KR20010083406A - High voltage regulation compensating circuit in a monitor - Google Patents

Abstract

PURPOSE: A circuit for compensating a high voltage change of a monitor is provided to minimize a high voltage change according to a beam current of a monitor and a brightness change of a screen by changing B+ voltage applied to a primary side of a flyback transformer. CONSTITUTION: A high voltage detector(22) outputs a high voltage detecting voltage. The high voltage detector(22) includes a resistor(R1), a resistor(R2), a capacitor(C3), and a capacitor(C4). The resistor(R1) is connected between variable resistors(VR1,VR2). The resistor(R2) is connected to a high voltage capacitor(C2). The capacitor(C3) connects the resistors(R1,R2). The capacitor(C4) is connected to the resistor(R2) in parallel. An anode voltage applied to a CRT through a secondary side high voltage output line of the flyback transformer(21) is detected to output a high voltage detecting voltage. A feedback output section(23) compares a high voltage detecting voltage with a reference voltage and outputs a high voltage feedback voltage according to the comparison result.

Description

HIGH VOLTAGE REGULATION COMPENSATING CIRCUIT IN A MONITOR}

The present invention relates to a high-voltage fluctuation correction circuit of the monitor, and more particularly to a high-voltage fluctuation correction circuit of the monitor to minimize the high-voltage change caused by the change in the beam current and the screen brightness of the monitor.

Referring to Fig. 1, the conventional high pressure variation correction circuit operates as follows.

As the high voltage driver 10 switches the B + voltage applied to the primary side of the flyback transformer 11, the flyback transformer 11 generates a high voltage (HV) supplied to the anode of the CRT through the secondary side.

At this time, the driving transistor Q1 of the high voltage driving unit 10 switches by a predetermined input driving signal and is protected by a diode D1 and a capacitor C1 connected in parallel between the emitter and the collector. do.

In addition, a horizontal focus adjustment variable resistor VR1 and a vertical focus adjustment variable resistor VR2 connected in series are connected in parallel to the secondary high voltage output line of the flyback transformer 11, and the high voltage capacitor C2 is connected in parallel. Connected.

When the predetermined high voltage HV is supplied to the anode of the CRT as described above, the high voltage detector 12 having the rectifying diodes D2 and D3 connected in parallel to each other is connected to the secondary high voltage detecting coil of the flyback transformer. The predetermined DC high voltage detection voltage is applied to the feedback output unit 13.

In addition, when the DC high pressure detection voltage of the high pressure detection unit 12 is input to the feedback output unit 13, the feedback output unit 13 is a predetermined reference voltage set in advance for the DC high pressure detection voltage and high pressure compensation According to the comparison result, a high-voltage feedback voltage is output and applied to the B + controller 14.

In this case, as shown in FIG. 2, the feedback output unit 13 buffers the input DC high voltage detection voltage by the buffer 13a and compensates the buffered DC high voltage detection voltage by the error amplifier 13b. Next, a predetermined high voltage feedback voltage is output based on a result of comparing the reference voltage Vref of the output control amplifier 13c with the DC high voltage detection voltage whose error is compensated for by the error amplifier 13b.

Accordingly, the B + controller 14 PWM-controls the B + voltage applied to the primary side of the flyback transformer FBT according to the high-pressure feedback voltage in order to minimize the change of the high-voltage (HV) caused by the change in the brightness of the screen of the monitor. Variable.

However, the conventional high voltage fluctuation adjusting circuit as described above compensates for the high voltage according to the feedback result of only the DC high voltage detection voltage of the high voltage (HV) output from the secondary side of the flyback transformer. As a result, the display is distorted when the high pressure is changed.

Accordingly, the present invention is to overcome the above-mentioned conventional problems, an object of the present invention is to fly according to the high-voltage detection voltage of the high-voltage (HV) DC high voltage detection voltage and the AC component of the high voltage output from the flyback transformer The present invention provides a high-voltage fluctuation correction circuit of a monitor that prevents screen distortion by minimizing a high-voltage change caused by a change in the beam current of the monitor and the brightness of the screen by varying the B + voltage applied to the primary side of the back transformer.

The high-voltage fluctuation correction circuit of the monitor for achieving the object of the present invention is connected in parallel to the variable resistance for horizontal focus adjustment and the variable resistance for vertical focus adjustment connected in series to the secondary high voltage output line of the flyback transformer, the high voltage capacitor is parallel When the high voltage detector outputs the high voltage detection voltage and the feedback output unit amplifies the high voltage detection voltage with the reference voltage to output the predetermined high voltage feedback voltage, the B + control unit outputs one of the flyback transformers according to the high voltage feedback voltage. In the high-voltage fluctuation correction circuit of the monitor configured to compensate for the high voltage by PWM controlling the B + voltage applied to the vehicle side,

The high voltage detector includes a resistor R1 connected to the variable resistors VR1 and VR2, a resistor R2 connected to the high voltage capacitor, a capacitor C3 connecting the resistors R1 and R2 to each other, and a capacitor C4 connected in parallel to the resistor R2. And an anode high voltage (HV) applied to the CRT through the secondary high voltage output line of the flyback transformer to output a high voltage detection voltage obtained by combining the DC high voltage detection voltage and the high voltage AC component detection voltage. do.

On the other hand, the high-voltage fluctuation correction circuit of another monitor for achieving the object of the present invention is a capacitor C5, the high-voltage detection unit is connected to the high-voltage capacitor, a resistor R3 is connected in parallel to the capacitor C5, and the high-voltage connected in series Resistors R4 and R5 connected in parallel to an output line, and capacitor C6 connecting common contacts of the capacitors C5 and R4 and R5, and are applied to the CRT through the secondary side high voltage output line of the flyback transformer. An anode high voltage (HV) is detected by outputting a high pressure detection voltage obtained by combining the DC high pressure detection voltage and the high pressure AC component detection voltage.

High-voltage fluctuation correction circuits of the monitor of the present invention according to the configuration as described above minimizes the high-voltage change according to the change in the beam current of the monitor and the brightness of the screen, thereby compensating the high voltage more stable than simply receiving a high-pressure DC feedback voltage feedback Can prevent the distortion of the screen.

1 is a configuration diagram showing a conventional monitor high pressure fluctuation correction circuit;

FIG. 2 is a diagram illustrating a feedback output unit of FIG. 1;

3 is a configuration diagram showing a high-voltage fluctuation correction circuit of the monitor according to the present invention;

4 is a block diagram showing a high-voltage fluctuation correction circuit of another monitor according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10,20,30: high pressure drive 11,21,31: flyback transformer

12,22,32: high pressure detector 13,23,33: feedback output

13a: buffer 13b: air amplifier

13c: output control amplifier 14, 24, 34: B + control unit

Q1: transistor R: resistance

VR: Variable resistor C: Capacitor

D: Diode

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

Referring to FIG. 3, a high pressure fluctuation correction circuit of a monitor including a high voltage driving unit 20, a flyback transformer 21, a high pressure detecting unit 22, a feedback output unit 23, and a B + control unit 24. The secondary high-voltage output line of the flyback transformer 21 includes a horizontal focus adjusting variable resistor VR1 and a vertical focus adjusting variable resistor VR2 connected in series, and a high voltage capacitor C2 in parallel. Is connected.

The high voltage detector 22 includes a resistor R1 connected to the variable resistors VR1 and VR2, a resistor R2 connected to the high voltage capacitor C2, a capacitor C3 connecting the resistors R1 and R2 to each other, and the resistor R2. It consists of a capacitor C4 connected in parallel.

By the above configuration, the high-voltage fluctuation correction circuit of the monitor according to the present invention operates as follows.

If the high voltage HV changes as the beam current and the brightness of the screen change, the feedback output unit 23 may detect the anode high voltage detected through the resistors R1 and R2 and the capacitors C3 and C4 of the high voltage detector 21. A predetermined high voltage feedback voltage is output by amplifying the high voltage detection voltage obtained by combining the DC high voltage detection voltage of the HV) and the high voltage AC component detection voltage with a predetermined reference voltage.

At this time, the DC high voltage detection voltage is fed back to the feedback output unit 23 through the resistors R1 and R2 acting as a reference resistor for feedback, and the high voltage AC component detection voltage is output to the feedback through the capacitors C3 and C4. It is fed back to the unit (23).

In addition, the high-voltage feedback voltage output after comparison and amplification by the feedback output unit 23 is a voltage corresponding to a difference from the reference voltage.

Subsequently, when a predetermined high voltage feedback voltage comparatively amplified by the feedback output unit 23 is input to the B + control unit 24, the B + control unit 24 amplifies the high pressure feedback amplified by the feedback output unit 23. In order to minimize the high voltage change according to the change in the beam current and the brightness of the screen according to the voltage and to prevent the distortion of the screen, the B + voltage applied to the primary side of the flyback transformer 21 is PWM-controlled.

Therefore, when a predetermined B + voltage PWM controlled by the B + control unit 24 is applied to the primary side of the flyback transformer 21, it is applied to the anode of the CRT through the secondary side of the flyback transformer 21. The high voltage (HV) is stabilized and the change can be compensated for.

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

Referring to FIG. 4, a high pressure variation correction circuit of a monitor including a high voltage driving unit 30, a flyback transformer 31, a high pressure detecting unit 32, a feedback output unit 33, and a B + control unit 34. In the secondary side of the high-voltage output line of the flyback transformer 31, a horizontal focus adjusting variable resistor VR1 and a vertical focus adjusting variable resistor VR2 connected in series are connected in parallel, and a high voltage capacitor C2 is connected in parallel. Is connected.

The high voltage detector 32 includes a capacitor C5 connected to the high voltage capacitor C2, a resistor R3 connected in parallel to the capacitor C5, resistors R4 and R5 connected in series with each other and connected in parallel to the high voltage output line, and And a capacitor C6 connecting the capacitor C5 and the common contact of the resistors R4 and R5.

By the above configuration, the high-voltage fluctuation correction circuit of the other monitor according to the present invention operates as follows.

If the high voltage (HV) changes as the beam current and the brightness of the screen change, the feedback output unit 33 is detected through the resistors R3, R4, R5, and capacitors C5, C6 of the high voltage detector 31. A predetermined high voltage feedback voltage is output by amplifying the high voltage detection voltage obtained by combining the DC high voltage detection voltage of the anode high voltage (HV) and the high voltage AC component detection voltage with a predetermined reference voltage.

In this case, the DC high voltage detection voltage is fed back to the feedback output unit 33 through the resistors R4 and R5 acting as reference feedback resistors, and the high voltage AC component detection voltage is fed back through the capacitors C5 and C6. It is fed back to the unit 33.

In addition, the high-voltage feedback voltage output after comparison and amplification by the feedback output unit 33 is a voltage corresponding to a difference from the reference voltage.

Subsequently, when a predetermined high voltage feedback voltage comparatively amplified by the feedback output unit 33 is input to the B + control unit 34, the B + control unit 34 amplifies the high pressure feedback amplified by the feedback output unit 33. In order to minimize the high voltage change according to the change of the beam current and the screen brightness of the monitor according to the voltage and to prevent the distortion of the screen, the B + voltage applied to the primary side of the flyback transformer 31 is controlled by PWM control.

Therefore, when a predetermined B + voltage PWM controlled by the B + control unit 34 is applied to the primary side of the flyback transformer 31, it is applied to the anode of the CRT through the secondary side of the flyback transformer 31. The high voltage (HV) is stabilized and the change can be compensated for.

As described above, the high-voltage fluctuation correction circuit of the monitor according to the present invention is connected to the primary side of the flyback transformer according to the high-voltage detection voltage of the high-voltage (HV) DC voltage output from the flyback transformer and the high-voltage detection voltage obtained by synthesizing the AC component of the high voltage. By changing the applied B + voltage to minimize the change in the high voltage due to the change in the beam current of the monitor and the brightness of the screen, it is possible to compensate the high voltage more stably than when only the high-voltage DC feedback voltage is fed back, and the screen distortion phenomenon It is effective to prevent.

What has been described above is just one embodiment for implementing the high-voltage fluctuation correction circuit of the monitor according to the present invention. Various changes can be made by those skilled in the art without departing from the gist of the present invention.

Claims (2)

A horizontal focus adjustment variable resistor (VR1) and a vertical focus adjustment variable resistor (VR2) connected in series to the secondary high voltage output line of the flyback transformer 21 are connected in parallel, and a high voltage capacitor (C2) is connected in parallel. , When the high voltage detector 22 outputs the high voltage detection voltage and the feedback output unit 23 amplifies the high voltage detection voltage with the reference voltage and outputs a predetermined high voltage feedback voltage, the B + controller 24 according to the high voltage feedback voltage. In the high-voltage fluctuation correcting circuit of the monitor configured to compensate for the high voltage by PWM controlling the B + voltage applied to the primary side of the flyback transformer 21, The high voltage detector 22 connects the resistor R1 connected to the variable resistors VR1 and VR2, the resistor R2 connected to the high voltage capacitor C2, the capacitor C3 connecting the resistors R1 and R2 to each other, and the resistor R2. Consists of a capacitor C4 connected in parallel, An anode high voltage (HV) applied to the CRT is detected through the secondary-side high voltage output line of the flyback transformer 21 to output a high voltage detection voltage obtained by combining the DC high voltage detection voltage and the high voltage AC component detection voltage. High-voltage fluctuation correction circuit of the monitor. The horizontal focus adjustment variable resistor (VR1) and the vertical focus adjustment variable resistor (VR2) connected in series to the secondary high voltage output line of the flyback transformer 31 are connected in parallel, and the high voltage capacitor (C2) is connected in parallel. , When the high pressure detector 32 outputs the high pressure detection voltage, and the feedback output unit 33 amplifies the high pressure detection voltage with the reference voltage and outputs a predetermined high voltage feedback voltage, the B + controller 34 according to the high pressure feedback voltage. In the high-voltage fluctuation correcting circuit of the monitor configured to compensate for the high voltage by PWM controlling the B + voltage applied to the primary side of the flyback transformer 31, A capacitor C5 connected to the high voltage capacitor C2, a resistor R3 connected in parallel to the capacitor C5, resistors R4 and R5 connected in parallel to the high voltage output line, and A capacitor C6 connecting the capacitor C5 and the common contact of the resistors R4 and R5, An anode high voltage (HV) applied to the CRT is detected through the secondary-side high voltage output line of the flyback transformer 31 to output a high voltage detection voltage obtained by synthesizing the DC high voltage detection voltage and the high voltage AC component detection voltage. High-voltage fluctuation correction circuit of the monitor.