JPH0459622B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a strobe device having a means for warning when the power supply voltage has decreased and the battery needs to be replaced.

[Prior Art] Generally, in a strobe device for a camera, a capacitor is connected in parallel with a strobe tube, and the strobe tube emits light by the charging voltage of the capacitor. Therefore, unless the capacitor was charged to a predetermined voltage value, the strobe tube could not emit light. Here, when the performance of the battery as a power source has deteriorated, it may take a long time to charge the battery to a voltage that allows light emission, or it may not be possible to charge the battery to that voltage, resulting in a missed shutter start. Therefore, a battery check was necessary. Traditional battery checks either measure the supply voltage directly when not in operation, or
Alternatively, this was done by passing a current through a dummy resistor and measuring the terminal voltage.

[Problems to be Solved by the Invention] However, in order to check the battery, it is desirable to measure the power supply voltage when an actual load is applied.
When a converter is used as a load, it is impossible to perform an accurate battery check simply by passing a current through a dummy resistor and measuring it.

The present invention has been made to address the above-mentioned circumstances, and an object of the present invention is to provide a strobe device that performs a battery check on the power supply while charging a capacitor and issues a warning when the power supply voltage is low.

[Means for Solving the Problems] A strobe device according to the present invention provides a strobe device in which, during charging of a capacitor connected in parallel to a strobe tube, the charging voltage of the capacitor reaches a first predetermined voltage until it reaches a second predetermined voltage. means for determining a value corresponding to the rate of increase in charging voltage by measuring time; and a time period from when the charging voltage reaches a second predetermined voltage to when it reaches a third predetermined voltage at which charging is completed based on this value; and means for issuing a warning when the calculated time is longer than a predetermined time.

[Function] According to the present invention, the remaining time until charging is completed is determined based on the rate of increase in charging voltage determined during charging of the capacitor, and a warning is issued when the remaining time is longer than a predetermined time. You can perform a battery check of the previous state.

[Embodiment] Hereinafter, an embodiment of a strobe device according to the present invention will be described with reference to the drawings. First, the principle of battery check according to the present invention will be explained. Generally, the charging voltage with respect to the charging time of a capacitor is determined by the power supply voltage, and this is schematically shown in FIG. That is, the charging completion time TD1 until the charging voltage of the capacitor reaches the light-emitting voltage VD when the power supply voltage Vcc is large is shorter than the charging completion time TD2 when the power supply voltage Vcc is small. The variation in charging completion time due to this power supply voltage is
It mainly depends on the rate of increase in charging voltage immediately before charging is completed. Therefore, from the charging characteristics of this capacitor, the voltage increase rate ΔV/ΔT in a certain voltage range is determined, and thereby the remaining time until charging is completed can be determined. In reality, the power supply voltage Vcc is calculated backward from the charging time ΔT in a predetermined voltage range ΔV, and the remaining time until charging is completed is determined from the charging characteristics at this power supply voltage Vcc. If this is longer than the predetermined time, The system is configured to determine that the power supply (battery) voltage is low and issue a warning.

Here, the charging completion voltage is 250V, and the predetermined voltage range is 150V to 200V. Then, the required charging time for a given voltage range at various power supply voltages Vcc
The relationship between TS and the remaining time TR until the charging voltage reaches 250 V (voltage capable of emitting light) from 200 V is determined in advance. This characteristic is shown in FIG. In other words, if you count the time from when the charging voltage reaches 150V until it becomes 200V, the remaining time from then until charging is completed can be determined from the characteristics shown in FIG. 2. Here, the power supply voltage Vcc used to determine the characteristics is 2.2V, 2.4V, 2.6V, 2.8V, 3.0V.
It is one.

Next, FIG. 3 shows an electric circuit diagram of an embodiment using this principle, and its specific configuration will be explained.
A main capacitor C1 made of an electrolytic capacitor is connected to a power supply circuit 2 made of a power supply battery E and a DC-DC converter 1. Main capacitor C
1, a series circuit of resistors R1, R2, and R3, and a resistor R
4. A neo lamp Ne and a series circuit of a resistor R5 are connected in parallel. Further, a strobe tube 3 is connected in parallel to the main capacitor C1, and its trigger terminal is connected to the anode end of the thyristor SCR via a transformer 4 and a capacitor C2 in series. A connection point between the primary winding and the secondary winding of the transformer 4 is connected to the cathode end of the thyristor SCR. The anode end of thyristor SCR is resistor R6
The cathode end of the thyristor SCR is connected to the other end of the strobe tube 3 through a diode D in the forward direction.
Further, the gate end of the thyristor SCR is connected to the anode end of the diode D via a resistor R7, and is also connected to the cathode end of the diode D via a resistor R8. Furthermore, the connection point between the resistor R7 and the anode side of the diode D is the capacitor C.
3. Connected to the cathode end of diode D via resistor R9 in series. Also, capacitor C3
The connection point between and resistor R9 is connected to one end of the strobe tube 3 via a resistor R10. Capacitor C
3. A trigger switch SW is connected between the connection point of the resistor R9 and the cathode end of the diode D.

Of the series-connected resistors R1, R2, and R3 connected in parallel to the main capacitor C1, both ends of the resistor R2 are connected to an exclusive OR gate (hereinafter referred to as
EX-OR gate) is connected to the input terminal of IC1. The output terminal of the EX-OR gate IC1 is connected to the clock input terminal CP of the binary counter 6 via a clock generating circuit 5 consisting of NAND gates IC2 and IC3. The neon lamp Ne is connected to the reset end R of the binary counter 6.
The output from the connection point between R and R5 is supplied. The Q output terminal of each digit of the binary counter 6 is connected to the input terminal of a decoder 12 via inverters 7 to 11. The reset terminal R of the decoder 12 is supplied with a signal from the connection point between the neon lamp Ne and the resistor R5, similarly to the reset terminal R of the binary counter 6. Each output terminal Q1 to Qn of the decoder 12 is connected to an OR gate 13.
-17 to one input terminal of AND gates 18-22. and gate 18~22
A signal from the connection point between the neon lamp Ne and the resistor R5 is supplied to the other input terminal of the inverter 23, and its output is a light emitting diode (LED).
24-28. This LED24~
28 is grounded via a resistor. these
The LEDs 24 to 28 are arranged in a horizontal row in a place that is easy to see, for example on the back of the strobe device, and above each LED,
A label indicating the remaining time (seconds) is provided at the bottom. Furthermore, the neon lamp Ne is also LED2
4 to 28.

Next, the operation of the strobe device configured as described above will be explained. First, before the strobe tube 3 emits light, the main capacitor C1 is charged by the power source E via the DC-DC converter 1. A voltage corresponding to this charging voltage is generated across the resistor R2. The EX-OR gate IC1 is configured to output a high-level signal only when the charging voltage of the main capacitor C1 is within a predetermined voltage range (here, 150V to 200V). During this period, a clock signal is output from the clock circuit 5, the clock signal is counted by the counter circuit 6, and this time is measured. That is, the counter circuit 6 detects a predetermined time TR (horizontal axis in FIG. 2) during which the charging voltage changes from 150V to 200V. Then, assuming that the charging completion voltage of the main capacitor C1 is 250V, the decoder 12 controls the LED 24 according to the predetermined time TR based on the characteristics shown in FIG.
Selectively drive any one of ~28 to determine the remaining time
Configured to display TS. for example,
If the predetermined time TR is 1.5 seconds or less, turn on the LED24,
Turn on LED25 for 1.5 to 1.7 seconds, turn on LED26 for 1.7 to 1.9 seconds, and turn on LED27 for 1.9 to 2.5 seconds.
If it is longer than 2.5 seconds, turn on LED28.
As a result, for example, when the LED 25 lights up, it can be seen that it will take 3 to 4 seconds to complete charging. Also, when LED 28 lights up, it is until charging is complete.
If it takes more than 10 seconds, you know you need to replace the battery. That is, the LED 28 is a warning display member for the battery check result. When the main capacitor C1 reaches a predetermined voltage (250V in this case) that enables light emission, the neon lamp Ne
At the same time that the neon lamp Ne is turned on, the binary counter 6 is reset by the current flowing through the neon lamp Ne, so that the LEDs 24 to 28 are turned off. The lighting of this neon lamp Ne indicates that charging has been completed. In this way, the remaining time until charging is completed is calculated from the charging time required in a predetermined voltage range before the charging voltage reaches the charging completion voltage, and the battery is checked accordingly, so when the power supply voltage drops, It is possible to accurately warn about battery replacement.

Note that the decoder 12 may be configured so that the LEDs do not emit light one by one sequentially, but emit light additionally. Also, the timing of starting this light emission may be when the count ends,
It can also be used while counting.

Then, after charging is completed, the trigger switch
When the SW is pressed, the thyristor SCR is turned on and the strobe tube 3 is triggered to start emitting light.

[Effect of Light Emission] As explained above, according to the present invention, there is provided a strobe device that can perform a power battery battery check based on the rate of increase in charging voltage while charging a capacitor, and can issue a warning to replace the battery. Ru.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the charging characteristics of a capacitor, Figure 2 is a diagram showing the charging characteristics of a capacitor.
The figure shows the relationship between the power supply voltage and the remaining time until the charging voltage of the capacitor reaches the charging completion voltage from a predetermined voltage, and FIG. 3 is a circuit diagram of an embodiment of the strobe device according to the present invention. C1...Main capacitor, Ne...Neon lamp, 3...Strobe tube, SCR...Thyristor,
SW...Switch, IC1...Exclusive OR gate, 5...Clock circuit, 6...Binary counter, 12...Decoder, 24-28...
LED.

Claims (1)

[Claims] 1. In a strobe device that emits light by a discharge current of a capacitor connected in parallel to a strobe tube, during charging of the capacitor, the charging voltage of the capacitor reaches a first predetermined voltage until it reaches a second predetermined voltage. clocking means for measuring the time and determining a value corresponding to the rate of increase in the charging voltage; and a third clocking means for determining a value corresponding to the rate of increase of the charging voltage, and a third clocking means for completing charging after the charging voltage reaches a second predetermined voltage based on the value determined by the timing means. A strobe device comprising means for determining the time required to reach a predetermined voltage and issuing a warning when the time is longer than the predetermined time.