KR200234417Y1 - Flyback Transformer with Capacitor Protection in Discharge of Tube - Google Patents

Abstract

The present invention relates to a flyback transformer for providing various voltages to a monitor and a CRT. In particular, a coupling capacitor for providing an alternating current (AC) component included in a focus voltage to a parabola circuit part is destroyed by an instantaneous discharge of the anode voltage. The present invention relates to a flyback transformer having a capacitor protection function during discharge in a tube.

In the flyback transformer according to the present invention, a function of providing an AC component included in a focus voltage to an external parabola circuit part by the coupling capacitor C2 is performed, and the anode voltage is instantaneously tolerated through a focus output terminal. In the case of discharging, since the anode voltage is attenuated in the voltage division resistance circuit and then passed through the coupling capacitor C2, the coupling capacitor is not damaged or destroyed as in the prior art even when the anode voltage is discharged in the tube. It becomes stable.

Description

Flyback transformer with capacitor protection during discharge

The present invention relates to a flyback transformer that provides various voltages required for a CRT of a large-sized television. In particular, a coupling capacitor for providing an alternating current (AC) component included in a focus voltage to a parabola circuit part provides an instantaneous discharge of an anode voltage. The present invention relates to a flyback transformer having a capacitor protection function during discharge in a tube to prevent breakage by the discharge.

In general, a flyback transformer is used to supply a high voltage (approximately 30 kV) to the anode and provide a focus (3 kV) and a screen voltage to a large monitor such as a television screen or a CRT tube for CAD.

A schematic circuit diagram of such a conventional flyback transformer is shown in FIG. 1. Referring to FIG. 1, the flyback transformer is described.

) Is a pulse generated at the collector side of the horizontal output transistor when the horizontal output transistor inside the horizontal output unit 10 is operated by the power applied to the primary coil L1 of the flyback transformer. It is induced from the primary coil (L1) to the secondary coil (L2).

The voltage induced in the secondary coil L2 is rectified by the high-voltage rectifier diodes D1 to DN, and then first provided as an anode voltage VA as an anode of the CRT, and also voltage division resistors R11, R12, Focus voltage (VF) and screen voltage (R21, R22, VR11, VR21, R3, VR3)

VS), respectively.

When the anode voltage VA is unstable, the CRT screen becomes unstable on the screen, so that a clear image cannot be provided, so that the focus voltage output terminal and the parabola circuit part (not shown) are stabilized. The coupling capacitor C2 is connected therebetween to provide the parabola input AC voltage vp through the coupling capacitor C2 to the parabola circuit portion, and the magnitude of the anode voltage in the parabola circuit portion to the magnitude of the AC component. In order to determine and stabilize the anode voltage, the power supply voltage B + of the primary coil L1 is controlled.

The coupling capacitor detects an AC component included in a focus voltage of about 3 KV and provides it to the parabola circuit part, and uses a capacitor that withstands a breakdown voltage of about 10 KV. This is because a capacitor having a breakdown voltage of 10 KV or more is used. In this case, the size becomes very large in proportion to the breakdown voltage, and the price is much higher, so that the flyback transformer is not practical when a capacitor withstanding a breakdown voltage of about 10KV or more and 30KV is used.

However, in such a conventional flyback transformer, when a high-voltage anode voltage of about 30 KV is momentarily discharged to the capacitor (aka, internal discharge), the capacitor having a withstand voltage of 10 KV cannot be tolerated. Damaged or destroyed, there was a problem that the flyback transformer loses its function.

The present invention is devised to solve the above problems.

Accordingly, an object of the present invention is to provide a capacitor protection function during in-discharge discharge to prevent the coupling capacitor for providing the alternating current (AV) component included in the focus voltage to the parabolic circuit portion to be destroyed by the momentary discharge of the anode voltage. To provide a flyback transformer.

1 is an internal circuit diagram of a conventional flyback transformer.

2 is an internal circuit diagram of a flyback transformer according to the present invention.

Explanation of symbols on the main parts of the drawings

10: horizontal output unit 20: flyback transformer

L1: Primary Coil L2: Secondary Coil

FC: Iron core D1 ~ DN: High pressure rectifier diode

R11, R12, R21, R22, R3: resistor VR11, VR21, VR3: variable resistor

C2: coupling capacitor VA: anode voltage

VF: Focus voltage

PI: Parabola Input Voltage VS: Screen Voltage

As a technical means for achieving the above object of the present invention, the flyback transformer of the present invention is voltage-converted from the primary coil to the secondary coil, and then supplies the anode voltage through the high-voltage rectifier diode, the secondary coil A flyback transformer for dividing a voltage rectified from an intermediate tap into a voltage division resistor circuit to a predetermined size to supply a focus voltage, and to provide an AC component included in the focus voltage to a parabola circuit unit as an external circuit. And a capacitor for providing an AC component in the focus voltage to the parabolic circuit portion by connecting a contact between an intermediate tap of the primary coil and a voltage division resistor circuit and an input terminal of the parabola circuit portion. Provides AC component included in the focus voltage and provides stable discharge function even when the anode voltage is discharged in the tube. Characterized in that to.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of the flyback transformer according to the present invention will be described in detail. In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

FIG. 2 is an internal circuit diagram of a flyback transformer according to the present invention. Referring to FIG. 2, the flyback transformer 20 shown in FIG. 2 is induced by the horizontal output unit 10 by the applied power. Primary and secondary coils L1 and L2 for transforming, High voltage rectifying diodes D1 to DN for rectifying the induced pulse to provide an anode voltage, and an intermediate tap MT of the secondary coil L2. A voltage dividing resistor circuit (R11, R12, R21, R22, VR11, VR21, VR21, R3, VR3) for variably dividing the voltage from the predetermined size to provide a focus voltage and a screen voltage;

A coupling capacitor C2 configured to be connected between a contact between the intermediate tap MT of L1 and the voltage dividing resistor circuit and an input terminal of the parabola circuit portion to provide an AC component in the focus voltage VF to the parabola circuit portion. ).

Here, ABL, which is not described in the drawings, is an abbreviation of Auto Beam Current Limiter or Auto Bright Limiter, which is a circuit block for detecting screen brightness and controlling screen voltage.

Operation according to the flyback transformer of the present invention configured as described above will be described in detail below based on the accompanying drawings.

Referring to the flyback transformer (Fly Back Transformer) according to the present invention with reference to Figure 2, the power supply voltage (B +) applied to the primary coil (L1) of the flyback transformer 20 shown in Figure 2 The pulse generated by the horizontal output unit 10 is induced from the primary coil (L1) of the flyback transformer 20 to the secondary coil (L1). Pulses induced in the secondary coil L2 of the flyback transformer 20 are rectified by the high-pressure rectifier diodes D1-DN. An anode voltage VA of approximately 30 KV rectified by the high-voltage rectifier diode is provided to the anode of the water pipe, and the voltage from the middle tap MT of the secondary coil L2 is a voltage division resistor circuit R11. And divided by R12, R21, R22, VR11, and VR21 (R3, VR3) to provide the focus voltage VF and the screen voltage VS of the CRT.

An AC component included in the focus voltage VF is provided to an external parabola circuit unit through a coupling capacitor C2 connected to the intermediate tap MT. In the parabola circuit unit, an AC component included in the focus voltage is provided. The magnitude of the component determines whether the anode voltage is stable or unstable. For example, when the anode voltage is 30KV, the AC voltage included in the focus voltage is 1kv, and when the anode voltage is 35KV, the AC voltage becomes 1.2kv, so the magnitude of the anode voltage can be known from the AC voltage. .

As described above, the coupling capacitor C2 performs a basic function of providing an AC component included in a focus voltage to an external parabola circuit part, and at the same time, when the anode voltage discharges instantaneously through a focus output terminal. Since the anode voltage is sufficiently attenuated in the voltage division resistor circuit, the coupling capacitor C2 passes through the coupling capacitor C2, so that the coupling capacitor is stable without damage or destruction as in the prior art even when the anode voltage is discharged in the tube.

According to the present invention as described above, there is a unique effect of preventing the coupling capacitor for providing the alternating current (AC) component included in the focus voltage to the parabola circuit portion to be destroyed by the momentary discharge of the anode voltage.

The above description is only a description of an embodiment of the present invention, and the present invention is capable of various changes and modifications within the scope of its configuration. In addition, one of ordinary skill in the art will readily recognize that the flyback transformer having the capacitor protection function during the discharge in the tube is not limited to the above-described embodiment.

Claims (1)

After voltage conversion from the primary coil L1 to the secondary coil L2, the anode voltage VA is supplied through the high voltage rectification diodes D1 to DN, and rectified from the intermediate tap MT of the secondary coil. Divided voltage into voltage division resistors R11, R12, R21, R22, VR11, and VR21 circuits to supply a focus voltage VF, and the AC component included in the focus voltage to an external circuit parabola circuit part. In a flyback transformer having a function of providing a voltage, a capacitor C2 for providing an AC component in the focus voltage VF to the parabola circuit part is divided into an intermediate tap MT of the primary coil L1 and voltage division. It is configured by connecting between the contact with the resistance circuit and the input terminal of the parabola circuit portion, to provide an AC component included in the focus voltage to the parabola circuit portion, and to perform a stable discharge function during the discharge of the anode voltage in the tube. Characteristic discharge chamber A flyback transformer having a sitter protection.