JPH0584091B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to an oscillation stop circuit device.

Conventional Structure and Problems There is an example of an oscillation stop circuit device that is placed in parallel with the horizontal oscillation circuit of a television receiver. An example of this is shown in FIG. Figure 2 is the first
The operating waveform diagram of the main part of the diagram is shown. The circuit operation will be explained below with reference to these figures.

When the horizontal oscillation pulse shown in FIG. 2a supplied from the horizontal oscillator 1 is applied to the base of the transistor 2, the pulse shown in FIG. 2b appears at the collector of the transistor. Furthermore, this pulse
A pulse shown in FIG. 2c is delivered to the horizontal oscillation output terminal 5 via the Darlington-connected transistors 3 and 4. Further, this pulse is divided by resistors 6 and 7 and supplied to the base of horizontal drive transistor 8. Although not shown, the horizontal oscillation pulse applied to the horizontal drive transistor 8 is normally supplied to a horizontal deflection coil and a flyback transformer via a horizontal output transistor. Here, the flyback pulse obtained from the flyback transformer is boosted and rectified to generate a voltage to be applied to the picture tube and a high voltage source for use in the circuitry within the television receiver.

In this way, the horizontal oscillation pulse is also used as an input pulse to create a high voltage source. However, if these high voltage sources become abnormally high for some reason, X-rays are excited and emitted, which can affect the human body or cause damage to television receivers. Therefore, the oscillation stop means 9 detects the voltage value and stops the function of the horizontal oscillator 1 to prevent the above-mentioned disadvantages.

The oscillation stop means 9 is mainly composed of transistors 10 and 11, which are constructed in the same manner as the equivalent circuit of a well-known thyristor. NPN
The collector of the transistor 10 and the base of the PNP transistor 11 are commonly connected, and the transistor 10
The configuration in which the base of the transistor 11 and the collector of the transistor 11 are commonly connected is a thyristor equivalent circuit. The emitter of the transistor 10 corresponds to the cathode side of the thyristor, the emitter of the transistor 11 corresponds to the anode side, and the base side of the transistor 10 corresponds to the gate side. The emitter of the transistor 11 is connected to the voltage V _cc from the power supply terminal 19 through a resistance (no code).
It is always given through. Now, when a voltage or current that detects an abnormal voltage is applied to the voltage detection terminal 12 and the transistors 10 and 11 are once turned on, the transistors 10 and 11 will still be in the on state even if the voltage (current) is subsequently cut off. A so-called thyristor effect occurs, which sustains the For this reason, the transistors 13 and 14 are also held in the on state, and the collector potential of the transistor 2 is always almost zero, and the potential generated at the horizontal oscillation output terminal 5 is also almost zero, as shown in FIG. 2d. Becomes electric potential. As a result, no flyback pulse is generated and the television receiver does not operate. In this case, in order to operate the television receiver again, the power switch must be turned off and then turned on again. In this way, if the thyristor effect is actively used, it is possible to completely stop the operation of the television receiver, so this system is referred to here as a shutdown system. On the other hand, the input terminal 1 of the oscillation stop means 9
A system in which the television receiver operates again when the voltage or current applied to the terminal 5 is cut off is referred to herein as a hold-down system. Note that the resistor 16 and the capacitor 17 constitute a voltage holding means 18.

Whether to adopt the shutdown method or the holddown method is determined by the purpose of the electronic device, usage conditions, level of safety measures, etc.
In any case, it would be advantageous if each method could be easily set and the design between the two could be easily changed. However, using the thyristor effect as it is has the disadvantage that it is limited to the shutdown method. However, the high-speed switching characteristic that characterizes thyristors is a desirable condition for safely protecting electronic equipment and the like.

Purpose of the invention The present invention has been made in view of the above,
Moreover, it is an object of the present invention to provide an oscillation stop circuit device that can be easily set to either a shutdown method or a hold-down method, and can be extremely easily changed between the two.

Composition of the Invention In order to achieve the above object, the present invention is an oscillation stop circuit device for an oscillation circuit means for extracting an output signal from an oscillation signal generated by an oscillator to a signal output terminal via a signal derivation means, The collector and base of the first transistor are each separately connected to the base and collector of the second transistor, the base side of the first transistor is coupled to an input terminal to which a voltage or current is applied, and the second transistor The emitter side of is coupled to the signal deriving means and is given an oscillation signal synchronized with the signal appearing at the signal output terminal, and when a voltage or current is applied to the input terminal that causes the first transistor to conduct. In the oscillation stop circuit device, the second transistor is also made conductive in response to the first transistor so that the signal deriving means stops transmitting the oscillation signal to the signal output terminal. According to this, in addition to being able to freely set the shutdown method or the holddown method, it is also possible to easily change the design from one of these methods to the other.

DESCRIPTION OF EMBODIMENTS FIG. 3 shows an oscillation stop circuit device according to an embodiment of the present invention. Here, parts having the same functions as those in FIG. 1 are given the same numbers. The present embodiment differs from the conventional example illustrated in FIG. 1 in the oscillation stop means 20, particularly in that the emitter of the transistor 11 corresponding to the anode side of the thyristor operating circuit element is connected to the collector of the transistor 2. differ. The operational waveform diagram of the main part in FIG. 3 is the same as that of the conventional example shown in FIG. That is, Figure 2a
The waveform is a horizontal oscillation pulse supplied from the horizontal oscillator 1 regardless of whether the oscillation stop means 20 is on or off. The waveforms in FIGS. 2a and 2c are horizontal oscillation pulses generated at the collector of the transistor 2 and the horizontal oscillation output terminal 5, respectively, when the oscillation stop means 20 is off. The waveform shown in FIG. 2d is the potential generated at the horizontal oscillation output terminal 5 when the oscillation stop means 20 is on, and is set to approximately zero potential.

Next, the circuit operation of the embodiment of the present invention will be explained with reference to FIGS. 2 and 3.

First, when the oscillation stop means 20 is off, that is, the voltage is applied to the voltage detection terminal 12 (input terminal 15).
When no current is applied, transistor 11
The signal (horizontal oscillation pulse) shown in FIG. 2b is applied to the emitter of. In other words, the emitter of the transistor 11 has approximately zero potential during the period indicated by X, and approximately the power supply voltage during the period indicated by Y.
V _cc is applied to each. Therefore,
Transistors 10 and 11 configured in an equivalent circuit with a thyristor are connected to an input terminal 15 of an oscillation stop means 20.
Regardless of the potential of , it is always off during the period of X. Of course, the horizontal oscillation pulse in FIG. 2b is also at almost zero potential during the period indicated by X, and the horizontal drive transistor 8 is off. No need to disconnect. On the other hand, in the period indicated by Y in FIG. 2, the horizontal drive transistor 8 is placed in the on period. Therefore, the oscillation stop means 20 only needs to be turned on during the period indicated by Y to cut off the transmission of the oscillation signal to the horizontal drive transistor 8. That is, the on/off of the oscillation stop means 20 and the on/off of the horizontal drive transistor 8 are synchronized.

Whether the oscillation stop means 20 is turned on or off during the period indicated by Y is determined by the potential holding state of the input terminal 15. In order to turn on the oscillation stop means 20, the base of the transistor 10 is connected to the input terminal 15.
Emitter voltage, so-called diode voltage Vd
It is only necessary to provide the above and maintain a voltage source higher than Vd at all times. 16 resistors, 1 capacitor
A voltage (current) holding means 18 composed of 7 is provided for this purpose. On the other hand, the condition for turning off the oscillation stop means 20 is that the voltage is Vd or less, and preferably zero volts. Voltage current)
The holding means 18 not only refers to the parallel circuit configuration of the resistor 16 and the capacitor 17, but also the voltage (current)
refers to something that is sufficient to maintain capacitor 17
The electric charge charged in is discharged through the resistor 16, but once the transistors 10 and 11 are turned on, part of the collector current of the transistor 11 charges the capacitor 17, and this action is repeated, so that the input The potential of terminal 15 is always approximately voltage
held at Vd.

When adopting the shutdown method here,
The time constant τ=R ₁₆ ·C _{17 of the value R 16 of} the resistor 16 and the value C ₁₇ of the capacitor 17 may be set to be sufficiently larger than the period T of the horizontal oscillation pulse. The period T is indicated by the sum of the above periods X and Y (T=X
+Y). On the other hand, when using the hold-down method, the time constant τ may be made smaller than the period T. If the time constant τ is made small, the potential of the input terminal 15 will follow the potential of the voltage detection terminal 12. Of course, in the case of the hold-down method, the capacitor 17 is not essential, but it is preferable to use it because it has the effect of attenuating and eliminating external noise.

Although the present invention has been described using a horizontal oscillator as an example, it is needless to say that the invention is not limited to this and can be applied to any device that includes an oscillator and requires disconnection or interruption of its oscillation signal. Furthermore, the oscillation stop circuit device of the present invention has the advantage of being able to reduce the number of circuit elements including the transistors 13 and 14, as is clear when compared with the conventional example shown in FIG.

Effects of the Invention As described above, the oscillation stop circuit device of the present invention allows the transistors constituting the equivalent circuit of the thyristor to synchronize with the horizontal oscillation output signal from the signal path from the horizontal oscillator to the horizontal oscillation output terminal. By supplying a signal and selecting whether to use a voltage (current) holding circuit on the gate side of the thyristor, it can be set to either the shutdown method or the holddown method, and it is extremely easy to change the design between the two. , and its practical value is great.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional oscillation stop circuit device.
FIG. 2 is an operational waveform diagram of the main part, and FIG. 3 is a diagram showing an oscillation stop circuit device according to an embodiment of the present invention. 1...Horizontal oscillator, 2, 3, 4, 13, 14...
...Transistor, 5...Horizontal oscillation output terminal, 6,
7... Resistor, 8... Horizontal drive transistor, 9, 20... Oscillation stop means, 10, 11...
Thyristor configuration transistor, 12... Voltage detection terminal, 15... Input terminal, 16... Resistor for voltage holding means, 17... Voltage holding capacitor, 18
...Voltage holding means, 19...Power terminal.

Claims (1)

[Claims] 1. An oscillation stop circuit device for an oscillation circuit means for outputting an oscillation signal generated by an oscillator to a signal output terminal via a signal deriving means, wherein the collector and base of a first transistor are connected to the base of a second transistor separately. and the collector of the first transistor, the base side of the first transistor is coupled to an input terminal to which a voltage or current is applied, and the emitter side of the second transistor is coupled to the signal deriving means and the collector of the signal An oscillation signal synchronized with a signal appearing at the output terminal is applied, and when a voltage or current that causes the first transistor to conduct is applied to the input terminal, the second transistor also becomes conductive in response to the first transistor. . An oscillation stop circuit device, characterized in that the signal deriving means stops transmission of the oscillation signal to the signal output terminal.