KR200164490Y1 - High-voltage regulation circuit in a monitor - Google Patents

Abstract

The high-voltage regulation circuit of the monitor is a flyback transformer 10 which boosts the B + voltage input from the primary winding and supplies it to the anode of the water pipe, and the horizontal / vertical size signal depending on the mode to adjust the horizontal / vertical size of the screen. Receives the B + voltage through the primary winding of the microcomputer 20 and the flyback transformer 10, and generates a horizontal / vertical deflection current by the horizontal / vertical size signal input from the microcomputer 20 In the monitor equipped with a horizontal / vertical deflection circuit 30 for supplying a vertical deflection coil, the high-pressure detection unit 40 for detecting the pulse voltage output from the secondary winding of the flyback transformer 10 and outputs a correction voltage , The horizontal / vertical size correction unit 50 adjusts the magnitude of the horizontal / vertical size signal supplied from the microcomputer 20 to the horizontal / vertical deflection circuit 30 according to the correction voltage. , To maintain a constant high pressure during a beam current change in the number of correlation by varying depending on the correction voltage of the horizontal size signal supplied to the horizontal deflection circuit 30 from the microcomputer 20, it is possible to prevent the screen size changes.

Description

A high-voltage regulation circuit in a monitor

The present invention relates to a high voltage regulation circuit of a monitor, and more particularly, to a high voltage regulation circuit of a monitor for preventing the sipe of the monitor screen from fluctuating due to a high pressure variation due to a beam current variation.

In general, the main power circuit of the monitor is implemented by a switched mode power supply (SMPS), and the power supply voltage output from the switching power circuit is supplied to each necessary portion of the circuit to drive the monitor circuit.

At this time, since the anode of the water pipe requires a high voltage, the highest voltage among the power voltages output from the switching power supply circuit is boosted through the flyback transformer and supplied to the anode of the water pipe.

FIG. 1 is a circuit diagram showing a general monitor circuit. After stabilizing the highest voltage (about 200V) among the power supply voltages output from the switching power supply circuit to the B + voltage, the B + voltage is the primary side of the flyback transformer 10. Input to the windings. The AC voltage output from the secondary winding of the flyback transformer 10 in accordance with the direct current high voltage by the rectifier diode (D1): is supplied to the anode of the kinescope and then converted to (V _H about 2,50OV). At this time, the B + voltage applied to the primary winding of the flyback transformer 10 is applied to the horizontal deflection circuit 30 to generate a sawtooth current.

Referring to FIG. 1, the operation of the horizontal deflection circuit of a general monitor will be briefly described as follows.

The horizontal synchronization signal H.sync output from the microcomputer 20 is appropriately signal-modulated from the horizontal oscillation IC IC to the horizontal driving signal H.drive and supplied to the horizontal driving transistor TR1. The horizontal driving signal H.drive turns on the horizontal driving transistor TR1 and supplies current to the base terminal of the horizontal output transistor TR2 through the horizontal driving transistor TR1 and the horizontal driving transformer HDT. When the horizontal output transistor TR2 is turned on by receiving sufficient base current, the B + power supply current of the flyback transformer FBT 10 flows to the horizontal output transistor TR2 through the horizontal deflection coil H.DY.

Thus, while the horizontal output transistor TR2 is turned on, it corresponds to the second half of the effective scanning period of the horizontal sawtooth wave. Then, when the horizontal output transistor TR2 is rapidly turned off in accordance with the horizontal drive signal H.drive, the horizontal deflection coil is turned off. The current accumulated in (H.DY) charges the retrace capacitor (RE.C). When the retrace capacitor RE.C is fully charged, it is discharged back to the horizontal deflection coil H.DY, and current is accumulated in the horizontal deflection coil H.DY. The period between the charging and discharging of the retrace capacitor RE.C determines the retrace period.

When energy is accumulated in the horizontal deflection coil (H.DY) and the deflection coil voltage is enough to apply a forward bias to the damper diode (DD), the damper diode (DD) is conducted and the current flowing through the deflection coil (H.DY). Will fall to zero. At this time, the current flowing through the damper diode D.D corresponds to the first half of the effective syringe of the horizontal sawtooth wave.

As described above, when the current becomes zero, the horizontal output transistor TR2 is turned on again by the horizontal drive signal H. drive, and the sawtooth current flows through the horizontal deflection coil H.DY while repeating the above process. Horizontal deflection is achieved and horizontal scanning is performed.

In general, a multi-mode monitor reproduces a video image according to a signal received from a video card in a computer, where adjustment of each part of a circuit is required according to a timing parameter of the received signal. Here, look at the classification of the monitor according to the video mode through Table 1 as follows.

TABLE 1

As shown in Table 1 above, video and video cards that support various modes, such as VGA and SVGA, and high-definition dedicated modes, are different from each other. If equipped, the horizontal frequency of each mode is about 30-75Hz.

That is, when the mode is changed in the multi-mode monitor, there are parts that need to be changed in the internal circuits of the monitor. For example, image size and position change, horizontal / vertical synchronization and deflection optimization, and various deflection corrections. The circuit must be readjusted.

When the mode is changed, the readjustment of each parameter is controlled by the microcomputer 20. The microcomputer 20 outputs different control signal levels depending on the mode. In particular, when the horizontal / vertical frequency is changed when the mode is changed, the horizontal / vertical screen size of the monitor is changed so that the microcomputer 20 maintains the horizontal / vertical size signal according to the changed mode. H.size, V.sixte).

For example, as described above, the size of the horizontal screen is determined by the amount of deflection, and the amount of deflection is changed by the current flowing through the bottle deflection coil H.DY. After adjusting, the microcomputer 20 outputs an appropriate PWM signal to adjust the horizontal size of the screen by varying the current flowing through the horizontal deflection coil (H.DY). That is, the current flowing through the horizontal deflection coil H. DY is corrected so that the horizontal size of the screen is constant at the top, bottom, and center.

However, in the conventional monitor, since the flyback transformer 10 is connected to the load of the water pipe, the high and low beam currents change, ie, the change in the brightness of the screen, causes the high voltage (V _H ) to change horizontally and vertically. The size fluctuates. In other words, as the beam current increases, the anode high voltage V _H decreases to increase the size of the screen. On the contrary, when the beam current decreases, the anode high pressure V _H increases to decrease the size of the screen.

As described above, in the conventional monitor, the fluctuation of the anode high voltage V _H becomes severe due to the variation of the beam current due to the change in brightness of the screen. For example, when the fluctuation of the high voltage V _H becomes severe, There is a problem that the size of the is changed and the image quality deteriorates.

Therefore, the present invention was devised to solve the above problems, and detects the amount of change in the high pressure (V _H ) to vary the magnitude of the horizontal / vertical size signal output from the microcomputer according to the amount of change in the high pressure to maintain a high pressure. The purpose of the present invention is to provide a high voltage regulation circuit of the monitor to prevent the screen size variation.

In order to achieve the above object, the high-voltage regulation circuit of the monitor according to the present invention, a flyback transformer to boost the B + voltage input from the primary winding and supply it to the anode of the water pipe, to adjust the horizontal / vertical size of the screen The microcomputer outputs the horizontal / vertical size signal according to the hazard mode, and receives the B + voltage through the primary winding of the flyback transformer, and generates the horizontal / vertical deflection current by the horizontal / vertical size signal input from the microcomputer. A monitor equipped with a horizontal / vertical deflection circuit for supplying a horizontal / vertical deflection coil, wherein the pulse voltage output from the secondary winding of the flyback transformer is sensed in order to detect a high voltage fluctuation amount, and according to the detected pulse voltage. High-pressure sensing unit for outputting correction voltage, horizontal / vertical yarn supplied from microcomputer to horizontal / vertical deflection circuit It characterized in that it is composed of a horizontal / vertical size correction unit that controls, depending on the size of the signal's voltage compensation.

That is, the present invention, if the high pressure sensing unit detects the pulse voltage output from the secondary winding of the flyback transformer to detect the variation of the high voltage, and outputs the correction voltage according to the detected pulse voltage to the horizontal / vertical size correction unit, The horizontal / vertical size correction unit changes the size of the horizontal / vertical size signal supplied from the microcomputer to the horizontal / vertical deflection circuit according to the correction voltage, thereby maintaining the high pressure at the time of changing the beam current of the water pipe to maintain the screen size variation of the water pipe. Prevent it.

1 is a circuit diagram showing a general monitor circuit.

2 is a circuit diagram showing a high voltage regulation circuit of the monitor according to the present invention.

* Explanation of symbols for main parts of the drawings

10: flyback transformer 20: micom

30: horizontal deflection circuit 40: high pressure detection unit

50: horizontal size correction unit 41: DC converter

42: current amplifier (darlington circuit: Q1, Q2)

43: correction voltage output unit Q3: transistor

D1: rectifier diodes R1 to R8: resistors

C1, C2: Capacitor

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

2 is related to the high-pressure regulation circuit of the monitor according to the present invention, the flyback transformer 10, the microcomputer 20, the horizontal deflection circuit 30, the high pressure sensor 40 and the horizontal size correction unit 50 Consists of.

Here, the high-pressure sensor 40 is composed of a rectifying diode (D1), the DC converter 41, a darlington circuit for converting the pulse voltage output from the secondary winding of the flyback transformer 10 into a DC voltage And a current amplifier 42 which receives the converted DC voltage through the base stage and amplifies a predetermined voltage Vcc1 supplied to the collector stage according to the base voltage and outputs it through the emitter stage. And a correction voltage output section 43 which is composed of a resistor R3 and a capacitor C1 and converts an amplified current into a voltage component to output a correction voltage.

In addition, the horizontal size corrector 50 receives a correction voltage from the base terminal through the resistor R4 and receives a horizontal size signal H.size from the microcomputer 20 through the resistor R5. In addition, the emitter stage is connected to the horizontal deflection circuit 30 and is composed of a transistor 03 that receives a predetermined voltage Vcc2 through the resistors R6, R7, and R8.

Next, the operation and effects of the present invention will be described in detail with reference to FIG. 2.

First, the pulse voltage output from the secondary winding of the flyback transformer 10 is converted into a DC voltage through the rectifying diode D1 of the DC converter 41, and then the first transistors of the Darlington circuits Q1 and Q2. It is applied to the base end of (Q1). In this case, since a predetermined voltage Vcc1 is supplied to the collector terminals of each of the first transistor Q1 and the second transistor Q2, the second transistor Q2 according to the magnitude of the voltage applied to the base terminal of the first transistor Q1. The magnitude of the current I ₁ flowing into the emitter stage through the collector stage of) is changed.

That is, when the high voltage changes due to the change in the beam current, the pulse voltage output from the secondary winding of the flyback transformer 10 also changes, and thus the voltage input to the base end of the darlington circuits Q1 and Q2 also changes. Accordingly, the magnitude of the current I ₁ output from the darlington circuits Q1 and Q2 also changes.

In general, since the Darlington circuits Q1 and Q2 are used for current amplification, the sensing current output from the secondary winding of the flyback transformer 10 can be set small so that it does not affect other systems. Accordingly, the current I ₁ output from the darlington circuit is converted into a voltage component through the resistor R3 and then input to the base end of the transistor 03 of the horizontal size correction unit 50. That is, the point voltage (A) sensed by the resistor R3 becomes the correction voltage and is applied to the base terminal of the transistor 03.

As a result, the collector-base current I ₂ of the transistor Q3 is changed according to the difference in the correction voltage input to the base terminal of the transistor Q3, and the change of the collector-base current I ₂ is caused. According to the change of emitter-collector current I ₃ , the point voltage (B) detected by the resistors R6, R7, and R8 becomes a horizontal size signal (H.size), resulting in a horizontal deflection circuit. It is input to 30.

That is, when the high voltage fluctuates, the pulse voltage detected from the secondary winding of the flyback transformer 10 is changed to (A) the point voltage and (B) the point voltage is changed accordingly. The size of the horizontal size signal H.size supplied from the microcomputer 20 to the horizontal deflection circuit 30 may be adjusted.

In addition, the present invention can extend its use to not only the horizontal size of the screen but also the vertical size of the screen.

As described above, in the present invention, when the high pressure sensor detects the pulse voltage output from the secondary winding of the flyback transformer to detect the variation of the high voltage, and outputs the correction voltage according to the detected pulse voltage, the horizontal voltage corrector The horizontal size corrector changes the size of the horizontal size signal supplied from the microcomputer to the horizontal deflection circuit according to the correction voltage to maintain the high pressure at the time of changing the beam current of the water pipe to prevent the screen size of the water pipe from changing.

Claims (2)

A flyback transformer 10 for boosting the B + voltage input from the primary winding and supplying it to the anode of the water pipe, and a microcomputer 20 for outputting a horizontal / vertical size signal according to a mode to adjust the horizontal / vertical size of the screen. , And receives the B + voltage through the primary winding of the flyback transformer 10, generates a horizontal / vertical deflection current by the horizontal / vertical size signal input from the microcomputer 20, and supplies it to the horizontal / vertical deflection coil. In the monitor equipped with a horizontal / vertical deflection circuit 30, the high voltage detecting unit 40 for detecting the pulse voltage output from the secondary winding of the flyback transformer 10, and outputs a correction voltage according to the detected pulse voltage ), And a horizontal / vertical size correction unit 50 that adjusts the magnitude of the horizontal / vertical size signal supplied from the micom 20 to the horizontal / vertical deflection circuit 30 according to the correction voltage. The high-pressure sensing unit 40 is composed of a rectifying diode (D1), the DC converter 41 for converting the pulse voltage output from the secondary winding of the flyback transformer 10 into a DC voltage, Darlington circuit ( Q1 and Q2), the current amplifying unit 42 which receives the converted DC voltage through the base stage and amplifies the predetermined voltage Vcc1 supplied to the collector stage according to the base voltage and outputs it through the emitter stage. And a correction voltage output section (43) configured to output a correction voltage by converting the amplified current into a voltage component and including a resistor (R3) and a capacitor (C1). According to claim 1, wherein the horizontal size correction unit 50 is the base end receives the correction voltage through the resistor (R4), the collector end receives the horizontal size signal from the microcomputer 20 through the resistor (R5) And a transistor (Q3) having an emitter stage connected to the horizontal deflection circuit (30) and receiving a predetermined voltage through the resistors (R6, R7, R8).