KR100501696B1 - Display device having cathod ray tube and Method for protecting the same - Google Patents

Abstract

Disclosed are a display device employing a CRT and a protection method thereof. The display apparatus detects occurrence of retrace from an AKB (Auto kine bias) signal. If it is determined that the occurrence of retrace occurs more than a predetermined number of times within a predetermined time, the commercial power supplied to the device is cut off and the power is turned off. At this time, the occurrence of retrace is determined through the instability of the IK from the AKB. If a return occurs even once in the normal operation state, the AKB error is displayed through the OSD. Accordingly, when the beam is excessively generated within a predetermined time and the return is continuously generated, the power of the device is cut off, thereby eliminating the risk of combustion due to the overheating of the high voltage transformer and the FBT.

Description

Display device having cathod ray tube and Method for protecting the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device and a method of protecting the same, and more particularly, to a display device employing a cathode ray tube (CRT) for forming an image on an image display surface using high pressure and a method of protecting the same.

In general, a display device employing a CRT is configured to form an image by emitting an electron beam corresponding to an image signal from an electron gun to emit a fluorescent material provided inside the image display surface. At this time, the electron beam is accelerated by the high pressure to reach the fluorescent surface, the display device is designed to supply a high pressure.

1 is a block diagram schematically illustrating a high pressure supply structure of a conventional display device. The display device includes a main block 110, a horizontal driving unit 120, a high pressure control circuit unit 130, a flyback transformer (FBT 140), a high pressure feedback unit 150, and a CRT (Cathode Ray Tube) driving unit. 160, and a controller 170.

The main block 110 performs various signal processing such as reception and processing of a video signal. At this time, the signal is changed to fit the CRT and output to the CRT, and performs signal processing such as a power control unit, a vertical and horizontal control circuit, and a screen control function through an OSD (on screen display).

The horizontal driver 120 generates a high voltage driving pulse by receiving a driving signal while the power is turned on in the main block 110.

The high pressure control circuit unit 130 operates to supply stable power to the CRT according to the high pressure driving pulse generated from the horizontal driving unit 120. The high voltage control circuit 130 includes a pulse width modulation (PWM) control unit 132, a PWM output unit 134, a high voltage output unit 136, and a high voltage transformer 138.

The FBT 140 rectifies the pulse voltage transmitted from the high voltage control circuit 130 and supplies it to the CRT driving unit.

The high pressure feedback circuit unit 150 detects the high pressure output from the FBT 140 and feeds it back to the high pressure control circuit unit 130.

The CRT driving unit 150 drives the CRT by the high pressure supplied from the FBT 140.

The controller 170 controls the overall display apparatus.

When the display device is powered on, the control unit compares the reference AKB (Auto kine bias) pulse with the AKB pulse fed back from the CRT driver and controls the main block to generate a return when it is determined that there is no feedback AKB pulse. do. In addition, a return occurs even when no power supply voltage is supplied to the CRT driving IC.

However, the conventional display device has a problem that the high-voltage transformer and the FBT may be burned because the electron beam is excessively output and the high-voltage surge is not designed for the protection operation. That is, in the absence of the AKB feedback signal, the screen state is retraced due to excessive electron beam, but the screen continues to operate, and the high-voltage control circuit unit also performs high-voltage feedback due to the excessive high-voltage current. There was a problem that can be burned due to overheating.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device employing a cathode ray tube that can protect a device from overheating when there is no AKB signal in order to solve the above problems, and a control method thereof.

The display device of the present invention for achieving the above object, the flyback transformer for outputting a driving power of a predetermined size, using the drive power output from the flyback transformer to drive the CRT, the electron beam output from the CRT And a control unit which cuts off the driving power when the AKB feedback signal is not detected from the CRT driving unit for a predetermined time period. If it is determined that the IK detected from the AKB feedback signal is in an unstable state, it may be determined that recursion has occurred. More preferably, the display device may further include an OSD for displaying information about the device on a screen. Can be. In this case, if it is determined that the IK is unstable even once during the normal display operation, the controller may control the OSD to display the AKB error on the screen for a predetermined time. Meanwhile, according to an embodiment of the present invention, The overheat protection method of the display apparatus may include driving a CRT by inputting a driving power having a predetermined size, detecting a predetermined AKB feedback signal corresponding to an electron beam output from the CRT, and transmitting the AKB feedback signal for a predetermined time. And if it is not detected during the operation, determining to shut down the driving power. Preferably, determining whether the IK detected from the AKB feedback signal is in an unstable state, and if the IK is in an unstable state, a return occurs. The method may further include shutting down the driving power. If it is determined that the instability state, it may further comprise the step of displaying the AKB error on the screen for a predetermined time.

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

2 is a schematic block diagram of a display device according to the present invention. The display device includes a main block 210, a horizontal driving unit 220, a high pressure control circuit 230, a flyback transformer (FBT 240), a high pressure error feedback unit 250, and a CRT (Cathode Ray Tube). The driver 260 and the controller 270 are included.

The main block 210 performs various signal processing such as reception and processing of a video signal. At this time, the signal is changed to fit the CRT and output to the CRT, and performs the screen control function through the power supply, vertical, horizontal CONTROL circuit, OSD (on screen display).

The horizontal driver 220 generates a high voltage driving pulse by receiving a driving signal while the power is turned on in the main block 110.

The high pressure control circuit 230 operates to supply stable power to the CRT according to the high voltage driving pulse generated from the horizontal driver 220. The high voltage control circuit 230 includes a pulse width modulation (PWM) controller 232, a PWM output unit 234, a high voltage output unit 236, and a high voltage transformer 238.

The FBT 240 rectifies and supplies the high pressure pulse transmitted from the high pressure control circuit 230 to the CRT driver 260.

The high pressure error feedback unit 250 detects the high pressure output from the FBT 240 and feeds it back to the high pressure control circuit 230.

The CRT drive unit 260 drives the CRT by the drive power supplied from the FBT 240.

The control unit 270 controls the system as a whole. In particular, when the power is turned on, the control unit 270 generates a reference AKB signal ref AKB, and compares it with the AKB feedback signal AKB F / B fed back from the CRT driver 260. If it is determined that there is no AKB feedback signal (AKB F / B), the main block 210 is controlled to generate a return. In addition, the state of IK is checked from the AKB feedback signal AKB F / B, and if a predetermined number of times of instability is detected within a predetermined time, the commercial power supplied to the display device is cut off.

When the display device is powered on, the controller 270 generates a reference AKB signal ref AKB, and drives the horizontal driver 220 through the main block 210. Then, the horizontal driving unit 220 outputs a high pressure driving pulse to the high voltage output unit 236 in response to the drive signal output from the main block 210, the high voltage output unit 236 is a high voltage transformer according to the high voltage driving pulse signal ( 238 is driven to output a high pressure pulse to the FBT (240). Then, the FBT 240 rectifies the transmitted high pressure pulse and outputs a high pressure to the CRT driver 260 so that the electron beam generated from the electron gun can reach the fluorescent surface. At this time, the high voltage error feedback unit 250 detects the high pressure output from the FBT 240 and transmits it to the PWM control unit 232 of the high voltage control circuit unit 230, and the PWM control unit 232 PWM according to the feedback high voltage signal The output unit 234 is controlled so that a stable high pressure pulse can be transmitted from the high pressure transformer 238 to the FBT 240.

On the other hand, the CRT driver 260 supplied with the high pressure from the FBT 240 outputs the AKB feedback signal (AKB F / B) to the main block 210 in accordance with the electron beam output from the electron gun, and the control unit 270 is the main When the AKB feedback signal AKB F / B outputted to the block 210 is compared with the generated reference AKB (ref AKB) signal, and it is determined that there is no AKB feedback signal (AKB F / B), the main block (A) may be returned. 210 is controlled.

When the AKB feedback signal AKB F / B does not exist as described above, the screen state is a state in which an electron beam is excessively output, and the screen continuously generates a blank. In addition, the high pressure control circuit 230 continuously performs the high pressure feedback operation. At this time, heat is generated in the high voltage transformer 238 and the FBT 240 by driving the high voltage transformer 238 by the high pressure feedback operation. In order to eliminate the risk of combustion due to overheating, the control unit 270 controls the AKB feedback signal. If a predetermined number of times retrace occurs within a predetermined time from (AKB F / B), the device is turned off. In this case, the controller 270 may turn off the power by stopping the driving of the horizontal driver 220 through the main block 210. On the other hand, the case where the state of IK is unstable is determined as the retrace generation signal.

FIG. 3 is a flowchart illustrating a protection operation against occurrence of overheating of the display apparatus shown in FIG. 2. First, when the power is turned on and the display operation is performed by the CRT driver 260, the controller 270 detects the AKB feedback signal AKB F / B through the main block 210 (S310). When an instability of IK is detected from the AKB feedback signal (AKB F / B) (S320), an AKB error is displayed on the screen through OSD control of the main block 210 (S330). When the instability state of IK continuously occurs for a predetermined number of times (for example, ten times) within a predetermined time (for example, 10 seconds) (S340), the device is turned off (S350).

Herein, the control unit 270 displays the AKB error through the OSD control even when the instability state of the IK occurs only once within a predetermined time. In addition, when an instability state of the IK is detected less than a predetermined number of times within a predetermined time, it is controlled to perform normal display operation again.

According to the display device and the overheat protection method of the display device of the present invention as described above, when the beam is excessively generated within a predetermined time and the return is continuously generated, the power of the device is cut off, so that the high voltage transformer and the FBT are overheated. It is possible to eliminate the risk of combustion by.

Although the above has been shown and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, it is usually in the art to which the invention belongs without departing from the spirit of the invention claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

1 is a block diagram showing a high pressure supply structure of a conventional display device;

2 is a schematic block diagram of a display apparatus according to an embodiment of the present invention, and

FIG. 3 is a flowchart illustrating a method for protecting overheating of the display apparatus shown in FIG. 2.

* Description of the symbols for the main parts of the drawings *

110, 210: main block 120, 220: horizontal drive unit

130, 230: high voltage control circuit section 132, 232: PWM control unit

134, 234: PWM output section 136, 236: high voltage output section

138, 238: High voltage transformer 140, 240: FBT (Flyback Transformer)

150, 250: high pressure error feedback unit 160, 260: CRT drive unit

170, 270: control unit

Claims (6)

In a display device employing a CRT (Cathode Ray Tube), A horizontal driving unit for outputting a predetermined high pressure driving pulse signal; A high pressure control circuit unit outputting a high pressure pulse in accordance with the high pressure driving pulse signal; A flyback transformer for rectifying the high voltage pulse and outputting a predetermined driving power; A CRT driver which drives the CRT using a driving power output from the flyback transformer and outputs a predetermined AKB feedback signal corresponding to the electron beam output from the CRT; And, And a controller which controls the high voltage driving pulse signal output operation of the horizontal driving unit to cut off the driving power when the AKB feedback signal is not detected from the CRT driving unit for a predetermined time. The method of claim 1, The controller, when it is determined that the IK detected from the AKB feedback signal is in an unstable state, determines that retrace has occurred. The method of claim 2, An OSD for displaying information about the device on a screen; And the controller controls the OSD to display an AKB error on a screen for a predetermined time when the IK is determined to be unstable even once during a normal display operation. In the overheat protection method of the display device employing the CRT, Driving by inputting driving power having a predetermined size to the CRT; Detecting a predetermined AKB feedback signal corresponding to the electron beam output from the CRT; And, And blocking the driving power when the AKB feedback signal is not detected for a predetermined time. The method of claim 4, wherein Determining whether the IK detected from the AKB feedback signal is in an unstable state; And, If the IK is in an unstable state, determining that retrace is occurring and shutting off the driving power; and overheating protection method of a display device further comprising. The method of claim 5, And displaying an AKB error on a screen for a predetermined time when it is determined that the IK is unstable even at least once during the display operation.