JPH046797A - Stroboscope - Google Patents

Abstract

PURPOSE:To make operation of a power MOSFET to be in its stable state independently of the operation timing of a trigger circuit by applying a set voltage to the gate of the power MOSFET by a voltage supply means in response to respond the operation start of a DC high voltage power supply. CONSTITUTION:When the operation of a DC high voltage power supply 1 is started by making a power supply switch, a DC high voltage outputted between its output terminals 1a and 1b begins to charge a main condenser 6 and so on. It also supplies simultaneously the DC high voltage to a voltage supplying means 12, a preset voltage is generated from both ends of a Zener diode 14 and this preset voltage is applied between the gate and the source of the power MOSFET through a resistance R In the state where the main condenser 6 and so on are charged, a high level pulse signal serving as a light emission starting signal is applied to the gate 15a of a SCR 15, the SCR 5 is switched on because of the power MOSFET in its electrification preparatory state. Then a trigger circuit 3 works and stimulates an Xe flash discharge tube.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a flash device in which a power MOSFET is connected in series with a flash discharge tube to control the light emission operation of the flash discharge tube. The present invention relates to a strobe device characterized by a simplified structure.

2. Description of the Related Art Conventionally, as a strobe device using an FET, devices disclosed in Japanese Patent Application Laid-open Nos. 61-50125 and 61-50126 are well known.

FIG. 5 is an electric circuit diagram showing the basic configuration of the devices shown in both of the above proposals.
- A DC high-voltage power supply 1 that is a DC converter circuit, a constant voltage circuit 2 that is attached to the power supply 1 and supplies a constant voltage to a light emission control circuit 5 to be described later, a known trigger circuit 3 that triggers a flash discharge tube Xe, a trigger circuit 3 a control circuit 4 that generates various output signals such as trigger signals for operating the
It includes a light emission control circuit 5 that controls on/off of an FET connected in series with the flash discharge tube Xe to control the light emission of the flash discharge tube Xe, and a main capacitor 6 that stores energy consumed by the flash discharge tube Xe. It is composed of

When the switch Sw is turned on in the above device, the DC high-voltage power supply 1 is activated, the main capacitor 6 is charged by the high voltage generated in the secondary winding Sa of the oscillation transformer T, and the control circuit 4 is charged by the low-voltage power supply E. The power supply capacitor Ce is charged.

At the same time, the secondary winding Sb1 diode 7 of the oscillation transformer T
, a Zener diode 8, etc., starts operating, and a predetermined constant voltage is output to point A in the figure.

Therefore, the control circuit 4 and the light emission control circuit 5 are each in a ready state for operation.

When each capacitor is charged, a light emission start signal, which is a high level signal, is output from the output terminal 4a of the control circuit 4 and input to the base of the transistor 9 of the light emission control circuit 5, which turns on the transistor 9. Therefore, the transistor 10 is also turned on.

Therefore, the constant voltage that the constant voltage circuit 2 outputs to point A is applied to the gate of the FET via the transistor 10 and a resistor (not numbered).

This turns on the FET, and the charging current of the capacitor Ct flows through the trigger capacitor Ct of the trigger circuit 3 and the primary winding of the trigger transformer Tt, a trigger pulse is generated in the secondary winding of the transformer Tt, and the flash discharge tube Xe
is applied to

As a result, the flash discharge tube Xe consumes the charge in the main capacitor 6 and emits light.

During the above-mentioned light emission, when a light emission stop pulse is generated by the photometry circuit included in the control circuit 4 and a low level light emission stop signal is output from the output terminal 4a, the transistors 9 and 10 are turned off.

Therefore, the supply of the predetermined voltage that had been supplied to the gate of the FET from the constant voltage circuit 2 is stopped, the FET is turned off, and as a result, the flash discharge tube Xe stops emitting light.

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

Problems to be Solved by the Invention The device shown in FIG. 5 applies a voltage to the gate of the FET in response to a light emission start signal, which is a single signal that operates the trigger circuit that excites the flash discharge tube Xe. Equipped with a control configuration that stops the voltage application in response to a light emission stop signal, this eliminates over-light emission compared to a system that uses a commutating capacitor to stop light emission, and also enables high-speed repeated light emission. .

However, if we look at the drive system of the FET in the above-mentioned device, it will operate in response to the light emission start signal as well as in response to the light emission stop signal.
This requires a light emission control circuit 5 that controls the voltage application to the gate of the ET, resulting in a complicated circuit configuration and an increase in cost.

In addition, since voltage application to the gate of the FET and activation of the trigger circuit are performed simultaneously in response to the light emission start signal,
Otherwise, the trigger circuit may operate when the FET is not turned on sufficiently. On the other hand, in this case,
Since the FET is in a high impedance state, the operating efficiency of the trigger circuit may deteriorate, and the flash discharge tube Xe may not be able to emit light.
Even if the flash discharge tube Xe can be made to emit light, the FET
There is also a risk that the equipment may be destroyed.

That is, based on the operation timing of the trigger circuit, there is a risk that the operation efficiency of the trigger circuit may deteriorate or the FET may be destroyed.

The present invention has been made in consideration of the above-mentioned disadvantages, and an object of the present invention is to provide a strobe device that has a simple configuration and can realize stable operation regardless of the operation timing of the trigger circuit. do.

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 the supply of the DC high-voltage power supply, a flash discharge tube, and a power supply. The series connection body is 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, and applies a driving voltage to the gate of the power MOSFET. a trigger switch element having a control pole to which a light emission command signal is supplied and whose low potential side terminal is connected to a connection point between the flash discharge tube and the power MOSFET; A trigger circuit that excites the flash discharge tube in response to an operation, and a control switch element having a control pole to which a light emission stop command signal is supplied and whose main pole is connected between the gaiter source of the power MO8FET. Prepared and configured.

Function: Since the strobe device according to the present invention has the above-described configuration, the gate of the power MOSFET is connected to the gate of the power MOSFET in response to the start of operation of the DC high voltage power supply, without responding to the light emission start signal that operates the trigger circuit. When charging of the capacitor starts, a driving voltage is applied from the voltage supply means.

By applying this drive voltage, the power MOSFET is brought into a conduction ready state.

Therefore, the above driving voltage application configuration, that is, the power M
The drive system of the OSFET is simplified as there is no need for a configuration to respond to the light emission start signal, and the power MOS
The FET can perform stable operation regardless of the operation timing of the trigger circuit.

Embodiments Hereinafter, embodiments of the strobe 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, components having the same symbols as those in FIG. 5 have the same functions.

A main capacitor 6 is connected to both ends of a DC high-voltage power supply 1 made of a well-known DC-DC converter circuit, a laminated power supply, or the like.

A flash discharge tube Xe and a power M are connected to both ends of the main capacitor 6.
A series connection body 11 in which an OSFET is connected in series, and a voltage supply means 12 in which a resistor 13 and a Zener diode 14 are connected in series are connected.

A series body is connected to both ends of the flash discharge tube Xe, in which a charging resistor Rt of the trigger capacitor Ct of the trigger circuit 3 is connected in series with a trigger switch element 5CR15 that operates the trigger circuit 3 when turned on. has been done. That is, the cathode, which is the low potential side terminal of 5CR15, is connected to point B, which is the connection point between the flash discharge tube Xe and the power MOSFET.

C, which is the connection point between the resistor 13 and the Zener diode 14
The point is connected to the gate of the power MOSFET via a resistor R.

Also, between the above point C and the ground, that is, the power MOSFE
A power MOSF is connected between the sources of T by turning it on.
A transistor 16 short-circuits the gate and source of the ET via a resistor R to turn off this power MOSFET.
Connected as a control switch element.

5CR15,) Gate 1 which is the control pole of transistor 16
5a and the base 16a are supplied with a light emission start signal to start light emission and a light emission stop signal to stop light emission, respectively.

Note that the circuit formed from capacitors, resistors, and diodes indicated by broken lines in FIG. 1 is 1. <A voltage doubler circuit 17 is shown which makes the potential across the flash discharge tube Xe a high potential when the power MOSFET is turned on, and it is needless to explain in detail that it can be installed in parallel as shown in the figure.

The operation of the first embodiment of the strobe device according to the present invention having the above-mentioned configuration will be explained below using the first embodiment shown in FIG.
This will be explained with reference to a signal waveform diagram at a predetermined point in the figure.

Now, at time t1, when the DC high voltage power supply 1 starts operating by turning on an appropriate power switch (not shown), the main capacitor 6, etc. is charged with the DC high voltage output between its output terminals 1a and lb. starts, and the terminal voltage of the main capacitor 6, for example, increases as shown in FIG. 2(a).

At the same time, since the DC high voltage output between the output terminals 1a and 1b is also supplied to the voltage supply means 12, a predetermined voltage as shown in FIG. 2(b) is applied across the Zener diode 14. is generated, and this predetermined voltage is applied via the resistor R between the gate and source of the power MOSFET.

That is, in the first embodiment of the present invention, the above time point 1.
A predetermined voltage is applied to the gate of the power MO8FET, and of course the power MO8FET is brought into a conduction preparation state by applying the predetermined voltage.

Time t when the main capacitor 6 etc. is charged
At step 2, when a high level pulse signal, which is a light emission start signal as shown in FIG. 2(C), is applied to the gate 15a of the 5CR15, the 5CR15 is turned on because the power MOSFET is in the conduction preparation state.

Therefore, the charging charge of the trigger capacitor Ct is 5CR1
5. The light is discharged through the trigger transformer Tt, that is, the trigger circuit 3 is operated, and the flash discharge tube Xe is excited.

At this time, the power MOSFET is in the conduction preparation state, so the power MOSFET is turned on, and the flash discharge tube Xe starts emitting light by consuming the charge in the main capacitor 6 from the above-mentioned time t2, as shown in FIG. 2(e). .

At an appropriate point in time when the flash discharge tube Xe is emitting light, for example at time t3 when the amount of light emitted by the flash discharge tube Xe reaches an appropriate amount of light, a light emission stop signal as shown in FIG. When a high level pulse signal having a predetermined pulse width Ts as shown in (d) is applied, the transistor 16 is turned on during the period Ts.

When the transistor 16 is turned on, the gate and source of the power MO8FET are short-circuited via the resistor R, and the gate potential is controlled to a level at which conduction cannot be maintained at the above-mentioned time point t3, as shown in FIG. 2(b). As a result, the power MO8FET is turned off at the above-mentioned time point t3.

Therefore, the discharge current flowing through the flash discharge tube Xe is cut off, and the light emission from the flash discharge tube Xe continues as shown in Figure 2(e).
It stops at time t3 as shown in FIG.

In addition, the cathode, which is the low potential side terminal of 5CR15, is connected to the drain of the power MOSFET, and therefore,
When the power MO8FET is turned off, the current loop flowing through the 5CR15 is also cut off at the same time, and this 5CR15 is also turned off reliably.

This means that the 5CR15 can be turned off without considering its holding current, which is an extremely 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, 5CR1
The low potential side terminal of the trigger switch element (5) is connected to the connection point between the flash discharge tube Xe and the power MOSFET. The trigger circuit 3 can be prepared for operation, and as a result, the high-speed light emission function of the flash discharge tube Xe can be realized.

Thereafter, as shown in FIG. 2(d), when the light emission stop signal disappears at time t4 after the above period Ts, the transistor 16 returns from on to off, and the power MOSFE
The short circuit between the gate and source of T is released, and the drive voltage is again applied to the gate of the power MO8FET by the operation of the voltage supply means 12. That is, the device returns to the initial state before emitting light, and one light emitting operation ends at this point.

In addition, to explain in more detail about the output period Ts of the light emission stop signal mentioned above, if the desired light emission operation is single light emission, the flash discharge tube is used for each light emission operation in order to prevent glow discharge. It goes without saying that consideration must be given to the arc extinction time of Xe. That is, in the case of single light emission, the period Ts needs to be longer than the extinction time of the flash discharge tube Xe.

In addition, if the desired light emission operation is a high-speed light emission operation, taking the above consideration may be disadvantageous. In other words, if the above Ts is set for each light emission during the high-speed light emission operation, the desired number of light emission cannot be achieved. Therefore, in such a case, it is only necessary to consider the extinguishing time of the flash discharge tube Xe described in the above Ts only at the end of the final light emission operation in order to prevent glow discharge.

[Embodiment 2] FIG. 3 is an electric circuit diagram showing a second embodiment of a strobe device according to the present invention, and in the figure, components having the same symbols as those in FIG. 1 have the same functions.

As is clear from FIG. 3, in this second embodiment, the voltage supply means 12, which was the main capacitor 6 in the first embodiment,
This is an example in which the power source is a low voltage power source such as the constant voltage circuit 2 in the conventional example described above.

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 power MOSFET is different.

That is, at the same time as the DC high-voltage power supply operates and starts charging the main capacitor 6, etc., the constant voltage circuit 2 also operates, thereby applying a predetermined voltage to the gate of the power MOSFET, and making the power MOSFET ready for conduction. Ru.

When a light emission start signal is supplied to the gate 15a of the 5CR15 and the trigger circuit 3 is activated, the flash discharge tube Xe consumes the charge in the main capacitor 6 and emits light. During the light emission, when a light emission stop signal is supplied to the base 16a of the transistor 16, the transistor 16 turns on and the power M
Short-circuit the gaiter source of the OSFET and connect the flash discharge tube
e stops emitting light. When the light emission stop signal disappears, the strobe device returns to the initial state before light emission, and at this point one light emission operation is completed, and the above operation is exactly the same as in the first embodiment. Become.

[Embodiment 3] FIG. 4 is an electric circuit diagram showing a third embodiment of a strobe device according to the present invention, and in the figure, components having the same symbols as those in FIG. 1 have the same functions.

As is clear from FIG. 4, this third embodiment has a transistor 18 as a switching element in the voltage supply means 12.
This is an example in which a transistor 19 for controlling the operation of this transistor 18 and a control means 20 for controlling the operation of this transistor 19 are provided.

Transistor 18 is turned on when transistor 19 is turned on, creating a state in which voltage can be applied to the gate of the power MO8FET. Further, the transistor 19 is turned on or off depending on the operating state of the control means 20.

That is, in the third embodiment, the timing of voltage application to the gate of the power MO8FET can be controlled by the operation of the transistors 18 and 19 based on the operation of the control means 20.

For example, when a high level signal is supplied from the control means 20 to the base of the transistor 19 in response to the start of operation of the DC high voltage power supply 1, the transistor 19 is turned on, and therefore the transistor 18 is also turned on, and the device is similar to the first embodiment. The circuit will be in the same state as . That is, the voltage supply means 12 operates to apply a predetermined voltage to the gate of the power MOSFET, and the power MOSFET is brought into a conduction preparation state.

Conversely, when a low level signal is supplied from the control means 20 to the base of the transistor 19 in the voltage supply state as described above, the transistor 19 is turned off, and therefore the transistor 18 is also turned off, and as a result, the operation of the voltage supply means 12 is The application of the predetermined voltage to the gate of the power MOSFET is stopped.

Therefore, for example, the control means 20 is supplied with 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 period of time has elapsed from the start of operation of the device in order to prevent waste of power. If this is done, a discharge loop of the main capacitor 6 by the power supply means 12 will not be formed during the auto-off operation, and the charging voltage of the main capacitor 6 will be maintained for a predetermined period after the auto-off operation. This will allow you to maintain a high level. Therefore, effective use of energy can be realized, that is, when the next light emitting operation is to be performed, the charging operation of the main capacitor 6 can be performed in a very short time.

When the transistor 18 is on and the voltage supply means 12 is operating, the flash discharge tube Xe emits light when the light emission start signal is supplied, and the flash discharge tube Xe emits light when the light emission stop signal is supplied. It goes without saying that the operations such as stopping are the same as those in the first or second embodiment.

Effects of the Invention The strobe device according to the present invention has a power M as described above.
Since the predetermined voltage is applied to the gate of the OSFET by the voltage supply means in response to the start of operation of the DC high voltage power supply, there is no need for a configuration that responds to the light emission start signal, and the application configuration can be extremely simplified. ing.

Also, before the light emission start signal is supplied, the power MOSFE
A voltage is applied to the gate of T, and this power MO8FE
Since T is in the conduction ready state, the power MO
The SFET is always in a sufficiently turned on state when the trigger circuit is operating, and as a result, the operating efficiency of the trigger circuit does not deteriorate, and the power MOSFET has the effect of eliminating the risk of being destroyed.

In other words, it has the effect of stably operating the power MOSFET regardless of the operation timing of the trigger circuit.

[Brief explanation of the drawing]

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. 4 is an electric circuit diagram showing a third embodiment of the strobe device according to the present invention, and FIG. 5 is an electric circuit diagram showing the third embodiment of the strobe device according to the present invention.
1-50125, etc.; FIG. 1... DC high voltage power supply, 2... Constant voltage circuit, 3...
Trigger circuit, 6... Main capacitor, 11... Series connection body, 12... Voltage supply means, 13... Resistor, 1
4... Zener diode, 15... SCR, 17
...Double pressure means, 16.18.19...Transistor, 20...Name of agent for control means Patent attorney Shigetaka Awano Slim Fe5 anti-one energy tie sparrow SCR transistor pressure circuit diagram 1B, 19
ta21)--Hayuri Seal pyPj

Claims (1)

[Scope of 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 the supply of the DC high-voltage power supply, a flash discharge tube, and a power MOSFET connected in series. a series connection body connected to both ends of the main capacitor; and a power MOSFET that operates in synchronization with the supply of the DC high voltage power supply to the main capacitor.
and a trigger switch element having a control pole to which a light emission command signal is supplied and whose low potential side terminal is connected to a connection point between the flash discharge tube and the power MOSFET. , 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 the power MOSFET is connected between the main poles thereof.
A strobe device comprising a control switch element connected between a gate and a source. (2) The strobe device according to claim 1, wherein the voltage supply means is formed from a series body formed by connecting in series a resistor connected to both ends of the main capacitor and a constant voltage element. (3) Claim (1) wherein the voltage supply means comprises a constant voltage power supply that generates a predetermined constant voltage in response to the operation of the DC high voltage power supply.
) The strobe device described in ). (4) The voltage supply means is formed to include a switch configuration that operates in response to the start of operation of the DC high voltage power supply and the elapse of a predetermined time from the start of operation.
The strobe device according to any one of 4).