JP4429414B2 - Power supply device, strobe device having the power supply device, and imaging device incorporating the strobe device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a booster circuit that boosts a DC low voltage output from a DC low-voltage power supply such as a dry battery, a power supply device that includes a power supply capacitor that is charged by the output of the booster circuit, and a strobe device incorporating the power supply device. More particularly, the present invention relates to a power supply device characterized by a charging operation of a power supply capacitor in the power supply device, a strobe device having the power supply device, and an imaging device incorporating the strobe device.
[0002]
[Prior art]
Conventionally, a strobe device as an artificial light source when recording an image to be recorded by an imaging device such as a photographic camera or an electronic still camera as optical image information or electrical image information is in an independent form or in an imaging device. It is useful in a built-in form.
[0003]
As a power supply device for the strobe device, a so-called self-excited booster circuit that boosts the terminal voltage of a DC low-voltage power source such as a dry battery through an oscillation structure, and a battery that is charged by the output of this booster circuit, via a flash discharge tube So-called boosting by supplying the terminal voltage of the power supply device including the power supply capacitor for accumulating the discharged electric charge or the DC low-voltage power supply to the step-up transformer via the switch means that operates on and off based on the pulse signal supplied from the outside. A power supply device including a separately excited booster circuit is well known.
[0004]
For example, FIG. 4 is a main part electric circuit diagram showing an example of a well-known strobe device adopting a power supply device D including a self-excited booster circuit S that boosts the terminal voltage of a DC low-voltage power supply through an oscillation configuration. .
[0005]
The booster circuit S includes a DC low-voltage power source 1 such as a dry battery, a switching element 2 as a transistor, a saturation type oscillation transformer 3, a starting resistor 4, a capacitor 5 for phase correction, and a rectifier diode 6.
[0006]
The power supply device D includes a booster circuit S and a main capacitor 7 which is a power supply capacitor charged by the output of the booster circuit S. Note that a flash discharge tube 8 is connected to both ends of the main capacitor 7 to emit light by consuming charges charged in the main capacitor 7 in response to an operation of a trigger circuit (not shown).
[0007]
In FIG. 4, when the DC low-voltage power supply 1 is supplied, a current flows through the DC low-voltage power supply 1, the emitter-base of the switching element 2, and the parallel body of the starting resistor 4 and the capacitor 5, and the switching element 2 is turned on. When the switching element 2 is turned on, current flows between the emitter and collector of the switching transformer 2 via the primary winding 3A of the oscillation transformer 3, so that the oscillation transformer 3 and the like start oscillating operation. 3B outputs a high-voltage AC voltage obtained by boosting the terminal voltage of the DC low-voltage power supply 1 in accordance with the turn ratio between the primary winding 3A and the secondary winding 3B of the oscillation transformer 3.
[0008]
The high-voltage AC voltage output from the secondary winding 3B is rectified by the rectifier diode 6 and supplied to the main capacitor 7, whereby the main capacitor 7 is charged.
[0009]
On the other hand, FIG. 5 shows an electric circuit diagram of a main part of an example of a strobe device provided with a conventionally known power supply device D1 including a booster circuit S1 of another excitation type. In FIG. Indicates requirements.
[0010]
The step-up circuit S1 includes a DC low-voltage power supply 1 such as a dry battery, a primary side switching element 9 which is a power MOS transistor, a non-saturated step-up transformer 10 and a rectifier diode 6.
[0011]
The control pole of the switching element 9 is provided outside the booster circuit S1, and is connected to a pulse signal output terminal of a control circuit 11 such as a microcomputer, which is a pulse generation circuit that outputs a rectangular wave pulse signal with an appropriate period. .
[0012]
The power supply device D1 includes the booster circuit S1 and the main capacitor 7 that is charged by the output of the booster circuit S1, as shown in the previous conventional example. A flash discharge tube 8 is connected to emit light by consuming the electric charge charged in the main capacitor 7 in response to the operation of the trigger circuit that is not.
[0013]
In FIG. 5, when a rectangular wave pulse signal with an appropriate period output from the control circuit 11 is supplied to the control pole of the switching element 9, the switching element 9 starts an on / off operation. Thus, the supply of power to the primary winding 10A is intermittently performed, and a high-voltage AC voltage corresponding to the turn ratio of the step-up transformer 10 is output from the secondary winding 10B.
[0014]
The high-voltage AC voltage output from the secondary winding 10B is rectified by the rectifier diode 6 and supplied to the main capacitor 7 as in the previous power supply device, whereby the main capacitor 7 is charged.
[0015]
In addition, as a power supply device including a separately excited booster circuit, the power supply state from the DC low-voltage power supply to the primary side of the boost transformer is, for example, the power supply elapsed time, the charging voltage value of the main capacitor, or the terminal voltage value of the DC low-voltage power supply. Various power supply devices that are controlled based on the above have been proposed. (Japanese Patent Laid-Open Nos. 7-192848, 7-85888, etc.)
[0016]
[Problems to be solved by the invention]
The power supply device D including the self-excited booster circuit S shown in FIG. 4 has the switching element 2 in the charging loop of the main capacitor 7, that is, the charging current of the main capacitor 7 is fed back to the booster circuit. Therefore, the supply current from the DC low-voltage power supply 1 has a characteristic that it drastically decreases as the charging of the main capacitor 7 progresses. Therefore, the conversion efficiency is good, and it is very commonly used as a power supply device for a strobe device. ing.
[0017]
However, when the characteristics of the supply current from the DC low-voltage power supply 1 described above are examined in detail, as shown in FIG. 6A, an excessive current of several amperes to ten amperes is, for example, a dry battery at the beginning of charging. It is output from the low-voltage power supply 1, and after a few seconds, it has a characteristic of rapidly decreasing to a few tenths.
[0018]
The excessive current generated at the beginning of charging temporarily drops the terminal voltage of the DC low-voltage power supply 1 and acts as a kind of noise source. For example, the DC low-voltage power supply 1 is used as a power supply for other electric circuits. In such a case, it may cause a malfunction of the other electric circuit. The same phenomenon occurs even after the charge of the main capacitor 7 is consumed, that is, after light emission.
[0019]
Therefore, for example, when an electronic still camera that electrically captures and records image information of a subject as an imaging device is considered, a fatal inconvenience of failure in capturing image information after shooting occurs due to a drop in the terminal voltage or the like. Have a fear.
[0020]
As a method of preventing fluctuations in the terminal voltage of the DC low-voltage power supply 1, a method of making the output current from the DC low-voltage power supply 1 constant at several hundred milliamperes, that is, a constant current circuit C as shown in FIG. A method of connecting between the DC low voltage power source 1 and the switching element 2 is known. However, this method uses a voltage drop method to make the current constant, and has the disadvantages of generating heat and increasing the charging time of the main capacitor 7.
[0021]
On the other hand, in the power supply device D1 including the separately excited booster circuit S1, the charging current of the main capacitor 7 is not fed back, and the operation of the switching element 9 is controlled by the cycle of the rectangular wave pulse signal output from the control circuit 11. Therefore, the characteristic of the supply current supplied from the DC low-voltage power supply 1 to the primary side of the step-up transformer 10 is not a characteristic that rapidly decreases with time as in the previous power supply device D, and is basically a constant current. It becomes a characteristic.
[0022]
That is, the characteristics of the supply current from the DC low-voltage power supply 1 in the power supply device D1 are as shown in FIG. 6 (b), from the time T0 when charging is started to a time T1 after a short time has elapsed. After the excessive current is supplied during the period T, the characteristic is controlled to a predetermined constant current, which can be regarded as a constant current characteristic when viewed largely.
[0023]
However, an excessive current is still generated in the period T, and the power supply device D1 also drops the terminal voltage of the DC low-voltage power supply 1 and generates noise when the excessive current is generated in the period T, as in the previous power supply device D. For example, when the DC low-voltage power supply 1 is also used as a power supply for another electric circuit, if the booster circuit S1 is operated during the operation of the other electric circuit, a drop in the terminal voltage or the like occurs. There is a risk that other electric circuits may malfunction.
[0024]
The present invention has been made in consideration of the above-described points. An excessive current is provided by giving constant current characteristics to the current supplied from the DC low-voltage power source to the primary side of the step-up transformer from the beginning of the charging of the capacitor for the power source. Therefore, it is possible to provide a power supply device that can prevent a drop in terminal voltage of a DC low-voltage power supply and noise generation, a strobe device having the power supply device, and an imaging device incorporating the strobe device. Objective.
[0025]
[Means for Solving the Problems]
The power supply apparatus according to the present invention boosts the output voltage of the DC low-voltage power supply by applying it to the primary side of the step-up transformer via a switch element whose on / off operation is controlled by the pulse output output from the pulse generation circuit. In the power supply device for charging the capacitor, the current limiting means is connected to the secondary output terminal of the step-up transformer and controls the charging state of the capacitor on the secondary side of the step-up transformer.
[0026]
As a result, the characteristic of the current supplied from the DC low-voltage power source to the primary side of the step-up transformer can be controlled to a constant current characteristic that does not generate an excessive current from the DC low-voltage power source in the initial charging stage of the capacitor.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, the output voltage of the DC low-voltage power supply is boosted by applying it to the primary side of the step-up transformer via a switching element whose on / off operation is controlled by the pulse output output from the pulse generation circuit. In the power supply device for charging the capacitor with the boost output, the current limiting means is connected to the secondary output terminal of the boost transformer so that the charging state of the capacitor is controlled on the secondary side of the boost transformer. Thus, the current supplied to the primary side of the step-up transformer from the DC low-voltage power supply can have constant current characteristics, and thus has the effect of preventing the generation of an excessive current from the DC low-voltage power supply in the initial stage of capacitor charging.
[0028]
The invention of claim 1 of the present invention, the current limiting means in the power supply device, the impedance in the charging loop of the capacitor through the secondary side output terminal of the to the step-up transformer in response to the charging current of the capacitor It is configured to control .
[0030]
According to the second aspect of the present invention, at least the output voltage of the low-voltage DC power supply is applied to the primary side of the step-up transformer via a switching element whose on / off operation is controlled by the pulse output output from the pulse generation circuit. A step-up circuit for boosting the voltage, a capacitor for power supply charged by the output of the step-up circuit, and a current limiting means connected to the secondary side output terminal of the step-up transformer. The power supply device is characterized in that the current supplied from the low-voltage DC power supply to the primary side of the step-up transformer has a constant current characteristic, and is connected to both ends of the capacitor to consume the charge charged in the capacitor. A strobe device comprising a discharge tube that emits light. A constant current is supplied to the primary side of the step-up transformer from a DC low-voltage power supply. It can have a gender, thus having the effect of preventing the occurrence of an excessive current from the DC low voltage power supply in the initial charging of the capacitor.
[0031]
The invention of claim 2 of the present invention, the current limiting means in the-in flash device, the impedance in the charging loop of the capacitor through the secondary side output terminal of the step-up transformer in response to the charging current of the capacitor Is configured to control .
[0033]
The invention described in claims 3 to 4 of the present invention includes the current limiting means described in claim 1 or 2, and controls the charge state of the capacitor on the secondary side of the step-up transformer. A power supply device characterized by having a constant current characteristic to a current supplied to a primary side of a step-up transformer from a low-voltage DC power supply, and a discharge tube connected to both ends of the capacitor to emit light by consuming the charge of the capacitor A strobe device equipped with a strobe device and an image pickup device incorporating the strobe device. The current supplied from the DC low-voltage power source to the primary side of the step-up transformer can have constant current characteristics. It has the effect | action which can prevent generation | occurrence | production of the overcurrent from the DC low voltage power supply in the charge initial stage.
[0036]
As is apparent from the drawings, the strobe device according to the present embodiment is connected to both ends of the power supply device DX and the main capacitor 7 including the separately excited booster circuit SX and the main capacitor 7 for power supply, and is not shown. It includes a discharge tube 8 that emits light by consuming the charged charge of the capacitor 7 by the operation of a trigger circuit that is not present.
[0037]
The booster circuit SX includes a switching element 9, a non-saturated transformer 10 having a primary winding 10A and a secondary winding 10B, and a rectifier diode 6, similar to the separately excited booster circuit S1 shown in FIG. It is connected between the secondary winding 10 </ b> B that is the secondary side of the step-up transformer 10 and the main capacitor 7, and includes current limiting means 12 that controls the charging state of the main capacitor 7.
[0038]
The current limiting means 12 has resistors 13 and 14 connected in series between the secondary winding 10B of the step-up transformer 10 and the main capacitor 7, and a base connected to a connection point between the resistors 13 and 14 via the resistor 15. A transistor 16 connected between the emitter and the collector at both ends of the connection body of the resistors 13 and 14, and a capacitor 17 connected between the base and the emitter of the transistor 16 and forming the delay circuit with the resistor 15 It is composed of
[0039]
In FIG. 1, when the control circuit 11 starts operation and a rectangular wave pulse signal having a predetermined period is supplied to the control pole of the switching element 9, the switching element 9 performs an on / off operation based on the period of the rectangular wave pulse signal. Start.
[0040]
When the switching element 9 starts an on / off operation, the step-up transformer 10 is excited because the DC low-voltage power supply 1 is supplied during the on period of the switching element 9, and the energy stored by the excitation in the on period during the off period is secondary. Step-up output from the winding 10B, that is, the secondary side.
[0041]
The step-up output from the secondary winding 10B of the step-up transformer 10 is supplied to the main capacitor 7 through the rectifier diode 6, and the main capacitor 7 is charged. In the present embodiment, it is shown in FIG. Thus, the resistor 13 and the transistor 16 are included, and the current limiting means 12 is connected between the secondary side of the step-up transformer 10 and the main capacitor 7. The charging operation is performed as follows.
[0042]
First, at the initial stage of charging, the resistors 13 and 14 constituting the current limiting means 12 are connected in series with the main capacitor 7, so that the charging current of the main capacitor 7 flows through the resistors 13 and 14. Unlike the example shown in FIG. 5 that does not have a resistor, the charging current is greatly suppressed.
[0043]
The fact that the charging current of the main capacitor 7 is largely suppressed is not only that the burden on the primary side of the step-up transformer 10 is reduced, and therefore the value of the current supplied from the DC low-voltage power supply 1 to the primary side of the step-up transformer 10. Will never grow.
[0044]
In other words, in the case of the present embodiment, since the charging state is controlled so that the charging current of the main capacitor 7 is largely suppressed in the initial stage of charging, the DC low-voltage power supply 1 is excessively connected to the primary side of the step-up transformer 10. No current is supplied.
[0045]
At this time, since the drop voltage generated in the resistor 14 by the charging current of the main capacitor 7 is supplied to the resistor 15 and the capacitor 17 forming the delay circuit, the capacitor 17 due to the drop voltage from the start of charging of the main capacitor 7. The battery will also be charged.
[0046]
When the charging of the capacitor 17 based on the charging current of the main capacitor 7 proceeds and the charging voltage value reaches a value capable of turning on the transistor 16, the transistor 16 is turned on. On the other hand, when the transistor 16 is turned on, the main capacitor 7 is turned on thereafter. A charging current flows through the transistor 16 that has been turned on.
[0047]
That is, when the transistor 16 is turned on, the charging loop of the main capacitor 7 has a low impedance through the transistor 16 not through the resistors 13 and 14 from the charging loop having the high impedance through the resistors 13 and 14 until then. Will be switched to the charging loop.
[0048]
In other words, the current limiting means 12 in the present embodiment controls the impedance of the charging loop of the main capacitor 7 via the secondary output terminal of the step-up transformer 10 in response to the charging current of the main capacitor 7. The charge state of the main capacitor 7 is controlled.
[0049]
Here, the resistance value of the resistor 15 and the capacitance value of the capacitor 17 constituting the current limiting means 12 are controlled so that the above-described transistor 16 is turned on, for example, at the time described at time T1 in FIG. As a result, the charging operation of the main capacitor 7 is performed in a high-impedance charging loop different from that of the conventional device in the period T up to the above-described time T1, in which excessive current has occurred in the case of the conventional device, and after the time T1 Can be performed by a low-impedance charging loop similar to the conventional device.
[0050]
As a result, the characteristic of the current supplied from the DC low-voltage power supply 1 to the primary side of the step-up transformer 10 in the present embodiment is the period T0 shown in the characteristics of the conventional device shown in FIG. Thus, the characteristic is controlled to have a constant current characteristic from the start of charging as shown in FIG.
[0051]
It should be noted that, by incorporating the strobe device in the present embodiment in the imaging device, it is possible to obtain an imaging device with a built-in strobe device that does not generate an excessive current supply from the DC low-voltage power supply during the charging operation of the main capacitor 7. Nor.
(Example 2)
FIG. 3 is a principal circuit diagram showing another embodiment of a strobe device having a power supply device according to the present invention. In the figure, components having the same reference numerals as those in FIG. 1 indicate the same components.
[0052]
The strobe device in the present embodiment is also connected to both ends of the power supply device DY and the main capacitor 7 including the separately excited booster circuit SY and the main capacitor 7 for power supply, as in the above-described embodiment. The discharge tube 8 is configured to emit light by consuming the charge of the capacitor 7 by the operation of the trigger circuit not shown.
[0053]
In this embodiment, however, the current limiting means connected to the secondary output terminal of the step-up transformer in the step-up circuit SY is composed of resistors 13 and 14, a transistor 16 and the like, and responds to the charging current value of the main capacitor 7. Unlike the current limiting means 12 in the above-described embodiment in which the impedance of the charging loop of the main capacitor 7 via the secondary output terminal of the step-up transformer 10 is controlled, the resistor 19 and bidirectional switching are performed. The voltage detection circuit 21 includes a parallel connection body of the elements 20, a voltage detection element 22, and resistors 23 and 24, and is connected to the main output via the secondary output terminal of the step-up transformer 10 in response to the charging voltage value of the main capacitor 7. This is an example using current limiting means 18 for controlling the impedance of the charging loop of the capacitor 7.
[0054]
As apparent from FIG. 3, a parallel connection body of a resistor 19 and a bidirectional switching element 20 is connected between the secondary winding 10 </ b> B that is the secondary output terminal of the step-up transformer 10 and the main capacitor 7. In addition, the control pole of the bidirectional switching element 20 is connected to a connection point between the resistor 23 and the resistor 24 constituting the voltage detection circuit 21.
[0055]
Therefore, the charging current of the main capacitor 7 flows through the resistor 19 connected in series between the secondary winding 10B of the step-up transformer 10 and the main capacitor 7 in the initial stage of charging. As in the embodiment described above, it is greatly suppressed as compared with the conventional apparatus shown in FIG.
[0056]
For this reason, in this embodiment, too, no excessive current is supplied from the DC low-voltage power supply 1 to the primary side of the step-up transformer 10 as in the previous embodiment.
[0057]
On the other hand, when the charging of the main capacitor 7 proceeds and the charging voltage value of the main capacitor 7 reaches an appropriate voltage value, the voltage detection circuit 21 starts operating and turns on the bidirectional switching element 20.
[0058]
That is, when the charging voltage value of the main capacitor 7 reaches an appropriate voltage value, the voltage detection circuit 21 turns on the voltage detection element 22 to flow current through the resistors 23 and 24, and bidirectionally reduces the voltage drop across the resistor 24. The bidirectional switching element 21 is turned on by applying it to the control pole of the bidirectional switching element 21.
[0059]
When the bidirectional switching element 21 is turned on, the charging current of the main capacitor 7 thereafter flows through the bidirectional switching element 21. That is, when the bidirectional switching element 21 is turned on, the charging loop of the main capacitor 7 is turned on. However, the charging loop having a high impedance through the resistor 19 is switched to the charging loop having a low impedance through the bidirectional switching element 21 not through the resistor 19.
[0060]
In other words, the current limiting means 18 in the present embodiment controls the impedance of the charging loop of the main capacitor 7 through the secondary output terminal of the step-up transformer 10 in response to the charging voltage of the main capacitor 7. The charge state of the main capacitor 7 is controlled.
[0061]
Here, the characteristics of the voltage detection element 22 constituting the voltage detection circuit 21, the resistance 23, and the like so that the on-time of the bidirectional switching element 20 described above is, for example, the time described at time T 1 in FIG. By controlling the resistance value, the charging operation of the main capacitor 7 is the same as that of the embodiment described with reference to FIG. This can be done in a high-impedance charging loop different from that of the device, and in a low-impedance charging loop similar to that of the conventional device after time T1.
[0062]
As a result, the characteristic of the current supplied from the DC low-voltage power supply 1 to the primary side of the step-up transformer 10 in the present embodiment is similar to the characteristic of the conventional device shown in FIG. The characteristics are controlled so as not to generate an excessive current even during the period T indicated by the times T0 to T1, in other words, the characteristics having the constant current characteristics from the charging start time as shown in FIG.
[0063]
Needless to say, by incorporating the strobe device in the present embodiment into the imaging device, it is possible to obtain an imaging device with a built-in strobe device that does not generate an excessive current during the charging operation of the main capacitor 7.
[0064]
【The invention's effect】
Since the power supply device according to the present invention includes current limiting means for controlling the charging state of the power supply capacitor on the secondary side of the step-up transformer, the current supplied to the primary side of the step-up transformer from the DC low-voltage power source This has the effect of providing constant current characteristics, that is, the effect of preventing the occurrence of excessive current at the beginning of charging of the power supply capacitor. As a result, the terminal voltage of the DC low-voltage power supply drops inadvertently. And the effect of preventing the generation of noise.
[0065]
Further, the strobe device having the power supply device according to the present invention has a power supply device provided with current limiting means for controlling the charging state of the power supply capacitor on the secondary side of the step-up transformer. The current supplied from the power source to the primary side of the step-up transformer has the effect of giving constant current characteristics, that is, the effect of preventing the occurrence of an excessive current at the initial stage of charging of the power supply capacitor. The terminal voltage of the DC low-voltage power supply does not drop inadvertently and noise does not occur, and when the DC low-voltage power supply is shared as the power supply for other electric circuits, it is possible to prevent the other electric circuits from malfunctioning Have
[0066]
Furthermore, an image pickup apparatus including a strobe device having a power supply device according to the present invention includes a power supply device including a power supply device having current limiting means for controlling a charging state of a power supply capacitor on a secondary side of a step-up transformer. As a result, the current supplied to the primary side of the step-up transformer from the DC low-voltage power supply can have a constant current characteristic, that is, the generation of an excessive current in the initial charge of the capacitor for the power supply can be prevented. Therefore, the terminal voltage of the DC low-voltage power supply does not drop inadvertently or noise is generated, and when the DC low-voltage power supply is shared as the power supply of another electric circuit, the other electric circuit malfunctions. This has the effect of preventing this. In particular, in the case of an electronic still camera that electrically captures and records image information of a subject as an imaging device, it has an effect of preventing a fatal inconvenience such as a failure in capturing image information after shooting.
[Brief description of the drawings]
FIG. 1 is a main part electric circuit diagram showing an embodiment of a strobe device having a power supply device according to the present invention. FIG. 2 is a characteristic diagram of a supply current from a DC low-voltage power source in the embodiment shown in FIG. FIG. 4 is a main part electric circuit diagram showing another embodiment of a strobe device having a power supply device according to the present invention. FIG. 4 is a main part electric circuit diagram showing an example of a conventional strobe device. FIG. 6A is a diagram showing a supply current characteristic from a DC low-voltage power supply in the conventional strobe shown in FIG. 4B. FIG. 6B is a current supply characteristic from a DC low-voltage power supply in the conventional strobe shown in FIG. FIG. 7 is a partial electric circuit diagram for explaining another example of a conventional strobe device.
DESCRIPTION OF SYMBOLS 1 DC low voltage power supply 6 Rectifier diode 7 Main capacitor 8 Discharge tube 9 Switching element 10 Step-up transformer 11 Control circuit 12 Current limiting means 13 Resistor 14 Resistor 15 Resistor 16 Transistor 17 Capacitor 18 Current limiting means 19 Resistor 20 Bidirectional switching element 21 Voltage Detection circuit 22 Voltage detection element 23 Resistance 24 Resistance

Claims (4)

A power supply device that boosts a voltage by applying an output voltage of a DC low-voltage power supply to a primary side of a step-up transformer through a switching element whose on / off operation is controlled by a pulse output output from a pulse generation circuit, and charges a capacitor by the boosted output A connecting body comprising a first resistor (13) and a second resistor (14) connected in series between the secondary winding (10B) of the step-up transformer and the capacitor (7), and a base A transistor (3) connected to the connection point of the first resistor (13) and the second resistor (14) via a third resistor (15), and between the emitter and collector connected to both ends of the connection body ( 16) and a sub-condenser connected between the base and emitter of the transistor (16) and connected to the connection point between the base of the transistor (16) and the third resistor (15). Power supply, characterized in that it comprises a current limiting means comprising (17) (12). In place of the current limiting means according to claim 1, a first resistor (19) and a bidirectional switching element (20) connected in series between the secondary winding (10B) of the step-up transformer and the capacitor (7). ) And a voltage detection circuit (21) in which a voltage detection element (22), a second resistor (23), and a third resistor (24) are connected in series to both ends of the capacitor (7). ) Are connected in parallel,
A control pole of the bidirectional switching element (20) is connected to a connection point between the second resistor (23) and the third resistor (24), and an electrode of the bidirectional switching element (20) is A power supply device connected to a connection point between a first resistor (19) and the third resistor (24). A strobe device comprising the power supply device according to claim 1. An imaging apparatus comprising the strobe device according to claim 3.

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