JPH06203987A - Stroboscope charging switch device - Google Patents

Abstract

PURPOSE:To provide a self-holding type stroboscope charging switch device simple in circuit structure and drivable at low voltage. CONSTITUTION:When a push switch 32 is ON, switching transistors 41, 54 are ON, and a capacitor 42 is quickly charged. A capacitor 51 is charged to the voltage level of the capacitor 42. When the push switch 32 is OFF, the voltage of the capacitor 51 is applied to the gate of the switching transistor 41, which is then continuously driven. Since a capacitor 52 is charged by the discharge of the capacitor 42, and the composed voltage of the capacitors 51, 52 is applied to the gate of the switching transistor 41, much more current is supplied from a power source feed line 35a to a booster circuit 40. Thereafter, the charges of the capacitors 51, 52 are leaked, and the drive of the switching transistor 41 is automatically stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a strobe charging switch device.

[0002]

2. Description of the Related Art When shooting a low-brightness subject, a strobe device can be incorporated in a low-priced camera such as a lens-fitted film unit because a good printed photograph can be obtained by illuminating the strobe. There is. When performing flash photography, it is necessary to charge the main capacitor to a specified voltage in advance, so the charging switch is normally turned on prior to flash photography.

The charging switch described above includes a push operation type and a slide operation type. The push operation type is kept on while the user presses the movable piece, and is turned off when the pressing is released. Therefore, it is possible to prevent useless consumption of the battery without leaving the charging switch turned on, but it is necessary to continue pressing the movable piece until charging is completed. I have a problem. Also, in the slide operation type, once the switch knob is set to the ON position, the charging switch is maintained in the ON state, so it is easy to turn on the charging switch, but after using the switch knob to the OFF position. There is a problem that the battery is uselessly consumed unless it is returned. Against this background, there is a camera that uses a self-holding charge switch that is automatically turned on until a predetermined time passes after it is turned on, or a charge switch that is turned on and off by a microcomputer. Are known.

[0004]

However, the above-mentioned self-holding type charging switch and microcomputer control type charging switch not only have a complicated circuit structure and a large cost burden, but also have a low voltage of, for example, about 1.5V. It can only be applied to so-called high-end cameras because it cannot be driven.
For this reason, a simple low-cost camera, and a film or a lens-fitted film unit with a single AA battery pre-installed, as is known for "Shashin-runda FLASH" (trade name), has the above-mentioned push-operation type and Since only a slide operation type charging switch can be installed, there is a problem in terms of operability and power consumption.

The present invention has been made in consideration of the above problems of the prior art, and provides a self-holding type strobe charging switch device having a simple circuit configuration, a low cost burden, and a low voltage drive. The purpose is to provide.

[0006]

In order to achieve the above object, in the present invention, when the push switch is turned on,
A power supply voltage is applied to the gate of a switching element that supplies a current from a power supply to a booster circuit to drive the same, and a plurality of capacitors connected in series to the gate are sequentially charged, and a plurality of capacitors after charging are completed. Applying the combined voltage of the capacitor to the gate to maintain the switching element in the ON state, and operating the booster circuit until a predetermined time elapses regardless of the release of the push button. Is. Embodiments of the present invention will be described below with reference to the drawings.

[0007]

FIG. 4 shows a lens-fitted film unit embodying the present invention. The lens-fitted film unit 2 is composed of a unit body 3 in which a film with a cartridge is previously incorporated, and an exterior body, for example, a paper box 4, which houses the film. On the front surface of the unit main body 3, a taking lens 5, a stroboscopic light emitting section 6, a viewfinder 7, and a charging knob 8 are provided. Further, on the upper surface of the unit main body 3, there are provided a release button 9, a remaining photographing number display window 10, and an opening 11 for confirming lighting of a neon tube indicating completion of strobe charging. Reference numeral 12 is a winding knob.

FIG. 3 is an exploded view of the unit body. The unit main body 3 includes a front cover 20, a main body portion 21, and a rear cover 22, which are resin molded parts.
A cartridge chamber 25 for accommodating the cartridge 24 and a film chamber 28 for accommodating the film roll 27 are integrally formed on the back surface of the main body portion 21. A strobe unit 30 is attached to the front surface of the main body 21.

The strobe unit 30 is a printed circuit board 3
1, a flash switch 6, a push switch 32 pressed by the charging knob 8, a main capacitor 33, a synchro switch 34, a battery contact piece, and the like are assembled.
Furthermore, one AA type battery 35 is incorporated in the lower part of the main body 21, and this battery 35 is connected via a battery contact piece.
A current is supplied to the strobe unit 30. A circuit pattern is formed on the printed circuit board 31, and a booster circuit for charging the main capacitor 33 on the printed circuit board 31 by connecting electric elements such as a transformer, a trigger coil and a transistor to the circuit pattern, A circuit and the like of the charging switch device in which the push switch 32 is incorporated are formed.

In FIG. 1 showing the circuit configuration of the charge switch device, a switching transistor 41 for supplying a current to a booster circuit 40 at the time of driving is connected to a power supply line 35a connected to the anode of the battery 35. .
A capacitor 42 having a very short charging time, for example, a charging time of 100 msec or less, and a capacitor 44 with a resistor 43 interposed are connected in parallel to the power supply line 35a via the push switch 32. . An IC circuit 45 is connected to the anode side terminal A of the capacitor 44, and this IC circuit 45 outputs the terminal voltage of the battery 35 or the capacitor 42 to the terminal B until the terminal A reaches a predetermined voltage V1. An IC circuit 46 is connected to this terminal B, and when the potential of the terminal B is at the earth level,
The terminal voltage of the battery 35 or the capacitor 42 is output to the output terminal C.

A gate of the switching transistor 41 and a capacitor 49 connected in series with a resistor 48 are connected to the terminal B via a diode 47. The terminal D on the anode side of the capacitor 49 and the terminal C are connected to the IC circuit 50 driven by the discharge of the capacitor 42.
Is connected to the input side of. This IC circuit 50 has a terminal D
Is a predetermined voltage V2 or less, and when the terminal voltage of the battery 35 or the capacitor 42 is output to the terminal C, the terminal voltage of the battery 35 or the capacitor 42 is output to the terminal E.

The switching transistor 41 includes:
A capacitor 51 charged to the terminal voltage of the battery 35 or the capacitor 42 output to the terminal B and a capacitor 52 charged to the terminal voltage of the battery 35 or the capacitor 42 output to the terminal E are connected. The pair of capacitors 51 and 52 are arranged in series by connecting the anode side terminal F of the capacitor 52 to the cathode side of the capacitor 51 and the anode side terminal G of the capacitor 51 to the gate.
When the push switch 32 is turned off, the voltage of the capacitor 51 is first applied to the gate, and after a while, the combined voltage of the capacitors 51 and 52 is applied. Since the input impedance of the switching transistor 41 is high, the capacitors 51 and 52 do not discharge, and the voltage is continuously applied to the gate for a certain period of time. Therefore, even if the push switch 32 is turned off, the switching transistor 41 is continuously driven for a fixed time.

The terminal E is connected to the terminal F via a diode 53, and a switching transistor 53 for setting the potential of the terminal F to the ground level during driving. The switching transistor 53
Is driven when the gate is connected to the terminal B and the terminal voltage of the battery 35 or the capacitor 42 is output to the terminal B.

The operation of the charging switch device of the present invention thus constructed will be described with reference to FIG. When the push switch 32 is turned on at T1, the capacitor 4
2 and 44 are started to be charged, respectively, and the IC circuit 45 is driven to connect the battery 35 or the capacitor 4 to the terminal B.
It outputs the terminal voltage of 2. As a result, the switching transistors 41 and 54 are driven and the capacitor 49 is charged. Switching transistor 41
When is driven, the current from the power supply line 35a starts to flow to the terminal H, and the current supply to the booster circuit 40 is started. When the switching transistor 54 is driven, the potential of the terminal F becomes the ground level, so that the capacitor 51 is charged.

Since the charging time of the capacitor 42 is short, the charging is already completed when the push switch 32 is turned off even if the time from T1 to T2 is 100 ms at T2. Therefore, even when the capacitor 44 is being charged at T2, this charging is continuously performed. Furthermore, the driving of the IC circuit 45 after T2 is also continuously performed by the discharge from the capacitor 42.

If the potential of the terminal A exceeds the voltage V1 at T3 while the charging is continued, the IC circuit 45 stops outputting the terminal voltage of the capacitor 42 and the potential of the terminal B becomes the ground level. As a result, the driving of the switching transistor 54 and the charging of the capacitor 49 are stopped. Since the voltage of the capacitor 51 is applied to the gate of the switching transistor 41, the driving of the switching transistor 41 is continued without being stopped. Further, since the discharge current from the capacitor 51 is blocked by the diode 47, the terminal B never becomes a high voltage.

As described above, when the potential of the terminal B becomes the ground level, the IC circuit 46 outputs the terminal voltage of the capacitor 42 to the terminal C. At this time, the potential of the terminal D is the voltage V
Since it exceeds 2, the IC circuit 50 does not output the terminal voltage of the capacitor 42 to the terminal E. After this, condenser 4
When 9 is discharged and the potential of the terminal D becomes lower than the voltage V2 at T4, the IC circuit 50 outputs the terminal voltage of the capacitor 42 to the terminal E. After that, the capacitor 52 is charged. Since the potential of the terminal F rises as the capacitor 52 is charged, the potential of the terminal G is further raised. As the potential rises, the amount of current supplied from the battery 35 to the terminal H increases.

When the discharge of the capacitor 42 is stopped at T5, the driving of the IC circuit 50 is stopped and the potential of the terminal E becomes the ground level, so that the current supply to the capacitor 52 is stopped. After that, capacitors 51 and 52 are connected to the terminal G.
Is applied, the current from the battery 35 does not drop in the switching transistor 41,
It is supplied to the booster circuit 40. Since the input impedance of the switching transistor 41 is very high, the capacitors 51 and 52 do not discharge, and the combined voltage continues to be applied to their gates.

When a sufficient current is supplied to the booster circuit 40, the booster circuit 40 charges the main capacitor 33. When this charging is completed, a neon tube (not shown) is turned on, and thereafter, flash photography becomes possible. In addition,
The lighting of the neon tube can be observed through the opening 11. After that, when the release button 9 is pressed, the synchro switch 34 is turned on, and flash photography is performed.

By the way, the charges of the capacitors 51 and 52 leak as a leak current, so that the potential of the terminal G continues to drop gradually and reaches the ground level after a few minutes. As a result, the driving of the switching transistor 41 is stopped, and the current supply to the booster circuit 40 is automatically cut off. Therefore, the battery 35 will not be consumed unnecessarily.

In the above embodiment, the capacitor 42 is used.
Although the charging time is 100 ms or less, the charging time is not necessarily 100 ms or less. For example, when the push switch 32 is pressed for N seconds, the charging time is N seconds. If it is within the range, the same effect can be obtained. Further, in the charge switch device of the present invention, since one operation is performed by the electric charge charged in the capacitor 32, the power consumption thereof can be suppressed to be small. Furthermore, since the voltage applied to the gate of the switching transistor 41 is set by a pair of capacitors connected in series, the charging switch can be operated at a low voltage.

FIG. 5 shows a circuit configuration of another charge switch device. In this charge switch, the capacitors 51 and 52 shown in FIG. 1 are charged by a pair of pulse current generating circuits connected to a power supply line 35a. This is done by The same reference numerals are used for the same elements as the electric elements shown in FIG. Between the diode 47 and the push switch 32, a pulse current generation circuit 60 that is driven at the timing when the push switch 32 is turned on and outputs a pulse current that charges the capacitor 51 to the output side terminal X is connected. Also, the terminal X and the diode 5
A pulse current generating circuit 61, which is driven by the fall of the pulse current and outputs a pulse current for charging the capacitor 52 to the output side terminal Y, is connected between the output terminal 3 and the output terminal 3.

The operation of the charging switch device thus constructed will be described with reference to FIG. When the push switch 32 is turned on, the pulse current generation circuit 60 is driven and the pulse current as shown in the figure is output to the terminal X.
As a result, the voltage of the pulse current is applied to the gates of the switching transistors 41 and 54, and these are turned on. At this time, since the potential of the terminal F becomes the ground level, the capacitor 51 is charged.

At the fall of the pulse current output to the terminal X, the pulse current generating circuit 61 is driven, and the pulse current as shown in the figure is output to the terminal Y. At this time, since the switching transistor 54 is turned off, the capacitor 52 is charged by the pulse current. Therefore, even if the push switch 32 is turned off, the combined voltage of the capacitors 51 and 52 is applied to the gate of the switching transistor 41.

[0025]

As described above, according to the present invention, when the push button is pressed, the power supply voltage is applied to the gate of the switching element which supplies the current from the power supply to the booster circuit to drive the same. , Sequentially charging a plurality of capacitors connected in series to the gate, and after completion of charging, apply a combined voltage of the plurality of capacitors to the gate to maintain a switching element in an ON state, and release the push button. Regardless of this, since the booster circuit is operated until the predetermined time elapses, without continuously pressing the push button,
You can reliably charge the flash. Further, this switching element is automatically turned off when electric charges of a plurality of capacitors leak, so that it is possible to prevent the battery from being consumed unnecessarily. Furthermore, since the strobe charging switch device of the present invention has a simple structure, it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration of a charging switch device of the present invention.

FIG. 2 is a diagram showing an output waveform at each terminal of the circuit shown in FIG.

FIG. 3 is an exploded perspective view of a lens-fitted film unit embodying the present invention.

FIG. 4 is a perspective view showing the outer appearance of a lens-fitted film unit embodying the present invention.

FIG. 5 is a diagram showing a circuit configuration of another charging switch device of the present invention.

6 is a diagram showing output waveforms at respective terminals of the circuit shown in FIG.

[Explanation of symbols]

 8 Charging Knob 32 Push Switch 35 Battery 35a Power Supply Line 40 Booster Circuit 41 54 Switching Transistor 42, 44, 49, 51, 52 Capacitor 45, 46, 50 IC Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keisuke Uchida 1-6 Matsuzakadaira, Yamato-cho, Kurokawa-gun, Miyagi Prefecture Fujifilm Microdevices Co., Ltd.

Claims (1)

[Claims] 1. A strobe charging device in which a switching element provided between a power supply and a boosting circuit is turned on by a push button pressing operation to activate the boosting circuit, thereby charging a main strobe capacitor. In the switch device, a plurality of capacitors serially connected to the gate of the switching element are sequentially charged by pressing the push button, and a composite voltage of the plurality of capacitors after charging is applied to the gate. A strobe charging switch device, characterized in that a switching element is maintained in an ON state, and the booster circuit is operated until a predetermined time elapses regardless of whether or not the push button is released.