KR920007332Y1 - Flyback transformer - Google Patents

Abstract

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Description

Flyback Trans Voltage Selection Circuit of Monitor

1 is a conventional configuration diagram.

2 is a circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

W1-W2: Power transformer ZD1: Zener diode

C1-C7: Capacitor X1-X2: Exclusive Oagate

R1-R6: resistor D1-D4: diode

Q1-Q2: transistor

The present invention relates to a flyback transformer voltage selection circuit of a monitor, and more particularly to a circuit capable of supplying two modes of voltage to the flyback transformer of the monitor according to the polarity of the vertical synchronization signal.

In general, a conventional configuration for supplying power to a flyback trans (FBT) from a monitor is shown in FIG. First, when a pulse is generated by the number of turns of the secondary coil of the power transformer 1 transforming the input voltage, the rectifier 2 rectifies the secondary pulse of the power transformer 1 to generate a constant DC voltage. Then, the FBT voltage adjusting unit 3 receiving the output of the rectifying unit 2 adjusts the received DC voltage through a variable resistor and outputs it to the power supply of the FBT 4. However, the above-described method has a problem in that it is difficult to maintain a constant high voltage and size according to each mode when the power of the FBT is fixed to one when two or more modes are converted. In addition, when the monitor is operated in two or more modes, the high voltage must be kept constant at all times. If the power supply of the flyback transformer is fixed as described above, it is impossible to maintain a constant voltage.

Accordingly, an object of the present invention is to provide a circuit capable of selectively outputting a voltage according to each mode using a vertical synchronization signal when the monitor is operated in two modes.

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

2 is a detailed circuit diagram of the present invention, in which a secondary coil includes a first coil W1 and a second coil W2, and a winding ratio of the first coil W1 is greater than that of the second coil W2. The power transformer 10, the zener diodes ZD1, the capacitors C1-C2, and the power generator 10 having a larger setting so that the power generated from the first coil W1 is larger than the power generated from the second coil W2. Comprising a resistor (R1) and an exclusive oar gate (X1, X2) and receives the vertical synchronous signal, waveform-forming the vertical synchronous signal in the form of an integral and digital form to generate a first mode signal in a negative logic and positive And a signal generator 20 for generating a second mode signal in logic, and transistors Q1 and Q2, resistors R3-R6, capacitors C6-C7, and diodes D3-D4. After the transistors Q1 and Q2 which are switching elements are connected between the coil W1 and the primary coil of the flyback transformer, the switching is performed. Self-controlled by the signal generation unit 10 to rectify the power supplied to the first coil (W1) when the switching device is turned on when receiving the first mode signal supplied to the first power of the flyback transformer, When the second mode signal is received, the switching element is turned off to block the output passage of the first coil W1, the diodes D1-D2, the resistor R2, and the capacitor ( C3-C5) and a coil C1, and are connected between the second coil W2 and the primary coil of the flyback transformer, when the output of the first power generator 30 is cut off. The second power generating unit 40 rectifies the power induced by the second coil W2 and supplies it to the second power supply of the flyback transformer.

The present invention will be described in detail based on the configuration of FIG.

When a vertical synchronization signal output from a computer is input, the zener diode ZD1 and the capacitor C1 remove noise included in the received vertical synchronization signal. The vertical synchronous signal from which the noise is removed is then waveform-formed into a signal having the same logic state as that of the vertical synchronous signal which is applied to the exclusive oragate X1 having a buffer function and is exclusively combined with the ground power source. The vertical synchronization signal outputting the exclusive ogate X1 is converted into a constant DC voltage by an integrating circuit composed of a resistor R1 and a capacitor C1. At this time, the output of the integrating circuit is again applied to the exclusive oar gate X2 and output as a signal having a "low" logic of OV or a signal having a "high" logic of 5V. At this time, the exclusive ogate X2 outputs a "low" signal in the case of a positive vertical synchronous signal and a "high" signal in the case of a negative vertical synchronous signal. Herein, when the positive type vertical synchronous signal is inputted as the second mode and the negative type vertical synchronous signal is inputted as the first mode, the exclusive oar gate X2 is set to "low" in the second mode. Outputs a signal, and outputs a "high" signal in a first mode.

First, a process of generating a second power source in the second mode (when receiving a positive vertical synchronization signal) generates a low logic signal from the exclusive oar gate (X2). Q2 is turned off, which causes the PNP transistor Q1 to be turned off. At this time, since the transistor Q1 is connected between the first coil W1 and the primary coil of the FBT, when the transistor Q1 is turned off, the path of the voltage induced in the first coil W1 is blocked. . Accordingly, the voltage induced in the second coil W2, the secondary coil of the power transformer, is converted into a DC voltage through a rectifier circuit composed of diodes D1, capacitors C3 and C4, and resistors R2 to convert the second power source. And the second power source is output to the primary side coil of the flyback transformer through the diode D2. At this time, the ripple component included in the DC voltage is removed through the coil L1 and the capacitor C5, and is used as the supply power of the FBT in the second mode.

Secondly, when the first power is generated in the first mode (when a negative vertical synchronization signal is received), the exclusive Q gate is turned on because the exclusive oar gate X2 outputs a high signal. As a result, the transistor Q1 is also turned on. When the transistor Q1 is turned on, a passage is formed between the first coil W1 and the primary coil of the FBT, so that the voltage induced in the first coil W1, the secondary coil of the power transformer, is diode D4. ), A rectifier circuit composed of resistors R3 and R4 and capacitors C6 and C7 is converted into a DC voltage and generated as a first power source. At this time, the number of windings of the first coil W1 should be wound more than the number of windings of the second coil W2, which means that the voltage induced in the first coil W1 is induced in the second coil W2. Because it must be greater than the voltage. The first power source, which is rectified after being output from the first coil W1, is applied to the primary coil of the FBT through the transistor Q1 and the diode D3. At this time, since the second power generated by the second coil W2 is smaller than the first power, the diode D2 operates in reverse bias, and thus the second power cannot be supplied to the FBT.

Therefore, by adjusting the winding ratio of the power transformer, the first power generated by the first coil W1 is set to be larger than the second power generated by the second coil W2, and according to the logic state of the vertical motion signal. The power supply to the FBT is changed by controlling the passage of the power generated by the power transformer. This is determined according to the logic state of the vertical synchronizing signal as described above, and when the second mode signal generated by the positive vertical synchronizing signal is generated, the passage of the first power generated by being induced in the first coil W1 is blocked and the second The second power generated by being induced in the coil W2 is supplied to the FBT, and when the first mode signal for the negative vertical synchronous signal is generated, a path of the first power generated by the first coil W1 is formed, thereby forming the FBT. The second power source is applied to the power supply of the second coil (W2) is blocked by the diode (D2).

As described above, when the monitor is operating in two modes, it is possible to supply the FBT driving voltage suitable for each mode by using the polarity of the vertical synchronizing signal, thereby maintaining a constant high voltage state when selecting each mode, and the power transformer. The secondary coil has a merit that it is easy to adjust the size.

Claims (1)

In the circuit for selectively supplying the flyback transformer voltage of the monitor according to the logic of the vertical synchronization signal output from the computer, the secondary coil is composed of the first coil and the second coil, the winding ratio of the first coil A power transformer 10 configured to be larger than a second coil so that the power generated by the first coil is larger than the power generated by the second coil; and receiving the vertical synchronous signal and integrating the vertical synchronous signal. Between the signal generator 20 generating a first mode signal in a negative logic and a second mode signal in a positive logic by waveform shaping in a digital form, and between the first coil and the primary coil of the flyback transformer. And a switching element connected thereto, wherein the switching element is controlled by the signal generator so that the switching element is turned on when the first mode signal is received. After the rectified power to the rectified power supply to the first power supply of the flyback transformer, when the second mode signal receiving the switching element is turned off the first power generating unit 30 to block the output passage of the first coil And connected between the second coil and the primary coil of the flyback transformer, and rectifying the power induced in the second coil when the output of the first power generator is cut off to rectify the second of the flyback transformer. The flyback transformer voltage selection circuit of the monitor, characterized in that consisting of a second power supply 40 for supplying power.