JPS59110276A - Correcting circuit for horizontal amplitude variation - Google Patents

Abstract

PURPOSE:To reduce power consumption by correcting horizontal amplitude variation without using any resistance. CONSTITUTION:A flyback transformer 1 includes correcting winding 1c. One terminal of this winding 1c is connected to primary winding 1a through a rectifying diode D2, and a capacitor C1 is connected between the connection point E of the diode D2 and winding 1a, and the other terminal of the winding 1c. Consequently, a pulse voltage P developed across the winding 1c during a flyback period is rectified by the diode D2 to charge the capacitor C1. Simultaneously, an induced current i3 flows. As this current i3 is smaller the potential at the connection point E is higher and i3 is larger the potential of the point E is lower. Therefore, a high output voltage drops (rises) by an increase (decrease) in high-voltage load current i1 and a horizontal amplitude which is to increase (decrease) is corrected horizontally because of the low (high) voltage held in the capacitor C1. Further, no resistance is used, so there is almost no electric power loss.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a circuit for correcting changes in raster width, ie, horizontal amplitude, of a television receiver or the like.

(b) The anode voltage C of the picture tube supplied from the flyback transformer of the prior art television receiver is referred to as "high output voltage")
varies depending on the beam current c (hereinafter referred to as "high voltage load current") flowing through the picture tube, and when the high voltage load current is minimum, the high voltage output voltage is maximum.

Further, the horizontal amplitude c (hereinafter referred to as "horizontal amplitude") of the screen of a television receiver decreases because the electron speed of the electron beam flowing through the picture tube increases as the high output voltage increases.

Therefore, when the deflection power supply voltage of the horizontal deflection circuit is kept constant, the high voltage output voltage increases due to a decrease in the high voltage load current, and the horizontal amplitude becomes small. Furthermore, as the high voltage load current increases, the high voltage output voltage drops and the horizontal amplitude increases.

In order to correct such amplitude changes, a circuit configuration as shown in FIG. 1 has conventionally been adopted.

In FIG. 1, (TR) is a horizontal output transistor, (
D (1) is a damper diode, (Cr) is a resonant capacitor, cLy) is a horizontal deflection coil, (CEl) is a figure-8 correction capacitor, m is a flyback transformer, (la) is the primary winding of the flyback transformer K fil line, (1b)
is the secondary winding of the flyback transformer ('1), Φ1)
is a high-voltage rectifier diode, (C) is the equivalent capacitance of the picture tube, and the picture tube is shown as a load (RX) under equal constraints. Further, one end of the secondary winding (la) is connected to a horizontal deflection coil (Ly
), the other end is connected to a capacitor (Co), and the connection point (G) is supplied with +Bo voltage (14-Bo) for supplying the horizontal deflection circuit through a resistor (Ro). There is.

The operation shown in FIG. 1 is as follows.

First, as the current (11) flowing through the load (Rx) increases, the charge on the equivalent capacitance (9) decreases [that is, the voltage at (C) decreases], which occurs in the secondary winding (lb) during the flyback period. Equivalent capacitance (C) for flyback pulse (FF)
) is sufficiently charged, but at this time, the current (12) flowing into the equivalent capacitance (C) is equal to the high voltage load current (11) during the scanning period.
The thicker it is, the larger it becomes. The flow of the above (12) during the flyback period causes the primary winding (1a) to
An induced current (13) due to (12) flows through. this(
If 13) is large, the voltage drop across resistor 0) will be large.

Therefore, the voltage stored in the capacitor (Co) becomes low, and in the scanning period starting after the end of the flyback period, the low voltage stored in the capacitor (Co) becomes low in the primary winding (l).
a) is supplied to the horizontal deflection circuit. Therefore, the horizontal amplitude, which tends to increase as the high voltage output voltage decreases due to the increase in the high voltage load current (11), is caused by the capacitor (11).
The horizontal amplitude is corrected due to the low deflection power supply voltage applied from Co.

In addition, when the high voltage load current (11) becomes small, the above operation is reversed and the voltage of the capacitor (CO) becomes high, so the horizontal amplitude that is about to increase is suppressed and the normal dimensions are maintained. be done.

As described above, the circuit shown in FIG. 1 can correct the horizontal amplitude distortion, but this conventional circuit has the following problems.

Since the force loss is large and the power consumption is large, there is a limit to the correction of horizontal amplitude changes. In addition, since the amount of heat generated by the resistor (0) is large, its mounting position is restricted when it is mounted on a printed circuit board, and it is not desirable in terms of reliability.

(c) Purpose It is an object of the present invention to provide a horizontal amplitude change correction circuit that can correct the horizontal amplitude without using the voltage drop of the resistor as described above.

2) Structure The horizontal amplitude change correction circuit of the present invention includes a flywheel transformer provided with a correction winding, means for rectifying the pulse generated in the correction winding, and a capacitor for receiving the rectified current of the rectification means. , the capacitor is connected to the secondary winding in order to use the voltage of this capacitor as a deflection power source.

(E) Embodiment An embodiment of the present invention will be described with reference to FIG. 2, in which the same parts as in FIG. 1 are given the same figure numbers.

In FIG. 2, a correction winding (IC) is wound around the fly transformer (1), and the correction winding (IC)
One end is connected to the +Bo power supply (+BO), and the other end is connected to the primary winding (1a) via a rectifier diode (D2) and the − secondary winding (
A capacitor (C1) is connected between the connection point with 1a)) and the one end of the correction winding (IC).

With such a configuration, the correction winding (1
The pulse voltage (g) generated in c) is passed through the rectifier diode (D2
) and charged to a condenser (C1).

At the same time, an induced current (13) flows during the flyback period as described with reference to FIG. This (13) corresponds to the discharge current of the capacitor (C1) during the flyback period, so if (13) is small, the connection point (
The potential of → is high, and if (13) is thick, the potential of the connection point (the slope potential is low. In this way, the potential of the connection point CF- set in the flyback period) is maintained during the scanning period. serves as a power source for the deflection circuit.

Therefore, the horizontal amplitude, which tends to increase as the high voltage output voltage decreases due to the increase in the high voltage load current (11), is suppressed and the horizontal amplitude is corrected due to the low deflection power supply voltage held in the capacitor (C1). Ru. Furthermore, when the high-voltage load current (11) becomes small, since the capacitor (C1) is held at a high voltage, the horizontal amplitude that tends to become sharp is suppressed and the normal dimensions are maintained. Furthermore, compared to conventional circuits, since no resistance is used, a horizontal amplitude change correction circuit with almost no power loss can be obtained.

Furthermore, if the voltage across the capacitor (C1) becomes too large relative to the K-1-Bo power supply, the change in the voltage across the capacitor (C1) in response to a change in the high-voltage load current (11) will become too large. Variable power of high output voltage (
Not only will it get bigger, but it will also become bigger.
) of the attached winding [for example, the heater winding (Xa):
The turns ratio of c) should be within 50:1! Preferable 0 In addition, the flyback transformer uses harmonic tuning to suppress fluctuations in the high-voltage output voltage, but in order to do this, it generally operates at a low voltage (low voltage power is supplied by a battery or other power source as a BO power source). The flywheel transformer used in television sets (supplied) suppresses distributed capacitance by reducing the number of turns in the primary winding and the number of turns in the secondary winding. Therefore, the voltage generated in the secondary winding (1a) is around 8 volts regardless of the magnitude of the operating voltage, so
In the case of low voltage operation, a capacitor (
Since the ratio of the voltages across C1) becomes large, the above-mentioned disadvantage occurs. Therefore, in carrying out the present invention, it is desirable to apply the present invention to a case where approximately 100 volts or more is supplied as a 10BO power source.

In addition, in order to control changes in the voltage across the capacitor (C1), horizontal amplitude changes can be corrected by bleeding the voltage across the capacitor (C1) with a resistor or by appropriately selecting the capacitance value of the capacitor (C1). You can also change the amount.

Figures 3 to 5 each show other embodiments of the present invention, and the same parts as in Figure 2 are given the same figure numbers, and point A corresponds to point A in Figure 2. ing.

In the embodiment shown in Fig. 3, the negative side of the capacitor (C1) is grounded, and in Fig. 4, the rectifier diode (D2) is connected to the BO power supply side of the correction winding (LC) and the capacitor (C1).
In the embodiment shown in Fig. 5, the winding direction of the correction winding (1c) is reversed and a rectifier diode (D2) is placed in parallel with the correction winding (IC). death,
A capacitor (C1) is placed between the BO power supply side of the correction winding (1c) and the anode end of the rectifier diode Q)2), but its operation is essentially the same as in the embodiment shown in Figure 2. Since they are essentially the same, their explanation will be omitted.

(f) Effects The horizontal amplitude change correction circuit of the present invention is capable of correcting horizontal amplitude changes without using a resistor, so power consumption can be significantly reduced. Furthermore, since there is almost no power consumption, there is no adverse effect on the circuit or board due to heat generation.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional horizontal amplitude change correction circuit, FIG. 2 is a diagram showing a horizontal amplitude change correction circuit according to the present invention, and FIGS. 3, 4, and 5 are diagrams showing other embodiments of the present invention, respectively. FIG. 3 is a circuit configuration diagram showing main parts of an example. fil...Flyback transformer, (la)...-
Next winding, (lc)... Correction winding, (D2)... Rectifier diode °, (C1) Fig. 1 Fig. 2

Claims (1)

[Claims] +1) The flyback transformer is provided with a correction winding, a means for rectifying the pulse generated in the correction winding, and a capacitor for receiving the rectified current of the rectification means, and the voltage of the capacitor is used as a deflection power source. A horizontal amplitude change correction circuit characterized in that the capacitor is connected to the primary winding of the flyback transformer.