JPH01280741A - Stroboscope - Google Patents

Abstract

PURPOSE:To check a battery in an actual loading condition by finding residual time required to complete charging based on the increase rate of a charging voltage obtained during charging a capacitor and giving an alarm when it is longer than a prescribed time. CONSTITUTION:The capacitor C1 is charged through a converter 1 prior to the light emission of a stroboscopic tube 3. A voltage is generated on both ends of resistance R2 corresponding to the charging voltage. A gate IC1 outputs a high-level signal only when the voltage of the capacitor C1 is within a prescribed range. A clock signal from a clock circuit 5 is counted at a counter circuit 6 so that the increase rate of the charging voltage is determined. The residual time required to complete the charging is timed based on this increase rate. LED 24-28 are driven selectively responding to this. When LED 28 is lighted, the alarm is given to indicate that the battery is needed to be replaced. Checking the battery can be thereby performed in the actual loading condition.

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, the strobe tube could not emit light unless the capacitor was charged to a predetermined voltage value.

Here, when the performance of the battery as a power source has deteriorated,
Sometimes it took a long time to charge the battery to a voltage that enabled it to emit light, or it was not possible to charge the battery to that voltage, resulting in missed photo opportunities. Therefore, a battery check was necessary. Conventional battery checks have been performed by directly measuring the power supply voltage during non-operation, or by passing current through a dummy resistor and measuring its terminal voltage.

[Problem to be solved by the invention] However, for battery checking, it is desirable to measure the power supply voltage when an actual load is applied, and when the load is a DC-DC converter such as a strobe device, However, 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 of the power source while charging a capacitor and issues a warning when the power source 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;
Since a warning is issued if this time exceeds a predetermined time, it is possible to check the battery under an actual load.

[Embodiment] Hereinafter, an embodiment of the Sui-Robo 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 high is shorter than the charging completion time TD2 when the power supply voltage Vcc is low. The variation in the charging completion time due to the power supply voltage largely depends on the rate of increase in the 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 relationship between the required charging time TS in this predetermined voltage range at various power supply voltages Vcc and the remaining time TR until the charging voltage reaches 200 V to 250 V (light emission enabled voltage) is determined in advance. This characteristic is shown in FIG. In other words, by counting 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 by the characteristics shown in FIG. 2. Here, the power supply voltage ■Cc used to determine the characteristics is 2.2V.

2.4V, 2.6V, 2.8V, 3.0V (7)5.

Next, FIG. 3 shows an electric circuit diagram of an embodiment using this principle, and its specific configuration will be explained.

Power source consisting of battery E and DC-DC converter 1 = 5
- A main capacitor C1 consisting of an electrolytic capacitor is connected to the source circuit 2. Resistor R to main capacitor C1
A series circuit of R1, R2, and R3 and a series circuit of resistor R4, neon lamp Ne, and 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 transformer 4. Capacitor C
2 in series to the anode end of the thyristor SCR. 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 the thyristor SCR is connected to one end of the strobe tube 3 through a resistor R6, and 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 resistor R7 and the anode side of diode D is connected to capacitor C3 and resistor R
9 in series to the cathode end of diode D. Further, a connection point between the capacitor C3 and the resistor R9 is connected to one end of the strobe tube 3 via a resistor RIO. Connection point of capacitor C3 and resistor R9 and diode D
A trigger switch SW is connected between the cathode end of the trigger switch SW and the cathode end of the trigger switch SW.

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 the input terminal of an exclusive OR gate (hereinafter referred to as EX-OR gate) ICI. The output terminal of the EX-OR gate IC1 is connected to a binary counter 6 via a clock generation circuit 5 consisting of Nant gates IC2 and IC3.
is connected to the clock input terminal CP. The neon lamp N is connected to the reset terminal R of the binary counter 6.
The output from the connection point between e and resistor 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. A neon lamp Ne is connected to the reset terminal R of the decoder 12 in the same way as the reset/reset terminal R of the binary counter 6.
A signal is supplied from the connection point between the resistor R5 and the resistor R5. Each output terminal Q1-Qn of the decoder 12 is connected to one input terminal of AND gates 18-22 via OR gates 13-17. A signal from the connection point between the neon lamp Ne and the resistor R5 is supplied to the other input terminals of the AND gates 18 to 22 via an inverter 23, and its output is connected to light emitting diodes (LEDs) 24 to 28. . The LEDs 24 to 28 are grounded via resistors.

These LEDs 24 to 28 are arranged in a horizontal line in an easy-to-see place, for example, on the back of the strobe device, and a label indicating the remaining time (seconds) is provided above or below each LED. Furthermore, neon lamps Ne are also arranged near the LEDs 24-28.

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 connected to the power source E via the DC-DC converter 1.
is charged by The voltage corresponding to this charging voltage is the resistance R
Occurs at both ends of 2.

Then, the EX-OR gate IC1 operates within a predetermined voltage range (here, 15
It is configured to output a high-level signal only when the voltage is between 0V and 200V. During this period, the clock circuit 5 outputs a clock signal, the counter circuit 6 increments the clock signal by R1, and this time is counted.

That is, the counter circuit 6 detects the time TR (horizontal axis in FIG. 2) required for the charging voltage to change from 150V to 200V. Then, assuming that the charging completion voltage of the main capacitor C1 is 250■, the decoder 2 selectively drives any one of the LEDs 24 to 28 according to the required time TR based on the characteristics shown in FIG. is configured to display. For example, if the required time TR is 1.5 seconds or less, turn on the LED 24, and if it is 1.5 to 1.7 seconds, turn on the LED 24.
Turn on D25, turn on LED26 for 1.7 to 1.9 seconds, turn on LED27 for 1.9 to 2.5 seconds, 2.5
If it is longer than a second, the LED 28 is turned on. 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 the LED 28 lights up, it will take more than 10 seconds to complete charging, which indicates that the battery needs to be replaced. That is, the LED 28 is a warning display member for the result of the battery check. When the main capacitor C1 reaches a predetermined light emission voltage (2.50V in this case), the neon lamp Ne is turned on and at the same time, the binary counter 6 is reset by the current passing through the neon lamp Ne, so that the LED 24~
28 is 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. Further, the timing for starting the light emission may be at the end of counting, or may be during counting.

After charging is completed, when the trigger switch SW is pressed, the thyristor SCR is turned on and the strobe tube 3 is turned on.
is triggered and starts emitting light.

[Effects of the Invention] As explained above, according to the present invention, there is provided a strobe device that can perform a battery check of the power source 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 relationship between the remaining time until the charging voltage of the capacitor reaches the charging completion voltage from a predetermined voltage and the power supply voltage, and Figure 3 is a diagram according to the present invention. FIG. 1 is a circuit diagram of an embodiment of a strobe device. C...Main capacitor, Ne...Neon lamp, 3...Strobe tube, SCR...Thyristor, SW...
...Switch, ICI...Exclusive OR gate, 5...Clock circuit, 6...Binary counter, ]2...Decoder, 24-28...LED0 Applicant's representative Patent attorney Junmi Tsuboi 2 -m Jito and Tsuyoshi) 1 Tsuyoshi 1

Claims (1)

[Claims] In a strobe device that emits light by a discharge current of a capacitor connected in parallel to a strobe tube, the time from when the charging voltage of the capacitor reaches a first predetermined voltage to when it reaches a second predetermined voltage during charging of the capacitor is provided. a timer for measuring time and determining a value corresponding to the rate of increase in the charging voltage;
Based on the value obtained by the timer, the time from when the charging voltage reaches a second predetermined voltage until it reaches a third predetermined voltage at which charging is completed is determined, and a warning is issued if this time is longer than a predetermined time. A strobe device comprising means.