JPH088089A - Electronic flash - Google Patents

Abstract

PURPOSE:To enable a charging circuit to be protected without the use of an ambient temperature detection means by detecting a charging voltage after a period of time set by a timer means, and stopping boosting action according to the detected result and the detected source voltage, and issuing an alarm. CONSTITUTION:Light energy is supplied to a flash discharge tube 14 from a main capacitor 6 which is charged by a booster means 3. A timer means that is started after the start of charging action to measure a set time is built into a one-chip microcomputer 17. After the period of time set by the timer means has elapsed, the voltage of the capacitor 6 is detected by a charging voltage detection means 5. Also, source voltage is detected by a source battery voltage detection means built into the microcomputer 17, and when the source voltage is at a set level or higher and the charging voltage is at the set level or lower, for example, the boosting action is stopped and an alarm is issued. Therefore, a charging circuit can be protected without the use of an ambient temperature detection means with a large circuit scale.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic flash device provided in a camera, and more particularly to control of abnormal operation stop of its oscillation booster circuit.

[0002]

2. Description of the Related Art Conventionally, in a camera having an electronic flash device, there is a booster circuit for boosting a power supply voltage and charging a main capacitor with a sufficiently high voltage for emitting light.

When a constituent element (eg, an oscillating transistor or a transformer) of this booster circuit malfunctions due to a defect or the like and causes abnormal heat generation, the ambient temperature detecting means detects the temperature, and when the temperature reaches a certain level, the boosting oscillation is stopped. Was controlled by.

Further, when the boosted voltage does not come for a certain time or longer, the charging is forcibly stopped.

[0005]

However, the use of the ambient temperature detecting means has a drawback that the circuit scale of the temperature sensor and the like becomes large.

If the method of forcibly stopping charging when the boosted voltage does not come for a certain period of time or more, heat generation may increase during measurement for a certain period of time, and the boosting oscillation operation cannot be stopped immediately after abnormal heat generation. There was a drawback.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electronic flash device capable of protecting a charging circuit without using an ambient temperature detecting means.

[0008]

In order to achieve the above object, according to claim 1 of the present invention, a flash discharge tube, a main capacitor for supplying emission energy to the flash discharge tube, and a boosting operation are performed to perform the boosting operation. A boosting means for charging the main capacitor; a charging voltage detecting means for detecting the main capacitor charging voltage; a power supply battery voltage detecting means; and a timer means for starting a charging time and counting a set time, After measuring the time set by the timer means, the charging voltage detecting means detects the charging voltage of the main capacitor, and then the power source battery voltage detecting means detects the power source voltage, and the boosting operation is performed by the charging voltage result and the power source voltage result. And the charging voltage detecting means is equipped with an A / D converter. When the power supply voltage detected by the power supply battery voltage detection means is equal to or higher than a set level and the charge voltage detected by the charge voltage detection means is equal to or lower than the set level, the boosting means is prohibited and a warning is issued. A flash discharge tube, a main capacitor that supplies emission energy to the flash discharge tube, a boosting unit that performs a boosting operation to charge the main capacitor, and a charging voltage detection unit that detects the main capacitor charging voltage, It has a power supply battery voltage detection means and a timer means which starts after the charging time starts and measures the set time. The first voltage detected by the charging voltage detection means at the start of the charging time and the timer means set. The second voltage detected by the charging voltage detection means after the time is counted, and then the power supply voltage is detected by the power supply battery voltage detection means, and the charging voltage is detected. The step-up operation is stopped and a warning is given according to the result of the difference between the second voltage and the first voltage and the result of the power supply voltage. In claim 5, the difference between the second voltage and the first voltage is the set voltage. When the power source voltage is smaller and the power source voltage detected by the power source battery voltage detecting means is equal to or higher than the set voltage, the stop and the warning are given.

[0009]

According to the first to fifth aspects of the present invention, the timer that starts at the start of the boosting operation is used to store the charging voltage after the set time, and then the battery is checked to check the charging level when there is sufficient battery. When is low, the charge boosting operation is stopped. And warn about this. further,
According to the fourth and fifth aspects, since the charging voltage of the capacitor before and after the timer is timed is compared and the compared voltage is compared with the power supply voltage, the charging operation can be performed finely.

Due to the above, the boosting oscillation operation can be stopped immediately after abnormal heat generation without using the ambient temperature detecting means.

[0011]

1 is a circuit block diagram showing an embodiment of the present invention.

Reference numeral 1 is a battery as a power source, and 2 is a battery 1.
Is a switch which is connected to the switch for controlling power supply to the load, 3 is a booster circuit for boosting the voltage of the battery 1, 31 is a PN
P-transistor with emitter via switch 2 to battery 1
Is an NPN transistor connected to the base of the PNP transistor 31, and 32 is a resistor for controlling the start of oscillation. 33 is a resistor connected between the base and emitter of the NPN transistor 32. 34 is a diode, the cathode is connected to the emitter of the NPN transistor 32, and the anode is grounded (earth)
Have been. Reference numeral 35 denotes a diode, the cathode of which is connected to the base of the NPN transistor 32 and the anode of which is connected to the one-chip microcomputer 17 described later. Reference numeral 36 is a transformer for boosting the oscillation, and the primary winding 36a is connected to the collector of the PNP transistor 31, and the feedback winding 36b is NP.
The emitter of the N-transistor 32 is connected to the resistor 37 described later, and the cathode of the diode 4 described later is connected to the secondary winding 36c. 37 is a resistor and one end is an oscillation transformer 36
Is connected to the feedback winding 36b, and the other end is grounded. 38 is a capacitor connected to both ends of the resistor 37, 3
Reference numeral 9 is a capacitor connected to the secondary winding 36c of the oscillation transformer 36, and the booster circuit 3 is composed of 31 to 39.

Reference numeral 4 denotes a high-voltage rectifying diode, the anode of which is connected to the secondary winding 36c of the oscillation transformer 36 and the cathode of which is connected to a voltage detection circuit 5 described later. A voltage detection circuit 5 detects the voltage of the main capacitor and sends a charging voltage (divided voltage proportional to the actual voltage) signal to the one-chip microcomputer 17. Reference numeral 51 is a capacitor, 52 and 53 are resistors for dividing the charging voltage of the main capacitor 6, the resistor 52 is connected to the cathode of the diode 4 and the capacitor 51, and one end of the resistor 53 is grounded to the resistor 52 and the other end is grounded. . The signal obtained by dividing the voltage of the main capacitor 6 is input to the one-chip microcomputer 17 (A / D converter in the microcomputer) as the SEN signal. 54 is connected to both ends of the resistor 53. The voltage detection circuit 5 includes 51 to 54. Reference numeral 29 denotes a diode, the voltage detection circuit 5 is connected to the anode, and the main capacitor 6 described later is connected to the cathode.

Reference numeral 6 is a main capacitor for charging energy required for flash light emission, 7 is a resistor connected to the positive electrode of the main capacitor 6, 8 is a trigger capacitor connected to the resistor 7, and 9 is for starting light emission. In the light emitting thyristor, one end of the resistor 7 and one end of the capacitor 8 are connected to the anode, and the cathode is grounded. Reference numeral 10 is a resistor and 11 is a capacitor, both of which are connected between the gate and cathode of the thyristor 9.

Reference numeral 12 is a resistor, one end of which is connected to the gate of the thyristor 9 and the other end of which is connected to the one-chip microcomputer 17.
TRG from the one-chip microcomputer 17 as a light emission start signal
One signal is output as a pulse, and the gate of the thyristor 9 is turned on to trigger. A trigger transformer 13 is connected to the other end of the trigger capacitor 8 on the primary winding. A flash discharge tube (trigger) is connected to the secondary winding. 14 is
In the flash discharge tube for light emission, the positive electrode of the main capacitor 6 and one end of the resistor 7 are connected to the anode, and the anode of the diode 28 described later is connected to the cathode. The voltage of the battery 1 is boosted by the booster circuit 3, the trigger capacitor 8 is charged through the resistor 7,
With the RG1 signal, the thyristor 9 is turned on, the trigger capacitor 8 is discharged, a pulse is generated in the primary winding of the trigger transformer 13, a high voltage pulse is generated in the secondary winding, and the flash discharge tube 1
Apply a light emission trigger to 4.

Reference numeral 26 is a capacitor, one end of which is connected to one end of the resistor 7 and the anode of the thyristor 9, and 27 is a resistor.
It is connected to the other end of the capacitor 26 and to the cathode of the flash discharge tube 14 at the other end. 28 is a diode whose anode is connected to the cathode of the flash discharge tube 14 and whose cathode is connected to the ground. 26-28 form a voltage doubler circuit.

Reference numeral 15 is a constant voltage circuit, which is a known circuit for outputting a constant voltage (Vcc) even if the voltage of the battery 1 changes.
6 is a switch control circuit for controlling the camera, 17
Is a one-chip microcomputer, CPU, RO
M, RAM (171), I / O control (I / O CONT
ROL) circuit (172), multiplexer (174),
This is a one-chip IC circuit with a built-in microcomputer including a timer circuit, which can control the camera system by software (hereinafter abbreviated as a microcomputer). When the constant voltage output Vcc is connected as a power supply and the switch 2 is turned on, the power supply battery 1 ( Vbat) is connected. Reference numeral 18 is a well-known automatic distance measuring (auto focus: AF) circuit, which automatically measures the distance to focus the subject and a lens (not shown).
A signal required for distance measurement (AFC signal) is sent from the microcomputer 17 in a circuit for driving the, and a signal required for distance measurement (AFD signal) is sent to the microcomputer 17. A known automatic exposure (AE) circuit 19 is a circuit for photometrically measuring the brightness of an object, and in order to determine an appropriate exposure (shutter speed, aperture), a signal (AFC signal) that determines a photometric operation is sent from the microcomputer 17. Data required for exposure (AED signal) is sent to the microcomputer 17
Send to.

Reference numeral 20 is a known display circuit, which is a circuit (LCD, LED, etc.) for displaying information relating to camera control (shutter speed, aperture, charging completion, film sensitivity, remote control mode, self timer, etc.), and 21 is ( A known shutter circuit (including a synchro switch) controls the shutter operation from the microcomputer 17. Reference numeral 22 denotes a known aperture control circuit, which controls the aperture of the lens from the microcomputer 17. Reference numeral 23 denotes a light emission stop circuit, which is composed of 231-234. That is,
231 is a thyristor, the anode of which is connected to the positive electrode of the main capacitor 6 and the cathode of which is grounded. A capacitor 232 is connected between the gate and cathode of the thyristor 231. A resistor 233 is connected between the gate and cathode of the thyristor 231. 234 is a resistor, which is a thyristor 23.
1 is connected between the gate and the microcomputer 17.

Reference numeral 24 is a known remote control reception circuit, 25 is a remote control transmission circuit block, 251 is a remote control transmission LED for outputting a remote control signal, 252 is a known remote control signal transmission circuit, 253 is a power supply battery for the remote control signal transmission circuit 252, 254 is a remote control release signal transmission switch,
A remote control mode selection switch 255 switches two types of transmission signals (for example, by changing the number of transmission pulses or changing the frequency) by turning on / off the switch 255. Each mode is a mode in which when the remote control release transmission signal switch 254 is turned on in the mode 1, the mode is released immediately.
Mode 2 is a mode in which when the remote control release transmission signal switch 254 is turned on, release is performed after a set time has elapsed (for example, after 2 seconds). The signal (visible light / infrared light) transmitted from the remote control transmission circuit block 25 is received by the remote control reception circuit 24, the signal is decoded, and the microcomputer 1
7 as T1 and T2 signals.

400 is a known film sensitivity detection circuit,
The film sensitivity is automatically detected by detecting the DX contact of the film, and the film sensitivity information (ISO) is sent to the microcomputer 17.
Signal). 600 is a known date imprinting circuit,
It is a circuit that imprints characters such as date and time on the film.

Next, the operation of the camera will be described with reference to the flow charts shown in FIGS. The following steps are abbreviated as “S”.

First, when the power switch 2 is turned on, the power supply battery 1 is connected to the booster circuit 3, and the constant voltage circuit 15 is activated. As a result, a constant voltage Vcc is generated in the constant voltage circuit 15, and these supply a constant voltage to the microcomputer 17 and each circuit block. When the power is input to the microcomputer 17, the internal CPU is reset.

The program operation of the microcomputer 17 will be described below. First, initial setting is performed. That is, the program flag is cleared and the memory contents are reset (FAL flag, RCHG flag, remSW flag 0, etc.) (S1).

Next, a switch circuit 16 is used to control the camera (shutter, aperture, flash mode switching, remote control, film sensitivity switching, zoom,
The release switch, etc.) is detected and a signal is transmitted to the microcomputer 17. Also, the film sensitivity is automatically read by the film sensitivity detection circuit 400 (for example, DX code).
(S2). The remote control switch detection operation will be described with reference to the flowchart of FIG.

As a result of detecting a remote control switch flag (described later), "1" (remSW =
If 1), proceed to S4, and if not, proceed to S3 (S
2a).

Next, a release switch (for example, the release switch is a double-press switch of half-press and full-press), and the half-press switch is set to S1. When this switch is turned on, a photographing preparation operation is performed and the main-press is pressed. Set the switch to S2, and switch S1 to perform the shooting operation when this switch is turned on.
It is determined whether or not is on (S3), and when it is off, the process returns to S2, and when it is on, the process proceeds to the next step.

Next, the voltage of the power supply battery 1 (battery voltage)
Is detected by the microcomputer 17. For example, the A / D converter in the microcomputer 17 converts the battery level from an analog value to a digital value and stores it (S4).

The microcomputer 17 determines the voltage of the detected battery voltage. If it is below an arbitrary level (for example, the minimum operating voltage of the camera), it is judged to be NG. If it is larger than the arbitrary voltage, it is judged to be OK. , Go to the next step (S5).

A signal (A) necessary for distance measurement is sent from the microcomputer 17 to the automatic distance measurement (auto focus: AF) circuit 18.
FC signal is sent, and automatic distance measurement (auto focus: A
F) A signal (AFD signal) required for distance measurement is sent from the circuit 18, distance measurement is automatically performed, and a lens (not shown) is driven to focus an object (distance measurement operation ... S6). Then, a signal (AFC signal) that determines the photometric operation is sent from the microcomputer 17 to the automatic exposure (AE) circuit 19, and the brightness of the subject is measured by the automatic exposure (AE) circuit 19, and the data necessary for the exposure (AED signal) To the microcomputer 17 to calculate and determine an appropriate exposure (shutter speed, aperture) (S7).

As a result of the photometry in S7, it is determined whether or not the subject brightness is below an arbitrary brightness (low brightness) (S8), and when it is below an arbitrary brightness, it is determined that a flash is necessary.
9, the flash flag FAL = 1 is set, and if not, the flash flag FAL = 0 is set, and S10a is set.
Go to. S9 is a flash charging sequence (flash mode), and this sequence will be described in detail with reference to FIGS.

Next, it is judged whether charging is completed (S1
0) When completed, the microcomputer 17 performs a latch operation for charging completion, displays charging completion on the display circuit 20, and proceeds to S11.
If not completed, the process returns to S2.

If it is determined in S8 that the subject brightness is not low, it is determined whether the remote control switch flag (described later) is "1" (remSW = 1) that the remote control is in use (SW).
10a), if remSW = 1, proceed to S10b, otherwise proceed to S11. Then, a remote control timer flag (described later) is "1" (remT =
1) or not (S10b). If remT = 1, the measurement remains at S10b until the measurement ends, and when the timer measurement ends, the remote control timer flag (remT) is set to 0, and S12
Go to.

Next, it is determined whether or not the switch S2, which is the full press of the release switch, is on (S11). If it is off, the process returns to S2, and if it is on, S12.
Go Then, the lens driving operation is performed. The lens is operated from the lens reset position, and the lens is moved by the lens movement amount based on the distance measurement data by the AF circuit 18 to bring the lens into focus (S12). Further, shutter aperture control and light emission control are performed (S13). This sequence is shown in FIG.
Will be described in detail. Then, the lens driving operation is performed. The lens is returned to the reset position (initial position) (S14). Further, the film winding operation is performed (S15).

Next, the flash flag is determined (S1
6) If the flash flag FAL = 1 and the flash is required, the process returns to S17, and if FAL = 0 and the flash is not required, the process returns to S2. Then, the flash charging sequence (flash mode) is performed (S17). This sequence is the same as S9 and will be described in detail with reference to FIGS.

FIG. 4 shows an operation flowchart for detecting the remote control switch in S2. The switch circuit 16 detects the state of the remote control switch (S201). Then, it is determined whether or not the state of the remote control switch is the remote control mode (S202), the process proceeds to S203 when the remote control is used (remote control mode is on), and proceeds to S209 when the remote control is not used. In S203, the remote control operation flag remSW = 1 is set.

Next, the remote control receiving circuit 24 waits for a reception signal, receives the transmission signal (pulse signal such as light) of the remote control transmission circuit block 25, and decodes (decodes) the remote control mode. Is determined (S20
4). If it can be determined, the process proceeds to S205, and if not, the process returns to S202.

Further, it is judged whether or not the remote control mode is the immediate release mode which is the mode 1 (S205), and if it is determined that the immediate release mode is the mode 1, the operation proceeds to S206 where the release is performed after a set time has elapsed (for example, after 2 seconds). If 2, the process proceeds to S207. If the mode 1 of the immediate release mode can be determined, the remote control mode flag remM = 0 and the remote control timer flag remT = 0 (timer measurement end at 0: immediate release) are set (S206). Then, it progresses to S2a. Further, in the mode of releasing after the set time which is the mode 2 is reached, the remote control mode flag remM =
Set to 1. A timer measurement is started (for example, a 2-second timer). This remote control timer flag remM is the microcomputer 1
From 7, the remote controller timer flag is set to 0 when remm = 1 is set and the timer measurement is completed (S207). This measures the timer in the later S10b. Then, it progresses to S2a.

Next, FIGS. 5 and 6 show operation flowcharts for the flash charging (flash mode) in S9.

First, in step S901, a flash mode flag FAL = 1 indicating that the flash is used is set ("0" when not used). Further, the state of the remote control switch is detected by the switch circuit 16 and it is determined whether or not the state of the remote control switch is the remote control mode (S902). When the remote control is used (remSW = 1), the operation proceeds to S903. If remSW = 0), the process proceeds to S911. Then, when the remote controller is used, the state of the remote controller mode is detected and it is determined whether the state of the remote controller mode is mode 1 or 2 (S903), and remote controller mode 1 (remM = 0).
If it is, go to S904, if in remote control mode 2 (rem
If M = 1), the process proceeds to S911. Remote control mode 1 (re
When mM = 0), the timer that starts at the start of the boosting operation is used to measure the time, the charge boosting at the set time is measured, and the process proceeds to the oscillation check routine that determines the operation of the boosting operation (S904). The oscillation check will be described in detail with reference to FIGS. 7, 8, S9101, and S9201.

Next, it is determined whether or not the charge voltage level measured in S904 is a flash charge level at which the flash discharge tube 14 can emit light at the light emission enable voltage (S905). When light emission is possible, the process goes to S906 and light emission is not possible. Then, the process proceeds to S909. When light emission is possible and when flash light emission is possible, similarly to S9108, the oscillation start signal OSC signal from the microcomputer 17 is set to "high level" to stop the boosting operation.
(Hereinafter “HL”) to “low level” (hereinafter “LL”)
(S906). Then, the light emission amount / exposure calculation is performed (S907). When the recharge flag RCHG is "0" (a flag indicating whether it has been charged to the minimum light emission level or has already been charged), it is in the state of being charged, and the voltage value at which the main capacitor 6 is being charged. Then, the light emission energy (1/2 · CV ² ) is calculated from the capacitor capacitance value, and the reading value of the film sensitivity detection circuit 400 (or the setting value by the film sensitivity setting switch) is added,
A shutter speed and an aperture value that give an appropriate exposure with this energy amount are calculated. When the recharge flag RCHG is "1" (when recharged below the lowest light emission level), the charge value at the lowest light emission level is calculated.

In S908, the recharge flag RCHG is set to "0", and the process proceeds to S10. If the light emission level is below the minimum light emission level in S905, the recharge flag RCHG is set to "1", and S9
It progresses to 10 (S909). In S910, similarly to S9101, the microcomputer 17 changes the oscillation start signal OSC signal from "LL" to "HL" to start the boosting operation. The operation is the same as in S9101, and the main capacitor 6 is charged.
Then, the process proceeds to S905.

Further, the remote control switch flag remSW
= 0 (no remote control used) or remote control mode flag remM = 1 (mode 2: release after set time), the divided voltage of the main capacitor voltage by the voltage dividing resistors 52 and 53 (stable detection of the capacitors 51 and 54). Capacitor)
A signal from the detection circuit is supplied to the internal A / D converter 173 by an instruction from the microcomputer 171 of the microcomputer 17.
Is also connected to a built-in multiplexer 174, and the charging voltage of the main capacitor 6 is converted from an analog value to a digital value (corresponding to the voltage), and the value stored in the microcomputer 171 and an arbitrary full-capacity that the flash discharge tube 14 can sufficiently emit light. It is determined whether the charging voltage is the (flash charging completion level) (S911), and when it is the charging completion level, S91
2; otherwise, proceed to S914. In S912,
As in S9108, the microcomputer 1 is used to stop the boosting operation.
From 7 the oscillation start signal OSC signal is changed from "HL" to "LL"
To Then, the recharge flag RCHG is set to “0”,
Proceed to S10 (S913). When the charge completion level is not reached, the timer that starts at the start of the boosting operation is used to measure the charge voltage at an arbitrary time, and the operation proceeds to an oscillation check routine that determines the operation of the boosting operation (S91).
4). (See S9101 and S9201 in FIG. 7). Then, in S911, when the charge is equal to or lower than the charge completion level, the recharge flag RCHG is set to "1", and the process proceeds to S916 (S91).
5). In S916, similarly to S9101, the microcomputer 17 changes the oscillation start signal OSC signal from "LL" to "HL" to start the boosting operation. The operation is the same as S904, and the main capacitor 6 is charged. Then, the process proceeds to S911 (S916).

Next, the oscillation check routine will be described with reference to FIG.
Will be done at. First, in order to start the boosting operation, the microcomputer 1
From 7 the oscillation start signal OSC signal is changed from "LL" to "HL"
(S9101). As a result, the NPN transistor 32 is turned on via the diode 35, and accordingly, the PNP transistor 31 is also turned on, and the oscillation transformer 36a is turned on.
The power of the battery power supply 1 is supplied to and the oscillation starts.
As a result, a high voltage is generated in the oscillation transformer 36c (secondary side), and the main capacitor 6 is charged via the diodes 4 and 29. Then, the time counting operation of the timer in the microcomputer 17 is started. (S9102).

Next, the counting is repeated until the timer measurement is completed, the charging operation is continued until the counting is completed, and when the counting is completed, the process proceeds to S9104 (S9103).

Then, the signal from the divided voltage (the capacitors 51 and 54 are capacitors for stable detection) detection circuit of the main capacitor voltage by the voltage dividing resistors 52 and 53 is supplied to the internal A / D by the command of the microcomputer 171 of the microcomputer 17.
The converter 173 is connected to the built-in multiplexer 174, and the charging voltage of the main capacitor 6 is converted from an analog value to a digital value (corresponding to the voltage) and stored in the microcomputer 171 (S9104).

Next, the main capacitor charging voltage stored in S9104 and the charging voltage level (XV) corresponding to the battery voltage in the timer time are used to determine the voltage. If the charging voltage is less than or equal to this setting, the process proceeds to S9106. If it is higher than this arbitrary charging voltage, exit from this routine (S
9105). If the charging voltage is below this setting, S
Similar to 4, the microcomputer 17 detects the voltage of the power supply battery 1 (battery voltage). For example, the A / D converter in the microcomputer 17 converts the battery level from an analog value into a digital value and stores it in memory (S9106). Next, the detected battery voltage is discriminated by the microcomputer 17 as in S5 (S9107). If it is below an arbitrary level (for example, the minimum camera operating voltage), it is judged as NG and the process proceeds to S9108. If it is larger than the arbitrary voltage. Judge that it is OK and skip this routine.

Then, in order to stop the step-up operation, the oscillation start signal OSC signal from the microcomputer 17 is changed from "HL" to "L".
L ″. As a result, through the diode 35, N
The PN transistor 32 is turned off, the PNP transistor 31 is also turned off accordingly, the power supply of the battery power supply 1 to the oscillation transformer 3a is cut off, and the oscillation is stopped. Display circuit 2
When 0, an abnormal operation is displayed and a warning is displayed (S9108).

Next, the oscillation check routine shown in FIG. 8 will be described as a second embodiment. S9201 to S920
Since 4 is the same as S9101 to S9104, the description is omitted. In S9205, the battery check is performed after the voltage of the main voltage capacitor is detected, as in S9106. S9206 is similar to S9105 and is a table of charging voltage according to the battery level (for example, E of the microcomputer 17).
The determination level is determined from the data stored in the EPROM, etc. (XV) If it is below that level, the process proceeds to S9207, and if it is above the level, this routine is skipped. Note that S9207
Is the same as S9108.

FIG. 9 shows an operation flowchart for the shutter / diaphragm control in S13. The shutter circuit 21 and the aperture circuit 2 for setting the shutter / aperture value determined by the photometric data of S7 and the light emission amount / exposure calculation of S907.
The operation of No. 2 is started (S1301).

Next, the flash flag is discriminated (S1
302), if the flash flag FAL = 1 requires a flash, the process proceeds to S1303, and if FAL = 0 does not require a flash, the process proceeds to S1306. Trigger signal (TRG) of microcomputer 17 when flash is required
Then, a pulse signal is output (S1302). And
When the booster circuit 3 operates, a charging current flows through the resistor 7 to the capacitors 8 and 26 to be charged, and when the main capacitor 6 is charged and the flash discharge tube 14 is under high voltage, the TRG signal is pulsed. When a signal is output, the gate of the thyristor 9 is turned on via the resistor 12, one ends of the capacitors 8 and 26 are grounded and discharged, and the terminal voltage of the main capacitor 6 and the capacitor 26 are discharged across the flash discharge tube 14. The sum of the terminal voltage is applied. Then, a pulse is generated on the primary side of the transformer 13 due to the discharge of the capacitor 8, which causes a high-voltage pulse on the secondary side, and the flash discharge tube 14 is triggered to emit light (S13).
04). Then, light is emitted by an amount of light emission corresponding to the charge level of the main capacitor 6, and when the discharge is completed, the light emission is stopped (S1305). Then, the photometric data of S7 and S
A shutter determined by the light emission amount and exposure calculation of 907
The operation of the shutter circuit 21 and the aperture circuit 22 is stopped to set the aperture value (S1306). Then, the process proceeds to S14.

In this embodiment, the A / D converter is used in S9104 as the main capacitor detecting means.
It may be configured by a comparator that detects the lowest light emission voltage (composed of two comparators for completion of charging and lowest light emission voltage).

Next, the oscillation check routine shown in FIG. 10 will be described as a third embodiment. S9101 is the same as S9101 of FIG.

Next, the signal from the divided voltage (the capacitors 51 and 54 are stable detection capacitors) detection circuit of the main capacitor voltage by the voltage dividing resistors 52 and 53 is sent to the internal A by the command of the microcomputer 171 of the microcomputer 17. / D
Multiplexer 1 built in like converter 173
The charging voltage of the main capacitor 6 is converted from an analog value to a digital value (corresponding to the voltage) and stored in the microcomputer 171 ... Vr1 (S9101-2).
Then, in order to stop the boosting operation, the microcomputer 17 changes the oscillation start signal OSC signal from "HL" to "LL" (S9101-3). As a result, the NPN transistor 32 is turned off via the diode 35, and P
The NP transistor 31 is also turned off, the power supply of the battery power supply 1 to the oscillation transformer 36a is cut off, and the oscillation is stopped. Up to this point, the operation is for reading the voltage charged in the main capacitor at the present time.

Next, in order to start the boosting operation, the oscillation start signal OSC signal is changed from "LL" to "H" by the microcomputer 17.
L "(S9101-4). As a result, the NPN transistor 32 is turned on via the diode 35, the PNP transistor 31 is also turned on accordingly, and the power of the battery power supply 1 is supplied to the oscillation transformer 36a to cause oscillation. Then, a high voltage is generated in the oscillation transformer 36c (secondary side), and the main capacitor 6 is charged through the diodes 4 and 29. S9102 to S9103 are the same as S9102 to S9103 in FIG. Is.

Next, a signal from the divided voltage (the capacitors 51 and 54 are stable detection capacitors) detection circuit of the main capacitor voltage by the voltage dividing resistors 52 and 53 is supplied to the internal A by the command of the microcomputer 171 of the microcomputer 17. / D
Multiplexer 1 built in like converter 173
The charging voltage of the main capacitor 6 is converted from an analog value to a digital value (corresponding to the voltage) and stored in the microcomputer 171 ... Vr2 (S9104-1).
Then, the charging voltage V before oscillation measured in S9101-2
The difference (Vr2-Vr1) between r1 and the charging voltage Vr2 after the timer time in S9104 is calculated, and the charging voltage with respect to the set time is obtained (S9104-2).

Next, the main capacitor charging voltage per timer time stored in S9104-2 and the charging voltage rising level (XV) corresponding to the battery voltage in advance in the timer time.
(S9105), the process proceeds to S9106 if the charging voltage is less than or equal to the set charging voltage, and the routine is skipped if the charging voltage is greater than or equal to the setting charging voltage. In S9106,
Similar to S4, the microcomputer 17 detects the voltage of the power supply battery 1 (battery voltage). For example, the A / D converter in the microcomputer 17 converts the battery level from an analog value to a digital value and stores it in memory.

Next, in the same manner as S5, the microcomputer 17 determines the voltage of the detected battery voltage (S9107), and when the voltage is below an arbitrary level (for example, the minimum operating voltage of the camera) N
If it is determined to be G, the process proceeds to step S9108. If it is higher than an arbitrary voltage, it is determined to be OK, and the routine is exited. S910
At 8, the microcomputer 17 changes the oscillation start signal OSC signal from "HL" to "LL" to stop the boosting operation.
As a result, the NPN transistor 32 is turned off via the diode 35, and along with this, the PNP transistor 31.
Is also turned off, the power supply of the battery power supply 1 to the oscillation transformer 36a is cut off, and the oscillation is stopped. At the same time, the display circuit 2
When 0, an abnormal operation is displayed and a warning is displayed.

Next, the oscillation check routine shown in FIG. 11 will be described as a fourth embodiment. S9201 to S92
04-2 is the same as S9101 to S9104-2 in FIG. S9205 is similar to S9106 of FIG. 10, and the battery check is performed after the voltage of the main voltage capacitor is detected. Step S9206 is the same as step S9105 in FIG. 10, and determines the determination level (XV) from the table of the charging voltage according to the battery level (for example, the data stored in the EEPROM of the microcomputer 17), and if it is less than that level, the step S920.
Go to 7 and skip this routine if you are above the level. S9
207 is the same as S9108 of FIG.

[0059]

Correspondence between the Invention and the Embodiment In the above embodiment, S91
The oscillation start signal OSC signal is changed from "LL" to "HL" by the microcomputer 17 to start the boosting operation of the NPN transistor 3 through the diode 35.
2 is turned on, the PNP transistor 31 is also turned on accordingly, the power of the battery power supply 1 is supplied to the oscillation transformer 36a, and oscillation is started. With this, the oscillation transformer 36c
A configuration in which a high voltage is generated on the (secondary side) and the main capacitor 6 is charged via the diodes 4 and 29, and S91
When the oscillation start signal OSC signal is changed from “HL” to “LL” by the microcomputer 17 to stop the boosting operation of 08, the NPN transistor 32 is turned off via the diode 35, and accordingly the PNP transistor 31 is turned off. The configuration in which the power supply of the battery power supply 1 is cut off to the oscillation transformer 36a and the oscillation is stopped corresponds to the boosting means of the present invention, and the divided voltage detection of the main capacitor voltage by the voltage dividing resistors 52 and 53 in S9104 is performed. The signal from the circuit is sent to the microcomputer 17
Internal A / by the instruction of the microcomputer 171 of
It is connected to a built-in multiplexer 174 like the D converter 173, and the charging voltage of the main capacitor 6 is converted from an analog value to a digital value (corresponding to the voltage) and stored in the microcomputer 171, and the stored main capacitor charging voltage and a timer are stored in advance. The configuration for performing the voltage discrimination according to the charging voltage level corresponding to the battery voltage in time corresponds to the charging voltage detecting means of the present invention, and the voltage of the power supply battery 1 is detected by the microcomputer 17, and the A / The D converter converts the battery level from an analog value to a digital value and stores it in memory, and the detected battery voltage is detected by the microcomputer 1
The operations of S4 and S5 for determining the voltage in 7 correspond to the power supply battery voltage detecting means of the present invention, and the configuration for causing the timer in the microcomputer 17 to perform the time counting operation corresponds to the timer means of the present invention.

[0060]

As described above, according to the first aspect of the present invention.
According to 5 to 5, the timer started at the start of the boosting operation is used to store the charging voltage after a fixed time, and then the battery is checked, and the charging boosting operation is stopped when the charging level is low even though there is sufficient battery. . And warn about this. In particular, according to the fourth and fifth aspects, since the voltage is compared for charging the capacitor before and after the timer is timed, and the compared voltage is compared with the power supply voltage, the charging operation can be performed finely.

As a result, the boosting oscillation operation can be stopped immediately after abnormal heat generation without using the ambient temperature detecting means, and the secondary breakdown due to heat generation can be easily prevented.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a first embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the circuit according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the circuit according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the circuit according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing the operation of the circuit according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the circuit according to the first embodiment of the present invention.

FIG. 7 is a circuit block diagram showing the first embodiment of the present invention.

FIG. 8 is a flowchart showing the operation of the circuit according to the second embodiment of the present invention.

FIG. 9 is a flowchart showing an operation of shutter / aperture control of the present invention.

FIG. 10 is a flowchart showing the operation of the third embodiment of the present invention.

FIG. 11 is a flowchart showing an operation according to the fourth embodiment of the present invention.

[Explanation of symbols]

 1 Power Battery 2 Power Switch 3 Booster Circuit 5 Voltage Detection Circuit 6 Main Capacitor 17 One-chip Microcomputer 21 Shutter Circuit 22 Aperture Circuit 24 Remote Control Reception Circuit 25 Remote Control Transmission Circuit

Claims (5)

[Claims] 1. A flash discharge tube, a main capacitor for supplying emission energy to the flash discharge tube, boosting means for performing a boosting operation to charge the main capacitor, and charging for detecting the main capacitor charging voltage. It has a voltage detection means, a power supply battery voltage detection means, and a timer means that starts after the charging time starts and clocks a set time, and charges the main capacitor voltage by the charging voltage detection means after the time set by the timer means is measured. An electronic flash device, which detects a voltage, and thereafter detects the power supply voltage by the power supply battery voltage detection means, and stops the boosting operation and gives a warning based on the charging voltage result and the power supply voltage result. 2. The electronic flash device according to claim 1,
The electronic flash device, wherein the charging voltage detecting means includes an A / D converter. 3. The electronic flash device according to claim 1,
An electronic flash device, wherein when the power supply voltage detected by the power supply battery voltage detection means is above a set level and the charge voltage detected by the charge voltage detection means is below a set level, the boosting means is prohibited to give a warning. 4. A flash discharge tube, a main capacitor for supplying emission energy to the flash discharge tube, boosting means for performing a boosting operation to charge the main capacitor, and charging for detecting the main capacitor charging voltage. A first voltage detected by the charging voltage detecting means at the start of the charging time, which has a voltage detecting means, a power source battery voltage detecting means, and a timer means for starting a charging time and measuring a set time. The second voltage detected by the charging voltage detecting means after the time set by the timer means is detected, and then the power supply voltage is detected by the power supply battery voltage detecting means, and the difference between the second voltage and the first voltage of the charging voltage is detected. An electronic flash device characterized in that boosting operation is stopped and a warning is issued according to the result of 1. and the result of power supply voltage. 5. The electronic flash device according to claim 4,
An electronic flash device, wherein a stop and a warning are performed when the difference between the second voltage and the first voltage is smaller than a set voltage and the power supply voltage detected by the power supply battery voltage detection means is equal to or higher than the set voltage.