JPS6126265B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a circuit that can solve the problem of screen changes in a television receiver in which the horizontal amplitude changes due to changes in audio signals. shall be.

First, a conventional example will be explained with reference to FIG. In the figure, A block is a power supply circuit, B block is a vertical output circuit, C block is a vertical line pink tension correction circuit, D block is a horizontal deflection output circuit, and E is an audio output circuit.

Let's start with the A block. T ₃ is a power transformer that separates the primary and secondary, and at the same time supplies the necessary power to the secondary side. diode
D ₁ , power supply E ₁ rectified and smoothed by capacitor C ₅
is supplied to the primary side of flyback transformer _T2 ,
Further, a power source E ₂ that has been rectified and smoothed by a diode D ₂ and a capacitor C ₆ is supplied to an audio output circuit C.

In the vertical output circuit of the B block, the transistor
Q ₁ and Q ₂ are vertical output transistors.

In the vertical line pink tension correction circuit of the C block, a sawtooth wave voltage as shown in Figure 3a is generated at the intersection of the vertical output transistors _Q1 and _Q2 , so this sawtooth wave voltage is applied to the resistor _R1 and the capacitor _C1. The parabolic current is integrated by , and the parabolic current is passed through the DC cut capacitor _C2 to the vertical winding of the pink cushion correction transformer _T1 . A resistor R ₂ is connected between the DC power source E ₃ and the vertical winding of the pink tension correction transformer T ₁ to supply a constant DC power.

Therefore, the current flowing through the vertical winding of the pink shock correction transformer _T1 has a current waveform as shown in FIG. 3b. This current waveform is used to change the inductance value of the horizontal winding of the pink tension correction transformer _T1 , and by modulating the horizontal deflection current, the vertical line pink tension is corrected.

In the D block horizontal deflection circuit, _L1 is the deflection yoke, _Q3 is the horizontal output transistor, _C3 is the resonance capacitor, _C4 is the S-shaped correction capacitor, _L2 is the horizontal linearity coil, and _T2 is the flyback transformer. It is.

A drawback of this conventional example is that the load current of the audio output circuit E changes depending on the content of the audio signal, and the power supply
There is a point that the voltages on E ₁ and E ₂ change. Then, when the voltage of _E1 changes due to the sound, the deflection current flowing through the deflection yoke _L1 changes, so the horizontal amplitude of the screen changes and fluctuations appear on the screen.

The purpose of the present invention is to provide a circuit that prevents fluctuations in screen amplitude due to such sound.
An example of this will be described below with reference to FIG. 2.

Power supply circuit A, vertical output circuit B, horizontal deflection circuit D
Since it is the same as that of the conventional example, the explanation will be omitted. In the vertical line pink tension correction circuit of block C, in this circuit, a transistor circuit is added as a variable impedance element as shown in the diagram in parallel to the bias resistor _R2 , and the audio output circuit E
By changing the bias current of the vertical line pink tension correction transformer _T1 in synchronization with load fluctuations, the horizontal amplitude of the screen is prevented from changing even with the content of the audio signal.

Specifically, the resistor R ₁ and capacitors C ₁ and C ₂ integrate the sawtooth wave signal of the vertical output circuit C and supply a parabolic correction current to the vertical pincushion correction transformer T ₁ as in the conventional case. There is. Resistor D ₂ is the bias resistor and transformer T ₁
DC bias current is supplied to the The added transistor circuit is connected in parallel with the bias resistor _R2 , and when the power supply voltage _E2 of the audio output circuit E changes, the base current of the transistor _Q4 changes via the DC cut capacitor _C7 , and the transistor _Q4 changes.
The collector current of will change. The bias current of the vertical line pink tension correction transformer _T1 is
Since it is the composite value of the current flowing through resistor R ₂ and the collector current of transistor Q ₄ , the power supply voltage of the audio circuit is
E ₂ allows the horizontal amplitude to be controlled.

Now, considering the case where the audio signal becomes louder, both the power supply voltages E ₂ and E ₁ change in a downward direction, and when E ₁ decreases, the deflection current decreases and the horizontal amplitude decreases. However, at the same time, E ₂ also decreases and the collector current of transistor Q ₄ increases, so that the vertical line pink tension correction transformer T ₁
The bias current in the vertical winding increases and the transistor
The inductance of the coil on the horizontal winding side of _T1 decreases, and the deflection current increases. Therefore, it operates so that changes in the deflection current are canceled out, and changes in the horizontal amplitude due to changes in the audio signal can be reduced. Resistor R ₃ is an emitter resistance of transistor Q ₄ , resistance R ₄ is a collector resistance, and resistances R ₅ and R ₆ are bias resistances of transistor Q ₄ . Also, since the resistors R ₄ and R ₃ are much larger than the resistor R ₂ , the h of the transistor Q ₄ is
e etc., the horizontal amplitude does not change significantly.

As is clear from the above embodiments, according to the present invention, it is possible to obtain a useful circuit in which the horizontal amplitude of the screen does not change even if the audio signal changes. Also, regarding specific means, a transistor circuit is connected in parallel to a resistor inserted between the vertical winding and a power supply that supplies a constant DC current to the vertical winding of the pink tension correction transformer.
Since the impedance of the transistor circuit is changed in response to changes in the power supply voltage of the audio output circuit, and the value of the DC current supplied to the vertical winding is changed, the circuit configuration is simple and can be constructed at low cost. can.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional vertical line pink tension correction circuit, Fig. 2 is a circuit diagram of a vertical line pink tension correction circuit according to an embodiment of the present invention, and Figs. 3 a and b.
is a waveform diagram for explaining the operation. A...Power supply circuit, B...Vertical output circuit, C...
Vertical line pink tension correction circuit, D...horizontal deflection output circuit, E...audio output circuit, _T1 ...pink tension correction transformer, _R2 ...bias current resistance, _R3 , _R4 , _R5 , _R6 ... …Resistor, C ₇ …Capacitor, D ₄ …Transistor.

Claims (1)

[Claims] 1. Supply power voltage from the secondary side of the power transformer to the audio output circuit and the horizontal deflection output circuit, respectively, connect one end of the horizontal deflection coil included in the horizontal deflection output circuit to the horizontal winding of the pink tension correction transformer, and The configuration is such that a parabolic current with a vertical period is supplied to the vertical winding of the pink tension correction transformer, and a constant DC current is supplied from the DC power supply terminal to the vertical winding through a resistor, and the resistor is connected to the vertical winding. A transistor circuit is connected in parallel, and the power supply voltage of the audio output circuit is directly applied to the transistor circuit, and the impedance of the transistor circuit is changed according to the change in the power supply voltage, and the direct current supplied to the vertical winding is changed. A vertical line pink tension correction circuit characterized in that it is configured to change a value.