JP2958744B2 - Power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for supplying power to a load such as a flash tube for outputting laser light.

[0002]

2. Description of the Related Art Flash tubes that output laser light (flash tubes)
Fig. 6 (a) as a conventional power supply device for supplying power to
(For example, JP-B-63-20032).
This device converts the power of the DC power supply 1 into a pulse width-modulated high-frequency pulse train, removes high-frequency components, and supplies short-time pulse power to the flash tube 7. That is, the power of the DC power supply 1 is converted into a high-frequency pulse train whose pulse width is modulated by the switching operation of the switch element (IGBT) 2, and is supplied to a series circuit of the reactor 3 and the capacitor 5. When the switching element 2 is turned off and the supply of the pulse power is stopped, the discharge current of the reactor 3 is changed to the diode 4
And a desired DC voltage from which high-frequency components have been removed is generated in the capacitor 5.
Is supplied to the flash tube 7 via the. In addition, a simmer power supply 9 and a resistor 8 for constantly supplying a small DC current (hereinafter referred to as a simmer current) for maintaining the flash tube 7 in a simmering state, and a high voltage for supplying the simmer current are provided. Trigger circuit to generate and start discharge of flash tube 7
It has ten.

The power supplied to the flash tube 7 is determined by the on / off duty ratio of the switch element 2, and is controlled as follows. That is, when the start signal 11 is input, the voltage pattern circuit 12 outputs the voltage reference v12 as shown in FIG.
The PWM circuit 13 outputs the voltage reference v12 and the high-frequency sawtooth modulation signal v output from the modulation signal generator 14.
14 and outputs a PWM signal v13 subjected to pulse width modulation, turns on / off the switch element 2 via the drive circuit 15, and supplies high-frequency pulse power to the reactor 3 and the capacitor 5. As a result, the high-frequency component of the voltage of the capacitor 5 is removed by a filter effect, and the voltage of the waveform similar to the waveform of the voltage reference v12 is supplied to the flash tube 7 so that a current according to the characteristics of the flash tube 7 can flow. it can.

[0004]

However, the above-mentioned conventional system has the following disadvantages. Since the PWM control is performed in the open loop, the voltage applied to the flash tube changes due to a voltage fluctuation of the DC power supply, a change or variation of the operation speed of the switching element, and the like. Even if the same voltage is applied due to a change in the characteristics of the flash tube, the value of the flowing current is different and the light output characteristics are likely to change. Since a capacitor with a relatively large capacity is used, the voltage applied to the flash tube may oscillate, turning off the simmer current, and preventing backflow between the circuit that supplies the main power and the circuit that supplies the simmer current. It is necessary to insert a diode.

SUMMARY OF THE INVENTION It is an object of the present invention to control a flash tube current to a set value without being affected by voltage fluctuations on the power supply side and without being affected by changes in the characteristics of a load such as a flash tube. An object of the present invention is to provide a power supply device that can stably supply a current with a small ripple current with high accuracy and can stably maintain a simmer current.

[0006]

A power supply apparatus for a load such as a flash tube according to the present invention comprises a DC power supply having one end connected to one end of a load such as a flash tube, and one end connected to the other end of the DC power supply. A series circuit of a switch element and a reactor connected to the other end of the load, and a diode having one end connected to a series connection point of the switch element and the reactor and the other end connected to one end of the load A chopper circuit comprising:
The clock pulse is configured to be turned on in synchronization with a clock pulse given at a constant cycle, and to be turned off based on a comparison result between a current reference and an output current detection value of the chopper circuit. Means for adding a dither signal, which gradually increases or decreases in synchronization with the cycle, to the current reference or the output current detection value of the chopper circuit. (Claim 1) (See FIG. 1) Further, a plurality of the chopper circuits are connected in parallel to supply a combined current to the load, and a plurality of the current control means are provided to control the pulse width of each current control means. A phase difference is provided in the control modulation cycle so that the ripple component of the output current of each chopper circuit cancels out. (Claim 2) (See FIG. 1) Further, a constant current (hereinafter, referred to as a simmer current) is supplied to at least a part of the chopper circuit to keep the flash tube 7 serving as the load in a simulating state. The reactor of this chopper circuit is a reactor having a saturation characteristic in which the inductance acts largely in the range of the simmer current and the inductance acts in the range exceeding the simmer current. (Claim 3) (See FIG. 1) Further, the PWM control means includes means for obtaining a correction signal from the modulation factor of the PWM signal and the amplitude of the dither signal, and adding the correction signal to the current reference. (Claim 4) (See FIG. 1) The DC power supply further includes voltage control means for variably controlling the DC output voltage, and sets the DC output voltage based on a predetermined current rise characteristic based on a current. .
(Claim 5) (Refer to FIG. 4) Further, there is provided a diode having one end connected to the other end of the DC power supply and the other end connected to the other end of a load such as the flash tube. (Claim 6) (See FIG. 4) Further, a snubber circuit including a resistor, a diode, and a capacitor is provided on the output side of the power supply device main body. (Claim 7) (See FIG. 5)

[0007]

The power supply device for a load such as a flash tube according to the present invention comprises:
The output current of the chopper circuit is directly supplied to the load such as a flash tube, and the current control means controls the current so that the current reference current pattern matches the chopper output current. A desired current pattern which is hardly affected by the above can be supplied to a load such as a flash tube. In this case, the switch element is subjected to pulse width modulation control at a constant modulation cycle by the PWM signal output from the current control means, and the output current of the chopper circuit is instantaneously controlled according to the current reference. In particular, even when the current reference is substantially constant, the OFF point of the switch element is stably detected by a gradual change of the dither signal, and stable pulse width modulation control is performed. In this case, the current reference is corrected by the correction signal, the current error caused by adding the dither signal is compensated, and stable PWM control and accurate current control are performed. (Claim 1) Further, the plurality of chopper circuits are controlled so that the ripple components of the respective output currents cancel each other by the phase difference of the modulation period of the pulse width modulation control. (Claim 2) Further, control is performed so that a simmer current for maintaining the flash tube in a simmering state is supplied from some of the chopper circuits. In this case, in the range below the simmer current, the inductance of the
Ripple is reduced, and in the range of the main current exceeding the simmer current, the inductance of the reactor acts small to perform fast-changing current control. (Claim 3) Further, even when the current reference is substantially constant, the OFF point of the switch element is stably detected by a gradual change of the dither signal, and stable pulse width modulation control is performed. In this case, the current reference is corrected by the correction signal, the current error caused by adding the dither signal is compensated, and stable PWM control and accurate current control are performed. (Claim 4) Further, when supplying a current to a load, the voltage of the DC power supply is set in advance when the rise of the current reference is rapid, and the voltage of the DC power supply is set when the rise of the current reference is gentle. Is set low. (Claim 5) Further, when the current of the shell load of the flash tube or the like is cut off, the discharge current of the reactor is returned to the DC power supply side via the diode, and the induced voltage of the reactor is clamped to the DC voltage to flash tube. And regenerate the stored energy of the reactor to the DC power supply side. (Claim 6) Further, a snubber circuit including a resistor, a diode, and a capacitor is provided on an output side of the power supply device main body to absorb a surge voltage. (Claim 7)

[0008]

FIG. 1 shows an embodiment corresponding to claims 1 to 4 and 12 to 17 of the present invention. In FIG. 1, reference numeral 22 denotes an AC power supply 20.
Is a diode bridge that converts an AC voltage input from the AC reactor 21 into a DC voltage, a switch element (IGBT) 23 that turns on and off the DC output side of the diode bridge 22 and short-circuits, 24 is a diode, and 26 is With a capacitor,
These constitute a step-up chopper circuit. When the switch element 23 is turned on, energy is stored in the AC reactor 21, and when the switch element 23 is turned off, the energy stored in the AC reactor 21 flows through the diode 24 as a discharge current to the capacitor 26, and The charging voltage is controlled to a desired value.

2A and 2B are switch elements (IGBTs) for controlling current, 3A and 3B are reactors for smoothing DC current, and 4A and 4B are diodes. Configured and connected in parallel. When each switching element 2A, 2B turns on, the capacitor 26
Is applied to the flash tube 7 via the reactors 3A and 3B, and a current is supplied to the flash tube 7. When the switching elements 2A and 2B are turned off, the discharge current of the reactors 3A and 3B returns via the diodes 4A and 4B, and a smoothed DC current is supplied to the flash tube 7.

Reference numeral 28 denotes simmering of the flash tube 7
A simmer current circuit for supplying a simmer current for maintaining the state, a trigger circuit 10 for starting the discharge of the flash tube 7,
A simmer current is supplied to the flash tube 7 using the charging voltage of the capacitor 26 as a power supply.

A voltage controller 31 compares the voltage reference Vd * supplied from the voltage reference generator 30 with the charging voltage Vd of the capacitor 26 detected via the voltage detector 27, and reduces the voltage deviation. To output the voltage control signal. A multiplier 32 multiplies a voltage control signal by an AC voltage (full-wave rectified waveform) detected via a voltage detector 40 to obtain a current reference I.
Output d *. A current control unit 33 compares the current reference Id * with the output current Id of the diode bridge 22 detected via the current detector 25 and outputs a current control signal.
The signal is converted into a pulse width modulated PWM signal by the circuit 34, and the switch element 23 is turned on / off. As a result, the current flowing from the AC power supply 20 is controlled to a high power factor (approximately 1) by approaching a sine wave, and at the same time, the voltage of the capacitor 26 is controlled to match the voltage reference Vd *.

Reference numeral 35 denotes a current reference generator which outputs a current reference I ^* having a predetermined current pattern when the start signal SA is input. Comparators 36A and 36B compare the current reference I ^* with the output currents I1 and I2 of the chopper circuits detected by the current detectors 29A and 29B, respectively, and output reset signals. 39A and 39B are flip-flop circuits, and the oscillation circuit 37
Are set by the fixed frequency clock pulses RA and RB output from the comparator 36A, reset by the reset signals output from the comparators 36A and 36B, output a PWM signal with pulse width modulation, and are switched via the driving circuits 15A and 15B. Element 2A, 2
B is controlled on and off respectively. Reference numerals 38A and 38B denote dither circuits, which output sawtooth-wave dither signals DA and DB synchronized with the clock pulse RA and input them to comparators 36A and 36B, respectively.

In the above configuration, the flash tube 7 is supplied with a current obtained by adding the currents I1 and I2 output from the two sets of current control type chopper circuits, so that a current with little ripple can be supplied. That is, when the start signal is input at time t1, as shown in FIG.
A current reference I ^* having a predetermined pattern is output from 35, and at the same time, the drive circuits 15A and 15B are activated. When the flip-flop circuits 39A and 39B are set by the clock pulses RA and RB output from the oscillation circuit 37, the ON PW
When the M signal is output, the switching elements 2A and 2B become conductive, respectively, and the currents I1 and I2 increase via the reactors 3A and 3B, and the combined current I1 + I2 is supplied to the flash tube 7. In addition, the currents I1 and I2 increase and the current reference I ^*
Is exceeded, the reset signals are output from the comparators 36A and 36B, the flip-flop circuits 39A and 39B are reset and output the PWM signal of OFF, and the switching elements 2A and 2B are turned off, respectively. When the switching elements 2A and 2B are turned off, the currents I1 and I2 of the reactors 3A and 3B return via the flash tube 7 and the diodes 4A and 4B and gradually attenuate. This operation is performed at high speed every clock pulse period,
7 is supplied with a smooth DC current I1 + I2 with little ripple corresponding to the pattern of the current reference I ^* . (Claim 1) The clock pulses RA and RB output from the oscillation circuit 37
By operating the flip-flop circuits 39A and 39B alternately with a phase difference between them, a current with less ripple can be supplied to the flash tube 7. FIG. 2 (b) shows in detail a part of the period when the clock pulses RA and RB have a phase difference of approximately 180 °. The period of the current I2 increases while the ripple component ΔI1 of the current I1 increases. The ripple component ΔI2 decreases, and ΔI2 increases while ΔI1 decreases. Therefore, .DELTA.I1 and .DELTA.I2 cancel each other out, resulting in a current having a small ripple component. Capacitor
If the voltage of 26 is selected to be twice the terminal voltage of the load 7, the ON and OFF periods of the switch elements 2A and 2B are equal (modulation rate = 0.
In the case of 5), the current change rates in the increasing direction and the decreasing direction of the currents are substantially equal to each other and cancel each other, resulting in an ideal current waveform having almost no ripple. (Claim 2) When the rate of change of the current reference I ^* is small, the current reference I ^* and the output current I1 of the chopper circuit are set as shown in FIG.
, I2 is reduced to a state close to zero, so that the reset points of the comparators 36A and 36B are affected by noise and the like, and the current waveforms of ΔI1 and ΔI2 may vary. In such a case, the above-described canceling action is lost, and the ripple component of the current increases. Dither circuits 38A, 38B
Is provided to allow the comparators 36A and 36B to perform a stable reset operation even in such a case. That is, the dither signals DA and DB output from the dither circuits 38A and 38B are
As shown in (a), the signal is a saw-tooth wave signal gradually decreasing in synchronization with the period of the clock pulses RA and RB, and the magnitude (amplitude) of the signal is smaller than the maximum value of the current reference I ^*. It is. FIG. 3A shows a case where the clock pulses RA and RB have a phase difference of 180 °. This dither signal DA, D
B is added to the inputs of the comparators 36A and 36B, and a stable reset operation is performed even when the deviation between the current reference I ^* and the output current of the chopper circuit is small. The same effect can be obtained by adding the dither signal as a signal of a gradually increasing sawtooth wave from the input. (Claim 4) Although adding a dither signal is advantageous for stabilizing pulse width modulation control, when a DC component is included in the dither signal, a deviation between the current reference and the output current of the chopper circuit is generated. Therefore, it is necessary to correct this error when high-precision current control is required.

FIG. 3B shows a current error .DELTA.I1 between the current reference I ^* and the output current I1 of the chopper circuit when the dither signal DA1 of a gradually increasing sawtooth wave is added to the output current I1 of the chopper circuit. In this case, I ^* and I1 +
When DA1 matches, a reset signal is output, and the current error ΔI1 is determined by the ratio T1 / T2 (= modulation rate M) between the ON period T1 of the switch element by pulse width modulation and the modulation period T2.
Is proportional to the amplitude ΔDA1 of the dither signal DA1 and ΔI1 = M *
Calculated as ΔDA1. Therefore, the current error can be compensated by obtaining the current correction value ΔI1 from the modulation factor M and the amplitude ΔDA1 of the dither signal DA1 and adding the current correction value ΔI1 to the current reference I ^* , thereby performing highly accurate and stable current control.
According to the present embodiment, stable current control can be performed with high accuracy, a large-capacity filter capacitor is not required in the chopper circuit for current control, and oscillation due to L and C does not occur. Therefore, even if the diode for preventing backflow is omitted, the simmer current can be stably flowed, and a compact and economical power supply device can be obtained.

Also, the simmer current circuit 28 can be omitted by always applying a simmer current reference to any one of the chopper circuits and keeping the drive circuit always operating.
In this case, the ratio of the ripple current to the simmer current increases because the simmer current is considerably smaller than the main current. In order to reduce the ripple of the simmer current, the inductance of the reactor of the chopper circuit that supplies the simmer current has a large value in the range of the simmer current, and the inductance of the reactor of the other chopper circuit in the range of the main current exceeding the range of the simmer current. It is assumed that the reactor has a saturation characteristic having an equal value. As a result, it is possible to stably supply the simmer current with little ripple and to control the main current with a fast response. (Claims 3 and 4) An embodiment corresponding to claims 5 to 9, 12 to 18 of the present invention is shown in FIG.

In FIG. 4, reference numeral 44 denotes a short-circuit switch for short-circuiting the DC output side of the chopper circuit, 46 denotes a small-capacity capacitor for suppressing overvoltage generated when the short-circuit switch 44 turns off, and 48 denotes a charge of the capacitor 46. A resistor for discharging, 47 is a discharge switch connected in series to a resistor 48, 45 is a diode, 41 is a starting circuit for controlling a starting current, 42
Is a current control for controlling the output current by comparing the current reference I ^* with the output current I of the chopper circuit detected via the current detector 29 and controlling the switching element 2 to turn on and off so as to reduce the deviation. Reference numerals 43 and 49 denote drive circuits for the short-circuit switch and the discharge switch.

In the above configuration, at time t1, the activation signal SA
Is input to the current reference generator 35 via the start circuit 41, and the current reference I ^* having a predetermined pattern is output as shown in FIG. 4 (b). Also, the starting circuit
41 simultaneously outputs a short-circuit signal BP and turns on the short-circuit switch 44 via the drive circuit 43. As a result, the entire voltage of the capacitor 26 is applied to the reactor 3, and the current flowing in the reactor 3 starts to flow as the bypass current Ib from the time t1 via the short-circuit switch 44, and the current change rate determined by the voltage of the capacitor 26 and the inductance of the reactor 3 And increase rapidly. Then, the current flowing through reactor 3 is changed to time t2.
When the current reference I ^* is reached, a comparator provided in the current control unit 42 outputs a short-circuit release signal OF to turn off the short-circuit switch 44, and the current flowing through the reactor 3 is changed from the time t2 by the chopper circuit. The output current I is supplied to the flash tube 7 via the diode 6. Therefore, an extremely fast rising waveform current can be supplied to the flash tube 7. (Claims 5 and 6) Further, when a start signal is not input or when the current reference I ^*
Is zero or a value close to zero, the discharge switch 47 is turned on to discharge the charge of the capacitor 46 via the resistor 48. This makes it possible to suppress the discharge current of the capacitor 46 when the short-circuit switch 44 is turned on. When the short-circuit switch 44 is turned off, the capacitor 46 operates as a snubber circuit that suppresses transient overvoltage, and also operates as a filter that suppresses ripple of the output current. If the overvoltage is less than the allowable voltage, the capacitor 46
Need not be described, and the switch element 47 and the resistor 48 are not required. Alternatively, a circuit in which a diode for blocking discharge current and a resistor are connected in parallel may be connected in series with the capacitor 46, and the discharge switch 47 may be omitted. In the case where the load is a laser tube, since the energization duty is small, the effect on power consumption can be almost ignored even if the resistor 48 is always connected. Also, a signal for turning on / off the short-circuit switch 44 is given from the higher-level control unit, and a short-circuit time required for a current rise according to the current pattern is calculated from the higher-level control unit at the time of startup. A command may be given to turn on / off the short-circuit switch 44. (Claim 7) When the current flowing through the flash tube 7 is cut off for some reason, the energy stored in the reactor 3 is regenerated to the capacitor 26 through the diodes 6 and 45, and the overvoltage is generated. Suppress. This energy regeneration circuit can be applied to circuits of other embodiments. (Claim 18) An embodiment corresponding to claims 10 to 11 of the present invention is shown in FIG.

In this embodiment, when the application of the simmer current is started, a high voltage may be required depending on the flash tube 7, and the configuration can cope with such a case.

In FIG. 5, a simmer current circuit 28 includes a chopper circuit including a switch element 281, a diode 283, and a reactor 282, and a constant current control circuit 285 for controlling a simmer current detected via a current detector 284 to a constant value. It consists of. The level detector 50 outputs a detection signal SR when a simmer current flows. The voltage reference circuit 30 outputs various values of the voltage reference Vd * according to the command. The DC power supply circuit 61 obtains a variable DC voltage from the AC power supply 20 and controls the voltage Vd of the capacitor 26. The voltage control unit 62 includes a reference voltage Vd * and a DC voltage Vd detected through the voltage detector 27.
And controls the DC power supply circuit 61 to make Vd equal to Vd *.

In the above configuration, when the simmer current is supplied to the flash tube 7, the voltage reference circuit 30 outputs a high voltage reference Vd ^* , and the voltage control unit 62 controls the DC power supply circuit 61 to control the capacitor. The voltage Vd of 26 is set to a high value. As a result, a high voltage is applied to the flash tube 7 by the current output from the simmer current circuit 28, discharge is started by the action of the trigger circuit 10, and the simmer current starts to flow. When the simmer current flows, a detection signal SR is output from the level detector 50, and the voltage reference circuit 30 sets the reference voltage Vd ^* to a normal set voltage. Therefore, even in the case of the flash tube 7 requiring a high voltage, the application of the simmer current can be easily started. When the trigger circuit 10 is operated to start the discharge of the flash tube 7, the rise of the current at the initial stage of the discharge is limited by the action of the reactor 282, and stable starting may not be performed. By charging the voltage to a high voltage and supplying the discharge current at the time of starting from the capacitor 51 via the resistor 53, stable starting can be performed. In this embodiment, the main power
DC power (capacitor 26) to supply power and simmer power
By sharing the supplied DC power,
When using two sets of DC power supplies (1 and 9) as in the past
It is smaller and more economical. The sine current circuit 28
Can be replaced with the resistor 8 shown in FIG.
Needless to say.

This embodiment can also be applied to a case where a plurality of chopper circuits are provided and a simmer current is supplied from any one of the chopper circuits.
(Claims 10 to 12) In addition, the reference voltage Vd * output from the voltage reference circuit 30 is made variable by the voltage command Vdx, so that when the current reference I ^* of a fast rising pattern is given, the reference voltage Vd * is increased. In order to reduce the delay of the rise of the output current of the chopper circuit and to provide a current reference I ^* having a gradual rise pattern, the reference voltage Vd * is lowered to reduce the ripple component of the output current of the chopper circuit. it can. (Claim 17)

As described above , according to the present invention, since the current is supplied by using the current control type chopper circuit, the characteristics of the load such as the flash tube can be changed without being affected by the voltage fluctuation on the power supply side. independently can be supplied a direct current of a predetermined pattern, also, by providing a phase difference to the modulation cycle of the pulse width modulation control of a plurality of chopper circuits, Li
It can supply DC current with few pulls with high accuracy and stability, and can control the voltage of the DC power supply and the on-time of the short-circuit switch according to the rise characteristics of the current reference. And a power supply device for a load such as a flash tube, which can stably maintain a simmer current, can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a power supply device according to the present invention.

FIG. 2 is a waveform chart for explaining the operation of the embodiment.

FIG. 3 is a waveform chart for explaining the operation of the embodiment.

FIG. 4 is a configuration diagram and a waveform diagram showing another embodiment of the power supply device according to the present invention.

FIG. 5 is a configuration diagram showing another embodiment of the power supply device according to the present invention.

FIG. 6 is a diagram showing a conventional device, (a) is a configuration diagram thereof, (b)
3 is a waveform chart for explaining the operation.

[Explanation of symbols]

2,2A, 2B, 23… Switch element (IGBT) 3,3A, 3B… Reactor 4,4A, 4B, 6,24,45,52… Diode 7… Flash tube 10… Trigger circuit 15,15A, 15B… Drive Circuit 20… AC power supply 21… AC reactor 22… Diode bridge 25,29,29A, 29B
... Current detector 26 ... Capacitor 27 ... Voltage detector 28 ... Simmer current circuit 30 ... Voltage reference circuit 31 ... Voltage control unit 32 ... Multiplier 33 ... Current control unit 34 ... PWM circuit 35 ... Current reference circuit 36A, 36B ... Comparison 37… Oscillation circuit 38A, 38B… Dither circuit 39A, 39B… Flip-flop circuit 40… Voltage detector (full-wave waveform) 41… Start-up circuit 42… Current control circuit 43,49… Drive circuit 44… Short-circuit switch 46,51 ... Capacitor (small capacity) 47 ... Discharge switch 48,53 ... Resistance 50 ... Level detector 61 ... DC power supply circuit 62 ... Voltage controller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification symbol FI H02M 3/155 H02M 3/155 W (58) Fields surveyed (Int.Cl. ⁶ , DB name) H02M 3/00-3 / 44 H02M 7/00-7/40 H02M 9/00-9/06 H01S 3/092 H05B 41/00-41/46

Claims (7)

(57) [Claims] A switch element having one end connected to one end of a load such as a flash tube, one end connected to the other end of the DC power source, and the other end connected to the other end of the load; A chopper circuit composed of a diode having one end connected to a series connection point of the switch element and the reactor and the other end connected to one end of the load, and a chopper circuit synchronized with a clock pulse given at a constant cycle. A switch element is turned on, and the switch element is turned off based on a comparison result between a current reference and an output current detection value of the chopper circuit, and a dither signal that gradually increases or decreases in synchronization with the cycle of the clock pulse is generated. Means for adding the current reference or the output current detection value of the chopper circuit to output a stable PWM signal to perform stable current control. And a power supply device. 2. The power supply apparatus according to claim 1, wherein a plurality of said chopper circuits are connected in parallel to supply a combined current to said load, and a plurality of said current control means are provided to control each current. During the modulation period of the pulse width modulation control of the means,
A power supply device characterized in that a phase difference is provided so that ripple components of output currents of respective chopper circuits cancel each other, and a current with little ripple is supplied. 3. The power supply device according to claim 2, wherein at least a part of the chopper circuit is configured to supply a simmer current for maintaining the load in a sine-marining state, and the chopper circuit supplies the simmer current. A power supply device, wherein the reactor of the circuit is a reactor having a saturation characteristic in which an inductance acts largely in a range of the simmer current and a small inductance acts in a range exceeding the simmer current. 4. The power supply device according to claim 1, wherein the PWM control unit includes a unit that obtains a correction signal from a modulation rate of the PWM signal and an amplitude of the dither signal and adds the correction signal to the current reference. A power supply device for compensating for a current error caused by a dither signal. 5. The power supply device according to claim 1, wherein the DC power supply includes voltage control means for variably controlling a DC output voltage of the DC power supply, and a current based on a predetermined current reference. A DC output voltage set based on a rising characteristic of the power supply. 6. The power supply device according to claim 5, further comprising a diode having one end connected to the other end of the DC power supply and the other end connected to the other end of a load such as the flash tube. When the current of a load such as is interrupted, the discharge current of the reactor is returned to the DC power supply through the diode to regenerate energy. 7. The power supply device according to claim 1, wherein a snubber circuit including a resistor, a diode, and a capacitor is provided on an output side of the power supply device main body. Power supply device.