KR0173269B1 - Generating device of synchronous signal - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous signal generator, comprising: a current controlled pulse width modulation IC for generating a switch pulse, a driving circuit for outputting a signal of the current controlled pulse width modulation IC, and a voltage suitable for mode conversion in the driving circuit. A step-down circuit to look for; a capacitor connected in series between the drive circuit and the step-down circuit; a horizontal output circuit for horizontal output from the step-down circuit; a flyback transformer for generating a high voltage in the horizontal output circuit; A synchronization signal generating circuit which is connected between a node of the horizontal oscillation circuit and the horizontal output circuit to generate a synchronization signal can quickly respond to the horizontal frequency required for mode conversion.

Description

Synchronous signal generator

1 is a circuit diagram showing a conventional synchronization signal generator.

2 is a circuit diagram showing a synchronization signal device according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Current control pulse width modulation IC 2: Driving circuit

3: step-down circuit 4: horizontal output circuit

5: flyback transformer 10: synchronization signal generating circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronization signal generator, and in particular, a synchronization signal generator for quickly responding to horizontal frequencies that change according to modes of various frequency bands by converting a square wave from a monitor horizontal output circuit into a pulse form in a synchronization signal generation circuit. It is about.

In recent years, as the demand for multimedia that satisfies various functions with a single computer increases rapidly, not only a computer body but also peripheral devices are being developed to display a still image and a high resolution moving image. Among them, a monitor having various resolution characteristics for displaying information efficiently according to a user's request is widely used.

In general, a monitor is an electron beam whose vertical or horizontal movement path is determined by an electric field. The monitor stimulates a fluorescent material applied to a display plate, which is one end of a cathode-ray tube (CRT), to visualize data from an actual user's perspective. It is a structure made to recognize the output of the R (Red: red), G (Green: green), B (Blue: blue) signals indicating the color transmitted from the main body is a current characteristic that the electron beam has a specific frequency When moved by the electron beam is carried together with the electron beam to stimulate the corresponding color material on the display panel to provide a clear color screen.

In order to deflect horizontally, especially in the path of movement of the electron beam, a circuit for inducing an electromagnetic field when the electron beam is emitted from one end of the cathode ray tube is required, which is called a horizontal deflection circuit and is implemented on the main board of the monitor. The resolution characteristic is influenced by the frequency characteristic of the current signal output from the horizontal deflection circuit. That is, as the frequency of the output increases, scan lines corresponding to the corresponding frequencies (phenomena caused by the collision of electron beams) are generated on the display panel, so that a clearer screen can be expected, and when the frequency of the output decreases, the density of the corresponding scan lines decreases on the contrary. Falls.

However, since the word processor does not actually require high resolution among the tasks performed using the computer, the high resolution is required for the graphic work, and therefore, horizontal signals of various sizes are input from the computer main body to the monitor screen controller as needed. This will adjust the resolution of your monitor.

Changing the frequency of the horizontal deflection signal output by the horizontal signal is called mode conversion, and one monitor is designed to automatically change the mode depending on whether it is performing word processing or graphic work. Therefore, at least 20 Hz to 86 Hz can be compatible depending on the characteristics of each signal.

However, when a single monitor is intended to realize modes of various frequency bands, it is difficult to obtain a constant output regardless of mode switching in the output amplifier stage because the operating voltages are different for each mode.

1 is a circuit diagram of a conventional synchronizing signal generator, wherein the horizontal synchronizing signal (H.SYNC) is a square wave which is a pulse for a switch which is the basis of horizontal deflection and high voltage generation in the current control pulse width modulation IC 1 Is applied to the furnace (2). The square wave signal output from the horizontal driving circuit 2 is applied to the step-down circuit 3. The voltage of the square wave is applied to the horizontal output circuit 4, and the waveform is shaped to form a sawtooth wave type horizontal output. In the horizontal output circuit 4, the horizontal sawtooth output signal is applied to the flyback transformer 5 to generate a high voltage by the diode and the capacitor, but the current control pulse width modulation by the feedback circuit using a part of the output as an input. Since a pulse is applied to the SYNC terminal of the IC, it is operated by the natural frequency of the resistor and capacitor connected to the horizontal oscillation circuit until the flyback transformer is operated. At this time, since the operation of the step-down circuit operates abnormally, the transistor Q2 operates.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to take a square wave from a monitor horizontal output circuit, convert it into a pulse form in a synchronization signal generating circuit, and quickly respond to a horizontal frequency port changing according to various frequency modes.

The present invention provides a current control pulse width modulation IC for generating a pulse for a switch to achieve the above object, a drive circuit for outputting a signal of the current control pulse width modulation IC, and the step of finding a voltage suitable for mode conversion in the drive circuit; A synchronization signal including a down circuit, a capacitor connected in series between the drive circuit and the step-down circuit, a horizontal output circuit for outputting horizontally in the step-down circuit, and a flyback transformer for generating a high voltage in the horizontal output circuit. A generator, comprising: a synchronization signal generation circuit connected between a node of the horizontal oscillation circuit and a horizontal output circuit and receiving a square wave output from a horizontal output circuit and converting the square wave into a pulse to generate a synchronization signal It features a device.

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

2 is a circuit diagram of a synchronization signal generator according to the present invention, which includes a current control pulse width modulation IC 1 for generating a switch pulse, a drive circuit 2 for outputting a signal of the current control pulse width modulation IC, A step-down circuit (3) for finding a voltage suitable for mode conversion in the drive circuit, a capacitor (C3) connected in series between the drive circuit and the step-down circuit, and a horizontal output circuit for horizontal output in the step-down circuit ( 4) and a synchronous signal generating circuit 10 connected between a flyback transformer 5 for generating a high voltage in the horizontal output circuit and a node of the horizontal oscillating circuit and a horizontal output circuit for generating a synchronization signal. A signal generator is shown. The synchronization signal generation circuit 10 includes a resistor R6 connected between the node A of the current control pulse width modulation IC and the ground voltage terminal, and a diode D2 connected between the node A and the ground voltage terminal. And a transistor (Q3) having an emitter terminal connected to a connection node of VCC and a collector terminal having a connection node of the resistor (R5), a resistor (R4) connected between a base terminal of the transistor (Q3) and VCC, and A capacitor C5 connected between the node A and the collector terminal, and a resistor R3 connected to the base terminal of the transistor Q3 are connected to one node.

When the power supply (VA, VB, + 12V) is applied, the horizontal synchronizing signal (H.SYNC) becomes a square wave, which is a switch pulse that is the basis of horizontal deflection and high voltage generation in the current control pulse width modulation IC 1, Is applied to the furnace (2). The square wave signal output from the horizontal driving circuit 2 is applied to the step-down circuit 3. The voltage of the square wave is applied to the horizontal output circuit 4, the square difference is output from the horizontal output circuit, and the output square wave generates an impulse type synchronization signal by differential operation to operate the current control pulse width modulation IC. To start. At this time, the horizontal transistor can be operated stably because the horizontal frequency of 31.5㎑-64㎑ of the horizontal circuit is directly applied without the natural frequency caused by the resistor and the capacitor of the current control pulse width modulation IC.

According to the present invention, a square wave is received from a horizontal output circuit and converted into a pulse form in a synchronization signal generating circuit, thereby quickly responding to a horizontal frequency changing according to a mode of various frequency bands.

Claims (1)

A current control pulse width modulation IC for generating a pulse for a switch, a drive circuit for outputting a signal of the current control pulse width modulation IC, a step-down circuit for finding a voltage suitable for mode conversion in the drive circuit, the drive circuit and a step A synchronization signal generator comprising a capacitor connected in series between a down circuit, a horizontal output circuit for performing a horizontal output in the step-down circuit, and a flyback transformer for generating a high voltage in the horizontal output circuit. A resistor R6 connected between the node of the width modulation IC and the horizontal output circuit and connected between the node A and the ground voltage terminal of the current control pulse width modulation IC, and between the node A and the ground voltage terminal. A transistor (Q2) connected to the connection node of the diode (D2), an emitter terminal connected to the VCC, and a collector terminal connected to the connection node of the resistor (R5), and a bay of the transistor (Q3). A synchronization consisting of a resistor R4 connected between the switch terminal and VCC, a capacitor C5 connected between the node A and the collector terminal, and a resistor R3 connected to the base terminal of the transistor Q3 by one node. A synchronization signal generator further comprising a signal generator circuit.