JP2606295Y2 - Horizontal deflection circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal deflection circuit provided in a CRT display device or the like. More specifically, the present invention relates to a horizontal deflection circuit capable of horizontal scanning corresponding to various horizontal synchronization signals having different frequencies. It is related to the circuit.

[0002]

2. Description of the Related Art FIG. 3 is a configuration diagram of a conventional horizontal deflection circuit.

[0003] (1) is an F / V conversion circuit (frequency / voltage conversion circuit) which outputs a voltage linearly corresponding to the frequency of the input horizontal synchronizing signal, and the F / V conversion circuit (1). Is supplied to the horizontal oscillation circuit (2).
The horizontal oscillation circuit (2) performs horizontal oscillation synchronized with the horizontal synchronization signal.

A signal from the horizontal oscillation circuit (2) is input to a horizontal drive circuit (3), amplified, and turned on.
The output signal (drive signal) whose period has been controlled is applied to the horizontal output transistor Q1 of the horizontal output circuit (4). Then, the horizontal output transistor operates in response to a signal from the horizontal drive circuit (3), a sawtooth wave current (horizontal deflection current) flows through the deflection coil L1, and horizontal scanning of an electron beam emitted from an electron gun (not shown) is performed. Is performed.

(7) A chopper power supply rectifies and smoothes the voltage output from the tertiary winding (5c) of the flyback transformer (5) through a rectifier diode D3 and a smoothing capacitor C5. ), The supply voltage + B to the flyback transformer (5) is controlled so that the anode voltage becomes constant. As a result, the anode voltage is always kept constant for various horizontal synchronizing signals having different frequencies.

(6) is a SW power supply for supplying a predetermined voltage to each circuit.

The horizontal output circuit (4) includes a horizontal output transistor Q1, a damper diode D1, and a horizontal deflection coil L
1. S-shaped correction capacitor C3.

FIG. 4 is a circuit diagram of the chopper power supply (7).

In the figure, VCC 1 is supplied by a SW power supply (6).
Is supplied, the transistor Q is connected through the starting resistor R4.
2, the base current starts flowing, and the collector current starts flowing. Since the windings N1, N2, and N3 are wound with the polarities as shown in the figure, a voltage is generated in the winding N1, and the winding N
2, a voltage is generated in the direction in which the base current increases, and C
7, a positive feedback that the base current increases through R5 and the collector current also increases, and the transistor Q2 turns on. At this time, a voltage is also generated at N3, but no current flows because the direction of the diode D5 is reversed.
The collector current of the transistor Q2 linearly increases due to the inductance of the transformer T1. When the collector current of the transistor Q2 increases to hfe times the base current, the collector current stops increasing and the windings N1, N2
Is generated, the base current is reduced, and the collector current is further reduced, so that the positive feedback reverse to the above operates, and the transistor Q2 is turned off. When the transistor Q2 is turned off, the energy stored in the winding N3 is
5, a current flows in the forward direction, and the capacitor C9 is charged.

In this manner, a blocking oscillation is formed, and the emitter current during the ON period of the transistor Q2 and
During the off period, the current from the winding N3 is smoothed by the capacitor C9 to supply the flyback supply voltage + B.

Note that a circuit including a resistor R3, a capacitor C6, and a diode D4 is a collector potential damping circuit for turning on / off the transistor Q2.

The basic operation of the chopper power supply (7) has been described above.

A circuit A enclosed by a broken line in FIG. 4 is a circuit for varying the supply voltage + B by feedback of a high voltage change applied to the circuit of the chopper power supply (7) for frequency change or the like.

The high detection voltage is input to the base of the transistor Q4 through the resistor R7. A Zener current flows through the Zener diode D7 through the VCC1 to R8 through the emitter of the transistor Q4 to generate a reference potential, which is compared with the high voltage detection voltage. When the high voltage increases and the detection voltage increases, the base current of the transistor Q4 increases, and the collector current increases. As a result, the base current of the transistor Q3 increases, the emitter current also increases, and the base current of the transistor Q2 decreases. As a result, the ON period of the transistor Q2 decreases, the current supplied to the capacitor C9 decreases, and the supply voltage + B output And acts to lower the high pressure. When the high pressure decreases, the operation is reversed, and the high pressure is stabilized.

[0015]

SUMMARY OF THE INVENTION In the conventional horizontal deflection circuit shown in FIGS. 3 and 4, a change in high voltage is detected by detecting the voltage of the tertiary winding (5c) from the flyback transformer (5) and choppers. Although feedback is applied to the power supply (7), it cannot detect a dynamic change such as a luminance change or a window pattern and cannot correct it. Also,
Even if the anode voltage is divided by resistance and used as the detection voltage,
There is a problem that the chopper power supply (7) cannot follow a high frequency dynamic change.

The horizontal deflection circuit of the present invention has been made in view of such circumstances, and provides a horizontal deflection circuit capable of correcting the flyback supply voltage + B for image shape correction accurately and with a fast time constant. The purpose is to do.

[0017]

The horizontal deflection circuit of the present invention has a frequency / voltage conversion means (F / V conversion circuit 1) for generating a voltage corresponding to the frequency of the horizontal synchronization signal, and a horizontal synchronization signal. Horizontal oscillation means (horizontal oscillation circuit 2) for generating a signal having a horizontal oscillation frequency, and horizontal drive means for outputting a drive signal for driving a horizontal output transistor (Q1) according to a signal output from the horizontal oscillation means (Horizontal drive circuit 3) and horizontal output means for driving a horizontal output transistor according to a drive signal output from the horizontal drive means to cause a current to flow to the deflection coil (L1) and to output a horizontal output to a flyback transformer (5) ( 4) and
A reference voltage control means (chopper power supply 7 ') for outputting a reference voltage serving as a reference for a supply voltage to the flyback transformer, and a reference voltage output from the reference voltage control means being input and obtained from the flyback transformer A
To flyback transformer so that node voltage is constant
-Voltage control means (high-voltage control circuit 8) for controlling the supply voltage of the power supply
Wherein the reference voltage control means outputs a reference voltage proportional to the level of the frequency of the horizontal synchronizing signal to the high voltage control means. A first transistor (Q5) having a base supplied with a predetermined power supply voltage and a collector supplied with a predetermined power supply voltage, an output voltage of the reference voltage control means being inputted to the base and an output of the reference voltage control means being supplied to the collector. A second transistor (Q4) to which a base of a third transistor (Q3) for controlling a voltage is connected,
An emitter of the first transistor is connected to an emitter of the second transistor, and a differential operation is performed by the first and second transistors.

[0018]

The reference voltage control means generates a reference voltage for the supply voltage of the flyback transformer in accordance with the frequency of the horizontal synchronizing signal, and the high voltage control means corrects the high voltage fluctuation based on the voltage. In addition, it is possible to follow a high-pressure dynamic change.

[0019]

FIG. 1 is a block diagram showing an embodiment of a horizontal deflection circuit according to the present invention, and FIG. 2 is a basic circuit block diagram of a chopper power supply (7 '). The same components as those of the conventional horizontal deflection circuit shown in FIGS. 3 and 4 are denoted by the same reference numerals, and description thereof is omitted.

The circuit shown in FIG. 1 differs from the conventional circuit shown in FIG. 3 in that an output of an F / V conversion circuit (1) for generating a voltage proportional to the frequency of a horizontal synchronizing signal controls a chopper power supply (7 '). Then, the output of the chopper power supply (7 ') and the voltage divided by the anode and the resistors R1 and R2 are input to the high-voltage control circuit (8) to generate the flyback transformer supply voltage + B and perform high-voltage control. is there. Here, the horizontal deflection circuit (4) specifically employs a diode modulator system, and additionally supplies a flyback transformer supply voltage + B to the left and right pincushion distortion and horizontal amplitude control circuit (9).
To perform horizontal amplitude control.

The circuit of the chopper power supply section (7 ') of FIG.
The difference from the conventional circuit of FIG. 4 resides in that the chopper power supply (7 ') is controlled by the F / V voltage and the reference voltage of the flyback supply voltage + B according to the horizontal synchronization frequency is output.
The collector of the transistor Q4 is connected to the base of the transistor Q3 that controls the base current of the transistor Q2 through the resistor R6, and a voltage obtained by dividing the chopper output by the resistors R10 and R11 is applied to the base of the transistor Q4. The emitter of the transistor Q4 is connected to a resistor R9.
To ground. Also, the transistor Q4
The emitter of the transistor Q5 is connected to the emitter, the collector of the transistor Q5 is connected to the power supply VCC2, and the base is supplied with the F / V voltage through the resistor R12. The transistors Q4 and Q5 operate differentially to control the chopper output by the F / V voltage.

When the frequency rises and the F / V voltage rises, a differential operation is performed, the base current of the transistor Q4 decreases, the base current of the transistor Q3 decreases, the base current of the transistor Q2 increases, and the chopper power supply The output increases. Also, as the output of the chopper power supply increases, negative feedback is applied to the base of the transistor Q4 by the resistors R10 and R11, and the transistors Q4 and Q5 enter a new equilibrium state and are stabilized at an output proportional to the F / V voltage. When the horizontal synchronizing frequency decreases, the operation is reversed, and the output decreases to a value proportional to the frequency and stabilizes. When the resolution is switched on the personal computer to which the CRT display device is connected, for example, when switching from VGA to SVGA, the synchronization signal supplied from the personal computer is temporarily not supplied. Things happen. In such a case, the F / V voltage is not supplied to the chopper power supply unit (7 ') in FIG. 2, but operates in the same manner as in the case where the horizontal synchronization frequency decreases.
Since the reference voltage of the flyback supply voltage + B decreases to a predetermined value and stabilizes, it is possible to prevent the flyback supply voltage + B from rising and breaking the circuit even when the F / V voltage is not input.

By controlling the chopper power supply (7 ') with the F / V voltage in this manner, a voltage which is proportional to the F / V voltage, that is, a reference voltage of the flyback transformer supply voltage which is proportional to the horizontal synchronization frequency is output. It is possible to
Accurate flyback supply voltage + B for image shape correction
In addition, the correction can be performed with a fast time constant, and the image quality of the monitor can be improved. Further, even when the F / V voltage is not input due to switching of the display resolution or the like,
Operates in the same manner as when the horizontal synchronizing frequency decreases, and the reference voltage of the flyback supply voltage + B decreases to a predetermined value and stabilizes, thereby preventing the flyback supply voltage + B from rising and damaging the circuit. Can be.

[0024]

As described above, according to the horizontal deflection circuit of the present invention, it is possible to correct the flyback transformer supply voltage for image shape correction accurately and with a fast time constant. Further, even when the F / V voltage is not input due to switching of the display resolution or the like, the same operation as in the case where the horizontal synchronization frequency is lowered is performed, and the reference voltage of the flyback supply voltage + B is reduced to a predetermined value, Since it is stabilized, it is possible to prevent the flyback supply voltage + B from rising and breaking the circuit.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a horizontal deflection circuit of the present invention.

FIG. 2 is a circuit diagram of the chopper power supply (7 ') of the present invention.

FIG. 3 is an overall configuration diagram of a conventional horizontal deflection circuit.

FIG. 4 is a circuit configuration diagram of a conventional chopper power supply (7).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 F / V conversion circuit 2 Horizontal oscillation circuit 3 Horizontal drive circuit 4 Horizontal output circuit 5 Flyback transformer 6 SW power supply 7 'Chopper power supply 8 High voltage control circuit 9 Left and right pincushion distortion and horizontal amplitude control circuit

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Katsumi Tanaka 2-18-18 Keihan Main Road, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (56) References JP-A-64-78578 (JP, A) JP-A-63 -311873 (JP, A) JP-A-3-6175 (JP, A) JP-A-2-68590 (JP, A) JP-A-63-99466 (JP, U) JP-A-63-171070 (JP, U) )

Claims (1)

(57) [Scope of request for utility model registration] A frequency / voltage converting means for generating a voltage corresponding to the frequency of the horizontal synchronizing signal; a horizontal oscillating means for generating a signal having a horizontal oscillation frequency corresponding to the horizontal synchronizing signal; Horizontal drive means for outputting a drive signal for driving a horizontal output transistor in accordance with a drive signal, and a flyback transformer which drives a horizontal output transistor by the drive signal output from the horizontal drive means to supply a current to a deflection coil, horizontal output means for performing horizontal output, a reference voltage control means for outputting a reference voltage for the supply voltage to the flyback transformer, the reference voltage output from the reference voltage control means is inputted to the fly Anode power obtained from back transformer
Supply voltage to the flyback transformer so that the pressure is constant.
A high voltage control means for controlling the pressure , wherein the reference voltage control means outputs a reference voltage proportional to the level of the frequency of the horizontal synchronization signal to the high voltage control means, A first transistor whose output voltage is input to a base and a predetermined power supply voltage is input to a collector; an output voltage of the reference voltage control means which is input to a base; A second transistor to which a base of a third transistor for controlling an output voltage of the control means is connected, wherein an emitter of the first transistor and an emitter of the second transistor are connected, and a difference between the first and second transistors is provided. A horizontal deflection circuit characterized in that the horizontal deflection circuit is configured to perform a dynamic operation.