KR100548141B1 - FBT stablization circuit - Google Patents

Abstract

The present invention relates to a high-voltage fluctuation correction circuit of a TV horizontal deflection circuit that can correct the phenomenon that the screen is distorted or changes in size due to the fluctuation of the high pressure of the FBT according to the change of the screen brightness.

According to the present invention, the horizontal deflection unit controls the current flowing through the horizontal deflection coil, and compares the input E / W signal with the signal obtained by integrating the flyback pulse detected by the horizontal deflection unit to output a PWM signal to output the horizontal deflection. A comparator for controlling the unit, a high pressure generator for applying high pressure to the horizontal parallel part, an ABL detector for detecting a high pressure change of the high pressure generator, and a correction unit for adjusting gain of the detection signal of the ABL detector and applying it to the output terminal of the comparator. It detects high-voltage fluctuation information and supplies the correction waveform to the horizontal deflection unit, so there is almost no fluctuation of the screen according to the brightness of the screen, and it increases the stability of the screen by increasing the response speed of the compensation circuit caused by the shaking of high pressure. .

High Pressure Stabilization, Horizontal Deflection, FBT, Buffer

Description

High pressure stabilization device {FBT stablization circuit}

1 is a block diagram of a high pressure stabilizer of a horizontal deflection circuit of a typical TV;

And,

2 is a block diagram of a high pressure stabilizer of a horizontal deflection circuit according to an embodiment of the present invention.

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

100: gain compensation 110: comparator

120: FET 130: horizontal deflection portion

140: FBT 150: ABL detection circuit

160: integral circuit

The present invention relates to a high pressure stabilization circuit of a horizontal deflection circuit of a TV, and more particularly, to a high pressure fluctuation correction circuit that can correct a phenomenon in which the screen is distorted or changes in size due to fluctuation of the high pressure of the FBT according to the change of screen brightness. It is about.

In general, for a monitor, the CRT beam current (i.e. anode current) depends on the brightness of the screen. This is a load change from the point of view of the FBT, and the high voltage of the FBT changes with the change of the beam current, and the screen size changes accordingly. In general, when the screen is dark and the beam current is small, the high pressure becomes high and accordingly, the horizontal size becomes small. On the contrary, when the screen is bright, the horizontal current increases because the beam current increases and the high pressure is lowered. That is, in the CRT, the size of the screen depends on the amount of deflection, but the larger the deflection amount, the larger the screen and the smaller the deflection amount, the smaller the screen. The deflection amount changes according to the anode voltage. As the anode voltage increases, the deflection amount decreases and thus the screen size decreases. As the anode voltage decreases, the deflection amount increases and the screen increases. In addition, since the current of the anode increases when the brightness of the screen becomes bright, and decreases when the screen becomes dark, the size of the screen changes according to the brightness of the screen. Therefore, it is required to prevent the size of the screen from changing according to the brightness of the screen.

A general high voltage correction circuit is shown in FIG. For convenience, a deflection circuit controlled by a PWM signal will be described.

Referring to FIG. 1, an E / W (east-west) signal, which is a parabola signal output from an integrated circuit having a pincushion correction circuit, is input as a comparison signal of the comparator 10, and the horizontal deflection unit 30 is provided. A sawtooth wave obtained by integrating a flyback pulse in the integrating circuit 60 is input to a reference signal of the comparator 10. The FET 20 is controlled by the PWM signal output from the comparator 10 and used to minimize the loss portion. By the output current of the FET 20, the deflection yoke (DY) current of the horizontal deflection portion 30 is controlled to adjust the horizontal size. In addition, it is preferable to add a predetermined coil to the output line of the FET 20 to remove and supply the horizontal noise of the control signal supplied to the horizontal deflection unit 30. On the other hand, the high-voltage fluctuation due to the brightness of the screen detects the signal using the ABL (Auto bright limit) detection circuit 50 in the FBT (flyback trans) 40. In general, the rectified voltage induced in the secondary winding of the FBT 40 is used as a high voltage applied to the anode of the CRT, and is also used as a high voltage applied to the focus of the CRT or the screen grid. The secondary voltage of the FBT 40 can be monitored using a winding) to detect a change in the anode voltage. In other words, the ABL detection circuit 50 is a circuit for monitoring the anode current and controlling the brightness of the screen. When the brightness is abnormally high, a large anode current flows and the high voltage generation circuit is overloaded so that the component is destroyed. It is a circuit for preventing. The signal detected by the ABL detection circuit 50 is input to the gain control unit 70, and the gain is adjusted so that the voltage of the E / W signal is changed by the voltage corresponding to the change of the high voltage to adjust the deflection current of the DY to adjust the brightness of the screen. It is to correct the size variation according to.

However, detecting the ABL signal and correcting it in the E / W signal stage as described above may cause distortion because the corrected signal is output from the comparator compared with the integrated signal, and thus a time delay occurs and the high voltage fluctuation is caused. As the response speed decreases, the desired correction effect is not seen. In particular, due to the slight shaking of the integral signal generated during the high-voltage fluctuation, the correction effect is further reduced.

The present invention is to solve the above problems, by detecting the high-voltage fluctuation information to supply the correction waveform to the horizontal deflection portion, the screen is almost no fluctuation according to the brightness of the screen and the response speed of the compensation circuit due to high-pressure shake The purpose is to provide a high pressure stabilization circuit with high screen stability.

As a preferred embodiment of the high-pressure stabilization circuit according to the present invention for achieving the above object, a horizontal deflection portion for controlling the current flowing in the horizontal deflection coil, the input E / W signal and the horizontal deflection portion detected A comparator for outputting a PWM signal and comparing the flyback pulse with the integrated signal to control the horizontal deflection unit, a high pressure generator for applying high pressure to the horizontal deflection unit, an ABL detector for detecting a high pressure variation of the high voltage generator and the ABL detector And a correction unit for adjusting the gain of the detection signal and applying the gain to the output terminal of the comparator.

The correction unit applies an impedance matching buffer, one end of which is connected to the detection signal of the ABL detector and the other end of which a first gain control resistor connected to the buffer, and an output signal of the buffer are finely adjusted to apply to the output terminal of the comparator. And a second gain adjusting resistor.

In addition, the output signal of the comparator is preferably to be supplied to the horizontal deflection portion through the FET and the coil.

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

2 is a block diagram of a high pressure stabilizer of a horizontal deflection circuit according to an embodiment of the present invention. The high pressure stabilizer is composed of a comparator 110, a FET 120, a horizontal deflection unit, an FBT 140, an ABL detection circuit 150, a correction unit 100, and an integrating circuit 160. The comparator 110 inputs an E / W (east-west) signal, which is a parabola signal output from an integrated circuit having a pincushion correction circuit, as a comparison signal, and uses a sawtooth wave signal of the integrating circuit 160 as a reference signal. Output PWM signal. FET (Field Effect Transistor) 120 is used to minimize the signal loss because the response speed is faster than the conventional TR or SCR and can greatly improve the energy efficiency, turn-on operation by receiving the PWM signal of the comparator 110 do. The horizontal deflection unit 130 is configured to control the current of the DY (not shown) by controlling the current by the output signal of the FET 120. The FBT (flyback trans) 140 is a high voltage generator, and the ABL (Auto bright limit) detection circuit 150 detects a high voltage variation due to the brightness of the screen in the FBT (flyback trans) 140. The correction unit 100 is configured to gain-adjust the detection signal of the ABL detection unit 150 and apply the output signal to the output terminal of the comparator 110. More specifically, the detection signal of the ABL detection unit 150 is applied to the base end of the buffer composed of TR1 through the first resistor R3, which is a large gain adjusting resistor. The emitter output of the buffer TR1 is applied to the second resistors R1 and R2 for fine gain adjustment to fine gain control and is applied to the output terminal of the comparator 110. Reference numeral R4 denotes a bias resistor of the buffer TR1. That is, the first resistor R3, which is a large gain adjusting resistor, is applied to the base end of the buffer TR1 to adjust the gain of the input signal in combination with the bias resistor R4 and a time constant. . The buffer TR1 is used for impedance matching to prevent distortion due to impedance difference when a gain control signal is directly applied to the output terminal of the comparator 110. In addition, the fine gain adjusting resistors R1 and R2 are used for the correction when a change in the fine gain occurs due to the temperature rise of the buffer in the signal largely gain-controlled through the buffer TR1. In other words, when the temperature of the TR increases, the hfe value decreases and thus the amplification rate decreases finely. The resistance of R1 and R2 is used to reduce the influence of the amount of change. The high pressure stabilization device of the horizontal deflection circuit configured as described above detects a signal of the high voltage fluctuation generated according to the brightness of the screen through the ABL detector 150 in the FBT 140. The detected signal adjusts the large gain through the R3 resistance of the compensator 100, is input to the base of the buffer TR1, and is gain-adjusted through the fine gain adjusting resistors R1 and R2 so that the comparator 110 is adjusted. Is applied to the output line. In this case, the comparator 110 compares the input E / W signal and generates a PWM waveform to which a DC tjdqns voltage is applied and controls the DY current of the horizontal deflection unit 130 according to the change of the DC voltage. Will be done. That is, when the screen is dark and the anode current of the CRT decreases, and accordingly the anode voltage increases, the output voltage of the ABL detector 150 is also increased, and the DC level of the compensator 100 is adjusted to a high gain so that the comparator 110 is increased. Is applied to the output level. Therefore, when the voltage applied to the gate of the FET 120 is increased and the current flowing in the horizontal deflection coil (not shown) of the horizontal deflection portion 130 is increased, the size of the screen is increased so that the screen becomes dark and the screen size becomes smaller. This can be prevented. On the contrary, when the screen is brightened and the anode current increases and the anode voltage decreases, the output voltage of the ABL detector 150 is lowered and the DC level of the compensator 100 is relatively low. Applied to the output level. Therefore, the voltage applied to the gate of the FET 120 is lowered and the current flowing in the horizontal deflection coil (not shown) of the horizontal deflection unit 130 is reduced to reduce the size of the screen so that the screen becomes brighter and the size of the screen It can be prevented to grow big.

On the other hand, when the temperature of the buffer TR rises due to prolonged use, the hfe value changes finely and the amplification rate decreases, resulting in a low output voltage of the buffer TR. However, R1 and R2 resistors prevent the microchange. will be.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

As described above, according to the high-pressure stabilization device of the horizontal deflection circuit of the TV according to the present invention, by detecting the high-pressure fluctuation information to supply a correction waveform to the horizontal deflection portion, there is almost no fluctuation of the screen according to the brightness of the screen, The response speed of the compensation circuit is increased to increase the stability of the screen.

Claims (3)

 In the high pressure stabilization circuit of a horizontal deflection circuit of a TV, A horizontal deflection portion for controlling a current flowing in the horizontal deflection coil; A comparator for controlling the horizontal deflection unit by outputting a PWM signal by comparing an input E / W signal and a flyback pulse detected by the horizontal deflection unit with an integrated signal; A high pressure generator for applying high pressure to the horizontal parallel part; An ABL detector detecting a high pressure change of the high pressure generator; And And a correction unit configured to gain-adjust the high voltage fluctuation detection signal of the ABL detection unit and apply the gain to the DC level of the PWM signal output from the output terminal of the comparator. The method of claim 1, wherein the correction unit An impedance matching buffer; A first gain adjusting resistor having one end connected to a detection signal of the ABL detector and the other end connected to the buffer; And a second gain adjusting resistor configured to finely adjust the output signal of the buffer and apply it to the output terminal of the comparator. The method of claim 1, And the output signal of the comparator is supplied to the horizontal deflection portion through the FET and the coil.

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