JPH028266Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a flashlight device used as a light source for photography, and includes a second power source for operating other circuits in addition to the power source for operating the flashlight device. It is.

Prior Art A flash light emitting device that uses a low voltage power source such as an AA dry cell as a power source and boosts the voltage with a converter is well known. Thanks to recent advances in electronics, this flashlight can now automatically control the amount of light emitted, and when combined with a camera, information can be exchanged with the camera, allowing flash photography using the flashlight. Now you can do it more easily. In the case of such a flashlight emitter, in addition to the power supply for operating the flashlight emitter itself, a second power supply is required for information exchange with the camera, control circuits for controlling the amount of light, etc. Since it is uneconomical to separately prepare this second power source, it is shared with the power source that operates the flashlight emitter. Generally, in order to share the ground line between the control circuit and the flashlight, a capacitor is connected in parallel to the power supply, and this capacitor is used as a second power supply. However, in a flashlight emitter, the load is heavy while the capacitor is in operation, especially immediately after the light is emitted, so the voltage of the power supply may drop and the control circuit may become inoperable. Therefore, in order to prevent such drawbacks, there is a known method in which the operation of the converter is temporarily stopped when the control circuit is in operation.

If the converter operation is temporarily stopped and the control circuit is activated in this way, the malfunction of the control circuit will be eliminated, but since the converter operation must be stopped for a certain period of time, the main capacitor will have to be charged extra time. In addition to having this drawback,
It also has the disadvantage that the circuit for stopping the operation of the converter is complicated.

Other means are known in which the ground line is not shared, but when the ground line is not shared, for example, when exchanging information with a camera, extra circuits such as signal conversion are required, which is undesirable.

Purpose of the invention The purpose of the present invention is to improve such drawbacks, and to provide a flashlight emitter having a second power source that does not require stopping the operation of the converter. .

Summary of the invention Therefore, the present invention is based on one of the converter transformers.
Next, connect a second capacitor to the coil that can charge the voltage generated by induction when the current to the coil is cut off, and charge the voltage charged to the capacitor to the first capacitor connected in parallel to the power supply. It is configured so that it can be done. This first capacitor is used as a second power source.

Embodiment 1 is a power source consisting of four AA size dry batteries, the positive side of which is connected to the emitter of a transistor 2 as a semiconductor element, and the negative side connected to a line 4 via a power switch 3. In this embodiment, transistor 2 is used with a grounded base. By doing so, line 4 can be used as a common ground line. A first capacitor 5 is connected to this power supply 1 via a diode 6. This first capacitor 5 is used as a second power source and is connected to a control circuit (not shown) or the like. The circuit consisting of transistor 2 and transformer 7 is a normal circuit with power supply 1 as the power source.
It is a DC-DC converter. As is well known, the transformer 7 has a primary coil 8, a feedback coil 9, and a secondary coil 10, and the primary coil 8 is connected to the power source 1 via a transistor 2. In this example,
Furthermore, a diode 1 is connected to both ends of this primary coil 8.
1, a resistor 12, and a second capacitor 13 are connected in series. This diode 11 is oriented to charge the second capacitor 13 with the voltage generated in the primary coil 8 when the transistor 2 is turned off. The connection point between this diode 11 and the resistor 12,
At the connection point between the first capacitor 5 and the diode 6, a diode 14 transfers the charge of the second capacitor 13 to the first
It is connected to charge the capacitor 5.

As is well known, the secondary coil 10 includes a diode 1.
A main capacitor 16 is connected through the main capacitor 5, and a discharge tube 17 is connected in parallel to the main capacitor 16. 18 is a trigger circuit for starting discharge of the discharge tube 17.

Although only the circuit for discharging the discharge tube 17 is shown in this embodiment, it is natural to add control circuits such as a circuit for controlling the amount of light and a circuit for exchanging information with the camera depending on the purpose. .

When the second capacitor 13 is connected in parallel to the primary coil 8 via the diode 11 as described above,
Each time the transistor 2 is turned off during converter operation, the voltage induced in the coil 8 is charged to the illustrated polarity. Therefore, when the transistor 2 is turned on, its voltage is charged to the first capacitor 5 via the resistor 12 and the diode 14.

In this way, according to this embodiment, the first capacitor 5
is charged with the voltage of the power source 1, and is also charged to the voltage that is the sum of the voltage of the power source 1 and the voltage of the second capacitor 13 when the transistor 2 is on.
The control circuit generally has an operating voltage of about 3V,
Although the voltage induced in the primary coil 8 is about 6V, there is no particular problem if a constant voltage element is connected to the first capacitor 5. Further, since the capacitance of the first capacitor 5 is larger than that of the second capacitor 13, the voltage of the first capacitor does not become so large. Furthermore, if you select their capacity appropriately,
Needless to say, even if the voltage of the power supply 1 decreases, charging through the second capacitor allows the voltage of the first capacitor 5 to be maintained at a value that allows the control circuit to operate normally.

Effects of the Invention As described above, according to the present invention, it is possible to prevent malfunctions of the control circuit, etc. due to a drop in the voltage of the second power source, without stopping the operation of the converter every time light is emitted.

In addition, since the first capacitor connected in parallel to the power supply can be used as the power supply for the control circuit, the ground line of the control circuit can be shared with the ground line of the flashlight, so the circuit design of the control circuit can be improved. It can be done easily.

Furthermore, the present invention has an extremely simple configuration because it is only necessary to connect a capacitor and a diode to the primary coil of the transformer, and to connect one diode between this capacitor and the capacitor used as the second power supply.

[Brief explanation of the drawing]

The figure is an electrical circuit diagram of an embodiment of the present invention. 1: power supply, 2: transistor, 5: first capacitor, 7: transformer, 8: primary coil, 11: diode, 13: second capacitor, 14: diode.

Claims (1)

[Claims for Utility Model Registration] A low-voltage power source is connected to the primary coil of a transformer having a primary coil, a feedback coil, and a secondary coil through a semiconductor element, and when the semiconductor element is turned on and off, the two Next, create a high voltage in the coil,
In a flash light emitting device in which the voltage is rectified and stored in a main capacitor, a first capacitor serving as a second power source is connected in parallel to the power source via a first diode, and a primary power source is connected when the semiconductor element is turned off. a second capacitor connected in parallel to the primary coil so that the voltage induced in the coil is charged; and a connection point between the first capacitor and the first diode and the anode of the second capacitor A flashlight emitter having a second power source, comprising: a second diode connected in a direction to charge the first capacitor from the second capacitor when the semiconductor element is turned on.