JPS63135070A - High voltage stabilizing device - Google Patents

Abstract

PURPOSE:To keep a high voltage output constant from a horizontal output circuit and a high voltage circuit even at no signal by discriminating the presence and absence of a synchronizing signal by a synchronizing signal discrimination circuit when no composite video signal exists and supplying a pseudo synchronizing signal from a synchronizing signal generating circuit by the output. CONSTITUTION:The emitter of a transistor 14 is connected to ground and a collector is connected to a +B power supply 17 via a load resistor 15 and connected to the input terminal of a synchronizing signal generating circuit 10 through a diode 10. When no horizontal synchronizing signal 11 is fed to a synchronizing signal discrimination circuit 9, a +B is supplied to the synchronizing signal generating circuit 10 to be in an operating state, and the pseudo synchronizing signal generated from the circuit 10 is fed to a phase detection circuit 7. Since the pseudo synchronizing signal and a comparison signal generated from a comparison signal generating circuit 6 make the phase comparison at the phase detection circuit 7, the correction voltage is almost kept constant and the horizontal oscillation frequency is not fluctuated and the stable high voltage is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high voltage stabilizing device capable of supplying a constant high voltage even when there is no signal in a television receiver.

[Conventional technology]

Generally, a horizontal output and high voltage stabilizing device in a television receiver is constructed as shown in FIG. In FIG. 3, 1 is a composite video signal including a synchronization signal;
2 is a synchronization separation circuit that extracts only a synchronization signal from the composite video signal 1;

On the other hand, the horizontal output circuit 4 generates a horizontal deflection signal and high voltage using the signal output from the horizontal oscillation circuit 3. The pulses generated from the horizontal output circuit 4 are added to the high voltage circuit 5, where the voltage is boosted. to generate high voltage.

Further, the pulses generated from the horizontal output circuit 4 are added to the comparison signal generation circuit 6, and the zero phase detection circuit 7 generates a signal whose phase can be compared with the comparison signal generation circuit 6.
compares the phase of the synchronization signal from the synchronization separation circuit 2 and the pulse generated by the horizontal output circuit 4 with the signal generated through the comparison signal generation circuit 6, outputs the difference in phase as a high or low voltage, and controls the horizontal oscillation circuit 3. It is something to do.

Further, 18 is a Zener diode that clips the output voltage from the phase detection circuit 7 so that it does not exceed a certain voltage.

Next, the operation will be explained. A composite video signal 1 is input into a synchronization separation circuit 2, where a horizontal synchronization signal is extracted and input into a phase detection circuit 7.

On the other hand, the oscillation frequency of the horizontal oscillation circuit 3 is controlled by the output voltage from the phase detection circuit 7, and the horizontal output circuit 4 is driven by the output oscillation waveform.

Further, a high voltage circuit 5 boosts the horizontal pulse generated by the horizontal output circuit 4 using a transformer or the like to supply a high voltage to the cathode ray tube, and a comparison signal generating circuit 6 integrates the horizontal pulse to generate a sawtooth wave. , are supplied to the phase detection circuit 7.

The phase detection circuit 7 compares the phases of the horizontal synchronization signal and the sawtooth wave signal generated by the comparison signal generation circuit 6, and if there is a phase difference, generates a corresponding correction voltage. The horizontal oscillation circuit 3 is controlled by the correction voltage.

For example, when the composite video signal l disappears, that is, when there is no signal, the phase detection circuit 7 is not supplied with a horizontal synchronization signal for phase comparison, so the correction voltage is not kept constant, and a free-run state occurs. becomes.

If the horizontal oscillation circuit 3 is configured so that the oscillation frequency decreases as the correction voltage increases, the relationship between the horizontal output pulse voltage and the horizontal oscillation frequency f is VCP''t/rw. Therefore, the output high voltage of the high voltage circuit 5 increases and becomes abnormally high voltage.

Here, when the correction voltage from the phase detection circuit 7 exceeds a certain voltage, the Zener diode 18 clips so that the voltage does not exceed the Zener voltage, thereby preventing an abnormally high voltage.

[Problem that the invention seeks to solve]

Since the conventional high voltage stabilizer is configured as described above, the voltage does not exceed a certain level when there is no signal, but it is still unable to prevent fluctuations in the high voltage, and the elements such as the horizontal output circuit 4 and the high voltage circuit 5 This resulted in problems such as an abnormal load being placed on the images and the actual images being out of sync, making them difficult to view.

The present invention was made to solve these problems, and an object of the present invention is to provide a high voltage stabilizing device that can maintain a constant high voltage output from a horizontal output circuit and a high voltage circuit even when there is no signal.

[Means for solving problems]

The high-voltage stabilizing device according to the present invention includes a sync signal discriminator circuit that detects the absence of a sync signal when there is no signal when the composite video signal is gone, and a sync signal detecting circuit that detects the phase of the sync signal even when there is no signal by using the output of this sync signal discriminator circuit. A phase detection circuit for supplying signals to the circuit is provided.

[For production]

In this invention, the synchronization signal discriminating circuit determines the absence of a composite video signal, and when it detects the absence of a synchronization signal, it outputs it to the synchronization signal generation circuit, and the synchronization signal generation circuit generates a pseudo synchronization signal even when there is no signal. By generating and outputting to the phase detection circuit, the correction voltage from the phase detection circuit is kept constant, and the horizontal or vertical oscillation frequency is also kept constant.
High voltage remains stable without fluctuations.

〔Example〕

Embodiments of the high-pressure stabilizing device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment, and when explaining the configuration, the same parts as in FIG. I will mainly discuss.

In FIG. 1, 8 is a block newly added according to the present invention, which includes a synchronous signal discriminating circuit 9 that determines whether a horizontal synchronous signal is output from the synchronous separating circuit 2, and The synchronization signal generation circuit 10 generates a pseudo-equivalent synchronization signal and outputs it to the phase detection circuit 7 when it is determined that there is no synchronization signal.

Further, FIG. 2 is a circuit diagram showing an embodiment of the synchronization signal discriminating circuit 9 for determining the presence or absence of a synchronization signal according to the present invention. In this FIG. 2, the horizontal synchronizing signal 11 is connected to the resistor 12.
The signal is supplied to the base of a transistor 14 that performs a switching operation via an integrator consisting of a capacitor 13 and a capacitor 13.

The emitter of the transistor 14 is grounded, and the collector is connected to a 10B power supply 17 through a load resistor 15 and to the input end of the synchronizing signal generating circuit 10 through a diode 16.

Next, the operation will be explained. In FIG. 1, when the composite video signal 1 disappears, that is, when there is no signal, the horizontal synchronization signal 11 (FIG. 2) is not output from the synchronization separation circuit 2, and the supply to the synchronization signal discrimination circuit 9 is It disappears.

Now, referring to FIG. 2, the detailed operation of the synchronization signal discriminating circuit 9 will be explained. When the horizontal synchronizing signal 11 is supplied, the horizontal synchronizing signal 11 is integrated by a resistor 12 and a capacitor 13 with a certain time constant.

Since this integrated voltage is supplied to the base of the transistor 14, the transistor 14 is turned on, a collector current flows, a potential difference is generated in the load resistor 15, and a voltage of 10B is generated in the synchronization signal generation circuit 10. Not supplied and in non-operational condition.

If horizontal synchronization signal 11 is not supplied, transistor 1
4 is in a cut-off state, and no potential difference occurs between both ends of the load resistor 15. Therefore, a voltage of 10 B is supplied to the synchronizing signal generating circuit 10 via the diode 16, and the synchronizing signal generating circuit 10 becomes in an operating state.

Here, the explanation returns to FIG. 1 again. When the horizontal synchronization signal 11 is not supplied to the synchronization signal discrimination circuit 9, 10B is supplied to the synchronization signal generation circuit 10 as described above, and the phase detection circuit 7 is supplied with a pseudo synchronization signal generated by the synchronization signal generation circuit 10.

Since the phase detection circuit 7 compares the phase of this pseudo synchronization signal with the comparison signal generated from the comparison signal generation circuit 6, the correction voltage is kept almost constant, and the horizontal oscillation frequency does not change and a stable high voltage is also generated. Obtainable.

Further, in the above embodiment, only the horizontal synchronizing signal was explained, but the same can be considered for the vertical synchronizing signal.

In other words, phase detection is performed using the vertical synchronization signal and the vertical output waveform,
When synchronization is stabilized, the vertical synchronization signal disappears when there is no signal, so the vertical oscillation frequency fluctuates, the vertical output becomes unstable, and it is thought that an abnormal load will be placed on the elements of the output circuit.

Therefore, according to the apparatus of the present invention, if a vertical synchronization signal is created in a pseudo manner when there is no vertical synchronization signal, stable vertical oscillation can be performed even when there is no composite video signal.

〔Effect of the invention〕

As explained above, in this invention, when there is no composite video signal, the presence or absence of a synchronization signal is determined by the synchronization signal discriminating circuit, and the output can supply a pseudo synchronization signal from the synchronization signal generation circuit. Also, the horizontal or vertical oscillation frequency can be kept constant, and the high voltage can also be kept constant without fluctuation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the high voltage stabilizing device of the present invention, Fig. 2 is a detailed circuit diagram of a synchronization signal discrimination circuit in the same high voltage stabilizing device, and Fig. 3 is a block diagram of a conventional high voltage stabilizing device. It is a block diagram. 2...Synchronization separation circuit, 3...Horizontal oscillation circuit, 4...
- Horizontal output circuit, 5... High voltage circuit, 6... Comparison signal generation circuit, 7... Phase detection circuit, 9... Synchronization signal discrimination circuit, 10... Synchronization signal generation circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A phase detection circuit that detects the phase of a synchronization signal from a video signal and a horizontal pulse from a horizontal output circuit or a vertical pulse from a vertical output circuit and controls a horizontal oscillation circuit or a vertical oscillation circuit according to the detected output voltage. , a horizontal output circuit or a vertical output circuit driven by the output of the horizontal oscillation circuit or the vertical oscillation circuit, a high voltage circuit that increases the voltage of pulses generated by the horizontal output circuit or the vertical output circuit, and the horizontal output circuit or the vertical oscillation circuit. a comparison signal generation circuit that outputs a comparison signal from the output of the vertical output circuit to the phase detection circuit;
A high voltage stabilizing device comprising: a discrimination circuit that discriminates the presence or absence of the synchronization signal; and a synchronization signal generation circuit that generates a pseudo synchronization signal based on the output from the discrimination circuit and outputs it to the phase detection circuit.