JPS6051078A - Horizontal deflecting circuit - Google Patents

Abstract

PURPOSE:To prevent occurrence of ringing due to current that penetrates a deflecting coil and sinuosity of a scanning line on a CRT by inserting a common mode choke coil between a horizontal deflecting coil and a coil driving circuit. CONSTITUTION:The common mode choke coil 4 is inserted and connected between the horizontal deflecting coil of a horizontal deflecting circuit that deflects electron beam in the CRT tube in horizontal direction and the coil driving circuit 1 that drives a coil. This choke coil 4 is wound on a troidal core coil 5. Ringing generated by current that penetrates the coil 2 is reduced by distributing capacity of the coil 2 to prevent sinuosity of the scanning line in the left side of the picture of the CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horizontal deflection circuit for horizontally deflecting an electron beam in a cathode ray tube of a television receiver or the like.

Generally, a horizontal deflection circuit is as shown in FIG.

It is composed of a horizontal deflection coil 2 and a coil drive circuit 1 that drives the horizontal deflection coil 2.

The horizontal deflection coil 2 is composed of a pair of upper and lower coils, and the outside thereof is covered with a vertical deflection coil and a core, which are considered to be grounded with respect to the horizontal deflection frequency. Therefore, since each part of the coil is considered to have a distributed capacitance with respect to the ground, a circuit equivalent to the horizontal deflection circuit of FIG. 1 that takes this into account is as shown in FIG. 2.

In FIG. 2, the signal source of the coil drive circuit 1 is represented by V3. The harmonic component (S) of the sawtooth waveform flow (S) output from this signal source is bypassed to the ground through the distributed capacitance 3 described above, so the current (Iy) flowing through the horizontal deflection coil 2 This had the disadvantage that ringing occurred in the image, and the undulations shown in FIG. 6 appeared in the scanning line on the left side of the screen of the cathode ray tube.

SUMMARY OF THE INVENTION An object of the present invention is to provide a horizontal deflection circuit which can eliminate such drawbacks and prevent waviness of the scanning line on the left side of the screen of a cathode ray tube.

According to the present invention, there is provided a horizontal deflection circuit for horizontally deflecting an electron beam in a cathode ray tube, the horizontal deflection circuit having a horizontal deflection coil and a coil drive circuit for driving the horizontal deflection coil. A horizontal deflection circuit characterized in that a common mode choke coil is inserted and connected between a horizontal deflection coil and a coil drive circuit is obtained.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 4 shows an embodiment of the present invention. In Figure 4, 1
is a coil drive circuit that drives the horizontal deflection coil 2.

4 is a common mode choke coil, and coil drive circuit 1
and the horizontal deflection coil 2.

The common mode choke coil 4 provides a low impedance for the current flowing through the horizontal deflection coil 2 (Io in Fig. 2), and a sawtooth current bypassed to ground through the distributed capacitance (Io in Fig. 2). Since it has a high impedance with respect to the harmonic components (d) in FIG. 2, a sawtooth wave current without ringing can flow through the horizontal deflection coil 2. That is, it is possible to eliminate the undulations that appear in the scanning line on the left side of the screen of the cathode ray tube.

The common mode choke coil 4 can be realized by simply winding a cable connecting the coil drive circuit 1 and the horizontal deflection coil 2 around the toroidal core 5, as shown in FIG. That is, the embodiment of the present invention shown in FIG. 4 can be concretely realized as shown in FIG.

As explained above, according to the present invention, waviness can be prevented in the scanning line on the left side of the screen of the cathode ray tube.

A high-performance horizontal deflection circuit can be provided with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional horizontal deflection circuit.
FIG. 2 is an equivalent circuit to the horizontal deflection circuit of FIG. 1, taking into account the distributed capacitance of each part of the coil. Further, FIG. 3 is a diagram for explaining the drawbacks of the conventional horizontal deflection circuit. FIG. 4 is a block diagram showing one embodiment of the present invention, and FIG. 5 is a diagram showing the embodiment of FIG. 4 more realistically. 1... Coil drive circuit, 2... Horizontal deflection coil. 6... Distributed capacitance (Fig. 2), 4... Common mode choke coil (Fig. 4), 5... Toroidal core (Fig. 5-).

Claims (1)

[Claims] 1. A horizontal deflection circuit for horizontally deflecting an electron beam in a cathode ray tube, the horizontal deflection circuit having a horizontal deflection coil and a coil drive circuit for driving the horizontal deflection coil. . A horizontal deflection circuit characterized in that a common mode choke coil is inserted and connected between the horizontal deflection coil and the coil drive circuit.