JPS59165570A - S-shape correction circuit - Google Patents

Abstract

PURPOSE:To connect an S-shape correction circuit directly to a power supply by supplying a DC current to the juncture between an S-shape correcting capacitor and a horizontal deflecting coil constituting a series resonance circuit from a DC power supply via a diode. CONSTITUTION:The release and short-circuiting are repeated by turning on and off a switching transistor TR. A DC power supply E supplies a DC current through a series resonance circuit consisting of a deflecting coil LY and an S-shape correcting capacitor CS and via a diode D'. That is, a current is supplied via the diode D' when the terminal voltage produced at the capacitor CS by the series resonance circuit of the coil LY and the capacitor CS is smaller than the power supply E. Then the supply of the current is discontinued when the terminal voltage of the CS is smaller than the power supply E.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) 1 Technical Field of the Invention The present invention relates to an S-shaped correction circuit, and more particularly to an S-shaped correction circuit that supplies direct current without using a coupling choke coil.

(b), Prior Art and Problems When the display surface of a cathode ray tube has a loading rate radius, if the radius of curvature of the display surface is larger than the distance from the deflection center to the display surface, the "saw" that increases linearly in the deflection coil “Wave style”
When rays are played, the raster on the cathode ray tube expands at both ends and contracts at the center. To correct this, it is sufficient to flow a ``sawtooth wave flow'' distorted into an S-shape, and this correction is called 8-character correction.

Conventionally, to obtain this figure-8 correction current, a capacitor was connected in series with the deflection coil, and an S-shaped "sawtooth wave" flow was caused by series resonance between the deflection coil and the capacitor.

According to the conventional technology, the deflection current i required for figure-8 correction is k
is a constant, L is the distance from the center of deflection to the display surface, H is the width of the display surface, R is the curvature of the display surface, t is the scanning period, and t is <1<hand.

FIG. 1 is a circuit diagram showing a conventional embodiment.

In Figure 1, Ly is a deflection coil, Cs is a figure-8 correction capacitor, Lo is a coupling choke coil, E is a power supply, and C
is a resonant capacitor, D is a damper diode, and Tr is a switching transistor.

As shown in Figure 1, a capacitor C is connected in series with the deflection coil Ly.
s was used, and an S-shaped "sawtooth wave current" was caused to flow through series resonance between the two. However, since power source E and deflection coil Ly cannot be directly connected, a coupling choke coil LO (or flyback coil LO) is connected between power source E and deflection coil Ly.
Lance) is required. Normally, a flyback transformer is used to generate high voltage, but in cases where screen size fluctuations (due to high voltage fluctuations) are a problem, such as in display devices, the high voltage circuit must be separated to stabilize the high voltage. Therefore, there is a disadvantage that an extra choke coil Lo must be used.

(C)0Object of the invention The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art,
It is an object of the present invention to provide an S-shaped correction circuit that can be directly coupled to a power source.

(d) 0 Structure of the Invention According to the present invention, in a horizontal deflection circuit in which a switching transistor and a resonant capacitor are connected to a horizontal deflection coil to flow a "sawtooth" current, one series This is achieved by providing an S-shaped correction circuit characterized in that a DC current is supplied via a diode from a DC power source to a connection point between the horizontal deflection coil and the three-shaped correction capacitor that constitute a resonant circuit.

(e) 1 Embodiment of the Invention FIG. 2 is an S-shaped correction circuit diagram showing an embodiment of the present invention, and FIG. 3 is its equivalent circuit.

In Figures 2 and 3, Ly is a deflection coil, E is a power supply, D' is a diode, C5 is a figure-8 correction capacitor, S is an equivalent switch, C is a capacitor, D is a damper diode, and Tr is a switching device.・It is a transistor.

In FIG. 2, the switching transistor Tr repeats open and short circuits by turning on and off, so that the equivalent circuit shown in FIG. 3 is obtained.

The present invention will be described in detail below with reference to FIG.

In this case, the DC power E is supplied via the diode D° by utilizing the series resonance between the deflection coil Ly and the figure-8 correction capacitor Cs. That is, when the terminal voltage of the figure-8 correction capacitor Cs, which is generated by series resonance between the deflection coil Ly and the figure-8 correction capacitor Cs, is smaller than the DC power supply E, current is supplied via the diode D', and conversely, the figure-8 correction capacitor When the terminal voltage of C3 is higher than the DC power supply E, the current supply is stopped. In this way, DC power can be supplied without using the conventional choke coil Lo.

(f) 3 Effects of the Invention As explained in detail above, according to the present invention, ■ without using a coupling choke coil as in the past, ■ using an inexpensive diode to connect the deflection coil Ly and the figure-8 correction capacitor. This has the great effect of being able to supply DC power to the series resonant circuit with Cs.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional embodiment. In Figure 1, Ly is a deflection coil, Cs is a figure-8 correction capacitor, Lo is a coupling choke coil, E is a power supply, and C
is a capacitor, D is a damper diode, and Tr is a switching transistor. FIG. 2 is an S-shaped correction circuit diagram showing an embodiment of the present invention, and FIG. 3 is an equivalent circuit thereof. In Figures 2 and 3, Ly is a deflection coil, E is a power supply, D' is a diode, Cs is a figure-8 correction capacitor, S is a switch, C is a capacitor, D is a damper diode, and Tr is a switching capacitor. It is a transistor.

Claims (1)

[Claims] In a horizontal deflection circuit in which a switching transistor and a resonant capacitor are connected to a horizontal deflection coil to flow a "sawtooth" current, at the connection point of the horizontal deflection coil and the figure-8 correction capacitor that constitute one series resonant circuit. An S-shaped correction circuit characterized by supplying DC current from a DC power supply via a diode.