KR950000291B1 - Horizontal laster compensating circuit for monitor - Google Patents

Abstract

The circuit enables each mode to be linearly and digitally controlled in correcting the position of a horizontal raster dependent on each frequency in the multiple mode monitor. This circuit comprises a horizontal output circuit (15) which outputs sawtooth wave current, a horizontal deflecting unit (14) which deflects the cathode current of CPT by the saw tooth wave current, a rectifying unit (11) which outputs DC current horizontally rectified over the input voltage (B+), a constant voltage unit (18) which keeps the output of the potential from the rectifying unit constant potential, a frequency voltage converting unit (16) which outputs a voltage that corresponds to the detected horizontal frequency, a bias correcting unit (17) which outputs the voltage (B+) by controlling the output of the constant voltage unit, a bias circuit (12) which outputs the bias voltage (VB) by amplifying the output (V3) of the bias correcting unit, and a raster correcting unit (13) which corrects the position of raster by changing the deflected currents (I1), (I2) of the horizontal deflecting unit.

Description

Horizontal Raster Correction Circuit of Monitor

1 is a horizontal raster correction circuit diagram of a conventional monitor.

2 is a horizontal raster correction circuit diagram of the monitor of the present invention.

3 is a waveform diagram of a sawtooth wave current according to deflection current correction.

* Explanation of symbols for main parts of the drawings

1, 11: rectifier 2, 12: bias circuit

3, 13: Raster Compensation 4, 14: Horizontal deflection

5, 15: horizontal output circuit 16: frequency voltage converter

17: bias adjustment unit 18: constant voltage unit

OP ₁ : Operational Amplifier FBT: Flyback Trans

Q ₁ , Q ₂ , Q ₁₁ -Q ₁₃ : Transistor PD ₁ : Light emitting diode

PT ₁ : Light receiving transistor ZD ₁₁ , ZD ₁₂ : Zener diode

D ₁ , D ₂ , D ₁₁ , D ₁₂ : Diodes C ₁ -C ₃ , C ₁₁ -C ₁₅ : Condenser

R ₁ -R ₁₁ : Resistance DY: Deflection coil

L ₁ : coil

The present invention relates to the position correction of a free spot in a monitor. In particular, in a multi-mode monitor, the horizontal raster of a monitor enables linear digital control in each mode in correcting a horizontal raster position according to each frequency. It relates to a stew correction circuit.

1 is a horizontal raster correction circuit diagram of a conventional monitor. As shown in FIG. ₁ , a diode D ₁ , a D ₂ , a capacitor C ₂ , and a C ₃ are formed of a flyback transformer FBT. In the secondary winding, the rectifier 1 rectifies and smoothes the potential and the negative potential with the voltage B ⁺ as the reference potential, and the resistor R ₂ -R ₄ is configured to receive the output of the rectifier 1 to receive the bias voltage ( A bias circuit 2 for outputting V _B ), a horizontal output circuit 5 for outputting a horizontal injection sawtooth current I, a horizontal deflection coil DY, a coil L ₁ , a resistor R ₁ and It consists of a capacitor (C ₁ ) and a horizontal deflection portion (4) for deflecting electrons emitted from the cathode of the CPT according to the sawtooth wave current of the horizontal output circuit (5), and transistors (Q ₁ ), (Q ₂ ) Raster correction unit (3) for correcting the horizontal raster of the screen by changing the direction of the deflection current of the horizontal deflection section 4 in accordance with the output of the bias circuit (2) The diodes D ₁ and D ₂ are damper diodes, and the capacitors C ₂ and C ₃ are resonance capacitors.

The resistor R ₃ is a variable resistor.

The operation process of the conventional circuit configured as described above will be described with reference to the waveform diagram of the sawtooth current according to FIG. 3 deflection current correction.

First, when the horizontal injection sawtooth current is output from the horizontal output circuit 5, the horizontal deflection coil DY of the horizontal deflection portion 4 horizontally deflects electrons emitted from the cathode of the CPT to form an image on the CPT screen. .

At this time, the rectifier 1 is a damper diode (D ₁ ), (D ₂ ) and the resonant capacitor (C ₂ ), (with the power source B ⁺ as the reference potential to the primary winding of the flyback transformer (FBT)). The rectified smooth DC voltage is output to the bias circuit 2 through C ₃ ).

Therefore, if the middle tap of the resistor R ₃ of the bias circuit 2 is adjusted close to the resistor R ₂ side to correct the raster position converted according to the horizontal frequency, the bias circuit receives the voltage of the rectifier 1. (2) turns on the transistor Q ₁ of the raster compensator 3.

Accordingly, since the current I ₁ amplified by the raster compensator 3 flows through the resistor R ₁ and the coil L ₁ of the horizontal deflection portion 4, the deflection current is increased as shown in FIG. 3. The raster is moved to the left side of the screen by parallel translation.

On the other hand, when the middle tap of the resistor R ₃ of the bias circuit 2 is adjusted toward the resistor R ₄ , the transistor Q2 of the raster adjusting section 3 is turned on and the current I ₂ is turned in the horizontal direction 4. As it flows through the coil L ₁ and the resistor R ₁ to the transistor Q ₂ , as shown in FIG. 3, the deflecting current is moved in parallel to the left side of the zero point to move the raster to the right side of the screen. Move it.

However, in such a conventional circuit, the midpoint potential output from the primary winding of the flyback transformer is not a ground potential, but a positive potential and a negative potential are generated based on the high voltage input to the flyback transformer. It should be operated at a potential similar to that of the backtrans.

In addition, since the conventional circuit uses a variable resistor to fix the raster position, there is a problem that it cannot be applied to a multi-mode monitor because it cannot interface with a digital circuit controlled by another microprocessor without changing the frequency according to the frequency. .

The present invention is designed to generate the bias voltage according to the horizontal frequency by using the photocoupler and to stabilize the electrostatic potential and the negative potential with the constant voltage part, and to correct the raster position by digital control according to the horizontal frequency. Invented a raster correction circuit, it will be described in detail with reference to the accompanying drawings as follows.

2 is a horizontal raster correction circuit diagram of the monitor of the present invention, as shown therein, according to the horizontal output circuit 15 for outputting the horizontal injection sawtooth current I and the sawtooth current of the horizontal output circuit 15 according to the present invention. A horizontal deflection portion 14 for deflecting electrons emitted from the cathode of the CPT, and a rectifying portion for outputting an electric potential and a negative potential smoothed at the primary winding of the flyback transformer (FBT) using the voltage B ⁺ as a reference potential. (11), a constant voltage unit (18) for stabilizing the static potential and the negative potential of the rectifier (11), and a bias circuit (12) for amplifying the output of the constant voltage unit (18) and outputting a bias voltage (V _B ). And a raster compensator 13 for correcting the raster position by changing the deflection current direction of the horizontal deflection section 14 according to the output of the bias circuit 12, and converting the change of the horizontal frequency into voltage. The frequency voltage converter 16 and the output of the frequency voltage converter 16 Comprising a bias adjusting unit 17 for converting the input voltage of the bias circuit 12, the constant voltage unit 18 is a resistor (R ₈ ), Zener diodes (ZD ₁₁ ), (ZD ₁₂ ) and the resistor (R ₉₎ ) Is connected in series to the Zener diodes (ZD ₁₁ ), (ZD ₁₂ ) and the capacitors (C ₁₄ ) and (C ₁₅ ) in parallel, respectively, and the bias adjustment unit 17 is a frequency voltage converter 16 The output of the grounded emitter of the transistor (Q ₃ ) connected to the base through the resistor (R ₁₀ ) through the resistor (R ₁₁ ), the light emitting diode (PD ₁₁ ), one side of the output of the constant voltage unit 18 ( The other side of the resistor R ₆ connected to V ₁ ) is connected to the bias circuit 12, and the emitter receives light connected to the output V ₂ of the constant voltage unit 18 through the resistor R ₇ . and configured to connect to the collector of the transistor (PT _11), the bias circuit 12 is connected via an output (V _3), the resistance (R ₅₎ of the bias adjusting unit 17 to the non-inverting terminal (+) The operational amplifier connected to the reference voltage (B ⁺⁾ of the constant-voltage unit 18 via a resistor (R ₄₎ hereinafter and as well as through a resistor (R ₃₎ (OP ₁ - an operational amplifier (OP _1), an inverting terminal of the () ) connected to the output (V _B) of the configuration and connected to the output (V _B) Las turbo unit 13 via a resistor (R _2).

A photocoupler is formed of the light emitting diode PD ₁₁ and the light receiving transistor PT ₁₁ .

The operation and effects of the horizontal raster correction circuit of the monitor according to the present invention configured as described above will be described in detail with reference to the waveform diagram of the sawtooth wave current according to FIG. 3 deflection current correction.

First, when the horizontal injection sawtooth current is output from the horizontal output circuit 11, the horizontal deflection coil DY of the horizontal deflection portion 14 horizontally deflects electrons emitted from the cathode of the CPT to form an image on the screen of the CPT. do.

At this time, the rectifier 11 using the voltage (B ⁺ ) input to the primary winding of the flyback trend (FBT) as the reference potential is the damper diodes (D ₁₁ ), (D ₁₂ ) and the capacitor (C ₁₂ ), ( C ₁₃ ) outputs the rectified smooth DC voltage to the raster compensator 13 and the constant voltage unit 18 through the constant potential and the negative potential, whereby the constant voltage unit 18 outputs the resistors R ₈ , R ₉ , and The stabilized constant voltages (V ₁ ) and (V ₂ ) are output through the zener diodes (ZD ₁₁ ) and (ZD ₁₂ ).

In addition, the frequency voltage conversion unit 16 that detects a change in the horizontal frequency in accordance with the multi-mode changes the horizontal frequency to a corresponding voltage to convert the transistor Q ₃ through the resistor unit R ₁₀ of the bias adjustment unit 17. Output to base

At this time, the transistor Q ₃ is turned on and the light emitting diode PD ₁₁ inputted by the voltage B ⁺ generates photoelectrons, and the phototransistor transistor PT ₁₁ inputted to the base by the photodiode turns on the constant voltage unit 18. Adjust the output of V ₁ .

Therefore, when the light receiving transistor PT ₁₂ adjusts the output V ₁ of the constant voltage unit 18 to the electrostatic potential because the amount of photoelectrons received at the base is small, the bias circuit 12 may have a resistance at the non-inverting terminal (+). R _5), a positive potential (V ₃₎ of the operational amplifier (OP _1), the resistance (R _3), raster adjustment element (13 amplifies the bias voltage (V _B) by the amplification degree of the (R ₄₎ input through) Turns on transistor Q ₁₁ .

That is, as shown in FIG. 3 as the deflection current I ₁ is input from the rectifier 11 through the raster compensator 13 to the coil L ₁ and the resistor R ₁ of the horizontal deflection portion 14. As described above, the raster is moved to the left side of the screen by moving the deflection current in parallel with respect to the zero point.

On the other hand, when the light receiving transistor PT ₁₁ of the bias adjusting unit 17 makes the output of the constant voltage unit 18 negative by the output of the frequency voltage converting unit 16, the operational amplifier OP ₁ of the bias circuit 12 becomes By outputting the amplified negative potential bias voltage B _B to the raster compensator 13, the transistor Q12 is turned on, so that the deflection current I ₂ causes the resistance R ₁ of the horizontal deflection portion 14, Since it flows through the coil L ₂ to the raster compensator 13, as shown in FIG. 3, the deflection current moves in parallel with the zero point to move the raster to the right side of the screen.

As described in detail above, the horizontal raster correction circuit of the monitor of the present invention adjusts the bias voltage according to the horizontal frequency to change the raster position according to the horizontal frequency in the multi-mode monitor. It can always appear in a certain position on the screen. In other words, the raster can be always displayed in the center of the screen by interfacing with a digital circuit controlled by a microprocessor.

Claims (4)

The horizontal output circuit 15 for outputting the horizontal injection sawtooth current, the horizontal deflection section 14 for deflecting the cathode current of the CPT according to the sawtooth current of the horizontal output circuit 15, and the flyback transformer FBT. A rectifier 11 for outputting a rectified smooth DC voltage using the voltage (B ⁺ ) input to the primary winding as a reference potential, and a constant voltage part for maintaining the output of the static potential and the negative potential of the rectifier 11 at a constant potential. 18, a frequency voltage converter 16 for detecting a horizontal frequency and outputting a voltage corresponding thereto, and adjusting the output of the constant voltage unit 18 by converting the output of the frequency voltage converter 16; And a bias circuit 17 for outputting a voltage B ⁺ , a bias circuit 12 for amplifying the output V ₃ of the bias controller 17 and outputting a bias voltage V _B , and the bias circuit The deflection currents I ₁ and I _{2 of} the horizontal deflection portion 14 are changed in accordance with the output V _B of (12). A horizontal raster correction circuit for a monitor, characterized by comprising a raster compensator (13) for correcting the position of the raster. The constant voltage unit 18 of claim 1, wherein one side of the constant voltage unit 18 connects the other side of the resistor R ₈ connected to the rectifier 11 and the raster compensator 13 through the zener diodes ZD ₁₁ and ZD ₁₂ . The capacitors C ₁₄ and C _{15 are} connected to the zener diodes ZD ₁₁ and ZD ₁₂ , respectively, by connecting to the other side of the resistor R ₉ connected to the rectifier ₁₁ and the raster compensator ₁₃ . connected to the capacitor _{(C 14), (C 15} ) and zener diode _{(ZD 11), (ZD 12} ) to input a voltage (B ⁺⁾ to the common connection point the capacitor and the Zener diode (C _14, ZD _11), A horizontal raster correction circuit of a monitor, characterized in that the voltage (V ₁ ) and (V ₂ ) are output at a connection point of (C ₁₅ , ZD ₁₂ ). The method of claim 1, wherein the bias adjusting unit 17 has an emitter resistor (R ₁₁₎ of the transistor (Q ₁₃₎ connected to the output of the frequency-to-voltage conversion unit 16 to the base via a resistor (R _10), a light emitting diode (PD _11), the ground and the light emitting diode through (PD ₁₁₎ photoelectron through the light-receiving transistor (PT _11), junction boxes and the well resistance (R ₆₎ to a bias circuit 12, the collector of the input to the base voltage portion of and connected to the output (V ₁₎ of the (18), characterized in that the light-receiving transistor configured the emitter (PT ₁₁₎ via a resistor (R ₇₎ connected to the output (V ₂₎ of the constant voltage portion 18 Horizontal raster correction circuit of the monitor. 2. The bias circuit 12 according to claim 1, wherein the bias circuit 12 amplifies the output V ₄ of the bias adjuster 17 according to the amplification degree of the resistors R ₃ and R ₄ so as to raise the bias voltage V _B. A horizontal raster correction circuit for a monitor, characterized by comprising an operational amplifier (OP ₁ ) output to (13).