JPH07120559B2 - Strobe device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated gate bipolar transistor (Insu) which controls a light emitting operation of a flash discharge tube in series with the flash discharge tube.
strobe device to which a lated Gete Bipolar Transistor (hereinafter referred to as IGBT) is connected.
The present invention relates to a strobe device characterized by a drive power supply system for a BT.

2. Description of the Related Art As a strobe device using an IGBT as described above, a voltage is applied to the gate of the IGBT in response to a trigger signal that activates a trigger circuit that excites the flash discharge tube, and a response to a light emission stop signal. Japanese Patent Application Laid-Open No. 64-17033 discloses a device having a control structure for stopping the voltage application.

The above proposed device is a system of most of the devices that have been put to practical use in the past, that is, a flash discharge tube and an SCR are connected in series.
As compared with a device that controls the operation of (1) using a commutation capacitor, over-emission is eliminated, and high-speed repetitive light emission can be realized.

However, looking at the IGBT drive system of the above-mentioned device, it operates in response to a trigger signal and also in response to a light emission stop signal.
There is a problem that a control means for controlling the voltage application to the gate of the IGBT is required, the circuit configuration becomes complicated, and the cost increases.

Also, in response to the trigger signal, the voltage is applied to the gate of the IGBT and the trigger circuit is activated at the same time, which may cause the trigger circuit to operate when the IGBT is not sufficiently turned on. Therefore, if the operating efficiency of the trigger circuit deteriorates and the flash discharge tube cannot be made to emit light, the IGBT is destroyed by the energy supply from the main capacitor even if the flash discharge tube can be made to emit light. There is also a risk that it may happen.

On the other hand, the applicant of the present application, as a strobe device considering the above-mentioned inconvenience, first applied a predetermined voltage to the gate of the IGBT in response to the start of operation of the high voltage DC power supply by the voltage supply means. A device as shown in Fig. 4 is proposed.

As is clear from FIG. 4, this proposed device by the applicant of the present application has a DC high-voltage power supply 1 composed of a known DC-DC converter circuit, a laminated power supply, etc., and a main capacitor 2 charged by this DC high-voltage power supply 1. , A series connection body 3 consisting of a flash discharge tube Xe and an IGBT connected to both ends of the main capacitor 2
And a resistor 5 and a Zener diode 6 are connected in series, the connection point of which is connected to the gate of the IGBT via a resistor R, and the voltage supply means 4 is connected between the connection point and the ground and turned on. A transistor 7, which is a control element for turning off the IGBT, a charging resistor 10 of a trigger capacitor 9 of a trigger circuit 8 and an SCR 12, which is a trigger switch element for operating the trigger circuit 8 by turning it on, are connected in series, and flash discharge is performed. It is configured by including a series body 11 connected to both ends of the pipe Xe.

The transistor 7 and the base 7a, which is the control pole of the SCR 12, and the gate 12a are supplied with a light emission command signal for starting light emission and a light emission stop command signal for stopping light emission, respectively.

In the above device, when the DC high-voltage power supply 1 operates now,
The main capacitor 2 and the trigger capacitor 9 are charged.

At the same time, the output voltage of the DC high-voltage power supply 1 is also supplied to the voltage supply means 9, so that a predetermined voltage is generated across the Zener diode 6, and this predetermined voltage is passed through the resistor R to the IGBT.
It is applied between the gate and emitter of T., and the above state is ready for conduction.

When a high level signal, which is a light emission command signal, is applied to the gate 12a of the SCR 12 in the above state, the SCR 12 is turned on, so that the charge of the trigger capacitor 9 is discharged and the trigger circuit 8 operates. As a result, the flash discharge tube Xe consumes the electric charge charged in the main capacitor 2 and emits light.

While the flash discharge tube Xe is emitting light, the transistor 7
When a high-level signal, which is a light emission stop command signal, is applied to the base 7a of the transistor 7, the transistor 7 is turned on to short-circuit the gate and emitter of the IGBT, thereby stopping the light emission of the flash discharge tube Xe.

The above operation is the basic operation of the apparatus shown in FIG.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the strobe device previously proposed by the applicant of the present invention shown in FIG. 4, application of a predetermined voltage to the gate of the IGBT is started by the voltage supply means as described above. Since it is done in response, the application configuration can be extremely simplified without the need for a configuration that responds to the trigger signal.
Is always turned on when the trigger circuit is operating, the operating efficiency of the trigger circuit deteriorates, or I.
It has the effect of eliminating the risk of the GBT being destroyed.

However, if the light emission start operation and the light emission stop operation are examined in more detail, there is a possibility that the following inconvenience may occur in the rising characteristics during the high-speed repeated light emission operation.

First, regarding the light emission start operation, it goes without saying that the operation is performed by supplying the drive voltage from the main capacitor 2 to the gate of the IGBT and the operation of the trigger circuit 8. As shown by the broken line in FIG. 4, there is an input capacitance C between the gate and the emitter of the above, and the supply of the drive voltage also means the supply after the input capacitance has been charged. .

In addition, the light emission stop operation is performed by turning on the transistor 7.
This is done by short-circuiting the gate-emitter of the GBT, so that at this time, the above-mentioned charge of the input capacitance is also discharged.

Therefore, when the next light emission is started, the input capacitance must be charged first, and in the circuit shown in FIG. 4, the input capacitance is charged by the main capacitor via the resistor 5. This charging operation requires a time constant determined by the resistance value of the resistor 5 and the input capacitance value.

It is needless to say that the time constant is required to be small in order to perform high-speed repetitive light emitting operation, but the resistor 5 is always connected via the Zener diode 6 and the transistor 7 is turned on. During this period, it is connected to the main capacitor 2 via the transistor 7, and setting the resistance value to a small value poses a problem in view of effective use of energy. In reality, the resistance value of the resistor 5 is high. It must be set to a value, and the circuit shown in FIG. 4 cannot reduce the time constant to a certain extent or more, that is, its rising characteristic cannot be abrupt to some extent.

Furthermore, it is also clear that the above time constant varies depending on the charging voltage value of the main capacitor, variations in the accuracy of parts of circuit elements, and the like.

As a result, the circuit shown in FIG. 4 has the disadvantage that the cycle is limited by the time constant when a high-speed repetitive light emission operation is performed, and when the high-speed repetitive light emission operation is performed, The higher the cycle, the more likely it was that stable operation would not be obtained.

The present invention has been made in view of the above-mentioned disadvantages, and an object of the present invention is to provide a strobe device that does not include a high resistance resistor in the drive voltage supply loop to the gate of the IGBT.

Means for Solving the Problems A first strobe device according to the present invention includes a direct current high voltage power supply,
A main capacitor connected to both ends of the DC high-voltage power supply and charged by supplying the DC high-voltage power supply, a flash discharge tube and an insulated gate bipolar transistor are connected in series, and both ends of the main capacitor are connected. A series connection body to be connected, a drive power supply that operates in synchronization with the start of operation of the DC high-voltage power supply to generate a voltage, a power supply capacitor and a constant voltage element are connected in parallel, and the voltage of the drive power supply is connected. A parallel connection body connected between the output terminal and the emitter of the insulated gate bipolar transistor, and a first pole connected between the main pole between the high potential side terminal of the power supply capacitor and the gate of the insulated gate bipolar transistor. Transistor, a gate means for turning on the first transistor by the charging voltage of the power source capacitor, and a base for the first transistor. A second transistor connected to the base of the transistor and having a main pole between the gate and the emitter of the insulated gate bipolar transistor, and a control pole to which a light emission stop command signal is supplied, and the main pole. And a control switch element connected between the base of the first transistor and the emitter of the insulated gate bipolar transistor, and a trigger circuit that operates to excite the flash discharge tube.

A second strobe device according to the present invention is a diode in which the anode is connected to the gate of an insulated gate bipolar transistor and the cathode is connected to the base of the first transistor instead of the second transistor in the first strobe device. Is provided and configured.

A third strobe device according to the present invention eliminates the power supply capacitor of the parallel connection body in the first and second strobe devices described above, and uses a Zener diode between the base of the first transistor and the emitter of the insulated gate bipolar transistor. Configured by connecting to.

Action Since the strobe device according to the present invention has the above-mentioned configuration, the drive power is supplied to the gate of the insulated gate bipolar transistor through the first transistor without passing through a high resistance, The rising characteristic will be improved.

Therefore, the cycle of the repeated light emitting operation can be made higher and the operation can be performed stably.

Examples Hereinafter, examples of the flash device of the present invention will be described.

[Embodiment 1] FIG. 1 is an electric circuit diagram showing a first embodiment of a strobe device according to the present invention. In the figure, constituent elements having the same reference numerals as those in FIG. 4 are elements having the same function.

A main capacitor 2 is connected to both ends of a DC high-voltage power source 1 including a well-known DC-DC converter circuit, a laminated power source, and the like, and the flash discharge tubes Xe and I.
A series connection body 3 in which the GBT and the GBT are connected in series is connected.

The drive power supply 13 starts its operation in synchronization with the start of operation of the DC high-voltage power supply to generate an appropriate output voltage, and its output terminal 13a is connected to a power supply capacitor 14 via a resistor Ra.

A Zener diode 15 that controls the charging voltage of the capacitor 14 to a predetermined value is connected to both ends of the power supply capacitor 14, and the transistor 1 is connected to the high voltage side terminal 14a.
It is connected to the gate of the IGBT between the main poles of 6 and the gate resistance Rb.

A base resistance Rc is provided between the collector and the base of the transistor 16.
And the base thereof is connected via the gate resistance Rd to the base of the transistor 17 whose main pole is connected between the gate and emitter of the IGBT. Further, the main pole of the transistor 18 is connected between the base of the transistor 16 and the emitter of the IGBT.

The trigger circuit section 19 shows a function including the trigger switch element shown in FIG. 4, that is, a well-known circuit that operates by receiving a light emission start signal and excites the flash discharge tube Xe.

The operation of the first embodiment of the strobe device according to the present invention having the above-mentioned structure will be described below.

Now, when the DC high-voltage power supply 1 starts operating by turning on an appropriate power switch (not shown), charging of the main capacitor 2 etc. is started by the DC high voltage which is the output, and at the same time, the drive power supply 13 The operation is started, and the power supply capacitor 14 is charged to a predetermined voltage determined by the Zener diode 15 via the resistor Ra.

Therefore, at this time, a current flows through the base resistance Rc, the base-emitter of the transistor 16, and the gate resistance Rb and the gate-emitter of the IGBT, so that the transistor 16 is turned on and the power supply capacitor 14 has a predetermined value. The charging voltage is IGB via the transistor 16 and resistor Rb.
The voltage is applied between the gate and the emitter of T. As a result, the input capacitance between the gate and the emitter is charged, and the IGBT is brought into the ready state for conduction.

When an appropriate light emission command signal is applied to the trigger circuit unit 19 while the main capacitor 2 and the like are charged, the trigger circuit unit 19 excites the flash discharge tube Xe, while the IGBT is described above. Is ready for conduction,
Therefore, the IGBT is turned on, and the flash discharge tube Xe consumes the electric charge charged in the main capacitor 2 to emit light.

When an emission stop command signal is applied to the base 18a of the transistor 18 by, for example, a photometry circuit (not shown) at an appropriate time when the flash discharge tube Xe emits light, for example, when the amount of light emission reaches an appropriate amount of light. , The transistor 18 is turned on during the application period.

Therefore, the bases of the transistors 16 and 17 are set to a low potential, the transistor 16 is turned off, and the transistor 17 is turned on, that is, the application of the drive voltage to the gate of the IGBT is stopped and the gate-emitter of the IGBT is disconnected. Shorted through resistor Rb, which results in I.
GBT will be turned off at the above point.

When the IGBT is turned off, the discharge current flowing through the flash discharge tube Xe is cut off, and the emission of light from the flash discharge tube Xe is stopped.

After that, when the light emission stop command signal disappears at the time when an appropriate period has elapsed, the transistor 18 returns from the on state to the off state, so that the transistor 17 can be turned on from the off state and the transistor 16 can be changed from the off state. It is controlled to the ON state, the short circuit between the gate and the emitter of the IGBT is released, and the drive voltage is applied to the gate of the IGBT again, that is, the device returns to the initial state before light emission, At this time point, one light emission operation ends.

At this time, looking at the application of the drive voltage to the gate of the IGBT when the transistor 16 is turned on, it is performed only from the power supply capacitor 14 through the transistor 16 and the gate resistance Rb, that is, the above-mentioned energy is effectively utilized. It is performed without interposing a resistor having a high resistance value such as the resistor 5 used for the purpose.

As a result, the input capacitance of the IGBT is charged with an extremely small time constant.
The rising characteristics of the driving voltage applied to the gate of T. can be controlled to be extremely steep.

It should be noted that the purpose of preventing waste of energy at the time of the light emission stop operation and effectively utilizing it is that the gate resistance Rc connected to the power supply capacitor 14 when the transistor 18 is turned on should originally be able to flow the base current of the transistor 16. Since a high resistance value can be obtained, this gate resistance Rc is fulfilled in this embodiment.

Further, the resistance Ra connected to the driving power source 13 is a transistor
Of course, it can be omitted if the withstand capacity of 16 is large, and for example, as shown by the broken line in FIG. 1, the power supply capacitor 14 is directly connected to the main capacitor 2, that is, the main capacitor 2 is also used as the drive power supply 13. May be.

[Embodiment 2] FIG. 2 is an electric circuit diagram showing a second embodiment of the strobe device according to the present invention. In the figure, constituent elements having the same reference numerals as those in FIG. 1 are elements having the same function.

As is clear from FIG. 2, in the second embodiment, the transistor 17 and gate resistance Rd used for short-circuiting the gate and emitter of the IGBT in the first embodiment.
This is an example in which the diode 20 is replaced with.

Therefore, the operation as the strobe device is the same as that of the first embodiment except that the short-circuiting operation between the gate and the emitter of the IGBT is different.

That is, when the DC high-voltage power supply 1 operates to start charging the main capacitor 2 and the like, the drive power supply 13 also operates at the same time, whereby a predetermined voltage is applied to the gate of the IGBT,
BT is ready for conduction.

When the trigger circuit 8 operates in a state where the main capacitor 2 and the like are charged, the flash discharge tube Xe consumes the electric charge charged in the main capacitor 2 and emits light.

When the light emission stop command signal is supplied to the base 18a of the transistor 18 during the light emission, the transistor 18 is turned on, the transistor 16 is turned off, and the supply of the charging voltage of the power supply capacitor 14 to the gate of the IGBT is stopped. ,
At the same time, the gate and the emitter of the IGBT are short-circuited via the diode 20, so that the flash discharge tube Xe stops emitting light.

When the flash stop command signal disappears, the strobe device returns to the initial state before flashing, at which point one flashing operation ends, and during this resetting operation, the charging operation of the input capacitance of the IGBT is extremely short. The operation to be performed in time is exactly the same as in the first embodiment.

In the second embodiment, as in the first embodiment, the resistor Ra may be omitted in some cases, and the main capacitor 2 may be used as the driving power supply 13.

[Embodiment 3] FIG. 3 is an electric circuit diagram showing a third embodiment of the strobe device according to the present invention. In the figure, constituent elements having the same reference numerals as those in FIG. 1 are elements having the same function.

As is apparent from FIG. 3, this third embodiment is based on the above
This is an example in which the power supply capacitor 13 used in one embodiment is eliminated, and the Zener diode 21 which is a constant voltage element is connected between the base of the transistor 16 and the emitter of the IGBT, that is, both ends of the transistor 18.

Therefore, only the operation of supplying power to the gate of the IGBT is different, and the operation as other strobe devices is the same as in the first and second embodiments.

That is, when the DC high-voltage power supply 1 operates to start charging the main capacitor 2 etc., the drive power supply 13 also operates at the same time to generate an appropriate output voltage, and this output voltage passes through the resistor Ra and the base resistor Rc. Is applied to the Zener diode 21 and a predetermined voltage is output across the Zener diode 21, which turns on the transistor 16, which results in the gate of the IGBT being output across the Zener diode 21. The specified voltage is applied and I.
The GBT is ready for conduction.

After that, when the trigger circuit 19 operates while the main capacitor 2 and the like are charged, the flash discharge tube Xe consumes the charge of the main capacitor 2 and emits light, and when the transistor 18 turns on during the light emission, the Zener diode When both ends of 21 are short-circuited and the transistor 16 is turned off due to the decrease of its base potential, the supply of the predetermined voltage across the Zener diode 21 to the gate of the IGBT is stopped, and at the same time,
The gate and emitter of the IGBT are short-circuited via the diode 20, and thus the flash discharge tube Xe stops emitting light.

The strobe device returns to the initial state before light emission when the light emission stop command signal disappears, and one light emission operation ends at that time, and at the time of this return operation, the charging operation of the input capacitance of the IGBT is performed by the Zener diode. It is performed in a very short time by supplying the predetermined voltage output to both ends of 21.

In the third embodiment, as in the first and second embodiments, the resistor Ra may be omitted in some cases, and the main capacitor 2 may be used as the driving power supply 13.

EFFECTS OF THE INVENTION The strobe device according to the present invention is, as described above, the IGBT.
Since the predetermined voltage is applied to the gate of the gate without passing through a high resistance resistor, the charging time constant of the input capacitance of the IGBT can be made extremely small, that is,
Since the rising characteristics of the IGBT can be made steep, the cycle of high-speed repetitive issuance operation can be made high and the operation can be stably performed.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of a strobe device according to the present invention, and FIG. 2 is a second strobe device according to the present invention.
3 is an electric circuit diagram showing a third embodiment of a strobe device according to the present invention, and FIG. 4 is an electric circuit diagram showing an example of a strobe device previously proposed by the applicant of the present application. is there. 1 ... DC high-voltage power supply, 2 ... Main capacitor, 3 ... Series connection body, 13 ... Driving power supply, 14 ... Power supply capacitor, 15
...... Zener diode, 16-18 …… Transistor, 19
...... Trigger circuit part, 20 …… Diode, 21 …… Zener diode

Claims (3)

[Claims] 1. A DC high-voltage power supply, a main capacitor connected to both ends of the DC high-voltage power supply and charged by supplying the DC high-voltage power supply, a flash discharge tube and an insulated gate bipolar transistor are connected in series. And a series connection body connected to both ends of the main capacitor, a drive power supply that operates in synchronization with the start of operation of the DC high-voltage power supply to generate a voltage, and a power supply capacitor and a constant voltage element in parallel. A parallel connection body connected between the voltage output terminal of the drive power supply and the emitter of the insulated gate bipolar transistor; a high-potential side terminal of the power supply capacitor between the main pole and the insulated gate bipolar transistor. A first transistor connected between the gates of the transistor and a gate transistor for turning on the first transistor with the charging voltage of the power supply capacitor. And a second transistor whose base is connected to the base of the first transistor and whose main pole is connected between the gate and emitter of the insulated gate bipolar transistor, and a light emission stop command signal. A control switch element having a control pole, the main pole of which is connected between the base of the first transistor and the emitter of the insulated gate bipolar transistor; and a trigger circuit which operates to excite the flash discharge tube. Strobe device with. 2. A DC high-voltage power supply, a main capacitor connected to both ends of the DC high-voltage power supply and charged by supplying the DC high-voltage power supply, a flash discharge tube and an insulated gate bipolar transistor are connected in series. And a series connection body connected to both ends of the main capacitor, a drive power supply that operates in synchronization with the start of operation of the DC high-voltage power supply to generate a voltage, and a power supply capacitor and a constant voltage element in parallel. A parallel connection body connected between the voltage output terminal of the drive power supply and the emitter of the insulated gate bipolar transistor; a high-potential side terminal of the power supply capacitor between the main pole and the insulated gate bipolar transistor. A transistor connected between the gates of the transistor, gate means for turning on the transistor by the charging voltage of the power source capacitor, Has a diode connected to the gate of the insulated gate bipolar transistor and a cathode connected to the base of the first transistor, and a control pole to which a light emission stop command signal is supplied. A strobe device comprising: a control switch element connected between a base of a transistor and an emitter of the insulated gate bipolar transistor; and a trigger circuit which operates to excite the flash discharge tube. 3. A DC high-voltage power supply, a main capacitor connected to both ends of the DC high-voltage power supply and charged when the DC high-voltage power supply is supplied, a flash discharge tube and an insulated gate bipolar transistor are connected in series. And a series connection body connected to both ends of the main capacitor, a drive power supply that operates in synchronization with the start of operation of the DC high-voltage power supply to generate a voltage, and a voltage output of the drive power supply between the main poles. A transistor connected between the terminal and the gate of the insulated gate bipolar transistor, gate means for turning on the transistor at the output voltage of the driving power supply, and between the base of the transistor and the emitter of the insulated gate bipolar transistor. A constant voltage element to be connected and a cathode whose anode is connected to the gate of the insulated gate bipolar transistor Operating a diode connected to the base of the first transistor, and a control switch element having a control pole to which a light emission stop command signal is supplied and having its main pole connected to both ends of the constant voltage element. And a trigger circuit that excites the flash discharge tube.