JPS5918846B2 - flyback transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-performance flypack transformer with little unnecessary radiation.

Figure 1 shows the structure of a conventional flypack transformer.

As shown in the figure, the primary winding 2 is wound around one leg of two sets of U-shaped cores 1, and the secondary windings 3 and 4 are wound around the outside of the primary winding 2. The induced voltage is transferred to diode 5
, 6, and T, and supplies 25 to 30 KV as a DC high voltage. Further, when a focus voltage of 5 to 7 KV is required, it is supplied from the center tap of the secondary winding 3. When such a flypack transformer is used in a television receiver, ringing occurs in the high voltage pulse shown in Fig. 2 induced in the secondary windings 3 and 4, and this ringing is generated as unnecessary radiation from the flypack transformer. It mixes with the video signal of a television receiver and appears as black vertical stripes on a CRT screen. This degrades the performance of the television receiver and also results in very unsightly images. The present invention aims to eliminate the above-mentioned vertical stripes and provide a flypack transformer that produces less unnecessary radiation and is necessary for manufacturing a high-quality television receiver.

An embodiment of the present invention will be described below with reference to FIG.

As shown in the figure, a portion 10 of the secondary winding is wound around one leg of two sets of U-shaped cores 8, a primary winding 9 is wound around the outside of the secondary winding, and the secondary winding is further wound around the outside of the primary winding 9. The remaining 11 windings are wound, and the voltage induced in the secondary windings 10 and 11 is rectified by diodes 12, 13, and 14, resulting in a DC high voltage of 25 to 30 K.
V is supplied to the anode electrode of the CRT.

Further, if a focus voltage (5 to 7 KV) is required, it can be supplied from the center tap of the secondary winding 10. In the case of the flyback transformer according to the present invention, the high voltage pulse ringing induced in the secondary winding is caused by the ringing from the flypack transformer because the secondary winding 10 is wound between the core 8 and the primary winding 9. Uneasy radiation is unnecessary radiation due to ringing only in the secondary winding 11 wound outside the primary winding 9.
There is almost no effect on the CRT screen.

Generally, when the secondary winding is divided into two and the focus voltage is extracted from the middle point, the high voltage fluctuation rate due to the CRT load is compared with the fluctuation rate of the focus voltage.It is designed so that the fluctuation rate of the high voltage is small. However, in this case, the amount of ringing in the secondary winding 10 is greater than the ringing in the secondary winding 11. Therefore,
As in the present invention, a secondary winding 10 is provided between the primary winding 9 and the core 8.
Winding the coil gives good results on unnecessary radiation and can supply a high-performance flyback transformer.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional flypack transformer, FIG. 2 is a voltage waveform diagram of a high voltage pulse of the same flypack transformer, and FIG. 3 is a schematic configuration diagram showing an embodiment of a flypack transformer according to the present invention. It is. 8... U-shaped core, 9... Primary winding,
I'... Part of the secondary winding, 11... The rest of the secondary winding.

Claims (1)

[Claims] 1. A flyback transformer characterized in that a part of the secondary winding is wound between two sets of U-shaped cores and the primary winding, and the rest of the secondary winding is wound outside the primary winding.