JPH05899Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a power supply circuit for a strobe device, and particularly when using a DC high-voltage power supply as a power source, it can be used more rapidly by regulating the voltage of the main capacitor and preventing glow in the flash discharge tube. The present invention relates to a power supply circuit that can perform charging.

Prior Art A power supply circuit for a strobe device that achieves constant voltage and rapid charging of the main capacitor with an extremely simple configuration even when using a DC high voltage power supply is disclosed in Japanese Utility Model Publication No. 55-40957, for example. The circuit shown is known.

As shown in FIG. 2, this power supply circuit consists of a DC high voltage power supply 1, a power switch 2, a resistor 3, and a first
SCR4, which is a switch element, capacitors C ₁ , C ₂ that control the operation of this SCR 4, resistors R ₁ , R ₂ ,
R ₃ , a diode D, a first gate means 5 consisting of a bidirectional diode SSS, and a second switch element for controlling the operation of the first gate means 5.
SCR6 detects the charging voltage of main capacitor 8
Second gate means 7 consisting of resistors R ₄ , R ₅ , R ₆ and Zener diode ZD for controlling the operation of SCR 6
It is composed of.

The operation will be briefly described below.

Now, when the power switch 2 is turned on, current flows from the DC high voltage power supply 1 through the resistor 3, the first gate means 5, and the main capacitor 8, and the capacitor C2 of the first gate means ₅ is charged. will be carried out.

When the charging voltage of capacitor _C2 reaches the breakover voltage of bidirectional diode SSS, the above bidirectional diode SSS turns on and the above capacitor
The charge on _C2 is discharged through resistor _R3 . Therefore, the gate operation of SCR4 is performed, and SCR4 is turned on.

When the SCR 4 is turned on, the main capacitor 8 is charged by the DC high voltage power supply 1, and the charging voltage is detected by the second gate means 7. When the charging voltage of the main capacitor 8 reaches a voltage value preset by the second gate means 7, the Zener diode ZD is turned on, and as a result, current flows through the resistor _R6 , turning on the SCR6.

When SCR6 turns on, resistor R ₁ , capacitor C ₁ ,
The potential at the connection point of SCR6 decreases and becomes lower than the anode potential of SCR4. Therefore, a reverse bias state is established between the gate and cathode of the SCR 4 and between the anode and the cathode, and the SCR 4 is reliably turned off. Due to this operation, the main capacitor 8 is not charged by the DC high voltage power supply 1. It will be forced to stop. That is, main capacitor 8
Charging is not performed while the SCR 6 is on.

On the other hand, when the charging voltage of the main capacitor 8 decreases due to leakage, the Zener diode ZD is turned off, and therefore the SCR 6 is also turned off. When the SCR 6 is turned off, the current from the DC high voltage power supply 1 flows through the first gate means 5 again, the SCR 4 is turned on, and charging of the main capacitor 8 is resumed.

After that, repeat the above operation and connect the main capacitor 8.
The charging voltage will be made constant.

Therefore, in the above power supply circuit, for example, there is no problem even if a power supply having an output voltage higher than the scheduled charging voltage value of the main capacitor 8 is used as the DC high voltage power supply 1, and as a result, the charging time can be shortened with a simple configuration. It was expected that the system would be able to achieve the desired results.

Problems to be solved by the invention The above-mentioned power supply circuit was able to achieve constant voltage and rapid charging when using a DC high-voltage power supply with a simple configuration, but when considering its application to an actual strobe device, Although not shown in Figure 2, the flash discharge tube that consumes the charging energy of the main capacitor 8,
There is a problem in that consideration must be given to glow discharge during light emission.

In other words, the above power supply circuit has no problem when applied to a well-known automatic flash control flash device and the flash discharge tube performs a light emission operation based on an automatic flash control operation, but when it is applied to a well-known automatic flash control flash device, there is no problem. When performing a so-called manual flash operation, if the energy supplied from the DC high-voltage power supply 1 to the main capacitor 8 and the flash discharge tube is too large in consideration of rapid charging, the flash discharge tube will absorb the charging energy of the main capacitor 8. It does not extinguish even after the regular light emission operation that consumes it.
There is a risk of causing a glow discharge condition.

For this reason, the above-mentioned power supply circuit has the trouble of having to take into account the prevention of the glow discharge while aiming to achieve rapid charging of the main capacitor 8 as described above, and therefore it is difficult to put it into practical use. In this case, by setting the resistance value of resistor 3 in the circuit diagram shown in Figure 2 to 150 to 300Ω, the current value that can be supplied from DC high voltage power supply 1 to main capacitor 8 etc. can be suppressed to some extent. is the current situation.

Suppressing the current value supplied from the DC high-voltage power supply 1 is, of course, negative in terms of the charging characteristics of the main capacitor 8. In other words, in the past, the charging characteristics of the main capacitor 8 were different from those of other power sources. Resistor 3 is used to set an appropriate supply current value that shortens charging time compared to when in use and prevents glow discharge, and the purpose of rapid charging has been fully achieved when considering the practical use of strobe devices. However, I could not say that.

The present invention has been developed in consideration of the above-mentioned problems, and provides a power supply circuit for a strobe device that can reliably prevent glow discharge when a flash discharge tube emits light, thereby shortening the charging time of the main capacitor 8. It is something to do.

Means for Solving the Problems The power supply circuit of the strobe device according to the present invention includes a power supply, a main capacitor charged by the power supply,
a first thyristor connected between the power source and the main capacitor; a first gate means for turning on the first thyristor by supplying the power; a second thyristor that controls the operation and reverse biases the first thyristor; a first transistor that turns on the second thyristor when turned on; and a first transistor that is normally kept off and that controls the charging voltage of the main capacitor. a second gate means including a second transistor that turns on when a predetermined level is reached and turns on the first transistor; a switch element that excites the flash discharge tube that consumes the charge in the main capacitor; and a trigger capacitor. , a transmission means for detecting a potential fluctuation accompanying the conduction of the switch element of the trigger circuit, such as a synchro switch, and transmitting the detected potential fluctuation to the first transistor to turn it on.

Function The power supply circuit of the strobe device according to the present invention has the above-described configuration, so that the second power supply circuit is activated both when the charging voltage of the main capacitor reaches a predetermined level and when the switch element of the trigger circuit is turned on.
By turning on the first thyristor and turning off the first thyristor, the energy supply from the DC high-voltage power supply to the main capacitor and flash discharge tube is ensured and compact.
This can be prevented with a simple configuration.

Embodiment FIG. 1 is an electrical circuit diagram of a strobe device including a power supply circuit of the strobe device according to the present invention, and the same reference numerals as in FIG. 2 indicate the same functional parts.

In the figure, 7' is a second gate means, which includes a transistor 9 which is a switch element that is normally kept off, resistors R ₄ and R ₅ , and a Zener diode ZD.
The transistor 10 is turned on when it is detected that the charging voltage of the main capacitor 8 has reached a predetermined level, and turns on the transistor 9, which is a switch element and a resistor _R6 . Like the gate means 7, the second thyristor 6
It controls the operation of the Reference numeral 11 denotes a well-known trigger circuit for the flash discharge tube 12, which includes a trigger capacitor TC, a trigger transformer TT, a thyristor SCR as a switch element, and a gate circuit GC of the SCR including a synchro switch (not shown), and 13 a diode. 14, resistance 1
5, which transmits the anode side potential change when the SCR of the trigger circuit 11 is turned on, that is, the potential at point A in the figure, to the base of the transistor 9 of the second gate circuit 7' described above. There is.

The operation of one embodiment of the above configuration will be described below.As is clear from FIG. 1, the relationship among the first gate means 5, first thyristor 4, and main capacitor 8 is the same as the circuit shown in FIG. The relationship is the same, and therefore, the operation in which the first thyristor 4 is turned on when the power switch 2 is turned on and charging of the main capacitor 8 is started is the same as described in FIG.

Now, when the charging voltage of the main capacitor 8 reaches a predetermined level, the voltage divided by the resistors R ₄ and R ₅ becomes the breakover voltage of the Zener diode ZD, and the Zener diode ZD is turned on. It will turn on. When the transistor 10 is turned on, the base current of the transistor 9 flows, so this transistor 9 is also turned on, and a current flows through the resistor _R6 , so that the second thyristor 6 is turned on, and the first thyristor 6 is turned on as explained in FIG. Thyristor 4 will be turned off.

That is, although the second gate means 7' shown in FIG. 1 also has transistors 9 and 10, it performs the same operation as the second gate means 7 in the device having the structure shown in FIG. In the circuit shown in FIG. 1 as well, the charging voltage of the main capacitor 8 can be made constant with the advantage of using the first thyristor 4.

On the other hand, when a synchro switch (not shown) is turned on with the main capacitor 8 fully charged, the well-known trigger circuit 11 performs a well-known operation, that is, by the operation of the gate circuit GC.
The SCR turns on and releases the charge in the trigger capacitor TC through the trigger transformer TT,
In order to trigger the flash discharge tube 12, the flash discharge tube 12 consumes the charge in the main capacitor 8 to emit light.

At this time, looking at the potential at point A in the diagram,
Needless to say, the potential at point A is at a high level until the SCR is turned on, and at a low level once it is turned on, and the potential at point A is supplied to the base of the transistor 9 mentioned above via the transmission means 13.

Therefore, when the trigger circuit 11 operates as described above, the base of the transistor 9 is brought to a low level at the same time, and the base current flows through the diode 14 of the transmission means 13, the resistor 15, and the trigger circuit 11.
It will flow through the SCR, thus turning on transistor 9.

As mentioned above, when the transistor 9 is turned on, the first thyristor 4 is turned off, and the supply of energy from the DC high voltage power supply 1 to the main capacitor 8 etc. via the first thyristor 4 is stopped. Of course, the operation of the trigger circuit 11 described above is no exception, and the fact that the energy supply from the DC high voltage power supply 1 to the main capacitor 8 etc. is stopped means that the glow discharge of the flash discharge tube 12 is stopped. The energy that was generated is gone,
In other words, it goes without saying that glow discharge cannot occur.

In other words, the power supply circuit according to the present invention shown in FIG. 1 prevents glow discharge when the flash discharge tube 12 emits light, regardless of the amount of energy supplied from the DC high voltage power supply 1. be.

As described above, one embodiment of the power supply circuit according to the present invention shown in FIG. In either case, the supply of energy from the DC high-voltage power supply 1 to the main capacitor 8, etc., which is the load, can be stopped with an extremely simple configuration.

Although not shown, in FIG. 1, the transmission means 13 connecting the base of the transistor 9 and the point A in the trigger circuit 11 is a diode 1.
4 is reversed and provided between the base of the transistor 10 and the gate circuit GC of the SCR of the trigger circuit 11, so that this gate circuit GC transmits the pulse signal generated to turn on the SCR to the transistor 10. However, it goes without saying that the same effect as the embodiment shown in FIG. 1 can be expected.

Effects of the invention Since the power supply circuit according to the invention does not cause flash discharge tube glow discharge, the charging loop of the main capacitor by the DC high voltage power supply 1 includes the first
All you need to do is insert a resistor with a resistance value that takes into consideration only the protection of the thyristor, etc., and the resistance value should be 40~
This means that it can be set to a small value of about 50Ω, and therefore a very effective practical effect can be expected in that the charging time of the main capacitor by the DC high-voltage power supply can be further shortened.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of a strobe device including a power supply circuit of the strobe device according to the present invention, and FIG. 2 is a power circuit diagram of a conventional strobe device. DESCRIPTION OF SYMBOLS 1... DC high voltage power supply, 4... First thyristor, 5... First gate means, 6... Second thyristor, 7, 7'... Second gate means, 8...
Main capacitor, 9, 10...transistor, 11
...Trigger circuit, 12...Flash discharge tube, 13...
...transmission means, 14...diode, 15...resistance.

Claims (1)

[Scope of utility model registration request] A power supply, a main capacitor, a first thyristor connected between the power supply and the main capacitor, a parallel body of a resistor and a capacitor, and a second thyristor, and a series body of the main capacitor and the first thyristor. a series body connected in parallel; a first gate means that includes the parallel body and turns on the first thyristor; and a resistor that divides the charging voltage of the main capacitor; the divided voltage by this resistor is supplied and breaks. A switch means comprising a control element having an overvoltage, a transistor that turns on the second thyristor when the control element is turned on, and a series body of a diode and a resistor connected between the switch means and the trigger circuit. transmission means for transmitting a signal generated by the operation of the trigger circuit to the switch means, the transmission means operates based on the detection result of the charging voltage of the main capacitor to turn on the second thyristor and switch the first gate. controlling the operation of the means and the first
and second gate means for reverse biasing between the anode and cathode and between the gate and cathode of the thyristor.