JPH02130090A - Convergence correcting circuit - Google Patents

Abstract

PURPOSE:To eliminate erroneous convergence by synthesizing the voltage obtained from a resonance circuit, forming a sawtooth wave voltage, integrating the sawtooth voltage and obtaining a horizontal parabolic wave current as a horizontal convergence correcting current. CONSTITUTION:The title circuit provides a first capacitor 6 connected in parallel with a switch 3 to switch at a horizontal period and a serially connected coil 5, a convergence yoke coil 7 of serial connection and a second capacitor 8 connected in parallel and a current source 9 connected in parallel to these convergence yoke coil 7 and second capacitor 8. The sawtooth wave voltage is obtained at both edges of the first capacitor 6. Consequently, as a correcting current, namery, a parabolic wave-shaped current can be used. Thus, the error convergence is eliminated and the 5-point adjustment is also respectively individually executed, and therefore, the adjustment is facilitated, the adjusting time can be shortened, and since the exclusive-use amplifier is made unnecessary, the circuit constitution is simplified no large energy consumption is required.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a convergence correction circuit suitable for use in CRT display devices such as television receivers and monitors.

[Summary of the invention]

This invention includes a switch that opens and closes in horizontal cycles, a coil connected in series with the switch, a first capacitor connected in parallel with these switches and the coil, and a series capacitor connected in parallel with the first capacitor. By this, the method is configured to include a connected convergence yoke coil and a second capacitor, and a current source connected in parallel to the convergence yoke coil and the second capacitor,
A horizontal parabolic waveform for convergence correction can be obtained with a simple circuit, making convergence correction easy and reducing adjustment time.

[Conventional technology]

Conventionally, for example, as a horizontal convergence correction circuit for a color television receiver, there is a horizontal convergence correction circuit that uses the resonant current of a parallel resonant circuit to flow a sinusoidal correction current to a convergence correction coil (convergence yoke coil). 57-29116).

That is, conventionally, the horizontal parabolic wave Wl as shown by the solid line in FIG. 9 has been used as the correction current of the horizontal convergence correction circuit.
Instead of O, use a horizontal periodic sine wave W as shown by the broken line in the same figure.
I was using 2.

[Problem to be solved by the invention] However, the waveform that actually needs to be corrected is
Geometrically, a parabolic waveform with a horizontal period is ideal.

However, in the conventional case, as mentioned above, since the parts that should be corrected with the parabolic waveform are corrected with the sine wave, there are parts that cannot be adjusted as shown by the arrows in Figure 9, and it is difficult to see on the screen. The disadvantage is that misconvergence occurs near the sides.

In addition, there are generally five types of misconvergence, and these are known as five-point adjustment (11-AMP, which changes the level of the horizontal parabolic wave by varying the voltage source in the circuit).
Adjustment, H-TILT adjustment by moving the phase of the horizontal parabola wave, Y-BOW adjustment by adding a vertical parabola wave current source to superimpose the vertical parabola wave on the horizontal component of the current flowing through the convergence yoke coil, horizontal C-BOW adjustment that modulates the amplitude of the horizontal component of the correction current flowing through the convergence yoke coil in a vertical parabola shape by modulating the current flowing through the convergence circuit that generates the component in a vertical parabola shape, which is perpendicular to the correction current waveform of the convergence yoke coil. Although the Y/CRO3S adjustment (which is performed by superimposing sawtooth waves) is performed, the adjustment is usually made by performing the above-mentioned horizontal parabolic wave current adjustment, but among the five points mentioned above, what is actually related to the above-mentioned horizontal parabolic wave current adjustment is 11
・AMP word round adjustment and H-TILT three round adjustment.

However, in the case of the conventional circuit, the five-point adjustments are interrelated, so it takes H to adjust the horizontal parabolic wave current.
- Even if the AMP adjustment, I/T I L, and T adjustments are performed, the remaining adjustment points will move, and as a result, convergence correction is not easy and takes a lot of time.

Further, in the case of the conventional circuit, it is necessary to amplify the output of the parallel resonant circuit using a dedicated amplifier, resulting in disadvantages such as high power consumption.

The present invention provides a convergence correction circuit that can eliminate the above-mentioned drawbacks.

[Means for Solving the Problems] The convergence correction circuit according to the present invention includes a switch (3) that opens and closes in a horizontal period, a coil (5) connected in series with this switch (3), and these switches (3). ) and a first capacitor (6) connected in parallel to the coil (5).
and a convergence yoke coil (7) and a second capacitor (8) connected in series with this capacitor (6), and these convergence yoke coils (7).
and a current source (
9).

[Operation] The time constant determined by the first capacitor (6) and the convergence yoke coil (7) is set in advance to be larger than the time constant determined by the first capacitor (6) and the coil (5).

When the switch (3) is off, the resonant circuit consisting of the first capacitor (6), the convergence squawk coil (7), and the second capacitor (8) resonates, and a second capacitor is connected across the first capacitor (6). 4 Obtain a voltage with a long period waveform as shown in Figure A. When the switch (3) is turned on, the resonant circuit consisting of the first capacitor (6) and the coil (5) resonates, and a fourth capacitor is connected across the first capacitor (6).
Obtain a voltage with a short period waveform as shown in Figure B. When these voltages are combined, a sawtooth wave voltage as shown in FIG. 5A is obtained across the first capacitor (6). Convergence yoke coil (The current flowing through the force is the integral of the sawtooth wave voltage across the first capacitor (6), so the convergence yoke coil (7)
A parabolic wave-like current as shown in FIG. 5B flows through. This may be used as the correction current of the second invergence yoke coil (7). As a result, a parabolic wave current can be used immediately as a correction current, so there is no misconvergence, and each of the five points can be adjusted independently, making adjustment easy and reducing adjustment time.Moreover, there is no need for a dedicated amplifier. The circuit configuration is simple and power consumption is low.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained in detail with reference to FIGS. 1 to 6. Figure 1 shows the overall circuit configuration of this embodiment. In the figure, (1) is a horizontal output circuit that generates horizontal pulses, and (2) is a phase shift circuit that adjusts the phase of the horizontal pulses. Thus, a rectangular waveform horizontal pulse is obtained as a switching pulse on the output side of this phase shift circuit (2).

(3) is a transistor as a switch (or) which opens and closes in horizontal cycles, and a coil (5) is connected in series to the collector of this transistor (3) via a diode (4) in the opposite direction. A capacitor (6) is connected in parallel between the emitter of the transistor (5) and the other end of the coil (5). In addition, a convergence yoke coil (7) and a capacitor (8) connected in series are connected to both ends of this capacitor (6).
) are connected in parallel. A current source (9) is connected in parallel to the convergence yoke coil (7) and the capacitor (8).

The current source (9) is, for example, a coil (1) for preventing high frequency noise.
0), capacitor (11), resistor (12), ) transistor (13), resistor (14) and variable resistor (1)
5), a series-connected coil (10) and a capacitor (11) are connected in series to a convergence yoke coil (7) and a capacitor (8), and a transistor (13)
The emitter of is connected to the transistor (3) via the resistor (12).
) is connected to the emitter of the transistor (
The collector of the transistor (13) is connected to the positive power terminal B, and the base of the transistor (13) is connected to the positive power terminal B via the resistor (14) and the variable resistor (15).
grounded via.

Then, an input terminal (1
6) is connected to the transistor (13) via the capacitor (17).
) is connected to the base of the

(18) is a vertical parabolic wave voltage generation circuit that generates a vertical parabolic wave voltage, (19) is a vertical sawtooth wave generation circuit that generates a vertical sawtooth wave, and (20) is an adder circuit. The output side of the adder circuit (20) is a transistor (
The emitter of the transistor (21) is grounded via a resistor (22), and its collector is connected to the connection point of the convergence yoke coil (7) and the capacitor (8).

Next, the operation of the main parts of this invention will be explained with reference to FIGS. 2 to 6. Figure 2 shows an equivalent circuit of the main part of Figure 1, where the convergence yoke coil (force inductance is Lcy, and the inductance of the coil (5) is L(
, the capacitance of the capacitor (6) is C, for example, here, time constants are set for ω2・LCV・CζIO1ω2・L, ・C#0.3, respectively. Note that ω=2πfl
l and fN is the horizontal frequency. In addition, the transistor (3
) is represented by a switch S.

In such an equivalent circuit, when the switch SW is turned off as shown in Figure 3, the convergence yoke coil (7) and capacitor (6) resonate, and the circuit changes as shown by the broken line a in Figure 3. A current flows. At this time, the convergence yoke coil (7) and the capacitor (6)
) is set to a large value of <10 as described above, a long-period sinusoidal voltage VCI as shown in FIG. 4A is generated across the capacitor (6). If the switch SW remains off, the resonance of the convergence yoke coil (7) and capacitor (6) continues.

Next, in the equivalent circuit of Fig. 2, when the switch SW is turned on as shown in Fig. 3B, the coil (5) and capacitor (6
) begins to resonate (more precisely, the resonance of the coils (5), (7) and the capacitor (6)), and a current flows through the circuit as shown by the broken line in Figure 3B. At this time, the energy stored in the capacitor (6) is stored in the coil (5) and then stored in the capacitor (6), but what should be noted here is that this energy transfer
) is reversed. Even if the polarity is reversed, the presence of the diode (4) allows current to flow only in the direction already indicated by the broken line in FIG. When the polarity is reversed, the switch SW is turned off, and resonance by the convergence yoke coil (7) and capacitor (6) begins. Here, as mentioned above, the resonance time constant of the coil (5) and the capacitor (6) is the convergence yoke coil (7).
) is set to be smaller than that of the capacitor "!-(6), so the voltage VC2 generated across the capacitor (6) at this time has a short period as shown in FIG. 4B.

Therefore, if we consider the circuit operations of FIG. 3A and B continuously, we can see that the voltage VC (-Vcy) with the waveform shown in FIG. ) is obtained. In the figure, when the switch S- is on, the resonant waveform is generated by the convergence yoke coil (force) and the capacitor (6), and when the switch is off, the resonant waveform is generated by the combination of the coil (5) and the capacitor (6). This is a kind of sawtooth wave voltage.Therefore, since Vc=Vcv, the waveform of the current flowing through the convergence yoke coil (6) is icy, as shown in Figure 2. It can be seen that by adopting this configuration, a parabolic wave current can be obtained immediately as a convergence correction current.It should be noted that the diode (4
), that is, the resonant current of the coil (5) and capacitor (6) due to the presence of the diode (4). Since it flows only in one direction, the waveform is as shown in FIG. 5C.

Figure 6 shows the waveform of the voltage VtV generated across the convergence yoke coil (7) when the switch SW is turned on. The purpose is to invert the voltage generated across the capacitor (6).

The energy stored in the capacitor (6) when the switch SW is off is transferred to the coil (5) when the switch SW is on.
), and as a result of being stored in the capacitor (6), the voltage across the capacitor (6) as shown in FIG. That is, the voltage ■CV across the convergence yoke coil (7) is reversed from ■→e.

Returning to FIG. 1 again, in this embodiment, the five-point adjustment is performed in the following manner. First, to adjust the TODO AMP, change the bias voltage of the transistor (13) by varying the variable resistor (15) of the current source (9), and thereby change the current flowing through the current source (9) and adjust the convergence yoke coil (force). Change the level of horizontal parabolic wave current flowing through H-TILT3jJ
By changing the phase of the switching pulse applied to the base of the transistor (3) by the phase shift circuit (2), the phase of the horizontal parabolic wave current flowing through the convergence yoke coil (7) is changed. For Y/BOW adjustment, a vertical parabolic wave phase current source is provided using a transistor (21) and a resistor (22), and a vertical parabolic wave voltage generation circuit (18) is used.
Vertical sawtooth wave generation circuit (1
The vertical sawtooth wave from 9) is added by an adder circuit (20) and supplied to the base of the transistor (21), thereby superimposing the vertical parabolic wave component on the horizontal parabolic wave current flowing through the convergence yoke coil (7). The level of the vertical parabolic wave current flowing through the convergence yoke coil (7) is changed by adjusting the level of the vertical parabolic wave voltage. The C-BOW8TR adjuster applies a vertical parabolic wave voltage from the input terminal (16) and modulates the current of the current source (9) into a vertical parabolic wave shape, thereby controlling the horizontal parabolic wave current flowing through the convergence yoke coil (7). Amplitude modulation is performed in the form of a vertical parabolic wave. Y-CRO3S adjustment involves superimposing a vertical sawtooth wave voltage on a vertical parabola wave voltage to change its phase, thereby changing the phase of the parabola wave current flowing through the convergence yoke coil (7) in a vertical period.

In this way, each of the five points can be adjusted individually here. In addition, in the case of H-AMP adjustment, the correction amount can be substantially changed by DC voltage, so the so-called bus control
is also possible. In other words, control using a pass line is based on the fact that the correction amount can be changed with a DC voltage, but a digital memory and a D/A converter (not shown) are provided for the variable resistor (15), and the digital memory is connected to the variable resistor (15). H-AMP adjustment becomes possible by storing various correction amounts, calling these correction amounts from the commander via a signal line, converting them from D/A, and changing the variable resistor (15). This is not limited to H-AMP adjustment but can also be applied to other adjustments.

〔Effect of the invention〕

As described above, according to the present invention, substantially two resonant circuits having different time constants are provided, voltages obtained from these resonant circuits are combined to form a sawtooth wave voltage, and this sawtooth wave voltage is integrated. Since the horizontal parabolic wave current can be obtained as the horizontal convergence correction current, misconvergence is eliminated, and since five-point adjustment can be performed individually, adjustment is easy and adjustment time is shortened. Furthermore, since a dedicated amplifier is not required as in the conventional case, the circuit is simple and the power consumption is low. Furthermore, compared to conventional circuits, it is possible to drive at a lower voltage.

[Brief explanation of drawings]

Fig. 1 is a circuit configuration diagram showing an embodiment of the present invention, Figs. 2 and 3 are equivalent circuit diagrams of the main parts of the invention, and Figs. 4 to 6 are explanations of the operation of the main parts of the invention. 7 are diagrams for explaining the conventional example. (3) is a transistor, (5) is a coil, (6), (
8) is a capacitor, (7) is a convergence yoke coil, and (9) is a current source.

Claims (1)

[Claims] A switch that opens and closes in a horizontal period; a coil connected in series with the switch; a first capacitor connected in parallel with the switch and the coil; and a convergence of series connections connected in parallel with the capacitor. A convergence correction circuit comprising a yoke coil, a second capacitor, and a current source connected in parallel to the convergence yoke coil and second capacitor.