KR0180639B1 - Flyback transformer - Google Patents

Abstract

Exterior case and mold (casting mold) It provides a flyback transformer which is cheap, easy to handle, easy to handle, and can reduce the alternating electric field without using expensive high-pressure condenser insulated with resin.

The high voltage rectifying diodes 3a to 3d are connected in series to the output sides of the respective high voltage coils 6a to 6d of the divided secondary side and the high voltage condenser 2 is connected to the cathode side of the final stage The high voltage output wire 22 of the secondary side is wound around the core of the flyback transformer in such a direction as to generate a pulse in the opposite phase to the horizontal pulse for deflection yoke driving, (19).

Description

Flyback trance

FIG. 1 is a circuit diagram of a flyback transformer according to an embodiment of the present invention; FIG.

FIG. 2 is an equivalent circuit diagram of a core winding coil.

FIG. 3 is an external view of a fly-back transformer according to an embodiment of the present invention; FIG.

FIG. 4 is an external view of a fly-back transformer according to another embodiment of the present invention; FIG.

FIG. 5 is a circuit diagram of a conventional fly-back transformer with an alternating electric field reduction; FIG.

FIG. 6 shows a system for alternating field reduction; FIG.

7 is an equivalent circuit diagram of the alternating field reduction.

FIG. 8 is an external view of a conventional high-voltage condenser with external electrodes; FIG.

FIG. 9 is an internal circuit diagram of a conventional high-voltage condenser with an outside. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

1: flyback transformer (FBT) 2: built-in high-voltage capacitor

3a to 3d: high voltage rectification diode 4: reverse side pulse generation winding

5: High-voltage condenser with external plating 6a to 6d: High-voltage coil

6e: Coil for generating a magnetic core winding reverse-phase pulse 7: Deflection yoke

8: built-in graphite membrane 9: deflection yoke electrostatic capacity:

10: High-voltage / deflection circuit 11: Braun tube

12: panel transparency front film 13: panel transparency surface resistance of the whole film

14: Panel Transparency Film Capacity 16: Horizontal Output Transistor

17: primary side low-voltage coil 18: waveform comparison controller

19: anode cap 20: high voltage connector

21: GND terminal 22: High voltage output wire

23: core 24: outer core winding coil

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flyback transformer (hereinafter abbreviated as FBT) of a display monitor using a cathode ray tube, and more particularly to a technique for reducing an alternating electric field transmitted from a water-

FIG. 5 shows an example of a circuit for reducing an alternating electric field transmitted from the surface of a cathode ray tube using an external high voltage condenser in an FBT of a general display monitor. This conventional method is an example of applying the invention described in U.S. Patent Specification No. 5,218,270.

(3) (3a), (3b), (3c) and (3d) are high voltage rectifying diodes, (4) is a reverse pulse generating winding on the tertiary side, 6 is a high voltage coil, 7 is a deflection yoke, 16 is a horizontal output transistor, 17 is a primary side low voltage coil, 18 is a high voltage coil, ) Is a waveform comparison controller.

FIG. 6 shows an example of the current alternating electric field reduction system. In this drawing, reference numeral 8 denotes a built-in graphite film, reference numeral 9 denotes a capacitance of the deflection yoke, reference numeral 10 denotes a high-voltage / deflection circuit, and reference numeral 11 denotes a cathode ray tube. In this system, the charge Q ₁ in the built-in graphite film 8 is represented by the following formula.

The pulse e _x of the overlapping coil for canceling the alternating electric field is selected so that the overlapping charge Q ₂ becomes equal to the charge Q ₁ in the built-in graphite film 8.

This is determined by the capacity of the built-in high voltage capacitors C _1, CRT capacitor C _2, and the pulse crest value e _p. The number of turns e ₂ of the coil for generating the reverse pulse is determined in consideration of the capacity C ₁ of the built-in high-voltage condenser, and the reverse pulse e _x is applied to the built-in graphite film 8 to increase the amplitude of the alternating electric field V _DY ' Is reduced.

FIG. 7 shows a circuit equivalent to an example of the alternating electric field reduction system of FIG. 6. In this drawing, reference numeral 12 denotes a panel transparent conductive film, 13 denotes a surface resistance of the panel transparent conductive film, and 14 denotes a panel transparent conductive film capacitance. In the equivalent circuit, the alternating electric field is reduced in accordance with the following operation.

A horizontal pulse V _DY (1000 Vpp) for driving the deflection yoke 7 generates a pulse voltage V _DY 'in the built-in graphite film 8 of the cathode ray tube 11 through the capacitance 9 (60 pF) of the deflection yoke. The pulse voltage V _DY 'is generated by the panel transparent conductive film 14 and the surface resistance 13 of the panel transparent conductive film 12 so that the impedance-divided Vp is generated in the panel transparent conductive film 12 and is a source of the alternating electric field .

As an example of reducing the alternating electric field, the reverse pulse V _F '(-150 Vpp) obtained in the reverse pulse generation winding of the tertiary side of the FBT is added to the high voltage condenser 5 (capacity: C _F = 200 pF), the pulse voltage V _DY 'is canceled by the inverse pulse V _F ' in the built-in graphite film 8, and the amplitude of the alternating development V _DY 'is reduced.

This relationship can be expressed by the following equation.

FIG. 8 is an external view of a conventional high-voltage condenser of the prior art, and FIG. 9 is an internal circuit diagram thereof. In these drawings, reference numeral 19 denotes an anode cap, reference numeral 20 denotes a high-voltage connector, and reference numeral 21 denotes a GND terminal. The external high voltage condenser 5 of the FBT is insulated at a high voltage as shown in FIG. 8, so that the external case of about 40 mm x 40 mm x 65 mm and the mold Type resin (epoxy resin or the like) is required, which is expensive, there is a limitation in the installation place in the display monitor, and there is a problem that it becomes difficult to handle in structure.

Further, since a high-voltage connection is required, there is a problem that it becomes difficult to secure the reliability of the high-voltage connecting portion (the high-voltage connector 20).

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to provide an inexpensive high-voltage insulator, which is insulated from expensive cases of high- In which the fly-back transformer can be reduced.

The above object is achieved by a flyback transformer in which a high-voltage rectifier diode is connected in series to the output side of each high-voltage coil of a divided secondary side and a high-voltage condenser is connected to the cathode side of the final- The high-voltage output wire is wound around the magnetic core of the fly-back transformer in a direction in which a horizontal pulse for driving the deflection yoke and a pulse of a reverse phase are generated, and is connected to the cathode-ray tube through the anode cap.

In the present invention, the flyback pulse having the same amplitude as the alternating electric field is superimposed on the high-voltage output wire by winding the high-voltage output wire to the magnetic core, thereby reducing the amplitude of the alternating electric field.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram of an FBT according to an embodiment.

The high voltage rectifying diodes 3a to 3d are connected to the output sides (winding ends) of the multi-divided high voltage coils 6a to 6d and the high voltage output wires 22 are connected to the magnetic core of the flyback transformer, And is wound in a direction in which a pulse of a reverse phase is generated with a horizontal pulse for deflection yoke driving. That is, a coil 6e for generating a magnetic core winding reverse-phase pulse is disposed.

2 is a diagram showing an equivalent circuit of a reverse pulse generating coil. The collector pulse generated at the collector side of the horizontal output transistor 16 of FIG. 1 is Vcp, the number of turns of the primary winding 17 is N ₁ , the number of turns of the reverse pulse generating core winding coil 16 e is e ₂ The pulse crest value e _p at both ends of the eccentric winding coil 6e is represented by the following equation.

In FIG. 2, the pulse crest value e _p at both ends of the core winding coil 6e is capacity-shared by the built-in high-voltage condenser capacity C ₁ and the cathode tube capacity C ₂ .

However, the pulse crest value ep at both ends of the eccentric winding coil 6e varies depending on the winding position of the coil 6e and the interelectrode capacity such as the surrounding line.

In FIG. 1, the cathode-ray tube 11 (see FIG. 6) has a structure-limited capacity, and the built-in high-voltage condenser 2 is disposed inside the FBT 1 for correcting the cathode ray tube capacity.

This high-pressure capacity (cathode-ray tube capacity + built-in high-pressure condenser capacity) is intended to stabilize the high-pressure, and if this high-pressure capacity is small, it causes a phenomenon such as warpage on the screen of the cathode ray tube 11.

The crest value of the reverse pulse applied to the high-voltage output wire 22 can be adjusted by changing the capacity of the built-in high-voltage condenser 2. When the capacity is increased, the crest value is increased. When the capacity is decreased, the crest value is lowered.

The present invention can use both the capacitive function of applying a reverse pulse to the cathode of a cathode ray tube and the cathode ray tube capacitance function for stabilizing the high voltage.

FIG. 3 is an external view of the FBT. As shown in this drawing, the magnetic core 23 is wound around a high-voltage output wire to form a coil 6e for generating a magnetic core winding reverse-phase pulse.

Fig. 4 is an external view of a fly-back transformer according to another embodiment. Fig.

As shown in this figure, it is also possible to construct the FBT 1 by incorporating the external magnetic core winding coil 24 as a separate coil in the FBT 1. [

According to the present invention, a pulse generated by winding a high-voltage output wire of a fly-back transformer having the same amplitude as an alternating electric field is superposed on a high-voltage output wire to induce (induce) Since the horizontal pulse of the deflection yoke can be canceled, there is no need to use a high-priced external high-voltage condenser insulated with the case and the mold resin, and the high-voltage portion is insulated integrally by the epoxy resin, And a flyback transformer that is easy to handle in terms of structure can be provided.

Claims (1)

A flyback transformer in which a high-voltage rectifier diode is connected in series to the output side of each high-voltage coil of a divided secondary side and a high-voltage condenser is connected to the cathode side of the final-stage diode, Wherein the electric wire is wound around the core of the fly-back transformer in a direction in which a horizontal pulse for driving the deflection yoke is generated and a pulse of a reverse phase is generated, and the fly-back transformer is connected to the cathode-ray tube through the anode cap.