KR19990005563A - Size compensation circuit of multi-mode monitor - Google Patents

Abstract

The present invention relates to a size compensation circuit for stabilizing a size of a multi-mode monitor. In the circuit of the present invention, the microcomputer 100 receives the vertical and horizontal synchronization (V.sync, H.sync) signals and the horizontal size (H.size), vertical size (V.size), and F / V signals, and the horizontal deflection unit 110 and the vertical deflection unit 160 receive the horizontal and vertical size signals from the microcomputer 100. In the monitor that receives the input and adjusts the current flowing in the deflection coil, the FBT 120 boosts the B + voltage applied to the primary winding according to the deflection amount of the horizontal deflection unit 110 to supply a high voltage to the secondary winding. The high voltage detector 130 outputs a voltage corresponding to the B + voltage change by feeding back the B + voltage applied to the primary winding of the FBT 120, and the microcomputer 100 is output according to the output voltage of the high voltage detector 130. Adjust the horizontal size (H.size) to the horizontal deflection unit 110 The horizontal size correction unit 140 and the vertical size beam supplied to the vertical deflection unit 160 by adjusting the vertical size (V.size) output by the microcomputer 100 according to the output voltage of the high pressure detection unit 130. It is composed of a government 150, detects the high pressure of the FBT according to the change in the brightness of the screen and prevents the size variation according to the frequency to transmit a constant size signal to the horizontal deflection portion and the vertical deflection portion, regardless of the brightness and frequency of the screen vertical And the horizontal width can be stabilized.

Description

Size compensation circuit of multi-mode monitor

The present invention relates to a screen size control technology of a monitor, and more particularly, to a size compensation circuit of a multi-mode monitor for maintaining a constant horizontal and vertical width regardless of screen brightness and frequency.

In general, the monitor receives rectified AC power, rectifies and induces the secondary side through the transformer to provide various powers required by the circuit, and to supply B + voltage to the FBT by receiving the DC voltage provided from the SMPS power supply. DC-DC converter, and FBT for providing high voltage, screen voltage, control grid voltage, etc. required by CRT.

Referring to FIG. 1, the B + voltage provided by the DC-DC converter 20 is applied to one end of the primary winding of the FBT 30, and the horizontal output unit 42 is connected to the other end thereof.

The horizontal output transistor Q1 is turned on and off in response to the horizontal drive signal to switch the B + voltage applied through the FBT primary winding, and at the same time, the damper diode Dd, the retrace capacitor Cr, and the horizontal deflection coil Ly, etc. The sawtooth current flows through the horizontal deflection coil Ly by the action of. At this time, the S-shaped correction capacitor Cs and the linearity correction coil Ls are connected to the horizontal deflection coil Ly to correct the horizontal linearity.

That is, when the deflection angle is large, the deflection angular velocity is larger than the deflection angular velocity of the center portion when scanning the peripheral portion of the screen so that the sawtooth current is S-shaped to prevent the peripheral portion of the screen from appearing longer than the center portion of the screen. Allow it to be less.

In addition, a transistor (Q2) connected to a diode modulator of the horizontal deflection unit is a horizontal size signal (H.size) input from a microcomputer (not shown) and a pincushion adjustment signal (Pincushion) input from a pincushion correction IC (not shown). It is possible to adjust the horizontal size of the screen by varying the base current of the circuit.

That is, 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 deflection coil. Therefore, the microcomputer outputs an appropriate PWM signal to vary the current of the horizontal deflection coil Ly to be horizontal. The size of the screen is adjusted, and the current flowing through the horizontal deflection coil Ly is corrected according to the pincushion signal so that the size of the screen is constant at the top, bottom, and center.

On the other hand, there are usually a plurality of secondary windings of the FBT 30, including secondary windings for generating a high voltage, and tertiary windings for monitoring a high voltage induced to the secondary side.

When the horizontal output transistor Q1 of the horizontal output unit 42 is turned off, high voltage is generated in the primary winding. Accordingly, a voltage according to the winding ratio is induced to the secondary winding, thereby obtaining a desired voltage on the secondary side.

Therefore, the high voltage (HV) applied to the anode of the CRT is used to rectify the voltage induced in the secondary winding of the FBT 30, and the high voltages (FOCUS, SCREEN) applied to the focus of the CRT and the screen grid are also FBT (30). In the secondary winding.

However, in the above circuit, the CRT beam current (ie, anode current) varies according to 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.

The reason why the size is not stabilized according to the brightness of the screen is that the high voltage section and the horizontal output section are not separated. However, if the high voltage part and the horizontal output part are designed separately, the manufacturing cost increases.

Therefore, in the system using the high voltage unit and the horizontal output unit integrally, it is necessary to stabilize the size as a separate system by providing a size compensation circuit of low cost and simple structure.

Accordingly, an object of the present invention is to provide a size compensation circuit of a multi-mode monitor for stabilizing a size regardless of brightness and frequency of a screen without separating the high voltage part and the horizontal output part. .

In the circuit of the present invention for achieving the above object, the microcomputer receives the vertical synchronization (V.sync) and horizontal synchronization (H.sync) signal, the horizontal size (H.size) signal and the vertical size (V.size) ) And an F / V signal, a horizontal deflection portion and a vertical deflection portion receive a horizontal size and a vertical size signal from the microcomputer to adjust a current flowing through the deflection coil, and the FBT is adjusted according to the amount of deflection of the horizontal deflection portion. A monitor for boosting a B + voltage applied to a secondary winding to supply a high voltage to a secondary winding, wherein the high voltage detector feeds back a B + voltage applied to a primary winding of an FBT to output a voltage corresponding to a B + voltage variation. The horizontal size correction unit which adjusts the horizontal size (H.size) output by the microcomputer according to the output voltage of the detector and supplies it to the horizontal deflection unit, and the number output by the microcomputer according to the output voltage of the high voltage detector. Adjusting the size (V.size) and characterized by consisting of a vertical size correction unit that supplied to the vertical deflection.

1 is a circuit diagram showing a general horizontal scaling circuit of the monitor,

2 is a circuit diagram showing a size compensation circuit of a multi-mode monitor according to the present invention.

Explanation of symbols for main parts of the drawings

100: micom 110: horizontal deflection portion

120: FBT 130: high pressure detection unit

131: OP amplifier 132: frequency compensation unit

140: horizontal size correction unit 150: vertical size correction unit

160: vertical deflection portion Q3, Q4, Q5, Q6: transistor

C1, C2, C3, C4: Capacitors R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11: Resistor

D1, D2: Diode

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

2 is a circuit diagram showing a size compensation circuit of a multi-mode monitor according to the present invention.

As shown in FIG. 2, the circuit of the present invention includes a microcomputer 100, a horizontal deflection unit 110, a vertical deflection unit 160, an FBT 120, a high pressure detector 130, and a horizontal size correction unit 140. , And the vertical size correction unit 150.

In this case, the high voltage detector 130 divides the high voltage of the FBT 120 by the resistors R1 and R2 to be input to the non-inverting input terminal, the inverting input terminal is grounded through the resistor R3, and the extraction voltage is the inverting input terminal. The OP amplifier 131 fed back to the transistor, the output voltage of the OP amplifier 131 is applied to the base terminal through the resistor (R4), the emitter terminal is grounded through the resistor (R5), the transistor Q3, and the OP amplifier And a frequency compensator 132 connected between the output terminal and the inverting input terminal of 131.

In addition, the horizontal size correction unit 140 has a base end connected to the high voltage detector 130 through a resistor R8 and a collector end connected to the microcomputer 100 through a resistor R9 and a capacitor C1. The emitter stage includes a PNP transistor Q4 connected to the horizontal deflection unit 110.

In addition, the vertical size correcting unit 150 has a capacitor C3 connected to the collector terminal, and is connected to the microcomputer 100, and the base terminal of the high voltage detector unit includes a resistor R11, a capacitor C4, and a diode D2. 130 is coupled to the emitter terminal is composed of a PNP transistor (Q6) connected to the vertical deflection (160).

In the circuit of the present invention configured as described above, as the brightness of the screen increases, the CRT beam current increases and the high pressure of the FBT 120 decreases. The lowered voltage is divided by the resistors R1 and R2 through the backflow prevention diode D1 and input to the non-inverting input terminal of the OP amplifier 131. Since the high voltage input to the non-inverting input terminal is lowered, the OP amplifier 131 transfers the voltage of the change to the input signal to the base terminal of the transistor Q3 through the resistor R4 and the transistor Q3 is turned on. .

Accordingly, the current at the collector stage flows to the emitter stage, and the emitter current is reduced because the emitter current is proportional to the base current. Thus, the point A voltage sensed by the resistor R5 is reduced, and the point A voltage is transmitted to the size correction unit 140 connected between the horizontal deflection unit 110 and the microcomputer 100.

Therefore, when the reduced point A voltage flows through the resistor R8 to the base terminal of the transistor Q4 and the transistor Q4 is turned on, the H.size signal output from the microcomputer 100 is a resistor R9. ) Is transferred to the horizontal deflection unit 110 through the transistor Q4 integrated by the capacitor C1 and turned on.

In addition, the point A voltage is transmitted to the horizontal size corrector 140 and also to the vertical size corrector 150 and applied to the base terminal of the transistor Q6 through the diode D2. Accordingly, the transistor Q6 is turned on so that the vertical size V. size output from the microcomputer 100 is transmitted to the vertical deflection unit 160.

That is, since the brightness of the screen is increased and the high pressure of the FBT 120 is increased, the horizontal and vertical sizes are increased, so that the horizontal size corrector 140 and the vertical size corrector 150 are reduced according to the reduced point A voltage. The horizontal and vertical sizes of the microcomputer 100 are reduced and transmitted to the horizontal deflection unit 110 and the vertical deflection unit 160.

However, the multimode monitor has a different size depending on the frequency since the amount of high pressure generation of the FBT varies according to each vertical and horizontal frequency. Generally, as the horizontal frequency increases, the base current supplied to the horizontal output transistor Q1 (shown in FIG. 1) increases, so that the sawtooth current increases, so that the horizontal width increases, and when the horizontal frequency decreases, the base current supplied to the horizontal output transistor decreases. The sawtooth current decreases, so the horizontal width decreases.

In the present invention, the frequency compensation unit 132 is used to compensate for the size change according to the horizontal frequency as described above.

The microcomputer 100 detects the vertical and horizontal synchronous signals (H.sync, V.sync) and determines a mode, and then outputs a PWM type F / V voltage to control the horizontal width according to the determined mode.

If the horizontal frequency is a low frequency, the microcomputer 100 outputs an F / V voltage for preventing the horizontal width from decreasing. The F / V voltage is integrated by the resistor R10 and the capacitor C2 to become a DC voltage proportional to the horizontal frequency, and is applied to the base terminal of the transistor Q5 through the resistor R6. Accordingly, the transistor Q5 is turned on and the output voltage of the OP amplifier 131 is fed back and flows from the collector terminal of the turned-on transistor Q5 to the emitter terminal through the resistor R7 to the inverting input terminal of the OP amplifier 131. Is entered.

In the above process, since the frequency and the voltage are proportional to each other, the DC voltage by the RC integration at the low frequency is reduced, so that a low current is applied to the base terminal of the transistor Q5, thereby reducing the emitter current. Therefore, since the voltage input to the inverting input terminal of the OP amplifier 131 decreases, the output voltage of the OP amplifier 131 increases.

Accordingly, the output voltage of the OP amplifier 131 is applied to the base terminal of the transistor Q3 to turn on the transistor Q3, and the emitter current of the transistor Q3 increases to increase the point A voltage. Thus, the horizontal size correction unit 140 receives the increased point A voltage and supplies the horizontal deflection unit 110 to increase the horizontal size output from the microcomputer 100.

As described above, the circuit of the present invention detects the high pressure of the FBT according to the change in screen brightness and prevents the size variation according to the frequency of the horizontal deflection part and the vertical deflection part without separating the high voltage part and the horizontal output part in the multi-mode monitor. By transmitting a constant size signal, the vertical and horizontal widths can be stabilized regardless of the brightness and frequency of the screen.

Claims (5)

The microcomputer 100 receives the vertical sync (V.sync) and horizontal sync (H.sync) signals and outputs a horizontal size (H.size) signal, a vertical size (V.size), and an F / V signal. The horizontal deflection unit 110 and the vertical deflection unit 160 receive the horizontal and vertical size signals from the microcomputer 100 to adjust the current flowing through the deflection coil, and the FBT 120 controls the horizontal deflection unit 110. In the monitor for boosting the B + voltage applied to the primary winding according to the deflection amount of, supplying a high voltage to the secondary winding, the B + voltage applied to the primary winding of the FBT 120 is fed back to correspond to the B + voltage variation. A high pressure detector 130 for outputting a voltage; A horizontal size correction unit 140 that adjusts a horizontal size (H.size) output by the microcomputer 100 according to the output voltage of the high pressure detection unit 130 and supplies the horizontal size correction unit 110 to the horizontal deflection unit 110; And a vertical size correction unit 150 that adjusts the vertical size (V.size) output by the microcomputer 100 according to the output voltage of the high voltage detector 130 and supplies the vertical size correction unit 150 to the vertical deflection unit 160. Monitor size compensation circuit. According to claim 1, wherein the high pressure detector 13, the high voltage of the FBT 120 is divided by the resistors (R1, R2) is input to the non-inverting input terminal and the output voltage is fed back to the inverting input terminal for the input signal An OP amplifier 131 for outputting a voltage of change; A transistor Q3 having an output voltage of the OP amplifier 131 applied to a base terminal through a resistor R4 and an emitter terminal grounded through a resistor R5; And a frequency compensator (132) connected between the output terminal and the inverting input terminal of the OP amplifier (131). The frequency compensator 132 of claim 2, wherein the F / V signal output from the microcomputer 100 is applied to the base terminal through the resistor R6, and the output voltage of the OP amplifier 131 is fed back to the collector terminal. And a emitter terminal comprising a transistor (Q5) connected to an inverting input terminal of the OP amplifier (131) through a resistor (R7). The horizontal size correction unit 140 of claim 1, wherein a base end is connected to the high pressure detector 130 through a resistor R8, a collector end is connected to the microcomputer 100, and an emitter end is the horizontal deflection. Size compensation circuit of the multi-mode monitor, characterized in that consisting of a transistor (Q4) connected to the unit (110). The vertical size corrector 150 of claim 1, wherein a base end is connected to the high voltage detector 130 through a diode D2, a collector end is connected to the microcomputer 100, and an emitter end is vertically deflected. And a transistor (Q6) connected to the unit (160).