JPH0713915B2 - 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 GATE BIPOLAR TRANSISTOR (hereinafter referred to as IGBT) is connected.
The present invention relates to a strobe device characterized by simplifying a drive control system of BT.

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. 5, this device includes a DC high-voltage power supply 1 which is a well-known DC-DC converter circuit, a constant voltage circuit 2 which is installed in the power supply 1 and supplies a constant voltage to a light emission control circuit 5 described later, It is connected to a known trigger circuit 3 for triggering the flash discharge tube Xe and the control means 7 in the camera body, and generates various output signals such as a trigger signal for exchanging various signals and operating the trigger circuit 3. Control circuit 4, light emission control circuit 5 for controlling on / off of the IGBT connected in series with the flash discharge tube Xe to control light emission of the flash discharge tube Xe.
And a voltage doubler circuit 6 for applying a voltage doubler to the flash discharge tube Xe.

When the switch Sw is turned on in the above device, the DC high-voltage power supply 1 operates and the main capacitor C _M and the voltage doubler capacitor C ₂ are charged by the high voltage generated in the secondary winding S ₁ of the oscillation transformer T ₁ . The low voltage power source E charges the power source capacitor C ₁ of the control circuit 4.

At the same time, charging of the capacitor C ₃ connected to the secondary winding S ₂ of the oscillation transformer T ₁ via the diode D is also started. Therefore, the control circuit 4 starts to operate and the light emission control circuit 5
Is ready to emit light.

When a light emission start signal is input from the control means 7 to the control circuit 4 in a state where each capacitor is charged, the control circuit 4 keeps the high level for a predetermined period considering the longest light emission time of the flash discharge tube Xe from the terminal O _1. Outputs the trigger signal of the transistor
Supply to Q ₁ . At this time, the terminal O ₂ of the control circuit 4 is maintained at a low level and the transistor Q ₃ is off.

Therefore, transistor Q ₁ turns on, and
Q ₂ turns on, and the charging voltage of capacitor C ₃ is applied to the gate of the IGBT.

This turns on the IGBT and trigger capacitor C ₄ ,
The charging current of the capacitor C ₄ flows through the primary winding of the trigger transformer T ₂ , and a trigger pulse is generated in the secondary winding of the transformer T ₂ . At the same time, the positive side of the voltage doubler capacitor C ₂ is grounded via the resistor R ₁ and the IGBT, and its charging voltage is superimposed on the charging voltage of the main capacitor C _M and applied to the flash discharge tube Xe.

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

When a light emission stop pulse is input to the control circuit 4 by the photometric circuit included in the control means 7 during the light emission, a high level light emission stop signal is output from the terminal O ₂ .

Therefore, the transistors Q ₃ and Q ₄ are turned on and the transistor Q ₁
Short the base and emitter of and the IGBT gate and emitter, and turn off each. As a result, the transistor Q _{2 is} also turned off, and the light emission of the flash discharge tube Xe is stopped.

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

The device shown in FIG. 5 is an IGBT in response to a trigger signal for operating a trigger circuit for exciting the flash discharge tube Xe.
It is equipped with a control configuration that applies a voltage to the gate of the device and stops the above voltage application in response to a light emission stop signal. It is possible to realize repeated light emission.

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.
The control means 5 for controlling the voltage application to the gate of the IGBT is required, that is, specifically described in FIG.
A control switch structure formed of the transistors Q _{1 to} Q _{3 and the} like is required, which complicates the circuit structure and raises the cost.

In addition, since the voltage is applied to the gate of the IGBT and the trigger circuit is activated at the same time in response to the trigger signal, the trigger circuit may operate when the IGBT is not sufficiently turned on. . On the other hand, in this case, the IGBT is in a high impedance state, so the operating efficiency of the trigger circuit becomes poor, and the flash discharge tube Xe
May not be able to be emitted,
Further, even if the flash discharge tube Xe can be made to emit light, the energy is supplied from the main capacitor C _M.
There is a risk that the IGBT may be destroyed.

That is, there is a risk that the operating efficiency of the trigger circuit may be deteriorated or the IGBT may be destroyed, depending on the operation timing of the trigger circuit.

The strobe device according to the present invention has been made in consideration of the above-mentioned inconveniences, has a simple structure, and has a stable IGB regardless of the operation timing of the trigger circuit.
It is configured with an IGBT drive system that can realize the operation of T.

Means for Solving the Problems The strobe device according to the present invention is insulated from 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 gate type bipolar transistor connected in series, the series connected body connected to both ends of the main capacitor, and the insulated gate bipolar transistor operating in synchronization with the supply of the DC high voltage power source to the main capacitor. A trigger having a voltage supply means for supplying a drive voltage to the gate of and a control pole for supplying a light emission command signal, the low potential side terminal of which is connected to the connection point between the flash discharge tube and the insulated gate bipolar transistor. A switch element, a trigger circuit that excites the flash discharge tube in response to the operation of the trigger switch element, and stop light emission A control switch element having a control pole to which a command signal is supplied and having a main pole between the gate and the emitter of the insulated gate bipolar transistor is provided.

Action Since the strobe device according to the present invention has the above-mentioned configuration, the insulated gate bipolar transistor gate does not respond to the trigger signal for operating the trigger circuit but responds to the start of operation of the DC high voltage power supply. When the charging of the main capacitor is started, the driving voltage is applied from the voltage supply means. By applying this drive voltage, the insulated gate bipolar transistor is brought into a ready state for conduction.

Therefore, the drive voltage application configuration, that is, the drive system of the insulated gate bipolar transistor does not need a configuration for responding to the trigger signal, and is simplified, and in addition, stable operation irrelevant to the operation timing of the trigger circuit is achieved. You can do it.

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 figure, constituent elements having the same reference numerals as those in FIG. 5 are elements having the same function.

A main capacitor C _{M 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.

Connected to both ends of the main capacitor C _M are a series connection body 8 in which a flash discharge tube Xe and an IGBT are connected in series, and a voltage supply means 9 in which a resistor 10 and a Zener diode 11 are connected in series.

Connected to both ends of the flash discharge tube Xe is a series body in which a charging resistor Rt of a trigger capacitor Ct of the trigger circuit 3 and a SCR12 which is a trigger switch element for operating the trigger circuit 3 by being turned on are connected in series. Has been done. That is, the cathode, which is the low potential side terminal of the SCR 12, is connected to the connection point B between the flash discharge tube Xe and the IGBT.

The connection point A between the resistor 10 and the Zener diode 11 is IGB
It is connected to the gate of T. through a resistor R.

Also, by turning on between the connection point A and the ground,
A transistor 13 that turns off the IGBT is connected as a control element.

A light emission command signal for starting light emission and a light emission stop command signal for stopping light emission are supplied to the SCR 12, the gate 12a, which is the control pole of the transistor 13, and the base 13a, respectively.

It is needless to say that the voltage doubler circuit 6 formed of the capacitor, the resistor and the diode shown by the broken line in FIG. 1 can be provided as in the conventional device described in FIG.

The operation of the strobe device according to the first embodiment of the present invention having the above-described structure will be described below with reference to the first operation shown in FIG.
A description will be given with reference to a signal waveform diagram at a predetermined point in the figure.

At time t ₁ , when the DC high-voltage power supply 1 starts operating by turning on an appropriate power switch (not shown),
The output terminal 1a, the charging of the main capacitor C _M or the like at high DC voltage output between 1b is started, for example, the main capacitor C _M
The terminal voltage of is rising as shown in FIG.

At the same time, since the high DC voltage output between the output terminals 1a and 1b is also supplied to the voltage supply means 9, a predetermined voltage as shown in FIG. 2 (b) is generated across the Zener diode 11. However, this predetermined voltage is applied between the gate and the emitter of the IGBT via the resistor R.

That is, in the first embodiment of the present invention is by applying a predetermined voltage to the gate of the IGBT at the time t _1, of course IGBT is made conductive ready state by application of the predetermined voltage.

Time point t ₂ when the main capacitor C _M etc. is charged
Then, when a high level pulse signal which is a light emission command signal as shown in FIG. 2 (c) is applied to the gate 12a of the SCR 12, the SCR 12 is turned on because the IGBT is in the ready state for conduction.

Therefore, the charge of the trigger capacitor Ct is discharged via the SCR 12 and the trigger transformer T, that is, the trigger circuit 3 operates and the flash discharge tube Xe is excited.

At this time, the IGBT is ready for conduction, and therefore,
The IGBT is turned on, and the flash discharge tube Xe consumes the charged electric charge of the main capacitor C _M and emits light from the time point t ₂ as shown in FIG. 2 (e).

Appropriate when the flash discharge tube Xe is emitting light, for example, at time t ₃ when the light emission amount reaches the proper amount of light, the transistor
When a high-level pulse signal having a predetermined pulse width Ts as shown in FIG. 2 (d), which is a light emission stop command signal, is applied to the base 13a of 13 by a photometric circuit (not shown), The transistor 13 is turned on during the period Ts.

Therefore, the gate and emitter of the IGBT are short-circuited via the resistor R, and the gate potential is controlled to a level at which conduction cannot be maintained at the time point t ₃ as shown in FIG. 2 (b). As a result, the IGBT is turned off at the time point t ₃ .

When the IGBT is turned off, the discharge current flowing through the flash discharge tube Xe is cut off and the flash discharge tube Xe emits light in the second
It stops at time t ₃ as shown in FIG.

The cathode, which is the low-potential side terminal of SCR12, is the IGBT.
, The current loop flowing through SCR12 is also cut off at the same time by turning off the IGBT, and this SCR12 is surely turned off.

This means that the SCR 12 can be turned off without considering its holding current, which is a very important requirement for realizing the function of causing the flash discharge tube Xe to emit light at high speed.

That is, in the present invention, as described above, the low potential side terminal of the trigger switch element, which is the SCR12, is connected to the flash discharge tube.
It is connected to the connection point between Xe and the IGBT, and when the IGBT is off, the SCR12 can be turned off without fail, and the trigger circuit for the next light emission operation can be prepared for operation.As a result, the flash discharge tube Xe The high-speed light emitting function can be realized.

After that, as shown in FIG. 2D, when the light emission stop command signal disappears at the time point t ₄ when the period Ts has passed, the transistor 13 returns from on to off, and the gate of the IGBT.
The short circuit between the emitters is released, and the drive voltage is again applied to the gate of the IGBT by the operation of the voltage supply means 9. That is, the device returns to the initial state before light emission, and at this time point, one light emission operation ends.

The output period Ts of the light emission stop command signal described above will be described in more detail. When the desired light emission operation is single-shot light emission, flash discharge is performed in each light emission operation in order to prevent glow discharge. Needless to say, it is necessary to consider the extinction time of the pipe Xe. That is, in the case of single emission, the period Ts needs to be longer than the extinction time of the flash discharge tube Xe.

Also, if the desired light emission operation is a high-speed light emission operation, the above consideration is contrary to the inconvenience, that is, if the above Ts is set for each light emission during the high-speed light emission operation, the desired light emission number cannot be realized. Therefore, in such a case, it is only necessary to consider the extinction time of the flash discharge tube Xe described in Ts above for the end of the final light emitting operation in order to prevent glow discharge.

[Embodiment 2] FIG. 3 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 apparent from FIG. 3, this second embodiment uses the power supply of the voltage supply means 9 which was the main capacitor C _M in the first embodiment as the low voltage power supply such as the constant voltage circuit 2 in the prior art described above. Is an example.

Therefore, the operation of the strobe device is the same as that of the first embodiment except that the supply source of the drive voltage for the IGBT is different.

That is, the DC high-voltage power supply operates to start charging the main capacitors C _{M and the} like, and at the same time, the constant voltage circuit also operates, whereby a predetermined voltage is applied to the gate of the IGBT,
Is ready for conduction.

When the light emission command signal is supplied to the gate 12a of the SCR12 and the trigger circuit 3 operates, the flash discharge tube Xe consumes the electric charge charged in the main capacitor C and emits light. When the light emission stop command signal is supplied to the base 13a of the transistor 13 during the light emission, the transistor 13 is turned on to short-circuit the gate and the emitter of the IGBT, and the light emission of the flash discharge tube Xe is stopped. When the light emission stop command signal disappears, the strobe device returns to the initial state before light emission, and at that time, one light emission operation ends, and the above operation is the same as the first operation.
It is exactly the same as the embodiment.

[Embodiment 3] FIG. 4 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. 4, in the third embodiment, the transistor 14 as the switch element in the voltage supply means 9 and the transistor for controlling the operation of the transistor 14 are provided.
15 and control means 16 for controlling the operation of the transistor 15.
Is an example in which is provided.

The transistor 14 turns on when the transistor 15 turns on, forming a state in which a voltage can be applied to the gate of the IGBT. Further, the transistor 15 is controlled to be turned on and off by the operating state of the control means 16.

That is, in the third embodiment, the voltage application timing to the gate of the IGBT can be controlled by the operation of the transistors 14 and 15 based on the operation of the control means 16.

For example, in response to the operation start of the DC high-voltage power supply 1, the control means
Applying a high-level signal from 16 to the base of transistor 15 turns on transistor 15 and thus transistor 14
Also, the device is in the same circuit state as that of the first embodiment. That is, the voltage supply means 9 operates to apply a predetermined voltage to the gate of the IGBT, and the IGBT is brought into the conduction preparation state.

Conversely, in the voltage supply state as described above, the transistor
When a low level signal is supplied from the control means 16 to the base of the transistor 15, the transistor 15 is turned off, the transistor 14 is also turned off, the operation of the voltage supply means 9 is stopped, and the application of the predetermined voltage to the gate of the IGBT is stopped. become.

Therefore, for example, the control means 16 supplies the low level signal in response to a so-called auto-off operation in which the operation of the DC high-voltage power supply 1 is stopped after a predetermined time elapses from the start of operation of the device in order to prevent waste of power. By doing so, the discharge loop of the main capacitor C _M by the power supply means 9 is not formed during the auto-off operation,
Therefore, the charge stored in the main capacitor C _M can be maintained at the high level for a predetermined period after the auto-off operation. Therefore,
When the effective use of energy can be realized, that is, when the next light emitting operation is performed, the charging operation of the main capacitor C _M can be performed in an extremely short time.

When the light emission command signal is supplied while the transistor 14 is turned on and the voltage supply means 9 is operating, the flash discharge tube Xe emits light, and when the light emission stop command signal is supplied, the flash discharge tube Xe emits light. It goes without saying that the operation such as the stop is the same as that of the first or second embodiment.

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 device in response to the start of operation of the DC high voltage power supply by the voltage supply means, there is no need for a structure that responds to the trigger signal, and the application structure can be greatly simplified. .

In addition, the voltage is applied to the gate of the IGBT before the trigger signal, that is, the light emission command signal is supplied.
Since the IGBT is in the conduction preparation state, the IGBT is always in a sufficiently ON state when the trigger circuit operates, and as a result, the operating efficiency of the trigger circuit does not deteriorate and there is a risk that the IGBT will be destroyed. Has the effect of disappearing.

In other words, it has an effect that the operation of the IGBT can be stably performed regardless of the operation timing of the trigger circuit.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of a strobe device according to the present invention, FIG. 2 is a signal waveform diagram at a predetermined point in FIG. 1, and FIG. 3 is a second embodiment of a strobe device according to the present invention. FIG. 4 is an electric circuit diagram showing a flash device according to a third embodiment of the present invention, and FIG. 5 is an electric circuit diagram showing the same.
It is an electric circuit diagram which shows an example of the apparatus shown by the publication. 1 ... DC high voltage power supply, 2 ... Constant voltage circuit, 3 ... Trigger circuit, 8 ... Series connection body, 9 ... Voltage supply means, 10 ...
… Resistance, 11 …… Zener diode, 12 …… SCR, 13,1
4, 15 ... Transistor, 16 ... Control means

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 and an insulated gate bipolar transistor are connected in series. And a serial connection body connected to both ends of the main capacitor, and operates in synchronization with the supply of the DC high-voltage power supply to the main capacitor,
The insulated gate bipolar transistor has a voltage supply means for supplying a drive voltage to the gate thereof, and a control pole to which a light emission command signal is supplied, and its low potential side terminal connects the flash discharge tube and the insulated gate bipolar transistor. A trigger switch element connected to the point, a trigger circuit that excites the flash discharge tube in response to the operation of the trigger switch element, and a control pole to which a light emission stop command signal is supplied, and between the main poles is the A strobe device comprising a control switch element connected between the gate and the emitter of an insulated gate bipolar transistor. 2. A DC high voltage power supply, a main capacitor connected to both ends of the DC high voltage power supply and charged by the DC high voltage power supply, a flash discharge tube, a diode and an insulated gate bipolar transistor. A first series connection body, which is connected in series and is connected to both ends of the main capacitor, operates in synchronization with the supply of the DC high-voltage power supply to the main capacitor, and drives the gate of the insulated gate bipolar transistor. A trigger switch element having a voltage supply means for supplying a voltage, a control pole to which a light emission command signal is supplied, and a low potential side terminal connected to a connection point between the diode and an insulated gate bipolar transistor, and the trigger switch. A trigger circuit that excites the flash discharge tube in response to the operation of the element, a voltage doubler capacitor, and a resistor are connected in series. And a second series connection body connected to both ends of the flash discharge tube and a control pole to which a light emission stop command signal is supplied, and a main pole is connected between the gate and the emitter of the insulated gate bipolar transistor. Strobe device having a control switch element. 3. The strobe device according to claim 1, wherein the voltage supply means is formed of a series body in which a resistor connected to both ends of the main capacitor and a constant voltage element are connected in series. . 4. The strobe device according to claim 1, wherein the voltage supply means comprises a constant voltage power source which generates a predetermined constant voltage in response to the operation of the DC high voltage power source. 5. The voltage supply means is formed by including a switch structure which operates in response to an operation start time point of the DC high voltage power supply and an elapse time point of a predetermined time from the operation start time. The strobe device according to any one.