JPH0689794A - Charging control device for flash emitting device - Google Patents

Abstract

PURPOSE:To shorten the charging time without dependency upon the supply voltage by starting charging on a main capacitor using the first boosting means, and executing the charging using the second boosting means when charging has reached a certain voltage level. CONSTITUTION:While the voltage VMC of a main capacitor 4 remains low, the voltage of a battery 1 for power supplying is boosted by a booster means 2 having a short charging time, and charging is started. When a voltage sensing means 5 senses that the VMC has reached a certain voltage level, a signal is given to a changeover means 7, and a selecting means 8 selects a booster means 3 having a high boost voltage to perform charging thereafter with this booster means, and the main capacitor 4 is charged to a voltage with which a light emitting tube can conduct light emission. This allows shortening of the charging time regardless of the supply voltage. It is also possible to adjust the charging time by means of adjusting the changeover timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control device for a flash light emitting device, and more particularly to a charge control device for a flash light emitting device for performing a charging operation by switching a plurality of transformers having different constants.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application No. 3-57293 proposes a technical means for forming a charging circuit by combining transformers having different boosting characteristics and switching the transformers when the charging voltage exceeds a predetermined voltage. ing. Also,
Japanese Patent Laid-Open No. 60-2 is a technical means similar to the above technical means, in which the switching operation is performed on the secondary side of the transformer.
No. 41775. Further, a similar technical means is disclosed in Japanese Patent Laid-Open No. 61-193400, Japanese Utility Model Laid-Open No. 2-.
It is proposed in Japanese Patent No. 39223 and Japanese Patent Laid-Open No. 57-194495.

The significance of switching the boosting characteristic of the boosting transformer during charging will be described with reference to FIGS. 20 to 21.

FIG. 20 is an electric circuit diagram showing the basic structure of a general booster circuit. In the figure, reference numeral 100 is a power supply battery, and the power supply voltage of the power supply battery 100 is the step-up transformer 1.
The voltage is boosted by 03, and the main capacitor 105 is charged. Reference numerals 101 and 102 are switching transistors of the step-up transformer 104, and reference numeral 104 is a rectifying diode. The main capacitor 105 is a capacitor for storing light emission energy.

Assuming that the current value flowing from the secondary winding of the step-up transformer 103 is I2, the capacity value of the main capacitor 105 is C, and the charging voltage is VMC, the following (1) is obtained.
The formula holds.

∫ I2 dt = CV (1) Here, the integration period on the left side of the above equation (1) is the period from the start of charging to the charging to the specified charging voltage VMC. is there.

Further, when the winding ratio (the number of secondary winding turns / the number of primary winding turns) of the step-up transformer 103 is n and the current value flowing into the primary winding of the step-up transformer 103 is I1, I1 = nI2. Since (2), from the above equations (1) and (2), ∫I1 dt = nCV (3) where the current value flowing from the power supply battery 100 is I0, and the direct current of the transistor 102 is DC. If the current amplification factor is β, then I0 = (1 + 1 / β) × I1 + I2 = (1 + 1 / β + 1 / n) × I1 (4)

From the above equations (3) and (4), ∫I0 dt = n (1 + 1 / β) CV + CV (5)

Therefore, the time integrated value of the current value flowing out from the power supply battery 100, that is, the consumed current is proportional to the winding ratio n of the step-up transformer 103. Here, in order to reduce the current consumption and improve the life of the power supply battery 100,
It is better to make the winding ratio n of the step-up transformer 103 as small as possible. However, if the winding ratio n is reduced, the charging time becomes longer.

The above logic will be described in more detail with reference to FIG.

FIG. 21 is a diagram showing an elapsed time characteristic of the charging voltage VMC for the main capacitor 105.

In FIG. 21A, reference numeral 106 shows the charging characteristics when the winding ratio n is high, and reference numeral 107 shows the charging characteristics when the winding ratio n is low. This Figure 2
As shown in FIG. 1 (a), the lower the winding ratio n is, the faster the charging voltage VMC becomes the voltage V1. However, when the charging voltage VMC is higher than the voltage V1, the winding ratio is reversed and the winding ratio n is high. It will be faster.

Therefore, when the winding ratio n is switched during charging, the characteristics shown in FIG. 21 (b) are obtained. For example,
When the winding ratio is switched when the charging voltage is the voltage V1, the characteristic shown by reference numeral 108 is obtained. In this case, it is possible to perform charging with high energy conversion efficiency to some extent without impairing the charging time. Further, when the winding ratio n is switched at a voltage V2 higher than the voltage V1, the charging characteristic is as shown by reference numeral 109, and the charging time is slightly delayed, but the energy charged by the transformer with a low winding ratio n is As the ratio increases, the energy conversion efficiency improves.

Further, when the voltage V3 is lower than the voltage V1, the winding ratio n
, The charging characteristic becomes as shown by reference numeral 110, and the charging time becomes slightly faster, but the winding ratio n
Since the ratio of energy charged by a transformer with a low power consumption decreases, the energy conversion efficiency deteriorates. In this way, by increasing or decreasing the switching voltage, it is possible to switch the switching setting that gives priority to the charging time or the switching setting that gives priority to the energy conversion efficiency.

[0015]

By the way, in the above-mentioned conventional technical means, since the switching point of the transformer is fixed, the charging time may be short when the power supply voltage is high, but the power supply voltage becomes low. When it comes, the shortest point of the charging time changes and there is a problem that charging cannot be performed faster.

For example, when the capacity of the power supply battery is lowered under conditions such as low temperature, the charging characteristic changes as shown in FIG. In FIG. 22, when the winding ratio n is high, the characteristics are as shown by reference numeral 111, and when the winding ratio n is low, the characteristics are as shown by reference numeral 112. That is,
If the switching voltage remains at the voltage V1, the charging time will be extremely delayed.

If the switching voltage is made higher than the voltage V1 by giving priority to the energy conversion efficiency, the boosting transformer having a low winding ratio up to the switching voltage level cannot be charged in some cases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a charge control device for a flash light emitting device, which can shorten the charging time without depending on the power supply voltage.

[0019]

In order to achieve the above object, a charge control device for a flash light emitting device according to the present invention boosts a power supply voltage to charge a main capacitor for storing light emission energy. Means and a second boosting means having a boosted voltage higher than that of the first boosting means, and the charging operation by the first boosting means is executed when the charging of the main capacitor is started to charge the main capacitor. A switching means for switching the charging operation by the second boosting means when the voltage reaches a predetermined value, and a charging voltage value for charging the main capacitor, which is switched by the switching means. And changing means for changing.

[0020]

In the present invention, when the charging operation of the first boosting means is executed by the switching means when the charging of the main capacitor is started, and the charging voltage of the main capacitor reaches a predetermined value. Is switched to execute the charging operation by the second boosting means. Further, in the changing means, the switching means changes the charging voltage value to the main capacitor for performing the switching.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the basic construction of a charge control device for a flash light emitting device according to a first embodiment of the present invention, and FIG. 2 is a diagram for charging the flash light emitting device according to the first embodiment. It is an electric circuit diagram showing composition of a control device.

In the first embodiment, as shown in FIG. 1, the power source battery 1 for supplying electric power, and the voltage of the power source battery 1 cannot be charged to a voltage at which the voltage of the main capacitor 4 can emit light. However, it is possible to charge up to the voltage at which the voltage of the first capacitor 1 and the first boosting means 2 having a short charging time when the voltage VMC of the main capacitor is low and the voltage of the main capacitor 4 becomes light emission, The charging time when the voltage VMC is low is compared with the second boosting means 3 having the characteristic that it is slower than the first boosting means 2 and the energy boosted by the first boosting means 2 and the second boosting means 3. A main capacitor 4 for storing, a main capacitor voltage detecting means 5 for measuring the voltage of the main capacitor 4, a power source voltage detecting means 6 for measuring the voltage of the power source battery 1,
According to the information of the main capacitor voltage detecting means 5, when the main capacitor 4 reaches a predetermined voltage, a signal for switching between the first boosting means 2 and the second boosting means 3 is sent out to supply the power supply voltage. Switching means 7 for changing a predetermined voltage for switching between the first boosting means 2 and the second boosting means 3 based on information from the detecting means 6, and the boosting means activated by an output signal from the switching means 7. The main part is composed of the selecting means 8 for selecting

The first embodiment will be described in more detail with reference to FIG.

The first boosting means 2 is a transistor 12, a transistor 13 and a resistor 1 which are connected in parallel to the power supply battery 1.
4 series circuit, primary windings 16a-16b of the transformer 16 connected in parallel to the power supply battery 1, the transformer 16
A series circuit of a transistor 17 connected to the primary side terminal 16b of, a resistor 15 connecting the transistor 13 and the transistor 17, a diode 24, a secondary winding of the transformer 16, and a series circuit of a resistor 18 are connected as shown in the figure. Is configured.

In the first boosting means 2 thus constructed, when an ON signal (base short-circuited to GND) is inputted to the base of the transistor 12 from the transistor 48, the emitter-collector of the transistor 12 → the transistor 13 is inputted. A current flows through the resistor 18 between the emitter and the base of the transistor, and a current flows between the emitter and the collector of the transistor 13, the resistor 15, and the base and the emitter of the transistor 17, so that the primary winding 16a-1 of the transformer 16
6b → Current flows between the collector and emitter of the transistor 17, and a high voltage is induced in the secondary winding due to the interlinkage magnetic flux of the primary winding of the transformer 16 with respect to the secondary winding. → It flows through the diode 25 and the trigger capacitor 31 through the main capacitor 4 and the resistor 30.

This charging current increases the base current of the transistor 17, and accordingly the transistor 1
7 collector current increased, and main capacitor 4
This leads to an increase in the charging current to the trigger capacitor 31, and this positive feedback action puts the transistor 17 in a saturated state. Then, the change in current on the primary side of the transformer 16 disappears, and therefore the change in magnetic flux on the secondary side also disappears. Therefore, energy is generated on the secondary side of the transformer 16 in the direction for reversely biasing the diode 24, and reverse biasing the transistor 13 stops the collector current of the transistor 13 and turns off the transistor 17.

At this time, vibration occurs in the secondary winding, and when the half-wave of the transistor 13 is positively biased, the transistor 13 is turned on again to return to the initial state and start the next cycle operation. The main capacitor 4 and the trigger capacitor 31 are charged by performing such an oscillating operation, but the first boosting means 2 charges the voltage of the main capacitor 4 and the trigger capacitor 31 to a voltage at which the arc tube 29 can emit light. However, it has a characteristic that the charging time is short when the capacitor voltage is low and the energy conversion efficiency is good.

The second boosting means 3 includes a transistor 19, a transistor 20 and a resistor 2 which are connected in parallel to the power supply battery 1.
1 series circuit, between the primary windings 16a-16c of the transformer 16 connected in parallel to the power supply battery 1, the transformer 1
Transistor 23 connected to the primary winding terminal 16c of 6
, A resistor 22 connecting the transistor 20 and the transistor 23 and a diode 24, a secondary winding of the transformer 16, and a resistor 18 are connected in series as shown in the figure. The transformer 16, the resistor 18, and the diode 24 are shared by the first booster 2 and the second booster 3, and the transformer 16 is connected to the first booster 2 at the primary winding terminal 16b. The second boosting means 3 is connected to the primary winding terminal 16c.

The operation of the second boosting means 3 is the same as the first
Since the operation is the same as the operation of the voltage boosting means 2 in FIG. 1, detailed description thereof will be omitted here. Charging is possible, but the charging time when the capacitor voltage is low is longer than the charging time of the first boosting means 2 and the efficiency is poor.

The main capacitor voltage detecting means 5 is connected in parallel to the main capacitor 4 with a diode 25 and a resistor 2.
7, the resistor 28 are connected as shown in the drawing, and the first boosting means 2 is connected.
By flowing a part of the charging current of the second boosting means 3 through the resistors 27 and 28, the voltage generated at both ends of the resistor 28 is input to the non-inverting input terminals of the comparator 36 and the comparator 40 to input the main capacitor voltage VMC. To measure.

The power supply voltage detecting means 6 is composed of a resistor 34 and a capacitor 35 connected in parallel to the power supply battery 1 in series, and is connected between the resistor 34 and the capacitor 35 to the inverting input terminal of the comparator 36 to provide a constant voltage. Is output to the comparator 36.

Further, in the switching means 7, the comparator 36 and the resistor 37 are connected as shown in the drawing, and the output signal of the main capacitor voltage detecting means 5 is low with reference to the output signal of the power source voltage detecting means 6. That is, when the voltage of the main capacitor 4 is low, the Lo signal is output from the switching means, the voltage of the main capacitor 4 becomes high, and the output of the main capacitor voltage detecting means 5 exceeds the output voltage of the power supply voltage detecting means 6. A Hi signal is output from the switching means 7. The output of the switching means 7 is input to the NAND circuit 43 and the NAND circuit 44 via the Not circuit 42.

The selection means 8 is a series circuit of a resistor 38 and a resistor 39, a comparator 40, a resistor 41, and a Not circuit 4.
2, a NAND circuit 43, a transistor 48, a NAND circuit 44, a transistor 49, a series circuit of a resistor 45 and a resistor 46, a switch 47, a series circuit of a resistor 50 and a transistor 51 are connected as shown in the figure.

Next, the operation of the first embodiment constructed as above will be described.

In the series circuit of the resistors 38 and 39, when the voltage of the main capacitor 4 is fully charged, a voltage equal to the value of the voltage generated from the output terminal 5a of the main capacitor voltage detecting means 5 is the comparator of the selection circuit 8. It is adjusted to be input to the inverting input terminal of 40. Since the voltage of the main capacitor 4 is 0V in the initial state, the output of the main capacitor voltage detecting means 5 is also 0V. Therefore, the outputs of the comparator 36 and the comparator 40 become Lo, and the resistors 45, 46, and the switch 4
Since the output terminal 54 of the charge control circuit composed of 7, the resistor 50 and the transistor 51 is Hi, the NAND circuit 43 and NA
Hi is output to both ND circuits 44.

When the switch 47 of the charge control circuit is closed, the output terminal 54 of the charge control circuit becomes Lo and all the input terminals of the NAND circuit 43 become Lo and the output becomes Hi. Since the input terminal of the NAND circuit 44 includes the Not circuit in the output of the comparator 36, the Hi signal is input to one input terminal and the output becomes Lo.
As a result, the transistor 48 is turned on and the transistor 48 is turned on.
Is on, the transistor 49 is off, and the first boosting means 2
Is activated, and the second booster 3 remains stopped.

When the first charging means 2 is activated, the main capacitor 4 and the trigger capacitor 31 are charged, and the output terminal voltage of the main capacitor voltage detecting means 5 also rises. Then, when the voltage value of the non-inverting input terminal of the comparator 36 becomes equal to the output voltage value of the power supply voltage detection means 6, the output of the comparator 36 becomes Hi and NAN.
The output of the D circuit 43 becomes Lo, the transistor 48 is turned off, and the first booster 2 is stopped. At the same time, the output of the comparator 36 causes the output of the Not circuit 42 to become Lo, and the output of the NAND circuit 44 to become Hi. As a result, the transistor 49 is turned on and the second booster is activated.

Then, the boosting means is switched to charge the main capacitor 4 and the trigger capacitor 31.
After that, when the output voltage of the main capacitor voltage detecting means 5 exceeds the divided voltage value of the resistors 38 and 39, the two capacitors are fully charged, the output of the comparator 40 becomes Hi, and the NAND circuit 44 becomes Lo. Then, the transistor 49 is turned off, the second boosting means 3 is stopped, and the charging is completed.

After that, when the switch S3 is closed, the transistor 52 is turned on, and the thyristor 33 is activated, the charge accumulated in the trigger capacitor 31 flows through the primary winding of the trigger capacitor 31 → thyristor → trigger transformer 32, The interlinkage magnetic flux of the primary winding of the trigger transformer with respect to the secondary winding induces a high voltage on the terminal side of the light-emitting discharge tube 29 of the secondary winding to ignite the trigger. Then, the light emitting discharge tube 29 emits light. After that, if the switches 47 and 53 are opened, the initial state is restored.

When this operation is repeated many times, the voltage of the power supply battery 1 gradually decreases. When the voltage of the power supply battery 1 decreases and the charging time is shortened by switching between the boosting means, the voltage of the main capacitor 4 at the switching point decreases, so that the power supply voltage detecting means 6 detects the voltage. The reference voltage for switching the boosting means is lowered.

In such a case where the boosting means is switched and charged in one charge, the charging time can be shortened by changing the time when the boosting means is switched depending on the power supply voltage. Further, even if the output state of the comparator 36 is switched from Lo to Hi, the NAND circuit 43 and the NAND circuit 44 do not switch simultaneously at the same time.
Since the NAND circuit 44 is delayed by the circuit delay of the ot circuit 42, the two boosting means are not turned on at the same time,
No malfunction occurs.

In the first embodiment, two boosting means are used for description, but charging is performed by switching two or more boosting means to change the switching point of the boosting means depending on the voltage value of the power source. There is no change even if it is performed, and there is no problem even if the transformer 16 is provided for each booster.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In the second embodiment, a fully automatic camera, that is, a camera that automatically performs photometry, distance measurement, exposure, film winding, etc., has a built-in charge control device for the flash light emitting device of the present invention. As shown in FIG. 3, the sequence controller for operating the camera is composed of the CPU 60, and the photometry and distance measurement operations are operated by the photometry and distance measurement drive circuit 61 controlled by the CPU 60. The taking lens is a lens driving motor M1.
The shutter is driven automatically by the shutter driving motor M2 and the film is driven by the winding motor M3. The motors M1 to M3 are driven by the motor control circuit 62.
It is controlled by. Further, the CPU 60
The first switch releases the release switch 63 by the first release to issue a photometry and distance measurement command, and the second release by pressing the second switch performs the light emission determination, exposure, and rewinding recharging.

First boosting means 2, second boosting means 3, main capacitor 4, main capacitor voltage detecting means 5,
Since the description of the discharge arc tube 29 and the trigger circuit 70 is exactly the same as that of the first embodiment, the description thereof is omitted here.
Further, the power supply voltage value is input from the power supply battery 1 to the CPU 60, and the main capacitor voltage value is input to the CPU 60 from the main capacitor voltage detection means 5, respectively, and the first boosting means 2,
The CPU 60 outputs an output signal to the second booster 3 and the trigger circuit 70.

The operation of the charge control device for the flash light emitting device according to the second embodiment of the present invention thus constructed will be described with reference to the flow chart of FIG.

When the release switch 63 of the camera is pushed down one step in step S1 and the 1st release is turned on, photometry is performed in step S2 and distance measurement is performed in step S3, and the CPU 60 stores the data. Here, when the 1st release is performed again, the stored data is refreshed to a new value.

Thereafter, when the second release is pressed in step S4, it is determined in step S5 whether or not the light emission is permitted.
If flash light emission is unnecessary, the process proceeds to step S6, the shutter is opened, and the process returns to step S9. If flash light emission is required, the process proceeds to step S7, the shutter is opened, a light emission signal is output to the trigger circuit 70 in step S9, and flash light emission is performed.
The shutter is closed in step S9 to end the exposure, the film is wound up one frame in step S10, and the film is charged in step S11 to return to the initial state.

FIG. 5 shows the charging subroutine in detail.

In the charging subroutine, the main capacitor voltage VMC is measured in step S20, and when the flash light emitter is not emitting light, the main capacitor voltage VMC remains fully charged, so that it is not necessary to perform charging and the return is returned as it is. And check the need for charging. In addition,
This check of the charging voltage shortens the check time of the charging voltage by using the boosting means capable of charging the main capacitor 4 to the full charge.

In step S21, the voltage value of the power supply battery 1 is measured, and in step S22, the main capacitor voltage value for switching the boosting means is set based on the voltage value measured in step S21. In this step S22, the data of the main capacitor voltage value for switching the boosting means in the voltage value of the battery is input as shown in FIG. 6, and the main capacitor voltage value for switching the boosting means is set according to this graph. . In step S23, when the main capacitor voltage VMC is lower than the voltage set in step S22, the first boosting means is started in step S24, and when the main capacitor voltage VMC is high from the beginning or the set value by charging in step S24. When it becomes higher, the process proceeds to step S25, the first booster is stopped, and step S25 is performed.
The second boosting means is started at 26, and when the main capacitor voltage VMC becomes the full voltage at step S27, the routine proceeds to step S28, the second boosting means is stopped, and the charging subroutine is ended.

In such a case where the boosting means is switched and charged by one-time charging, if the boosting means or the switching point is changed depending on the condition of the power supply voltage, when the power supply voltage is high as shown in FIG. Charging is switched at the main capacitor voltage value point as shown in FIG. 7 (a), and when the power supply voltage value is low, the boosting means is switched at the main capacitor voltage value point as shown in FIG. 7 (b). As a result, the charging time corresponding to the time in the shaded area in FIG. 7B can be shortened, and a photo can be taken without missing a photo opportunity.

In the flow chart of the second embodiment, the charging subroutine is performed after the winding step, but there is no problem even in other places.

Next, a third embodiment of the present invention will be described with reference to FIGS.

While the second embodiment has only one data for switching the boosting means, the third embodiment has a structure having two data for switching the boosting means. It's different.

The third embodiment configured as described above will be described with reference to the flow chart of FIG. 8. In the charging subroutine, first, in step S30, the main capacitor voltage VMC is measured, and the flash light emitter does not emit light. Since the main capacitor voltage VMC is still fully charged, it is not necessary to charge it, and return is performed to check the necessity of charging. In step S31, the voltage value of the power supply battery 1 is measured. If the voltage value is larger than the set value, the process proceeds to step S32 to set the charging time-oriented switching voltage, and if it is smaller than the set value, the process proceeds to step S33 to set the efficiency perspective switching voltage.

As shown in FIG. 9, even if the boosting means is switched at the point where the charging time becomes the fastest, the charging is not efficient. Therefore, the charging time is reduced when the power supply voltage is low (when the battery capacity is low). This is because the battery will run out quickly if the battery is charged with priority.

In step S34, if the main capacitor voltage VMC is lower than the voltage set in step S32 or step S33, the first boosting means is activated in step S35. When the main capacitor voltage VMC is high from the beginning or when it is higher than the set value due to the charging in step S35, the process proceeds to step S36, the first boosting device is stopped, and then the second boosting device is operated in step S37. to start. Then, when the main capacitor voltage VMC is fully charged in step S38, step S3
In step 9, the second boosting means is stopped and the charging subroutine is completed.

As described above, by having a plurality of data for switching the boosting means according to the power supply voltage, charging is performed by automatically selecting whether to prioritize charging time or efficiency. It is possible to provide a charge control device for a flash light emitting device that achieves both improved charging efficiency performance.

In the third embodiment, the charging time priority and the efficiency priority are automatically selected, but there is no change even if the manual selection is performed, and the ambient temperature and the like also select the charging time and efficiency. It is the same as the standard.

Next, a charge control device for a flash light emitting device according to a fourth embodiment of the present invention will be described.

FIG. 10 is a block diagram showing a schematic structure of a charge control device for a flash light emitting device of the fourth embodiment, and FIG. 11 is an electric circuit diagram showing a detailed structure of the fourth embodiment. Is. In the drawings, the constituent elements denoted by the same reference numerals as those in the first embodiment are the same as those in the first embodiment, and detailed description thereof will be omitted here.

In the fourth embodiment, as shown in FIG.
First boosting means 2A for boosting the power supply voltage of the power supply battery 1 to charge the main capacitor 4 for storing the light emission energy.
A second boosting means 3A having a boosted voltage higher than that of the first boosting means 2A, and a main capacitor voltage detecting means 5 for measuring the charging voltage of the main capacitor 4.
When the main capacitor 4 is charged, first, the first boosting means 2A is charged, and when the main capacitor voltage detecting means 5 reaches a predetermined switching voltage, the second boosting means 3A is charged. The switching means 6A for switching to and the changing means 7A for changing the switching voltage of the switching means 6A constitute a main part.

Next, the charge control device for the flash light emitting device according to the fourth embodiment will be described in more detail with reference to FIG.

Like the first embodiment, the fourth embodiment is a fully automatic camera, that is, a camera that automatically performs photometry, distance measurement, exposure, film winding, and the like. FIG. 1 shows a built-in charging control device.
As shown in FIG. 1, the sequence controller for operating the camera is composed of the CPU 60, and the photometry and distance measurement drive circuit 61 controlled by the CPU 60 for the photometry and distance measurement operations.
Is designed to work with. The taking lens is automatically driven by the lens driving motor M1, the shutter is by the shutter driving motor M2, and the film is by the winding motor M3. The motors M1 to M3 are controlled by the motor control circuit 62. It is supposed to be done.
Further, the CPU 60 issues a photometry and distance measurement command by the 1st release (63a) in which the release switch 63 is pushed down by one step, and performs light emission determination, exposure, and rewinding recharge by the 2nd release (63b) by pushing down in 2 steps. Has become.

The first boosting means is a transistor 12, a transistor 13 and a resistor 14 which are connected in parallel to the power supply battery 1.
Of the primary winding 16a-16b of the transformer 16 connected in parallel to the power supply battery 1, the primary side terminal 16b of the transformer 16 connected in series, the transistor 13 and the transistor 17 are connected in series. A series circuit of a resistor 15 to be connected, a diode 24, a secondary winding of the transformer 16 and a resistor 18 is connected as shown in the figure.

In the first booster having the above-described structure, when an ON signal (setting the base to L level) is input to the base of the transistor 12 from the CPU 60, the emitter-collector of the transistor 12 → the transistor 13 is turned on. Between the emitter and the base → a current flows through the resistor 18,
Between the emitter and collector of the transistor 13 → resistor 15 →
A current flows between the base and the emitter of the transistor 17 so that the primary windings 16a and 16b of the transformer 16 are →
A current flows between the collector and the emitter of the transistor 17, and a high voltage is induced in the secondary winding due to the interlinkage magnetic flux of the primary winding of the transformer 16 with respect to the secondary winding, whereby the charging current is changed from the diode 24 to the diode 25. Through the main condenser 4.

This charging current increases the base current of the transistor 17, and accordingly the transistor 1
7 collector current increased, and main capacitor 4
This leads to an increase in the charging current to the trigger capacitor 31, and this positive feedback action puts the transistor 17 in a saturated state. Then, the change in current on the primary side of the transformer 16 disappears, and therefore the change in magnetic flux on the secondary side also disappears. Therefore, energy is generated on the secondary side of the transformer 16 in the direction for reversely biasing the diode 24, and reverse biasing the transistor 13 stops the collector current of the transistor 13 and turns off the transistor 17.

At this time, vibration occurs in the secondary side winding, and when the half-wave of the transistor 13 is positively biased, the transistor 13 is turned on again to return to the initial state and start the next cycle operation. Such an oscillating operation is performed to charge the main capacitor 4. The first boosting means cannot charge the voltage of the main capacitor 4 to a voltage at which the arc tube 29 can emit light, but when the capacitor voltage is low. It has the characteristic of short charging time and good energy conversion efficiency.

The second boosting means is a transistor 19, a transistor 20, and a resistor 21 connected in parallel to the power supply battery 1.
Series circuit, between the primary windings 16a-16c of the transformer 16 connected in parallel to the power supply battery 1, the transformer 16
The series circuit of the transistor 23 connected to the primary winding terminal 16c of the above, the resistor 22 and the diode 24 connecting the transistor 20 and the transistor 23, the secondary winding of the transformer 16, and the series circuit of the resistor 18 are connected as shown in the figure. It is configured. The transformer 16, the resistor 18, and the diode 24 are shared by the first boosting means and the second boosting means. As for the transformer 16, the first boosting means is the primary winding terminal 16
b, and the second booster is connected to the primary winding terminal 16c.

Since the operation of the second boosting means is the same as that of the first boosting means, a detailed description thereof will be omitted here, but the second boosting means is the main capacitor 4
Can be charged up to the voltage at which the arc tube 29 can emit light, but the charging time when the capacitor voltage is low is
It has a characteristic that it is longer than the charging time of the first boosting means and inefficient.

The main capacitor voltage detecting means is connected in parallel to the main capacitor 4 with the diode 25, the resistor 27,
The resistor 28 is connected as shown in the drawing, and is connected to the first boosting means and the second boosting means.
By passing a part of the charging current of the boosting means of the resistor 27 and the resistor 28, the voltage generated across the resistor 28
Input to the C3 terminal of 60. The C3 terminal of the CPU 60 is an A / D conversion input terminal, and the voltage charged in the main capacitor 4 can be detected by A / D changing the voltage input to this terminal. Has become.

In the figure, reference numeral 29 is a discharge arc tube, and reference numeral 70 is a trigger circuit for causing the arc tube 29 to emit light. The trigger circuit 70 operates by the light emission start signal output from the C5 terminal of the CPU 60, and
Is designed to emit light. Reference numeral 71 is an IGBT (Insulated Gate Bipolar Transistor) for turning on / off the current flowing through the arc tube 29, and reference numeral 7
Reference numeral 2 is a buffer amplifier for driving the IGBT 71. Further, reference numeral 75 is a DC for supplying a constant voltage Vcc to the circuit system when the power supply battery 1 changes.
/ DC converter.

In the vicinity of the power supply battery 1, the power supply battery 1
The temperature detection circuit is provided. This temperature detection circuit is composed of a resistor 73 and a thermistor 74,
The thermistor 74 is arranged directly or in the immediate vicinity of the power supply battery 1 so as to accurately detect the temperature of the power supply battery 1 itself. The resistor 73 and the thermistor 74 are connected to the voltage Vcc from the DC / DC converter 75.
Is divided, and the division ratio varies depending on the temperature of the thermistor 74. Therefore, the midpoint voltage between the resistor 73 and the thermistor 74 changes due to the temperature change of the power supply battery 1.

The midpoint potential is input to the C6 input terminal of the CPU 60. The C6 input terminal of the CPU 60 is A
It becomes the / D conversion input terminal, which allows the CPU60
Converts the voltage at the input terminal into A / D, and
It is designed to detect the temperature of.

The operation of the charge control device for the flash light emitting device according to the fourth embodiment thus constructed will be described with reference to the flowchart of FIG.

When the release switch 63 of the camera is pushed down by one step in step S1 and the 1st release is turned on, photometry is performed in step S2 and distance measurement is performed in step S3, and the CPU 60 stores the data.

After that, when the second release is pressed in step S4, it is determined in step S5 whether or not the light emission is permitted.
If flash light emission is unnecessary, the process proceeds to step S6, the shutter is opened, and the process returns to step S9. If flash light emission is required, the process proceeds to step S7, the shutter is opened, a light emission signal is output to the trigger circuit 70 in step S9, and flash light emission is performed.
The shutter is closed in step S9 to end the exposure, the film is wound up one frame in step S10, and the film is charged in step S11 to return to the initial state.

If the 2nd release is not ON in step S4 and the 1st release is in the ON state in step S12, the process returns to step S4 and step S1.
If the 1st release is OFF in step 2, the process returns to step S1.

Next, details of the light emission sequence in step S8 will be described.

Although not shown, the amount of strobe light emission is first calculated. The amount of strobe light emission is calculated based on the subject distance obtained in the distance measurement subroutine of step S3 and the film sensitivity. Light emission is performed according to the light emission amount according to the timing chart of FIG. First, at time t0, the CPU 60 sets the C5 output terminal to "H" level,
An “H” level voltage is applied to the gate of the IGBT 71. As a result, the IGBT 71 is turned on. Next, at time t1, the CPU 60 sets the C4 output terminal to the "H" level to activate the trigger circuit 70. As a result, the arc tube 29 enters an excited state and starts emitting light. Next, at time t2, the CPU 60 sets the C5 output terminal to the "L" level to turn off the IGBT 71. Thus, the light emission ends.

In FIG. 13, the bottom row shows the light emission current waveform. Further, the period from t1 to t2 is the light emission period, which is determined by the calculated light emission amount. When the distance to the subject is long and the light is to be emitted fully, the ON signal of the IGBT is turned off at time t3. As a result, the emission current waveform becomes as shown by the broken line, and the full emission state is achieved.

Details of the charging subroutine of step S11 will be described below.

First, in step S120, the CPU 6
0 detects the temperature of the power supply battery 1 by A / D converting the voltage of the C6 input terminal. Next in step S12
According to the battery temperature detected at 0, step S12
At 1, the switching voltage is set. Next, step S122.
At 60, the CPU 60 sets the C1 output terminal to the “L” level to activate the first boosting means. Next in step S123
At this time, the CPU 60 sets the voltage of the C3 input terminal to A / D.
After conversion, the charging voltage is monitored. If the charging voltage is equal to or higher than the switching voltage, the process proceeds to the next step S124, and if the charging voltage is lower than the switching voltage, step S123 is repeated.

At step S124, the first boosting means is stopped, and then at step S125, the second boosting means is stopped.
The boosting means of is started. Then, in step S126, the charging voltage is monitored. If the charging voltage is equal to or higher than the stop voltage, the second step-up means is stopped in next step S127, and if the charging voltage is lower than the stop voltage, step S126 is repeated.

FIG. 15 is a diagram showing an example of the switching voltage which changes with the temperature change of the power supply battery in the charge control device of the flash light emitting device of the fourth embodiment.

In this embodiment, the switching voltage is 150V to 280V depending on the temperature of the power supply battery 1 as shown in FIG.
The optimum voltage value is set within the range.

By the way, in the present embodiment, as described above, the temperature detecting circuit including the resistor 73 and the thermistor 74 is arranged near the power supply battery 1. This is based on the following reasons.

Assuming that the power supply battery and the temperature detection circuit are provided separately from each other, the thermistor 74 will detect the ambient temperature around the power supply battery, and the true temperature of the power supply battery itself will be instantaneously detected. Difficult to detect. For example, when flash photography or the like is repeatedly performed, the power supply battery supplies a large current to the circuit, which causes heat generation. In such a case, even if the temperature around the power supply battery is relatively low, the power supply battery rapidly rises, but the ambient temperature around the power supply battery does not follow this, and therefore the temperature of the power supply battery is accurately detected. Can not do it.

As described above, when the temperature of the power supply battery rises, it is advantageous in view of energy conversion efficiency to increase the switching voltage, but the power supply battery and the temperature detection circuit are arranged separately. As described above, the temperature cannot be accurately detected. In the present embodiment, since the temperature detection circuit is arranged in the immediate vicinity of the power supply battery, the temperature of the power supply battery can be accurately detected and an appropriate switching voltage can be set.

Next, a charge control device for a flash light emitting device according to a fifth embodiment of the present invention will be described.

The fifth embodiment basically has the same structure as the fourth embodiment, but does not include the temperature detecting circuit including the resistor 73 and the thermistor 74. The other structure is the same as that of the fourth embodiment, and the description thereof is omitted here.

The operation of the fifth embodiment will be described below.

The operation of the charge control device for the flash light emitting device of the fifth embodiment is the same as the operation of the fourth embodiment except that the charging sequence is different. Only explain.

FIG. 16 is a flow chart showing the operation at the time of charging of the charge control device of the flash light emitting device of the fifth embodiment.

First, in step S130, the first booster is activated. Next, in step S131, the charging voltage is monitored. If the charging voltage is 180 V or less, the process proceeds to step S132. The amount of light emitted by flashing varies depending on the distance to the subject. When the distance to the subject is short, the amount of light emission is small, and the residual voltage after light emission of the main capacitor is 180V.
It is possible that there is more than one. When the charging voltage is 180 V or more in step S131, step S131
Proceed to 138. Further, the charging voltage is monitored in step S132, and when the charging voltage becomes 180 V or higher, the process proceeds to step S133.

In step S133, the timer is reset and started, and in step S134, when the charging voltage becomes 200 V or more, the timer is stopped in step S135, and then step S136.
At, the switching voltage is set based on the count value of the timer.

In the CPU 60, on the ROM,
The relationship between the switching voltage and the count value of the timer is stored as a table. The switching voltage is set by referring to this table.

Next, when the charging voltage becomes equal to or higher than the switching voltage in step S137, the first boosting means is stopped in step S138, and the second boosting means is activated in step S139. And step S14
If the charging pressure becomes equal to or higher than the stop voltage at 0, the second boosting means is stopped at step S141.

In this embodiment, the time until the charging voltage of the main capacitor rises from the first voltage to the second voltage is measured, and the switching voltage is determined according to this time.

Therefore, according to the fifth embodiment, it is possible to obtain the same effect as that of the fourth embodiment without providing the temperature detecting circuit.

Next, a charge control device for a flash light emitting device according to a sixth embodiment of the present invention will be described.

Like the fifth embodiment, the sixth embodiment basically has the same structure as the fourth embodiment,
It does not include a temperature detection circuit including the resistor 73 and the thermistor 74. The other structure is the same as that of the fourth embodiment, and the description thereof is omitted here.

The operation of the sixth embodiment will be described below.

The operation of the charge control device for the flash light emitting device of the sixth embodiment is the same as the operation of the fourth embodiment except that the sequence at the time of charging is different. Only explain. FIG. 17 is a flowchart showing the charging operation of the charge control device for the flash light emitting device according to the sixth embodiment.

First, in step S150, the first booster is activated. Next, in step S151, the charging voltage is monitored. If it is higher than 180V, step S151
If it is 180 V or less, the process proceeds to step S152. In step S152, the charging voltage is 180
If it is equal to or higher than V, the timer is next reset / started in step S153, and in step S154,
If the timer times out after a certain period of time, the charging voltage is read in step S155,
In step S155, the switching voltage is set.

The ROM in the CPU 60 stores, as a table, the correspondence relationship between the charging voltage value and the switching voltage at this time. By referring to this table, the switching voltage can be set. There is.

Note that steps S157 to S16.
1 is step S137 to step S of the fifth embodiment.
Since it is the same as 141, the description here is omitted.

In the sixth embodiment, the charging voltage of the main capacitor is charged for a fixed time from the time when the charging voltage reaches the first voltage, and the switching voltage is determined according to the voltage increase charged during that time. .

According to the sixth embodiment as well, similar to the fifth embodiment, the same effect as the fourth embodiment can be obtained without the temperature detecting circuit.

Next, a charge control device for a flash light emitting device according to a seventh embodiment of the present invention will be described.

FIG. 18 is an electric circuit diagram showing the configuration of the charge control device of the flash light emitting device of the seventh embodiment.

The seventh embodiment basically has the same structure as the fourth embodiment, but does not include the temperature detecting circuit in the fourth embodiment, but instead, for battery checking. The difference is that the dummy load circuit is provided. Since the other structure is the same as that of the fourth embodiment, the description thereof is omitted here.

The dummy load circuit is composed of a switching circuit composed of a transistor 81 connecting the dummy load resistor 82 to the power supply line. The resistor 83
Is the base resistance of the transistor 81, and the other end is CP
It is connected to the C7 input / output terminal of U60. The power supply battery 1 is connected to the C8 input terminal of the CPU 60.

Next, the operation of the seventh embodiment will be described.

FIG. 19 is a flow chart showing the basic sequence of the charge control device of the flash light emitting device of the seventh embodiment.

The operation of the seventh embodiment is basically the same as the operation of the fourth embodiment, except that the flowchart shown in FIG. 19 and the flowchart showing the operation of the fourth embodiment (see FIG. 12). ) And, as you can see from the comparison,
The only difference is that a battery check operation (step S13) is inserted between step S4 and step S5 in the flowchart of FIG.

In the battery check operation in step S13, first, the C7 output terminal of the CPU 60 is set to "L".
Level, the dummy load circuit is turned on, and the voltage applied to the C8 input terminal after a certain time has passed,
That is, the voltage of the power supply battery 1 is detected by A / D converting the voltage of the power supply battery 1. At this time, if it is determined that the battery state is good according to the detected voltage, the subsequent sequence is continued, and if the battery state is bad, the sequence is stopped. In the charging sequence, the battery detected in step S13
The switching voltage is set according to the check voltage. The operation thereafter is from step S122 to step S in FIG.
Since it is the same as 127, the description is omitted here.

Also in the seventh embodiment, the same effect as that of the fourth embodiment can be obtained.

That is, depending on the state of the power supply battery, the first
Since the switching voltage of the boosting means and the second boosting means is changed,
It can be charged with high energy conversion efficiency without increasing the charging time at any time regardless of the state of the power battery.

[0122]

As described above, according to the present invention, there is an effect that it is possible to provide a charge control device for a flash light emitting device which can shorten the charging time without depending on the power supply voltage.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a charge control device for a flash light emitting device that is a first embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing a configuration of a charge control device of the flash light emitting device according to the first embodiment.

FIG. 3 is an electric circuit diagram showing the configuration of a charge control device for a flash light emitting device that is a second embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the charge control device for the flash light emitting device according to the second embodiment.

FIG. 5 is a flowchart showing in detail a charging subroutine in the second embodiment.

FIG. 6 is a diagram showing switching points of the boosting means in the second embodiment.

FIG. 7 is a first boosting means and a second boosting means in the second embodiment.
It is a diagram showing a switching point with the boosting means of.

FIG. 8 is a flowchart showing the operation of the charge control device for the flash light emitting device according to the third embodiment of the present invention.

FIG. 9 is a diagram showing switching points of the boosting means in the third embodiment.

FIG. 10 is a block diagram showing a schematic configuration of a charge control device for a flash light emitting device according to a fourth embodiment of the present invention.

FIG. 11 is an electric circuit diagram showing a detailed configuration of a charge control device of the flash light emitting device according to the fourth embodiment.

FIG. 12 is a flowchart showing the operation of the charge control device of the flash light emitting device according to the fourth embodiment.

FIG. 13 is a timing chart showing a light emission sequence in the charge control device of the flash light emitting device according to the fourth embodiment.

FIG. 14 is a flowchart showing a subroutine of a charging operation in the charging control device of the flash light emitting device according to the fourth embodiment.

FIG. 15 is a diagram showing an example of a switching voltage that changes with a temperature change of a power supply battery in a charge control device for a flash light emitting device according to a fourth embodiment.

FIG. 16 is a flowchart showing a subroutine of a charging operation in the charging control device for the flash light emitting device in the fifth embodiment of the present invention.

FIG. 17 is a flowchart showing a subroutine of a charging operation in the charging control device of the flash light emitting device according to the sixth embodiment of the present invention.

FIG. 18 is an electric circuit diagram showing the configuration of a charge control device for a flash light emitting device according to a seventh embodiment of the present invention.

FIG. 19 is a flowchart showing the operation of the charge control device of the flash light emitting device according to the seventh embodiment of the present invention.

FIG. 20 is an electric circuit diagram showing a basic configuration of a conventional general booster circuit.

FIG. 21 is a diagram showing an elapsed time characteristic of the charging voltage VMC for the main capacitor shown in FIG. 20.

22 is a diagram showing charge characteristics in the electric circuit shown in FIG. 20 when the capacity of the power supply battery is lowered under conditions such as low temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Power supply battery 2,2A ... First boosting means 3,3A ... Second boosting means 4 ... Main capacitor 5 ... Main capacitor voltage detecting means 6 ... Power supply voltage detecting means 7,6A ... Switching means 8 ... Selecting means 7A … Change means

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[Procedure amendment]

[Submission date] August 6, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

FIG. 20 is an electric circuit diagram showing the basic structure of a general booster circuit. In the figure, reference numeral 100 is a power supply battery, and the power supply voltage of the power supply battery 100 is the step-up transformer 1.
The voltage is boosted by 03, and the main capacitor 105 is charged. Reference numerals 101 and 102 are switching transistors of the step-up transformer 103 , and reference numeral 104 is a rectifying diode. The main capacitor 105 is a capacitor for storing light emission energy.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

∫ I2 dt = C VMC (1) Here, the integration period on the left side of the above equation (1) is the period from the start of charging until the charging to the specified charging voltage VMC. Is.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

Further, when the winding ratio (the number of secondary winding turns / the number of primary winding turns) of the step-up transformer 103 is n and the current value flowing into the primary winding of the step-up transformer 103 is I1, I1 = nI2. Since (2), from the above equations (1) and (2), ∫I1 dt = nC VMC (3) where the current value flowing from the power supply battery 100 is I0, When the DC current amplification factor is β, I0 = (1 + 1 / β) × I1 + I2 = (1 + 1 / β + 1 / n) × I1 (4)

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

From the above equations (3) and (4), ∫I0 dt = n (1 + 1 / β) C VMC + C VMC (5)

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

Therefore, the time-integrated value of the current value flowing out from the power supply battery 100, that is, the consumed current is substantially proportional to the winding ratio n of the step-up transformer 103. Here, in order to reduce the current consumption and improve the life of the power supply battery 100, it is better to make the winding ratio n of the step-up transformer 103 as small as possible. However, if the winding ratio n is reduced,
Charging time becomes longer.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0079

[Correction method] Change

[Correction content]

After that, when the second release is pressed in step S4, it is determined in step S5 whether or not the light emission is permitted.
If flash light emission is unnecessary, the process proceeds to step S6, the shutter is opened, and the process returns to step S9. If flash light emission is necessary, the process proceeds to step S7, the shutter is opened, and a light emission signal is output to the trigger circuit 70 in step S8 to perform flash light emission.
The shutter is closed in step S9 to end the exposure, the film is wound up one frame in step S10, and the film is charged in step S11 to return to the initial state.

Claims (7)

[Claims] 1. A first boosting means for boosting a power supply voltage to charge a main capacitor for storing light emission energy, and a second boosting means having a boosted voltage higher than that of the first boosting means. When the charging of the main capacitor is started, the charging operation by the first boosting means is executed, and when the charging voltage of the main capacitor reaches a predetermined value, the charging operation by the second boosting means is executed. A charging control device for a flash light-emitting device, comprising: switching means for switching as described above; and changing means for changing the charging voltage value to the main capacitor, the switching means performing the switching. 2. The charge control device for a flash light emitting device according to claim 1, wherein the changing means changes a switching voltage of the switching means according to a state of a power source. 3. A temperature detecting means for detecting the temperature of the power supply battery, wherein the changing means changes the switching voltage of the switching means on the basis of information from the temperature detecting means. Item 1. A charge control device for a flash light emitting device according to item 1. 4. A charging speed detecting means for detecting a charging speed of the main capacitor, wherein the changing means changes the switching voltage of the switching means based on the information from the charging speed detecting means. The charge control device for a flash light emitting device according to claim 1, which is characterized in that. 5. The charging speed detecting means is characterized in that the charging voltage is changed from the first voltage to the second voltage during charging of the main capacitor.
The charging control device for a flash light emitting device according to claim 4, wherein the charging speed is detected by measuring the time until the voltage changes to the above voltage. 6. The charging speed detecting means measures a predetermined time after the charging voltage reaches a predetermined voltage during charging of the main capacitor, and measures the charging voltage after the predetermined time elapses. The charging control device for a flash light emitting device according to claim 4, wherein the charging speed is detected by detecting the charging speed. 7. A load circuit for causing a predetermined load current to flow from the power supply, and a power supply voltage measuring means for measuring the power supply voltage while the load circuit is operating, The charge control device for a flash light emitting device according to claim 2, wherein the state of the power supply is detected based on the measured power supply voltage.