JPH0713918B2 - 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.
The present invention relates to a strobe device to which a lated gate bipolar transistor (hereinafter referred to as IGBT) is connected, and particularly to a strobe device characterized by a voltage supply system to the flash discharge tube which is effective when light is repeatedly emitted at high speed.

2. Description of the Related Art Conventionally, as a strobe device using the above-described IGBT, a device disclosed in Japanese Patent Laid-Open No. 64-17033 is well known.

As shown in FIG. 3, this device includes a DC high-voltage power supply 1 which is a well-known DC-DC converter circuit, a main capacitor 2 charged by the power supply 1, and a light emission control circuit 6 which will be described later and which is provided in parallel with the power supply 1. Is connected to a constant voltage circuit 3 for supplying a constant voltage, a known trigger circuit 4 for triggering the flash discharge tube Xe, and a control means 8 in the camera body, for exchanging various signals and operating the trigger circuit 4. Control circuit 5 for generating various output signals such as trigger signal, flash discharge tube
A light emission control circuit 6 for controlling on / off of the IGBT connected in series with Xe to control light emission of the flash discharge tube Xe and a voltage doubler circuit for applying a double voltage of the charging voltage of the main capacitor 2 to the flash discharge tube Xe. 7 and 7.

When the switch Sw is turned on in the above device, the DC high voltage power supply 1 operates, and the main capacitor 2 and the voltage doubler capacitor 7a are
The high voltage generated in the secondary winding Sa of the oscillating transformer T charges the battery as shown by the polarity, and the low voltage power source E charges the power source capacitor C that functions as the power source of the control circuit 5.

At the same time, charging of the capacitor 3a connected to the secondary winding Sb of the oscillation transformer T via the diode D is also started. Therefore, the control circuit 5 starts to operate, and the light emission control circuit 6
Is ready to emit light.

When a light emission start signal is input from the control means 8 to the control circuit 5 in a state where the above-mentioned respective capacitors are charged, the control circuit 5 outputs a high signal for a predetermined period considering the longest light emission time of the flash discharge tube Xe from the terminal Oa. A level trigger signal is output and supplied to the transistor Qa of the light emission control circuit 6. At this time, the terminal Ob of the control circuit 5 is maintained at the low level, and thus the transistor Qc is turned off.

The supply of the trigger signal turns on the transistor Qa and further turns on the transistor Qb, so that the charging voltage of the capacitor 3a is applied to the gate of the IGBT, and the IGBT is turned on.

As a result, the trigger capacitor 4a, the trigger transformer
The charging current of the capacitor 4a flows through the primary winding of 4b, and a trigger pulse is generated in the secondary winding of the transformer 4b. At the same time, the positive side of the voltage doubler capacitor 7a is grounded via the resistor Ra and the IGBT, and its charging voltage is superimposed on the charging voltage of the main capacitor 2 and applied between the main electrodes of the flash discharge tube Xe.

As a result, the flash discharge tube Xe consumes the electric charge charged in the main capacitor 2 and emits light.

When a light emission stop pulse is input to the control circuit 5 by the photometric circuit included in the control means 8 during the light emission, the control circuit 5 outputs a high level light emission stop signal from its terminal Ob.

The light emission stop signal turns on the transistors Qc and Qd,
Therefore, between the base and emitter of transistor Qa and IG
The gate and emitter of BT are short-circuited, and they are turned off. This stops the flash discharge tube Xe from emitting light. Needless to say, the transistor Qb is also turned off at this time.

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

Problem to be Solved by the Invention The apparatus shown in FIG. 3 is different from the conventionally known apparatus or the like in which a flash discharge tube Xe and an SCR are connected in series and light emission is stopped by using a commutation capacitor. Since a commutation capacitor is not required, over-emission of light does not occur, high-speed repetitive light emission and downsizing of the device can be realized.

However, looking at the high-speed repetitive light emitting operation in detail, when the cycle is a high cycle of a certain range of several tens Hz or more, it is greatly affected by the ionization state of the flash discharge tube Xe, and the light emitting operation cannot follow. In some cases, there is a disadvantage that light emission is lost in such a case.

4 (a), (b), and (c) are voltage waveforms at appropriate points when the light emitting operation is performed in the conventional device shown in FIG. 3, that is, at points indicated by A and B in the figure. FIG. 3 is a diagram showing a light emission waveform of a flash discharge tube Xe.

As shown in FIG. 3A, the gate A of the IGBT is
The high level voltage is applied to the point at time T1,
If the application is stopped at T2, the IGBT5 is turned on and off as described above, so the flash discharge tube X
e emits light as shown in FIG.

Looking at the cathode potential of the flash discharge tube Xe at this time, as shown in FIG. 4 (b), it once sharply drops at time T1, and then sharply rises on the contrary at time T2. Has a characteristic of gradually decreasing. That is, the flash discharge tube Xe
It is well known that even if the IGBT is turned off at time T2, it does not immediately return to the steady state and is in an ionized state where it does not emit light.In such an ionized state, the cathode potential of the flash discharge tube Xe is Therefore, the charging operation of the voltage doubler capacitor 7a is not started from the time point T2, that is, when the flash discharge tube Xe is in the ionized state and its cathode potential is at a high level,
The voltage doubler capacitor 7a is never charged.

Therefore, for example, as shown by the broken line in FIG. 4 (a), when the cathode potential has not yet returned to the zero level.
Even if a high level voltage is supplied to the point A at T3, the charging voltage for the voltage doubler capacitor 7a cannot be applied to the flash discharge tube Xe.

In addition, the charging circuit of the voltage doubler capacitor 7a is composed of a plurality of resistors although not shown in the figure, and when the time constant is taken into consideration, a predetermined period elapses after the cathode potential returns to zero level. Up to that time, the charging voltage value is not sufficient. Therefore, if a high level voltage is supplied to the point A during this period, the voltage doubler capacitor 7a is added to the flash discharge tube Xe.
It goes without saying that the charging voltage in the desired state cannot be applied.

By the way, in the case of performing the repeated light emission operation in a high cycle of several tens Hz or more, the next time during the period when the cathode potential does not drop to the zero level as described above or the period when the voltage doubler capacitor 7a is not sufficiently charged, It is conceivable that the state in which the above light emitting operation must be performed.

In this case, the flash discharge tube Xe
Since it is not possible or expected to expect a high potential between the main electrodes of the main electrode, for example, when the number of times of light emission increases and the charging voltage of the main capacitor 2 decreases, The flash discharge tube Xe cannot emit light in a certain period band having a high period of several tens Hz or more, and light emission is lost, that is, a reliable light emitting operation cannot be realized, and the light emitting operation is made to follow a desired period in the above period band. Will not be possible.

In the case of an extremely high cycle exceeding the above-mentioned certain cycle band, the operation for the next light emission will be performed when the flash discharge tube Xe is in a state where it can emit light without being triggered, The flash discharge tube Xe emits light very easily,
It is well known that repeated light emission operation can be realized without causing light emission omission.

The present invention has been made in consideration of the inconvenience at the time of the repeated light emission operation in a certain period band having a high period of several tens Hz or more as described above, and the voltage doubler capacitor is instantly charged when the IGBT is off. By doing so, it is an object of the present invention to provide a strobe device capable of reliably performing the next light emitting operation even in the above-described periodic band.

Means for Solving the Problems A strobe device according to the present invention includes 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, and a flash discharge tube. A first diode and an insulated gate bipolar transistor are connected in series, and a first series connection body connected to both ends of the main capacitor, a control switch element having a control pole, and a second diode are connected in series. And a second series connection body connected to both ends of a series body of the first diode and the insulated gate bipolar transistor, a connection point of the first diode and the insulated gate bipolar transistor, the control switch element, and A voltage doubler capacitor connected between the connection points of two diodes, and the voltage doubler capacitor connected across the second diode. Of the discharge circuit for forming a discharge path through the insulated gate bipolar transistor and supplying the voltage generated at the time of forming the discharge path to the control electrode, and a terminal connected to the first diode have a high potential. As described above, a charging circuit for forming the charging circuit for charging the voltage doubler capacitor together with the second diode and the presence / absence of supply of an on-voltage to the gate of the insulated gate bipolar transistor are controlled to control the insulated gate bipolar transistor. A light emission control circuit that controls on / off and controls light emission of the flash discharge tube, and a trigger circuit that operates to excite the flash discharge tube are configured.

Action Since the strobe device according to the present invention has the above-mentioned configuration, the voltage doubler capacitor is charged through the charging circuit so that the terminal connected to the first diode, that is, the cathode side of the flash discharge tube has a high potential. Will be done.

Further, when the insulated gate bipolar transistor is turned on, the charge stored in the voltage doubler capacitor is discharged through the discharging means, and the control switch element is turned on by the voltage generated by the discharging means. Will be applied to both ends of the flash discharge tube via the insulated gate bipolar transistor, the main capacitor and the control switch element.

On the other hand, when the insulated gate bipolar transistor is turned off, the light emission of the flash discharge tube is stopped, the discharge loop of the voltage doubler capacitor is also cut off, and the charging state is set.

Therefore, the flash discharge tube is in an ionized state, and its cathode potential becomes high potential.

However, since the voltage doubler capacitor according to the present invention is configured such that the cathode side is charged to a high potential, the charging is started when the insulated gate bipolar transistor is turned off regardless of the cathode potential. It will be. The charging is performed through the flash discharge tube Xe in the ionized state, the second diode, etc., and the charging time constant can be set to an extremely small value. That is, the voltage doubler capacitor in the present invention is an insulated gate bipolar transistor. When is turned off, it will be instantly charged.

As a result, the charging voltage of the voltage doubler capacitor can always be applied to the flash discharge tube even when performing high-cycle repetitive light emitting operations.
The repetitive light emitting operation can be realized without causing light emission omission.

Embodiments Embodiments of the flash device of the present invention will be described below.

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

A main capacitor 2 is connected to both ends of a DC high-voltage power supply 1 including a known DC-DC converter circuit and a laminated power supply.

A first series connection body 9 in which a flash discharge tube Xe, a first diode 10 and an IGBT are connected in series is connected to both ends of the main capacitor 2.

The gate of the IGBT is connected to a light emission control circuit 11 for controlling the on / off state of the insulated gate bipolar transistor by controlling the supply of an on-voltage to the gate and controlling the light emission of the flash discharge tube Xe. Has been done.

At both ends of a series body composed of the first diode 10 and the IGBT, a transistor 13 which is a control switch element having a resistor and a control electrode not shown in the figure and a second diode 14 are connected in series. The serial connection body 12 is connected.

A voltage doubler capacitor 15 is connected between a connection point X between the first diode 10 and the IGBT and a connection point Y between the transistor 13 and the second diode 14, and a resistor 17 is provided between both ends of the second diode 14. The discharge circuit 16 is formed of 18 and is connected to a discharge circuit 16 which forms a discharge path through the IGBT of the voltage doubler capacitor 15 and supplies a generated voltage when the discharge path is formed to a control pole of the transistor 13.

The charging path 19, which is the resistor 20, forms a charging circuit that charges the voltage doubler capacitor 15 together with the second diode 14 so that the terminal connected to the first diode 10 has a high potential.

Furthermore, it consists of a trigger capacitor 22 and a trigger transformer 23.
Flash discharge tube Xe due to discharge through transformer 23 above
Trigger circuits 21 for exciting the are formed at both ends of the IGBT.

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

Now, when the DC high-voltage power supply 1 starts operating by turning on an appropriate power switch (not shown), its output terminal 1a,
Charging of the main capacitor 2, the voltage doubler capacitor 15, and the trigger capacitor 22 to the illustrated polarities is started by the high DC voltage output during 1b.

At an appropriate point in time when the main capacitor 2 and the like are charged, the light emission control circuit 11 outputs a high level pulse signal
When the IGBT is applied to the gate of BT and the IGBT is turned on, the trigger circuit 21 operates, the flash discharge tube Xe is excited, and the charge charged in the voltage doubler capacitor 15 is discharged through the IGBT and the discharge circuit 16.

Therefore, the drop voltage generated in the resistor 17 forming the discharge circuit 16 is applied between the base and the emitter, which are the control pole of the transistor 13, and the transistor 13 is turned on.

Therefore, at both ends of the flash discharge tube Xe, the transistor 13, IGB
A double voltage that superimposes the charging voltage of the main capacitor 2 and the voltage doubler capacitor 15 is applied via T. The flash discharge tube Xe consumes the charge of the main capacitor 2 from the time when the IGBT is turned on. To emit light.

At the appropriate time when the flash discharge tube Xe is emitting light, the IGB
When the high level pulse signal applied to the gate of T. is changed to the low level, the IGBT turns off as described above.

When the IGBT is turned off, the discharge current flowing through the flash discharge tube Xe is cut off, so that the flash discharge tube Xe stops its light emission and returns to the initial state through the ionization state described above.

At the same time, the IGBT of the voltage doubler capacitor 15 and the discharge loop via the discharge circuit 16 are interrupted, and as a result,
The voltage doubler capacitor 15 is ready to be charged.

As a result, a current flows through the loop of the main capacitor 2, the flash discharge tube Xe, the voltage doubler capacitor 15, the second diode 14, and the loop of the main capacitor 2, the flash discharge tube Xe, the trigger capacitor 22, and the trigger transformer 23. The voltage doubler capacitor 15 and the trigger capacitor 22 are instantly charged.

That is, even if the flash discharge tube Xe is in the ionized state and its cathode potential is high, the voltage boosting capacitor 15 and the trigger capacitor 22 are charged so that the cathode side is originally charged to have a high potential. From the moment it became, it was done without any problem, in other words, the IGBT.
It is started at the same time as when the power is turned off, and as a result, even when performing repeated light emission operation with a high cycle of several tens Hz or more, the IGBT
When ON, the charging voltage of the voltage doubler capacitor 15 can be always applied between the main electrodes of the flash discharge tube Xe.

[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, the components having the same reference numerals as those in FIG. 1 have the same functions.

As is apparent from FIG. 2, this second embodiment is an example in which the formation positions of the charging path 19 and the trigger circuit 21 in the first embodiment are changed.

That is, one end of the resistor 20 forming the charging path 19 is connected to the connection point between the flash discharge tube Xe and the first diode 10.

Also, the trigger circuit 21 uses a transistor so that the trigger capacitor 22 is discharged through the transistor 13.
It is formed at both ends of the series body composed of 13 and the second diode 14.

The operation of the second embodiment having the above-mentioned configuration will be described below. The operation of the strobe device differs from that of the first embodiment only in the operation timing of the trigger circuit 21 having a different formation position. The operation is the same as in the first embodiment.

That is, in the state where the main capacitor 2, the voltage doubler capacitor 15, and the trigger capacitor 22 are charged to the illustrated polarities by the operation of the DC high-voltage power supply 1, the light emission control circuit 11 applies a high level pulse signal to the gate of the IGBT. Then, like the first embodiment, the IGBT is turned on.

However, in the second embodiment, the trigger circuit 21 does not operate as in the first embodiment at the stage when the IGBT is turned on.
It will be discharged through the BT and the discharge circuit 16.

Therefore, the transistor 13 is turned on by the drop voltage generated in the resistor 17, and at this point, the trigger capacitor 22 is discharged through the trigger transformer 23, that is, the trigger circuit 21 is operated.

Therefore, the flash discharge tube Xe has the transistor 13,
A double voltage, which is a superposition of the charging voltage of the main capacitor 2 and the voltage doubler capacitor 15, is applied via the IGBT and is excited at the same time, so that the main capacitor 2 consumes the charge and emits light.

At the appropriate time when the flash discharge tube Xe is emitting light, the IGB
When the high level pulse signal applied to the gate of T. is changed to the low level, the IGBT is turned off as in the first embodiment, so that the discharge current flowing through the flash discharge tube Xe is cut off. The light emission stops, and the voltage doubler capacitor
The discharge loop of 15 through the discharge circuit 16 and the like is also cut off, and the voltage doubler capacitor 15 is brought into a chargeable state.

Therefore, the flash discharge tube Xe returns to the initial state after passing through the ionization state described above, and in the ionization state, a current flows through the loop including the flash discharge tube Xe. Similar to the embodiment, the voltage doubler capacitor 1
5, the trigger capacitor 22 will be charged instantly.

As a result, even when the IGBT is turned on in the case of repeatedly emitting light with a high cycle of several tens of Hz or more, the flash discharge tube is always
The charging voltage of the voltage doubler capacitor 15 can be applied between the main electrodes of Xe.

EFFECTS OF THE INVENTION The strobe device according to the present invention is equipped with a voltage doubler capacitor capable of performing charging at the same time when the flash discharge tube is in the ionized state. Therefore, when the IGBT is turned on, a double voltage is always applied between main electrodes of the flash discharge tube. Since the charging voltage of the piezoelectric capacitor can be applied, it is possible to realize a high-frequency repetitive light-emission operation of several tens of Hz or more without causing light emission omissions. It has the effect of being able to emit light.

[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.
An electric circuit diagram showing an embodiment, FIG. 3 is an electric circuit diagram showing an example of the device disclosed in Japanese Patent Laid-Open No. 64-17033, and FIG. 4 is a voltage at an appropriate point in the conventional circuit shown in FIG. It is a figure which shows a waveform and a light emission waveform. 1 ... DC high-voltage power supply, 2 ... Main capacitor, 9 ... First
Series connection body, 10 ... First diode, 11 ... Emission control circuit, 12 ... Second series connection body, 13 ... Transistor, 14 ...
… Second diode, 15 …… Double voltage condenser, 16 …… Discharge circuit, 17,18 …… Resistance, 19 …… Charging path, 20 …… Resistance, 21
...... Trigger circuit, 22 …… Trigger capacitor, 23 ……
Trigger transformer

Claims (5)

[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, a first diode and an insulated gate bipolar transistor. Is connected in series, and a first series connection body connected to both ends of the main capacitor, a control switch element having a control pole, and a second diode are connected in series, and the first diode and the insulated gate are connected. Second series connection body connected to both ends of a series body with a bipolar transistor, a connection point between the first diode and the insulated gate bipolar transistor, and a connection point between the control switch element and the second diode Connected to both ends of the second diode, and the insulated gate bipolar transistor of the voltage doubler capacitor. A discharge circuit that forms a discharge path via the battery and supplies the voltage generated when the discharge path is formed to the control electrode; and the voltage doubler capacitor so that the terminal connected to the first diode has a high potential. The charging circuit for charging the second
A charge path formed together with a diode and the presence / absence of supply of an on-voltage to the gate of the insulated gate bipolar transistor are controlled to control the on / off of the insulated gate bipolar transistor and control the light emission of the flash discharge tube. A strobe device comprising: a light emission control circuit that operates and a trigger circuit that operates to excite the flash discharge tube. 2. The strobe device according to claim 1, wherein the control switch element is a transistor. 3. The strobe device according to claim 1, wherein the discharge circuit includes a plurality of resistors. 4. The charging means is a resistor having one end connected to a connection point between the main capacitor and the flash discharge tube and the other end connected to a connection point between the first diode and the insulated gate bipolar transistor. The strobe device according to (1). 5. The charging means is a resistor having one end connected to a connection point between the main capacitor and the flash discharge tube and the other end connected to a connection point between the flash discharge tube and the first diode. The strobe device according to 1).