JPH01314230A - Protective flash device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a flash device, and more particularly to a protective flash device that completely prevents leakage of the power source battery used therein, as well as explosions.

[Prior Art] When two or more alkaline batteries or lithium batteries are connected in series and the stored energy of the batteries is almost completely used up, a capacity imbalance occurs in each cell of the series-connected batteries. When power is supplied to the device, that is, when a battery circuit is formed, a battery with a high consumption rate is reversely charged compared to a battery with a low consumption rate, which poses a risk of leakage and explosion. This tendency was particularly noticeable when the flash device served as a load, since the current flowing from the battery could reach a large current of several amperes.

In conventional flash devices, the above-mentioned danger is extremely high because the instruction manual simply instructs the user to replace the battery with a new one when the time from turning on the power switch to becoming ready to emit light becomes long.

For example, when using a flash device that has been left unused for a long time, the user typically turns on the power switch and checks to see if it has taken longer for the flash device to become ready to emit light. At this time, a large current flows, causing the battery to explode.

[Problems to be Solved by the Invention] In the present invention, the timing means is provided so that when the flash device is not ready to emit light for a predetermined period of time determined by the timing means after the power switch is turned on or after the flash is emitted, the power switch is turned on.・Regardless of whether it is off or off, the step-up circuit that boosts the voltage applied to both ends of the main capacitor of the flash device is prohibited from operating with a large current, and the inhibited state of the b lever is maintained with a small current of ri, and the l of the battery is ? i or the risk of explosion has been completely eliminated.

[Means for Solving the Problems] The present invention includes a timing circuit that starts timing when a power switch is turned on or starts timing when a discharge tube emits light, and further uses a main capacitor charging power source of a conventional flash device. A holding circuit made of an SCR is interposed on the power supply side of the booster circuit, and when the completion of charging of the main capacitor is not detected within a predetermined time from the start of time measurement by the timer circuit, the holding circuit is activated to supply voltage to the booster circuit. I made sure to cut off the power supply.

[Example] The figure shows an example circuit of the present invention.

When the power switch 50 is turned on (state shown), the comparator 9 becomes operational via the constant voltage circuit 3, but since the voltage of the capacitor 5 is low immediately after the start of charging, the comparator 9
The output of is at low (L) level. Therefore transistor 2
2 is off, and transistor 26 is on.

Also, since the low level output of the comparator 9 is given to the input terminal to which the resistor 11 of the ANt1 circuit 14 is connected, the AND
The output of circuit]4 is at a low level. Therefore, 5CRI8 is turned off and transistor 25 is turned on.

When the power switch 50 is turned on, the transistors 25 and 28 are on, so the transistor 23 is on, and the transistor 30 is also on, and the booster circuit consisting of the transistor 29, transformer 32, resistor 31, and diode 33 is activated. , starts charging the main capacitor 25.

([) When the battery is new, after turning on the power switch, the voltage of the timekeeping capacitor 5 increases sequentially due to the current flowing through the resistor 4, and after a predetermined period of time (for example, about 5 minutes), the output of the comparator 9 is reversed to a high level. becomes.

When the battery is new, the main capacitor will be fully charged within the above-mentioned time, for example within 5 minutes, and the neon lamp 37 will turn on.
Completion of charging is notified, and this lighting current turns on the transistor 13. Due to the inversion of the output of the comparator 9, the high (H) output is applied to the AND circuit 14 for a short time determined by the capacitor 10 and resistor 11.
The output of circuit 14 remains at a low level.

Also, due to the inversion of the output of the comparator 9, the transistor 22
is turned on and transistor 26 is turned off, transistors 23 and 30 are turned off, and the booster circuit becomes inoperative.

However, once the power switch 50 is turned off, the voltage of the capacitor 5 is discharged through the diode 6 and the switch 50, so when the switch 50 is turned on again, the booster circuit starts operating again and starts the next light emission. Be prepared.

(ii) When an old battery is used In this case, since the battery voltage is low, charging of the main capacitor C will not be completed within the predetermined time period, and the collector of the transistor 13 will be at a high level during this time. Also, after a predetermined time has elapsed, as mentioned above, the human power connected to the resistor 11 becomes H level for a short time, so the two inputs of the AND circuit both become H level, and therefore the output also becomes H level, turning SC818 on. . Therefore, the transistor 25 is turned off and the booster circuit stops operating.

Next, even if the power switch 50 is turned off and then turned on again, the SCR 18 continues to be on, so the booster circuit no longer operates.The current at this time is the current of the constant voltage circuit, the clock circuit, the AND circuit and the 5CR18. It is determined by
It is very small compared to the current flowing in the booster circuit, in fact 100μ.
It is about A or below. 1 [If it is 10 μA or less, there is no risk of battery leakage or explosion.

Also, if you want to release the above condition, just replace the battery with a new one.

When replacing the battery - the holding current of 5CR18 is cut off, so the operation is the same as when using a new battery.

The above is the operation after the power switch is turned on. However, since the battery is new and the main capacitor C is fully charged within the predetermined time,
o When Ji12 is performed and the synchro switch 40 is closed, the timekeeping capacitor 5 is discharged via the diode 42 and the synchro switch 40, so that the output of the comparator 9 is inverted after a predetermined period of time. After that, the same operation as from when the power switch was turned on is repeated.

[Effects] According to the present invention, a relatively expensive flash device can be completely electrically protected from damage due to leakage or explosion of its built-in battery. It is possible to avoid bulking up and bulking up, and its commercial value is great.

Although the present invention has been described with reference to a flash device as a relatively expensive and large-load device that uses a series connection of multiple batteries as its power source, the present invention is equally applicable to devices under such conditions. It is a matter of course that it can be applied.

[Brief explanation of the drawing]

The accompanying drawing is a circuit diagram of a flash device showing an embodiment of the present invention. 1... Series connected batteries 3... Constant voltage circuit 50.
・・Power switch 5・・Timekeeping capacitor 9・
...Comparator 14...AND circuit C...
Capacitor 37...Charging completion notification neon lamp

Claims (1)

[Scope of Claims] 1. A power source consisting of a series connection of a plurality of batteries, a flash discharge tube, a main capacitor that stores energy for discharging and emitting light from the discharge tube, a booster circuit that generates a charging voltage for the main capacitor, and A flash device comprising means for detecting the completion of charging of the main capacitor by the booster circuit, and a timing means for starting time measurement by turning on the power switch of the flash device or by discharging and emitting light from the discharge tube. and a holding circuit that keeps power supply cut off to the booster circuit, and operates the holding circuit when completion of charging of the main capacitor is not detected within a predetermined time from the start of time measurement by the timing means. A protective flash device featuring: