JPH04100485A - Flyback transformer - Google Patents

Abstract

PURPOSE:To reduce ringing by rectifying a 1st layer through which a large amount of a ringing current flows to double voltage and shaping the waveform of a voltage applied during a scanning period. CONSTITUTION:A double voltage rectifying system is adopted to the first layer of the laminated winding for outputting high-voltage of the flyback transformer by using diodes and rectifying capacitors 7 and 8. Therefore, such a flyback transformer for receivers using cathode ray tubes that can reduce ringing induced by a high voltage, because the rectifying capacitors 7 and 8, etc., become loads of ringing-wave voltages during a scanning period ts can be constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flyback transformer equipped with a voltage doubler rectifier circuit on the output side of a high voltage or the like supplied to an anode electrode of a cathode ray tube receiver or the like.

BACKGROUND OF THE INVENTION Flybank transformers are widely used as high voltage supply components for various cathode ray tube receivers and other high voltage power supplies. The operating frequency tends to be higher year by year due to demands for higher resolution of cathode ray tube receivers, smaller size of high voltage power supplies, etc., and operating frequencies of 100 KHz or more are now in practical use. However, increasing the operating frequency leads to an effective increase in the leakage inductance and distributed capacitance of the secondary winding, which tends to increase high voltage induced ringing. Conventionally, in order to reduce the generation of such high-voltage induced ringing waves, countermeasures were taken by making the secondary winding a laminated winding in a circuit as shown in Figure 3, and inserting a resistor 6 at the beginning of the winding of the -th layer. was. However, with this method, as the operating frequency increases, the power consumed by the resistor increases, which may eventually lead to burnout of the resistor, so it could not be used in high-frequency operation.

There is also a method of rectifying the ringing voltage using a diode and dissipating it in the resistor 5, as shown in the circuit shown in Figure 4, but this method has the drawbacks of reducing efficiency and increasing heat generation due to the resistor. there were.

Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned problems, and aims to reduce high-pressure induced ringing in a high-frequency region without reducing efficiency.

Means to Solve the Problem It has been found that the ringing current in the secondary winding of a flyback transformer is related to the leakage inductance and distributed capacitance of the secondary winding, and that especially in the laminated winding method, a large amount of current flows in the first layer. ing. Normally, in a flyback transformer, the scanning period tB is as shown in the horizontal scanning voltage waveform shown in Figure 5.
K This ringing is what appears. In a normal flyback transformer, only the high pulse voltage portion generated during the retrace period tr in FIG. 6 is rectified to obtain a high voltage output.

Function: According to the present invention, ringing can be reduced by voltage-doubling rectification in the first layer through which a large amount of ringing current flows, and also by rectifying the voltage waveform during the scanning period.

Embodiment FIG. 1 is a circuit diagram showing an example of a flyback transformer according to the present invention, and FIG. 2 is an embodiment in which the present invention is applied to a horizontal output circuit of a cathode ray tube receiver.

In other words, in FIGS. 1 and 2, the flybank transformer T has circuit elements such as the primary winding of the core 6 in the 1i/l direction 9, the S-shaped correction capacitor 10, the resonant capacitor 11, and the damper diode 12 horizontally. Output transistor 1
The secondary winding 2 of the flyback transformer shown in FIG. 1 is loaded with a high-voltage rectifier diode 3, a high-voltage protection resistor 4, and the like.

In Figure 2, the first layer of the high-voltage output laminated winding of the flyback transformer T is connected to a diode and a rectifier capacitor.
8 is used as a double voltage rectification system.

As a result, during the scanning period t shown in FIG. 5, the rectifier capacitors 7, 8, etc. become a load of the ringing wave voltage, so that it is possible to construct a flyback transformer for a cathode ray tube receiver that reduces high-voltage induced ringing. In the present invention, only the voltage doubler rectification in the first layer has been described, but the -th layer and the second layer may be voltage doubler rectified, and the capacitor 8 in FIGS. 1 and 2 is particularly problematic in terms of performance. If it is not available, it can be omitted. In this embodiment, a high-voltage three-layer laminated winding is exemplified, but it goes without saying that it does not particularly depend on the number of laminated layers.

Effects of the Invention The F3A of the present invention can reduce high voltage induced ringing without reducing efficiency or increasing heat generation, and is therefore particularly suitable for fly bank transformers that require high frequency operation. Further, even when used in a flyback transformer operating at a low frequency, the efficiency is further improved, and the number of turns of the secondary winding can be reduced due to voltage doubler rectification.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a rectification system according to the present invention, Fig. 2 is a circuit diagram showing an example of the use of the present invention in a horizontal output circuit of a cathode ray tube receiver, and Figs. 3 and 4 are conventional examples. The circuit diagram shown in FIG. 5 is a high voltage induced voltage waveform diagram. T...Flyback transformer, 2...
Secondary winding, 3... Direct voltage rectifier diode, 7,
8... Rectifier capacitor. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (1)

[Claims] A flyback transformer with a voltage doubler rectifier circuit installed in the middle of the secondary output winding to generate high voltage.