JPS60100882A - Flyback transformer - Google Patents

Abstract

PURPOSE:To sufficiently make higher harmonic ringing small with a simple circuit by installing a means forming a closed circuit of a ringing current of the higher harmonic ringing. CONSTITUTION:A closed circuit means 11 forming a closed circuit of a ringing current I of the higher harmonic ringing is installed opposite to the 2nd windings 62-64 and in parallel with the 1st winding 61. The closed circuit means 11 is provided with an auxiliary winding 111 and a resistance element 112 and has a large impedance for the shot pulse frequency. Consequently since almost all the basic pulse currents inputted to the 1st winding 61 flow through the 1st winding 61, the loss of the basic pulse current can be made small. Almost of the ringing current I flow through the closed means 11. In this way, the ringing current I is speedily attenuated by the resistance element 112. Thus, the higher harmonic ringing can be sufficiently made small with the simple circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flyback transformer used for supplying high DC voltage to a cathode ray tube of a TV receiver, etc. This invention relates to a flyback transformer that reduces induced ringing.

#! Figure 1 is an electrical circuit diagram of a high-voltage output circuit in which a flyback transformer is connected to a horizontal deflection circuit, where 1 is a horizontal output transistor, 2 is a damper diode, 3 is a resonant capacitor, 4 is a horizontal deflection coil, and 5 is a figure-8 correction. It is a capacitor for 6 is a flyback transformer, and this flyback transformer 6 has a primary winding 61 and a plurality of secondary windings 62.
．． 63.64. 71, 72, and 73 are diodes connected alternately to this secondary winding. 81 is a high voltage output terminal, and 82 is a ground terminal. Typically, such a flyback transformer has a pair of closed magnetic circuits fitted with a low-voltage bobbin on which a primary winding is wound, and on which multiple 2* windings are wound through diodes. It is constructed by fitting a split-type high-pressure bobbin with a large number of winding grooves. These windings are housed in an insulating case and molded with A1 resin.

By the way, 2 of the 7-live back transformer with this configuration
As shown in FIG. 2, a shot pulse 9 is induced in the next winding during the blanking period of the horizontal deflection circuit, and harmonic ringing 10 is induced during the scanning period.

This harmonic ringing 10 is caused by, for example, the TV of a TV receiver.
It is necessary to make the size as small as possible because it causes deterioration of image quality such as the occurrence of bright and dark vertical stripes on the screen. This harmonic ringing 10 is caused by the secondary winding 62. G
This is caused by the presence of leakage inductance and distributed capacitance of 3.64, so in order to reduce harmonic ringing 10, it is sufficient to configure the flyback transformer with a structure that reduces leakage inductance and distributed capacitance. However, there is a limit to creating a structure that bends. Therefore, in the past, electrical characteristics were improved by tuning the series resonant circuit of the leakage inductance and distributed capacitance of the secondary winding to the harmonics of the high frequency of the input power supply of the primary winding, so-called harmonic tuning. I try to do that.
However, even if such improvement measures were taken, there was still a limit to the improvement of the electrical characteristics6. The present invention makes it possible to sufficiently reduce harmonic ringing with an extremely simple configuration, thereby improving image quality. The purpose is to provide a modern flyback transformer.

In order to achieve such an object, the present invention creates a closed circuit for harmonic ringing current together with the secondary winding by being connected to the 2* winding through distributed capacitance between the secondary winding and the secondary winding. A closed circuit means is provided opposite the secondary winding t, and the closed circuit means has a large impedance v1 with respect to the shot pulse frequency.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings. FIG. 3 is a high voltage output circuit diagram including the flyback transformer of this embodiment, and parts corresponding to those in FIG. 1 are designated by the same reference numerals. In FIG. 3, numeral 1 is a horizontal output transistor, 2 is a goomba diode, 3 is a resonant capacitor, 4 is a horizontal deflection coil, and 5 is a six-figure correction capacitor.

60 is a flyback transformer, and this flyback transformer 60 has a primary winding 61 and a plurality of secondary windings 62.
, 63 and 64. 7 L72.73 is this 2
This is a diode connected alternately with the next winding. 81 is a high voltage output terminal connected to the 7)-dead of the cathode ray tube, 82 is A
This is a ground terminal connected to ground via the BL circuit or directly. Note that the diode 73 may be connected if necessary.
7 orcus voltage is taken out from the cathode side of the

Such a configuration is similar to the conventional example shown in FIG.

The embodiment of this invention is characterized by the following configuration.

That is, the 7-life back transformer 60 of this embodiment is provided facing the secondary windings G2, 63, 64, and
2,63. G4 and the secondary winding 6 due to the distributed capacitance between
2, 63, and 64 to connect the secondary winding 62.
63, 64 and the DC type 1 (
-1-B) A closed circuit means 11 that forms a closed circuit for a ringing current I of harmonic ringing together with a smoothing capacitor 30 is provided. This closed circuit means 11 includes an auxiliary winding 111 and a resistive element 112. This closed circuit means 11 also includes:
It is connected in parallel to the primary winding 61. The closed circuit means 11 has a larger impedance than the primary winding 61 with respect to the shot pulse frequency (the fundamental pulse frequency input to the primary winding 61) due to the auxiliary winding 111 and the resistive element 112. Therefore, since most of the basic pulse current input to the primary winding 61 flows through the primary winding 61, the loss of the basic pulse current can be extremely reduced. Also,
Most of the ringing current (2) flows through a closed circuit including the auxiliary winding 111 and the resistive element 112, as shown by the arrow in FIG. Incidentally, since the impedance of the closed circuit means 11 has a value of ν) which is small for the shot pulse as described above, the shot pulse current hardly flows into the closed circuit means 11. As a result, the ringing current (2) is quickly attenuated by the resistive element 112, and as a result, the above-mentioned problem caused by the linking current (2) is solved.

FIG. 4 is a sectional view of the structure of the flyback transformer 60 of this embodiment. In Fig. 4, 12 is an insulating case;
Reference numeral 13 denotes a closed magnetic circuit core passing through the insulating case, 14 a low voltage bobbin fitted into the closed magnetic circuit core 13, and a primary winding 61 is wound around the low voltage bobbin 14. (=1 is added. The auxiliary winding 111 of this embodiment is further wound around the primary winding 61 on this low-pressure bobbin 14.15
is a high-pressure bobbin, and this high-pressure bobbin 15 is fitted onto the low-pressure bobbin 14. Secondary windings 62, 63, and 64 are wound around this high voltage bobbin 15, and diodes '/i and 72, 73 are arranged alternately with these secondary windings. 16
is +a+fat, 1'7 is the high voltage output lead wire.

Although not shown, a resistance element 112 connected to the auxiliary winding 111 is attached to the base of the low-voltage bobbin 14 where the pin terminal is implanted.

FIG. 5 is a sectional view showing another modification of the flyback transformer 60 of this embodiment, and parts corresponding to those in FIG. 4 are given the same reference numerals. Flyback transformer 60 in Figure 5
What should be noted is that the auxiliary winding 111 of this embodiment is created separately from the low-voltage bobbin 14 and is wound around an auxiliary winding bobbin 18 arranged between the low-voltage bobbin 14 and the high-voltage bobbin 15. In this case, the resistance element 112 is attached to the lower part of the auxiliary winding 18 or the like.

In the above embodiment, the resistive element 112 was placed at the lower end of the auxiliary winding 111, but the position is not necessarily limited to this, and the auxiliary element 112 can be placed at any position where the ringing current can be sufficiently attenuated. An intermediate position of the winding 111 may be used. Further, in the above embodiment, the closed circuit means 11 is formed from the auxiliary winding 111 and the resistive element 112, but in another embodiment, the resistive element 112 is not provided, and instead, the auxiliary winding @111 itself is wire, nichrome wire, C
It may be constructed by winding a resistance wire such as a u-Ni alloy wire, and the ringing current may be damped by this resistance wire. In this case, only a part of the auxiliary winding 111 may be formed of a resistance wire. Furthermore, the closed circuit means 11 does not necessarily need to be connected in parallel to the primary winding 61; for example, the collector side end of the horizontal output transistor 1 may be open. In such a case, the ground side of the closed circuit means 11 may be directly grounded without using a capacitor. Further, the secondary winding side of the above embodiment may be configured such that a diode is also connected to the ground terminal side of the secondary winding 64, or the diode may be removed from the high voltage output terminal side of the secondary winding 62. Furthermore, the secondary winding may not be divided into a plurality of parts using diodes, but only one. Furthermore, in the case where the flyback transformer of the present invention is configured with a plurality of secondary windings and a plurality of diodes on the secondary winding side, the secondary winding and the diode as in the above embodiment can be connected to a bobbin. Needless to say, the present invention is applicable not only to a structure in which the secondary windings are arranged alternately in the axial direction, but also to a structure in which a plurality of secondary windings are sequentially stacked in the radial direction.

As described above, according to the present invention, by connecting the open distribution capacitor 11 with the secondary winding to the secondary winding, a closed circuit for the ringing current of harmonic ringing is formed together with the secondary winding. Since the closed circuit means is provided opposite to the secondary winding, and the closed circuit means has a structure having a large impedance with respect to the shot pulse frequency, harmonic ringing can be sufficiently reduced with an extremely simple structure, and image quality can be improved. of,
It can be done better.

[Brief explanation of the drawing]

Fig. 1 is a high-voltage output circuit diagram including a conventional flyback transformer, Fig. 2 is a voltage waveform diagram induced in the secondary winding to explain ringing, and Fig. 3 is a 7-river circuit diagram of an embodiment of the present invention. FIGS. 4 and 5 are cross-sectional views showing various modifications of the structure of the 7-live back transformer according to the embodiment. 60 is a flyback transformer, 61 is a primary winding, 62.
63 and 64 are secondary windings, 11 is a closed circuit means, 111 is an auxiliary winding, and 112 is a resistance element. Applicant: Material Manufacturing Co., Ltd. Agent: Patent Attorney Oka 1) Kazuhide Figure 1 76 Figure 2 Figure 3 0

Claims (3)

[Claims] (1) It is connected to the 2* winding due to the distributed capacitance between the secondary winding and forms a closed circuit for the ringing current of harmonic ringing together with the secondary winding, and has the effect of attenuating the ringing current. A flyback transformer is provided with a closed circuit means facing the secondary winding, and the closed circuit means has a large impedance with respect to the shot pulse frequency. (2) The flyback transformer according to claim 1, wherein the closed circuit means is a 1U series circuit of an auxiliary winding and a resistance element. (3) In the flyback transformer according to claim m, the closed circuit means is an auxiliary winding,
This auxiliary winding is a flyback transformer made by winding a resistance wire.