JPH0713917B2 - 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 supplying drive power to a BT in response to a charging operation of a main capacitor of the strobe device.

2. Description of the Related Art One example of a strobe device that supplies driving power to an IGBT in response to a charging operation of a main capacitor of the strobe device was previously proposed by the applicant in Japanese Patent Application No. 2-99506. .

This proposed device, as shown in FIG.
DC high-voltage power supply 1 which is a DC-DC converter circuit, main capacitor 2 connected in parallel to this DC high-voltage power supply 1, flash discharge tube 4 and IGBT 5 are connected in series, and are connected in parallel to the main capacitor 2 in series A connection body 3, a resistor 7 and a constant voltage diode 8 whose output is supplied to the gate of the IGBT 5 via a resistor R are connected in series, and a voltage supply means 6 connected in parallel to the main capacitor 2 and a trigger capacitor 10, SCR 12 and the like having a trigger transformer 11 and a control pole 12a to which a light emission start command signal is supplied, and a trigger circuit 9 for triggering the flash discharge tube 4 and a control pole 13a to which a light emission stop command signal is supplied. In addition, a control switch element 13 connected between the gate and the emitter of the IGBT 5 is provided between its main poles.

In the above device, when the DC high-voltage power supply 1 operates now,
The main capacitor 2 and the trigger capacitor 10 are charged.

At the same time, the constant voltage generated across the constant voltage diode 8 of the voltage supply means 6 is supplied to the gate of the IGBT 5 via the resistor R.

At this point, the flash discharge tube 4 is not emitting light, so that no current flows through the IGBT5.
Is only in the so-called ready state.

When the light emission start command signal is supplied to the control pole 12a of the SCR 12 while the main capacitor 2 and the like are charged, the SCR 12 is turned on, and the charge of the trigger capacitor 10 is discharged through the trigger transformer 11, that is, The trigger circuit 9 operates and the flash discharge tube 4 is excited.

At this time, a constant voltage diode 8 is connected to the gate of IGBT5.
Is applied to the flash discharge tube 4, and as a result, the flash discharge tube 4 consumes the charge charged in the main capacitor 2 and emits light.

During the light emission, when a light emission stop command signal is input to the control pole 13a of the control switch element 13 from, for example, a well-known photometric circuit (not shown), the control switch element 13 is turned on and the gate-emitter of the IGBT5 is connected between them. Short circuit.

As a result, the IGBT 5 is turned off, so that the light emission of the flash discharge tube 4 is stopped.

The example of the strobe device that supplies the driving power to the IGBT in response to the charging operation of the main capacitor of the strobe device has been described above, but as another example, although not shown, instead of the main capacitor described above, It goes without saying that, for example, a device that uses a separate winding provided in a DC-DC converter circuit that a strobe device normally has or a separate power source that is formed or provided independently can be considered.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the device shown in FIG. 4, the driving voltage application structure to the gate of the IGBT 5 is composed of a voltage supply means 6 which operates in response to the start of operation of the DC high-voltage power supply 1. , IG
The drive system of BT5 does not need a structure for responding to a trigger signal, is simplified, and in addition, can perform stable operation regardless of the operation timing of the trigger circuit 9.

However, looking at the amount of power consumption in the voltage supply means 6 of the above-mentioned device, for example, the strobe device detects that the main capacitor 2 has been charged and stops the operation of the DC high-voltage power supply 1. In this case, in the above configuration, it is conceivable that the leakage current from the main capacitor 2 via the voltage supply means 6 increases, that is, in such a case, the voltage drop speed of the main capacitor 2 does not include the voltage supply means 6. It will be faster than it would be without it. As a result, it is necessary to frequently recharge the main capacitor 2 in order to keep the strobe device operable.
There is a risk that the energy consumption for that purpose will increase, which will cause an inconvenience.

Also, when the voltage is supplied to the voltage supply means from a device other than the main capacitor, as in the case described above, there is a large amount of leakage current through the voltage supply means, which is disadvantageous in terms of effective use of energy.

The strobe device according to the present invention has been made in consideration of the above-described inconvenience, and has a simple structure and is provided with a voltage supply means to the gate of the IGBT with a small leak current through the voltage supply means. Is configured.

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. Insulation gate type bipolar transistors are connected in series, and a series connection body connected to both ends of the main capacitor, a resistor, a first constant voltage element, and a break lower than the breakover voltage of the first constant voltage element. A second constant voltage element having an overvoltage is connected in series and connected to both ends of the main capacitor or another power source such as another winding, and the output voltage of the second constant voltage element is connected to the insulated gate. Supply means for supplying a driving voltage to the gate of a bipolar transistor and a trigger switch element having a control pole to which a light emission command signal is supplied. Control circuit having a trigger circuit for exciting the flash discharge tube in response to the operation, and a control pole to which a light emission stop command signal is supplied, and the main pole thereof being connected between the gate and the emitter of the insulated gate bipolar transistor. And a switch element.

Action Since the strobe device according to the present invention has the above-described configuration, after the DC high-voltage power supply starts to operate, the charging voltage of the main capacitor or the output voltage of another power supply such as another winding becomes the first constant voltage element. When the breakover voltage is reached, the first constant voltage element operates, and after a while, the second constant voltage element operates.

The second constant voltage element outputs an appropriate voltage for driving the insulated gate bipolar transistor by operating, and as a result, the output voltage of the second constant voltage element is output to the gate of the insulated gate bipolar transistor. It will be supplied as a drive voltage.

In other words, the driving voltage is supplied to the gate of the insulated gate bipolar transistor by the operation of the DC high-voltage power supply so that the charging voltage of the main capacitor or the output voltage of the other power supply becomes equal to or higher than a predetermined voltage value. Is operated based on the output voltage of the second constant voltage element.

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. 4 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.

At both ends of the main capacitor 2, a flash discharge tube 4 and an IGBT 5
A series connection body 3 in which and are connected in series is connected.

A resistor 15, a first zener diode 16 that is a first constant voltage element, and a second zener diode 17 that is a second constant voltage element are connected in series at both ends of the series connection body 3, and 2 Capacitors across Zener diode 17
A voltage supply means 14 formed by connecting 18 is connected. That is, the voltage supply means 14 in this embodiment uses the main capacitor 2 as a power source.

A well-known trigger circuit 19 composed of a charging resistor 20, a trigger capacitor 21, a trigger transformer 22, and an SCR 23, which is a trigger switch element for releasing the charge charged in the trigger capacitor 21 by being turned on, is provided at both ends of the main capacitor 2. Are connected.

First Zener diode 16 and second Zener diode 17
The connection point A with is connected to the gate of the IGBT 5 through the resistors 24 and 25, and the connection point B between the resistors 24 and 25 and the IGBT.
By turning on between the emitters of T.5, the gate of the IGBT5 and the emitter are short-circuited via the resistor 25.
A transistor 26 for turning off T.5 is connected as a connecting 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 23, the control pole of the transistor 26, and the base 26a.

The constant voltage circuit 27 is connected to both ends of the main capacitor 2, detects the charging voltage of the main capacitor 2, and stops the operation of the DC high-voltage power supply 1 when the charging voltage value reaches a predetermined value. The configuration itself is well known, and detailed description thereof will be omitted.

Needless to say, the trigger circuit 19 described above may be replaced with the trigger circuit 9 having the configuration described with reference to 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 Ta, when the DC high-voltage power supply 1 starts to operate by turning on an appropriate power switch (not shown) as shown in FIG. 2 (a), the output is output between its output terminals 1a and 1b. The charging of the main capacitor 2 and the like is started by the generated high DC voltage, and the terminal voltage of the main capacitor 2, for example, rises as shown in FIG. 2 (b).

The DC high voltage output between the output terminals 1a and 1b is also supplied to the voltage supply means 9, so that the charging voltage of the main capacitor 2 rises, and at time Tb, the charging voltage value is the first Zener. Breakover voltage of diode 16
When reaching Va, the first Zener diode 16 will be
A breakover occurs at Tb, and as a result, the potential at point A in FIG. 1 rises as shown in FIG. 2 (c) in accordance with the subsequent increase in the charging voltage of the main capacitor 2, and the capacitor Charging of 18 will start.

At the same time, the potential at the point A is applied to the gate of the IGBT5 via the resistors 24 and 25, and therefore the gate potential is also shown in FIG. 2 (d).
As shown in, the voltage rises in accordance with the rise of the point A potential.

The charging of the main capacitor 2 progresses, and at the time Tc, the charging voltage value is the breakover voltage of the first Zener diode 16.
Breakover voltage of the second Zener diode 17 to Va
When the voltage Vc plus Vb is reached, that is, the capacitor 18
When the charging voltage value of 2 reaches the above-mentioned voltage Vb, the second Zener diode 17 breaks over, and as a result, the potential at the point A is maintained at the predetermined voltage after the time Tc.

Therefore, the gate of the IGBT 5 is also maintained at the predetermined voltage, and this predetermined voltage is applied between the gate and the emitter of the IGBT 5 after the time Tc.

That is, in the present embodiment, the IGB
A predetermined voltage set by the second Zener diode 17 is applied to the gate of T.5, and the IGBT 5 is of course brought into the conduction preparation state by the application of the predetermined voltage.

When the charging of the main capacitor 2 further progresses and the charging voltage value reaches the voltage value Vd at which the charging is completed at time Td,
The constant voltage circuit 27 starts operating, and the operation of the DC high voltage power supply 1 is stopped as shown in FIG. 2 (e).

When the operation of the DC high voltage power supply 1 is stopped, the main capacitor 2
The charging voltage of is gradually discharged through the voltage supply means 14, and the terminal voltage value is Td in FIG. 2 (b).
As shown below, it gradually descends.

However, the potential at the point A and the gate of the IGBT 5 does not change carelessly even after the time point Td due to the charge of the capacitor 18 connected to both ends of the second Zener diode 17. In other words, the capacitor 18 is connected to the above-mentioned A when the constant voltage circuit 27 is operating.
It can be said that the capacitor is provided to control so that the potential at the point does not drop.

When the charging voltage of the main capacitor 2 continues to decrease and the charging voltage value reaches the voltage value Vc described above, this point of time of arrival
The first Zener diode 16 is turned off at Te, so that the leakage current from the main capacitor 2 thereafter via the voltage supply means 14 is blocked, the energy consumption in the entire device is extremely reduced, and the main capacitor is reduced. Two
As shown in FIG. 2 (b), the decrease of the charging voltage is also more gradual.

At this time, the gate potential of IGBT5 is the same as the previous capacitor 1
It is controlled by the charge of 8 and does not fall sharply.

The charging voltage of the main capacitor 2 further decreases, and at time Tf, the voltage indicated by Ve in FIG. 2B, that is, the voltage for restarting the operation of the DC high-voltage power supply 1 preset by the constant voltage circuit 27. When Ve is reached, the DC high-voltage power supply 1 restarts its operation as shown in FIG. 2 (e), so that the charging of the main capacitor 2 is restarted and the charging voltage value thereof rises again. .

After that, the device of this embodiment maintains the operation state as described above,
Therefore, the voltage set by the operation of the voltage supply means 14 is always supplied to the gate of the IGBT 5 after the time Tc.

When a high level pulse signal, which is a light emission start command signal as shown in FIG. 2 (f), is applied to the gate 23a of the SCR 23 at an appropriate time Tg when the so-called constant voltage operation as described above is performed. , SCR23 is turned on, and the charge stored in the trigger capacitor 21 is discharged through the SCR23 and the trigger transformer 22, that is, the trigger circuit 19 operates, and as a result, the flash discharge tube 4 is excited.

At this time, the IGBT 5 is ready for conduction by the operation of the voltage supply means 14, therefore the IGBT 5 is turned on, and the flash discharge tube 4 is charged to the main capacitor 2 from the time Tg as shown in FIG. 2 (h). Consumes and emits light.

At an appropriate time when the flash discharge tube 4 is emitting light, for example, when the emitted light amount becomes an appropriate light amount Th, the transistor
When a high level pulse signal as shown in FIG. 2 (g), which is a light emission stop command signal, is applied to the base 26a of 26 by a photometric circuit (not shown), the transistor 26 is turned on during the application period. Will be done.

Therefore, the gate-emitter of the IGBT5 is short-circuited via the resistor 25, and the gate potential thereof is controlled to a level at which the conduction cannot be maintained at the time Th as shown in FIG. 2 (d). , As a result, IGBT5
Turn off at h.

When the IGBT 5 is turned off, the discharge current flowing through the flash discharge tube 4 is cut off, and the light emission of the flash discharge tube 4 is stopped at time Th as shown in FIG. 2 (h).

After that, when the light emission stop command signal disappears at time Ti, the transistor 26 returns from ON to OFF, the short-circuit between the gate and the emitter of the IGBT 5 is released, that is, the circuit state returns to the initial state, and the circuit is first Then, the operation as described after the time point Ta is restarted, and as a result, the charging voltage of the main capacitor 2 is controlled by the constant voltage circuit 27, and the voltage supply means
By the operation of 14, the drive voltage is applied to the gate of the IGBT 5 again. That is, one light emission operation ends at this point.

[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, in the second embodiment, the constant voltage circuit 27, which was constructed independently in the first embodiment, is provided in parallel with the voltage supply means 14 to further simplify the circuit structure. It is an example.

Now, when the DC high-voltage power supply 1 operates to start charging the main capacitor 2 etc. and the charging voltage value reaches Va, the first Zener diode 16 turns on as in the first embodiment, and thereafter the capacitor 18 Will start charging. When the charging voltage of the capacitor 18 reaches the ON voltage of the second Zener diode 17, the second Zener diode 17 turns ON, and thereafter,
The voltage corresponding to the charging voltage of the main capacitor 2 is a constant voltage circuit
The voltage is applied to the voltage detection unit 28 including a series body of 27 resistors 29 and 30.

The connection point C of the resistors 29 and 30 is connected to the base of the transistor 31. Therefore, when the voltage value at the connection point C reaches the above-mentioned Vd at which the charging voltage value of the main capacitor reaches Vd, the transistor 31 is connected. If the relationship of the resistance values of the resistors 29, 30 and 15 is set in advance so that the voltage value can be turned on, the transistor 31 will turn on when the charging voltage value of the main capacitor 2 reaches the Vd. ,
The ON operation can be applied to the operation control of the DC high-voltage power supply 1, that is, the well-known constant voltage operation can be performed.

On the other hand, after the first Zener diode 16 turns on, the IG
The voltage at point A in the figure is applied to the gate of BT5,
As in the first embodiment, T.5 is brought into the conduction preparation state. However, in the case of the second embodiment, the voltage detector 28 is connected in series with the second Zener diode 17, and the potential at the point A rises in response to the rise of the charging voltage of the main capacitor 2. Therefore, unlike the first embodiment, the voltage supplied to the gate of the IGBT 5 does not have a predetermined value. However, the above IGBT5
The gate voltage required to drive the transistor without any problem usually has an appropriate allowable range. If this allowable range is taken into consideration and the setting relationship of each resistance value described above is considered, no particular problem occurs. .

Then, in the state where the driving voltage is supplied to the gate of the IGBT 5 as described above, the light emission command signal is supplied to the gate 23a of the SCR 23, and when the trigger circuit 19 operates, the flash discharge tube 4 consumes the charge stored in the main capacitor 2. And emit light. During the light emission, the base 26 of the transistor 26
When the light emission stop command signal is supplied to a, the transistor 26
Turns on and short-circuits the gate and emitter of IGBT5,
Therefore, the light emission of the flash discharge tube 4 is stopped. When the light emission stop command signal disappears, the strobe device returns to the initial state before light emission, and one light emission operation ends at that time, and the above operation state is the same as that of the first embodiment. Becomes

EFFECTS OF THE INVENTION The strobe device according to the present invention is, as described above, the IGBT.
The voltage applied to the gate of the main capacitor is connected to both ends of the main capacitor or another power source to charge the main capacitor from the connection point of the first and second constant voltage elements having different breakover voltages forming the voltage supply means. Since it is performed in response, the leak current flowing through the voltage supply means can be controlled to be extremely small, and as a result, the power consumption in the voltage supply means can be significantly reduced.

[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. The electric circuit diagram of FIG. 4 is shown in FIG.
It is an electric circuit diagram showing the device proposed in No. 6. 1 ... DC high voltage power supply, 2 ... Main capacitor, 3 ... Series connection body, 4 ... Flash discharge tube, 5 ... IGBT, 6, 14 ...
... Voltage supply means, 7, 15, 20, 24, 25, 29, 30 ... Resistor, 8 ... Zener diode, 9, 19 ... Trigger circuit, 10, 21 ... Trigger capacitor, 11, 22 ... Trigger Transformer, 12, 23 ... SCR, 13, 26,31 ... Transistor, 16 ... First Zener diode, 17 ... Second Zener diode, 18 ... Capacitor, 27 ... Constant voltage circuit, 28 ... Voltage Detection unit

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. The series connection body connected to both ends of the main capacitor, the resistor and the first
And a second constant voltage element having a breakover voltage lower than the breakover voltage of the first constant voltage element connected in series, and connected to both ends of the main capacitor, and In response to the operation of the trigger switch element having the voltage supply means for supplying the connection point voltage of the first and second constant voltage elements to the gate of the insulated gate bipolar transistor as a drive voltage and the control pole to which the light emission command signal is supplied. A trigger circuit for exciting the flash discharge tube, and a control switch element having a control pole to which a light emission stop command signal is supplied and having a main pole connected between the gate and the emitter of the insulated gate bipolar transistor. Strobe device with. 2. The strobe device according to claim 1, wherein the voltage supply means has a capacitor connected to both ends of the second constant voltage element. 3. A voltage detecting unit for detecting a voltage at a connection point between a first constant voltage element and a second constant voltage element to detect a charging voltage value of the main capacitor, the second constant voltage element and The strobe device according to claim 1, wherein the strobe device is connected in series. 4. A DC high-voltage power supply, a main capacitor connected to both ends of the DC high-voltage power supply, 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. And an insulated gate bipolar transistor are connected in series, a series connection body connected to both ends of the main capacitor, a power supply unit for appropriately generating and outputting a voltage in response to a charging operation of the main capacitor, A resistor, a first constant voltage element, and a second constant voltage element having a breakover voltage lower than the breakover voltage of the first constant voltage element are connected in series and connected to both ends of the power supply unit. At the same time, voltage supply means for supplying the connection point voltage of the first and second constant voltage elements to the gate of the insulated gate bipolar transistor as a drive voltage, and a light emission command signal are supplied. A trigger circuit that excites the flash discharge tube in response to the operation of a trigger switch element having a control pole, and a control pole to which a light emission stop command signal is supplied, and a main pole between the main gate and the insulated gate bipolar transistor. A strobe device having a control switch element connected between the gate and the emitter. 5. The strobe device according to claim 4, wherein the voltage supply means has a capacitor connected to both ends of the second constant voltage element.