KR0139549Y1 - X-ray protecting circuit - Google Patents

Abstract

The present invention is to protect the CRT from generating a certain level of X-rays.

The present invention effectively suppresses the emission of X-rays from the CRT, prevents the circuit from malfunctioning due to the generation of static electricity, rectifies the voltage induced by the secondary coil of the flyback transformer with the rectifier, and levels the rectified voltage level. The detection unit detects whether a high voltage of a predetermined level or more is generated, and when a high voltage of a predetermined level or more occurs, the switching element operates and the control signal generator generates an X-ray suppression control signal and emits X-rays according to the suppressed control signal. The suppression unit operates to suppress the emission of X-rays, and the X-ray emission suppression unit suppresses the operation power by blocking the operation power by the DPMS method of the power supply unit, or suppresses by blocking the horizontal synchronization signal and the vertical synchronization signal.

Description

X-ray protection circuit

1 is a conventional X-ray protection circuit diagram.

2 is an X-ray protection circuit diagram of the present invention.

3 is a circuit diagram showing an embodiment of the X-ray emission suppressing unit in the X-ray protection circuit of the present invention.

4 is a circuit diagram showing another embodiment of the X-ray emission suppressing unit in the X-ray protection circuit of the present invention.

* Explanation of symbols for main parts of the drawings

11: rectifier 12: level detector

13 control signal generator 14 X-ray emission suppression

15: duration FBT ₁₁ : flyback trance

SW: switching element

The present invention provides a screen display device such as a monitor and a television receiver using a CRT (Color Picture Tube) and a CRT (Cathode Ray Tube) as a screen display device. It relates to an X-ray protection circuit.

In general, a CRT is provided with an electron gun behind the neck portion to generate an electron beam, and is scanned on the front fluorescent surface while accelerating the generated electron beam to display a predetermined image.

In order to accelerate the electron beam, high pressure is required, and high pressure is applied to the anode of the CRT. Accelerated electrons generated by the high pressure collide with the fluorescent surface to generate X-rays, and the generated X-rays are very harmful electromagnetic waves.

Therefore, the screen display device using the CRT includes an X-ray protection circuit that determines whether X-rays are generated at a set level and prevents X-rays from occurring when X-rays are generated above the set level.

The X-ray protection circuit determines the occurrence of X-rays by using the generated high voltage level.

1 is a conventional X-ray protection circuit diagram. Thus as shown, the secondary coil of the flyback transformer (FBT ₁₎ for generating a high voltage through the diode (D ₁₎ connected to the ground capacitor (C ₁₎ and the diode (D ₁₎ and a ground capacitor (C ₁₎ The connection point of the resistor (R ₁ ), the ground resistor (R ₂ ), the constant voltage diode (ZD ₁ ) and diode (D ₂ ) in order through the ground resistor (R ₃ ), ground capacitor (C ₂ ) and deflection integrated device The X-ray protective terminal XR of (1) was connected.

In the conventional X-ray protection circuit configured as described above, when the flyback transformer FBT ₁ operates to generate a high voltage, a pulse signal of a predetermined level is induced to the secondary coil thereof, and the induced pulse signal is rectified through the diode D ₁ . Then, it is smoothed by the ground capacitor C ₁ and converted to the DC level.

The charging power of the capacitor C ₁ is divided by the resistors R ₁ and R ₂ and applied to the cathode of the constant voltage diode ZD ₁ .

In this case, the resistance (R _1, R _2), the level of the divided power is in the off state the constant voltage diode zener diode (ZD ₁₎ in the case lower than the Zener voltage (ZD ₁₎ by integrated for the deflector element (1) The low potential is applied to the X-ray protective terminal XR of the.

Then, the deflection integrated device 1 determines that the X-rays are generated below the set level, and deflects the electron beam while continuing to operate in the current state.

And the resistance when the level of the power divided by the (R _1, R ₂₎ is higher than the zener voltage of the zener diode (ZD ₁₎ is said on the contrary that the zener diode (ZD ₁₎ Since the conductive state resistance (R _1, The power divided by R ₂ is applied to the X-ray protection terminal XR of the deflection integrated device 1 through the constant voltage diode ZD ₁ and the diode D ₂ in sequence.

Then, the deflection integrated device 1 determines that a lot of X-rays are generated above a set level, and operates so that X-rays are not generated.

Here, the level at which X-rays are not generated is set to the values of the resistors R ₁ and R ₂ and the zener voltage of the constant voltage diode ZD ₁ .

However, the above-described conventional technology operates an X-ray protection circuit even when a high level voltage is momentarily generated. In this case, a malfunction occurs in which the X-ray protection circuit operates without a high level of static electricity. There are various problems such as lowering the reliability of the.

Accordingly, an object of the present invention is to provide an X-ray protection circuit that effectively suppresses the emission of X-rays from the CRT.

Another object of the present invention is to provide an X-ray protection circuit for preventing the circuit from malfunctioning due to the generation of static electricity.

The X-ray protection circuit of the present invention for achieving this purpose rectifies the voltage induced by the secondary coil of the flyback transformer with a rectifier, and detects the rectified voltage level with a level detector to determine whether a high voltage above a predetermined level is generated. When a high voltage of a predetermined level or more occurs, the control element generator generates an X-ray suppression control signal while the switching element operates, and the X-ray emission suppression unit operates according to the suppression control signal to suppress the emission of X-rays.

The X-ray emission suppression unit suppresses the operation power by blocking the operation power by the DPMS (Display Power Management Signaling) method of the power supply unit, or suppresses by blocking the horizontal synchronization signal and the vertical synchronization signal.

Hereinafter, the X-ray protection circuit of the present invention will be described in detail with reference to the accompanying drawings of FIGS. 2 to 4.

2 is an X-ray protection circuit diagram of the present invention. As shown here, the rectifier ₁₁ is composed of a diode (D ₁₁ ) and a capacitor (C ₁₁ ) rectifying the power induced by the secondary coil of the flyback transformer (FBT ₁₁ ), and the output level of the rectifier (11) A level detector 12 comprising resistors R ₁₂ and R ₁₃ and a capacitor C _{12 for} detecting a voltage, a switching element SW for determining whether an output voltage of the level detector 12 is equal to or greater than a preset level; And a control signal generator 13 comprising transistors Q ₁₁ and resistors R ₁₃ to R ₁₆ which generate a suppression control signal for X-ray emission when the switching element detects a predetermined level or more, and the control. The X-ray emission suppression unit 14 which suppresses X-ray emission under the control of the signal generator 13 and the switching element SW are continuously set when the control signal generator 13 generates the suppression control signal. diode to determine the level or higher (D ₁₂₎ and a resistor (R ₁₇₎ coming The duration was composed of unit 15. In the drawing description of FIG. 2, reference numeral B ⁺ denotes a power source.

The X-ray suppression circuit of the present invention configured as described above has a power source that is induced to the secondary coil of the flyback transformer FBT ₁₁ while the power source B ⁺ is applied, that is, the flyback pulse signal is a diode D ₁₁ of the rectifier _11. ) Is rectified and smoothed by the capacitor C ₁₁ and output to the DC power supply.

The output power of the rectifier 11 is divided by the resistors R ₁₁ and R ₁₂ of the level detector 12, stabilized by the capacitor C ₁₂ , and applied to the control terminal of the switching element SW.

At this time, when the output power level of the level detector 12 is equal to or less than a predetermined level, power of a level lower than its operating power level is applied to the control terminal of the switching element SW so that the switching element SW is cut off.

Then, the high potential is applied to the base of the transistor Q ₁₁ of the control signal generator 13 so that it is turned off and the low potential is output so that the X-ray emission suppressing unit 14 does not operate.

Here, even if a high voltage is generated instantaneously, the output power level of the level detector 12 is stabilized by the condenser C ₁₂ , and thus the level fluctuation hardly occurs due to the instantaneously generated high pressure. Does not malfunction to suppress the emission of X-rays.

In addition, when a large amount of X-rays are generated by applying a high pressure above a predetermined level in the CRT, the level of the power induced by the secondary coil of the flyback transformer FBT ₁₁ is increased to increase the output power level of the rectifier 11. As a result, the output power level of the level detector 12 is increased, and when the output power level of the level detector 12 becomes higher than the operating power level of the switching element SW, the switching element SW is in a conductive state.

Then, in contrast to the above, a low potential is applied to the base of the transistor Q ₁₁ of the control signal generator 13 so that it is turned on, and the power source B ^{+ is} supplied through the transistor Q ₁₁ and the resistor R ₁₆ . Since the X-ray emission suppression unit 14 is input, the X-ray emission suppression unit 14 operates to suppress X-ray emission from the CRT.

In this case, since the power output to the emitter of the transistor Q ₁₁ is applied to the control terminal of the switching element SW through the diode D ₁₂ and the resistor R ₁₇ of the sustain unit 15, the switching element SW ) Continues to be in a conductive state, whereby the X-ray emission suppression unit 14 continues to suppress the X-ray emission.

3 is a circuit diagram showing an embodiment of the X-ray emission suppression unit 14 to suppress the emission of X-rays by blocking the operation power in the X-ray protection circuit of the present invention by the DPMS method. As shown therein, the AC power source AC is connected to the ground capacitor C ₂₁ and the power input terminal PO of the power output integrated device ₂₁ through the power transformer T and the diode D ₂₁ . In addition, the connection point is connected to the power supply control terminal CS and the collector of the transistor Q ₂₁ of the power output integrated device 21 through the resistor R ₂₁ , and the control output from the microcomputer is provided at the base of the transistor Q ₂₁ . The signal was connected to be applied through the diode D ₂₂ and the resistor R ₂₂ , and the control signal output from the control signal generator 13 was applied.

In one embodiment of the X-ray emission suppressing unit 14 configured as described above, the AC power input AC is stepped down through the power transformer T, rectified through the diode D ₂₁ , and condensed by the capacitor C ₂₁ . After being smoothed and converted to DC power, it is applied to the power input terminal PO of the power output integrated device 21 and applied to the power control terminal CS of the power output integrated device 21 through the resistor R ₂₁ again. do.

In this state, when the control signal generator 13 outputs a low potential, the transistor Q ₂₁ is turned off and a high potential is applied to the power control terminal CS of the power output integrated device 21. The integrated device 21 operates normally to output the operating power, and the device operates normally.

When a large amount of X-rays are emitted from the CRT and the control signal generator 13 outputs the high potential as described above, the high potential is applied to the base of the transistor Q ₂₁ so that it is turned on and the power output integrated device. Since the low potential is applied to the power supply control terminal CS of 21, the power output integrated device 21 does not operate and does not output the operating power, so that the operation of the device is stopped and X-rays are not emitted.

4 is a circuit diagram showing another embodiment of the X-ray emission suppressing unit 14 in the X-ray protection circuit of the present invention. In the illustrated as a control signal outputted from control signal generation section 13 is to be connected to the base of the transistor (Q _31), and the collector of the transistor (Q ₃₁₎ has a horizontal and a vertical synchronizing signal to the horizontal and vertical circuits Connected to the input line.

In another embodiment of the X-ray emission suppressing unit 14 of the present invention configured as described above, when the low potential is output from the control signal generator 13, the transistor Q ₃₁ is turned off, so that the horizontal and vertical synchronization signals are horizontal and vertical. Normally input into the circuit, the device will operate normally.

When a large amount of X-rays are emitted from the CRT and the control signal generator 13 outputs the high potential as described above, the high potential is applied to the base of the transistor Q ₃₁ so that it is turned on. Flows to the ground through transistor Q ₃₁ and is not input to the horizontal and vertical circuits, thereby suppressing the emission of X-rays.

As described above, the present invention is to suppress the generation of X-rays by cutting off the power or blocking horizontal and vertical synchronizing signals when a large amount of X-rays occur in the CRT, thereby reducing power consumption and generating static electricity. It also does not malfunction, thereby improving the reliability of the product.

Claims (1)

Rectifier 11 for rectifying the power induced by the secondary coil of the flyback transformer FBT ₁₁ , a level detector 12 for detecting the output level of the rectifier 11, and an output voltage of the level detector 12. A switching element SW for determining whether the level is equal to or higher than the preset level, a control signal generator 13 for generating a suppression control signal for X-ray emission when the switching element SW detects the predetermined level or higher; And an X-ray emission suppressing unit (14) for blocking horizontal and vertical synchronization signals input to the horizontal and vertical circuits according to the control signal output from the control signal generator (13).