore, when using a photo coupler (PC) instead of a relay (RELAY), by blocking the output of the alternating voltage (AC) to the output terminal at a low voltage, there is no contact sound and the spike does not occur can reduce the failure rate .

Although the 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, in the present invention, by using the photo coupler (PC) instead of the relay on / off according to the power on / off signal (power ON / OFF signal), there is no contact sound and the spike phenomenon occurs The failure rate can be reduced.

Claims (12)

A first switch coupled to the first coil on the primary side of the transformer for converting the input DC voltage, the power supply unit supplying power to the second coil on the secondary side of the transformer according to the operation of the switch; An output terminal including a first capacitor having a first end electrically connected to the second coil, and outputting a voltage across both ends of the first capacitor, A switch controller which controls an on time of the first switch according to an output load of the output terminal in a state where a bias voltage is supplied, and When a power on signal is input, a bias voltage is supplied to the switch controller to operate the first switch. When a power off signal is input, a bias voltage is not supplied to the switch controller so that the bias switch does not operate the first switch. A power supply for a plasma display device comprising a portion. The method of claim 1, The bias voltage supply unit, A second capacitor charged with a bias voltage, A second switch having a first end connected to the first capacitor, and The second switch is connected to a second end of the second switch, and when the power on signal is input, the voltage is not output. A power supply device for a plasma display device including a second switch controller. The method of claim 2, And the second switch is a photo coupler having one end of a light receiving transistor connected to a first capacitor and an anode of a second diode connected to the second switch controller. The method of claim 2, When the second switch is turned off, the bias voltage charged in the second capacitor is supplied to the switch controller, and when the second switch is turned on, the bias voltage charged in the second capacitor is discharged through the second switch. Power supply of plasma display device. The method of claim 3, When the voltage is output from the second switch controller, the second diode of the photo coupler emits light, and the light receiving transistor is turned on. If the voltage is not output from the second switch controller, the second diode of the photo coupler does not emit light. A power supply of a plasma display device in which a light receiving transistor is turned off. The method of claim 3, The bias voltage charged in the second capacitor is discharged through the transistor when the light receiving transistor is turned on, and the bias voltage charged in the second capacitor is supplied to the switch controller when the light receiving transistor is turned off. Power supply of the device. A plasma display panel including a plurality of row electrodes and a plurality of column electrodes, A driving unit applying a driving signal to the row electrode and the column electrode, and It includes a power supply for supplying power to the drive unit, The power supply unit, A first switch coupled to the first coil on the primary side of the transformer for converting the input DC voltage, the power supply unit supplying power to the second coil on the secondary side of the transformer according to the operation of the switch; An output terminal including a first capacitor having a first end electrically connected to the second coil, and outputting a voltage across both ends of the first capacitor, A switch controller which controls an on time of the first switch according to an output load of the output terminal in a state where a bias voltage is supplied, and When a power on signal is input, a bias voltage is supplied to the switch controller to operate the first switch. When a power off signal is input, a bias voltage is not supplied to the switch controller so that the bias switch does not operate the first switch. A plasma display device comprising a portion. The method of claim 7, wherein When the power on signal is input, power of the power supply unit is induced to the output terminal, and thus power is not supplied from the power supply unit to the driving unit. The method of claim 7, wherein When the power off signal is input, power of the power supply unit is not induced to the output terminal, and thus power is not supplied from the power supply unit to the driving unit. The method of claim 7, wherein The bias voltage supply unit, A second capacitor charged with a bias voltage, A photo coupler (PC) controller for outputting a voltage when the power-off signal is input without outputting a voltage when the power-on signal is input, and And a photo coupler having one end of a second switch connected to the first capacitor and an anode of a second diode connected to the photo coupler controller. The method according to claim 7 or 10, And a second diode of the photo coupler emits light when the voltage is output from the photo coupler controller so that the second switch of the photo coupler is turned on. The method according to claim 7 or 10, When the second switch is turned on, the voltage charged in the second capacitor is discharged through the second switch, and when the second switch is turned off, the plasma display supplies the voltage charged in the second capacitor to the switch controller. Device.

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