JPS6246366Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horizontal deflection circuit, and more particularly to a horizontal deflection circuit for a television receiver.

A conventional example of a horizontal deflection circuit for a television receiver is shown in FIG. In this figure, the output of the horizontal drive circuit 1 is connected to the base of the horizontal output transistor 2. A damper diode 3, a resonance capacitor 4, and a horizontal deflection coil 5 are provided in parallel between the collector and emitter of the horizontal output transistor 2. An S-shaped correction capacitor 6 is connected in series to the horizontal deflection coil 5, and the capacitor 6 functions as an actual power source for supplying a sawtooth wave deflection current to the horizontal deflection coil 5. A voltage V _B is applied to the collector of transistor 2 and a flyback transformer 7
The voltage is applied through the primary coil.

In a horizontal deflection circuit with such a configuration, first,
Horizontal drive circuit 1 to horizontal output transistor 2
When the horizontal output transistor 2 is turned on in response to a horizontal drive pulse supplied to the deflection coil 5, the current flowing from the capacitor 6 to the deflection coil 5 increases linearly. Next, when the transistor 2 is turned off, the magnetic energy stored in the deflection coil 5 flows to charge the capacitor 4, and the terminal voltage of the deflection coil 5 becomes extremely high. This voltage becomes a horizontal retrace pulse, which is stepped up by the flyback transformer 7 to become an even higher voltage, and is then supplied to the anode of the picture tube (not shown) via the rectifier diode 8. Once the magnetic energy is charged in the capacitor 4, current will no longer flow in the deflection coil 5, but after that, the electrostatic energy stored in the capacitor 4 will be discharged towards the deflection coil 5, and the deflection coil 5 will receive a current in the opposite direction. Current flows. Next, when the capacitor 4 finishes discharging, the energy stored in the deflection coil 5 is discharged by flowing a so-called damper current through the damper diode 3, and the capacitor 6 is charged. Then, the transistor 2 is turned on again, and the above operation is repeated to generate a high voltage and at the same time, a sawtooth wave deflection current flows through the deflection coil 5.

However, in such a conventional horizontal deflection circuit, a high voltage and a deflection current are generated due to resonance between the capacitor 4 and the deflection coil 5, so changing the voltage V _B changes the high voltage level and the deflection current level. This was a problem because the high voltage and deflection current could not be changed separately because they changed at the same time.

Conventionally, in order to eliminate such problems, a second
A horizontal deflection circuit as shown in the figure was used.
In this figure, the output of the horizontal drive circuit 1 is connected to the bases of two horizontal output transistors 2a and 2b. A damper diode 3a and a resonant capacitor 4a are connected between the collector and emitter of the transistor 2a, as in the circuit shown in FIG. 1, and a direct circuit of a dummy coil 9 of the deflection coil and an S-shaped correction capacitor 6a is connected has been done. A voltage V _B1 is applied to the collector of the transistor 2 via the primary coil of the flyback transformer 7.
are being supplied. On the other hand, a damper diode 3b, a resonance capacitor 4b, a horizontal deflection coil 5, and an S-shaped correction capacitor 6b are connected between the collector and emitter of the transistor 2b, as in the circuit shown in FIG. A voltage V is applied to the collector of the transistor 2b via a choke coil 10 which is a dummy of a flyback transformer.
_B2 is supplied.

That is, in the horizontal deflection circuit having such a configuration, the flyback transformer 7 is provided exclusively for supplying high voltage, the deflection coil 5 is provided exclusively for supplying deflection current, and the power supplies are provided respectively. There is. Therefore, by changing the voltage V _B1 , the high voltage level changes, and by changing the voltage V _B2 , the deflection current level changes, so that the high voltage and the deflection current can be changed separately.

However, such conventional horizontal deflection circuits have a problem of high cost due to the large number of parts.

Therefore, an object of the present invention is to provide a horizontal deflection circuit that can change the high voltage and the deflection current separately with a small number of parts.

The horizontal deflection circuit according to the present invention includes a capacitor forming a series resonant circuit with the primary coil of a flyback transformer, and a diode, that is, a unidirectional conduction element, between the primary coil and a parallel resonant circuit including the deflection coil. The DC voltage is supplied to the series resonant circuit by a power source different from the power source which supplies the DC voltage to the parallel resonant circuit.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.

In the horizontal deflection circuit according to the present invention shown in FIG. 3, parts equivalent to those in FIG.
A damper diode 3a and a resonant capacitor 4a are connected between the emitters, and a voltage V _B1 is applied to the collector via the primary coil of a flyback transformer 7. The diode 11 is for preventing backflow, and the cathode of the diode 11 is connected to the collector of the transistor 2. A deflection coil 5 and a capacitor 6b are connected to the anode of the diode 11 as in the circuit shown in FIG.
A direct circuit with the damper diode 3b and a resonant circuit of the resonant capacitor 4b are connected. A voltage V _B2 is applied to this parallel circuit and the anode of the diode 11.

In the horizontal deflection circuit according to the present invention having such a configuration, first, when the horizontal output transistor 2 is turned on, a current due to the voltage V _B1 flows to the primary coil of the flyback transformer 7, and a current due to the voltage V _B2 flows to the flyback coil 10. Current flows from the capacitor 6b into the deflection coil 5, and these currents become the collector current of the transistor 2. next,
When the transistor 2 is turned off, the magnetic energy stored in the deflection coil 5 flows to charge the capacitor 4b, so that the terminal voltages of the deflection coil 5 and the primary coil of the flyback transformer 7 temporarily become very high. At this time, the pulse width of the high voltage pulse generated in the flyback transformer 7 is _H1 , the voltage level (peak value) is _VH1 , and the pulse width of the high voltage pulse generated in the deflection coil 5 is
H ₂ and voltage level V _H2 , H ₁ > H ₂ and V _H1
＞V _H2 , or adjust the voltage V _B
1. If V _B2 is set, the diode 11 is cut off, and the high voltage pulse generated in the flyback transformer 7 is transmitted to the deflection coil 5 and capacitor 4.
The resonance effect caused by b does not affect the deflection current flowing through the deflection coil 5.

Therefore, by varying the voltage V _B1 within the range of H ₁ > H ₂ and V _H1 > V _H2 , the voltage level of the high voltage pulse generated in the flyback transformer 7, that is, the voltage level supplied to the anode of the picture tube The high voltage level can be varied, and by varying the voltage V _B2 the deflection current level can be varied.

In this way, according to the horizontal deflection circuit of the present invention,
The high voltage supply section and the deflection current supply section each have a power supply, and a unidirectional conduction element is provided between the high voltage supply section and the deflection current supply section to prevent them from influencing each other. The deflection current can be changed separately. In addition, the high voltage supply section does not require a dummy coil or an S-shaped correction capacitor, and the primary coil of the flyback transformer and the resonant capacitor perform the resonance action, and a single horizontal output transistor is sufficient. The number of parts can be reduced compared to the conventional circuit shown in FIG. 2, and costs can be reduced.

In addition, in the horizontal deflection circuit according to the present invention,
_The present invention is not limited to providing a flyback transformer on the cathode side of the backflow prevention diode and a deflection coil on the anode side as in the above _{embodiment .}
If ₁ <V _H2 , a deflection coil may be provided on the cathode side of the diode, and a flyback transformer may be provided on the anode side. Further, in the above embodiment, the horizontal deflection circuit of a television receiver was explained, but the present invention can also be applied to a horizontal deflection circuit of a television camera.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams showing a conventional example of a horizontal deflection circuit, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. Explanation of symbols of main parts, 2, 2a, 2b...Horizontal output transistor, 3, 3a, 3b...Damper diode, 4, 4a, 4b...Resonance capacitor, 5...Deflection coil, 7...Flyback Transformer, 10...Chiyoke coil.

Claims (1)

[Scope of utility model registration request] a parallel resonant circuit including a horizontal deflection coil of a CRT; a first power supply supplying a first DC voltage to both ends of the parallel resonant circuit; and a first power supply connected in parallel to the parallel resonant circuit to horizontally drive both ends of the parallel resonant circuit. A horizontal deflection circuit including a switching circuit that short-circuits in response to a pulse, the switching circuit consisting of a series circuit of a switch element and a diode that are turned on and off in response to the horizontal drive pulse, and the switch element and the diode connected in series. a flyback transformer including a primary coil having one end connected to the connection point; a capacitor having one end connected to the connection point, connected in parallel to the switch element and forming a series resonant circuit with the primary coil; 1
a second power supply for applying a second DC voltage between the other end of the secondary coil and the other end of the capacitor;
A horizontal deflection circuit characterized by deriving the anode voltage of a CRT.