JP2000152668A - Power supply for pulse laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain pulse laser light having a pulse width which is neither too short not peak too large an output with a simple structure. SOLUTION: Series circuits of saturable reactors ALn1, ALn2 and transferr capacitors Cn1, Cn2 are connected in parallel to a peaking capacitor Cp. The saturable reactors ALn1, ALn2 are connected magnetically, and saturable reactors BLn1, BLn2 for the fine adjustment of transfer starting time are connected in series to each of the reactors ALn1, ALn2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse laser power supply using a magnetic switch (saturable reactor) used for laser pulse discharge, and more particularly to a pulsed laser power supply without lowering energy per pulse. The present invention relates to an improvement for reducing a peak power of a laser.

[0002]

2. Description of the Related Art As a high power pulse laser or a pulse power supply for an accelerator,
In recent years, those using a magnetic pulse compression circuit are often used to improve the durability of main switches such as thyratrons and GTOs.

FIG. 11 shows an equivalent circuit of a general capacity shift type magnetic pulse compression device used for a pulse power supply of a pulse laser. FIG. 12 shows waveform examples of voltages and currents in respective parts of the circuit of FIG. Things.

The discharge circuit shown in FIG. 11 is a two-stage magnetic pulse compression circuit utilizing the saturation phenomenon of three magnetic switches AL0 to AL2 composed of saturable reactors.

In FIG. 11, first, a capacitor C0
Then, the electric charge from the high voltage power supply HV is charged via the magnetic switch AL0 and the coil L1.

Thereafter, when a pulse oscillation synchronizing signal (trigger signal) TR which is turned on in synchronization with the pulse laser oscillation repetition frequency is inputted, the main switch SW is turned on at this time (time t0 in FIG. 12). ). When the main switch SW is turned on, the potential VSW of the main switch SW sharply drops to 0, and thereafter, the time product of the voltage difference VC0-VSW between the capacitor C0, which is the voltage across the magnetic switch AL0, and the main switch SW (the voltage VC0). When the time integral value S0 reaches a limit value determined by the setting characteristics of the magnetic switch AL0, the magnetic switch AL0 saturates at this time point t1, and the current pulse i0 flows through the loop of the capacitor C0, the magnetic switch AL0, the main switch SW, and the capacitor C1. Flows.

The time δ0 from the start of the flow of the current pulse i0 until it becomes 0 (time t2), that is, the charge transfer time δ0 until the charge is completely transferred from the capacitor C0 to the capacitor C1, is determined by the main switch SW and the like. If the loss is ignored, the inductance after saturation of the magnetic switch AL0,
It is determined by each capacitance of the capacitor C0 and the capacitor C1.

On the other hand, when the time product S1 of the voltage VC1 of the capacitor C1 reaches a limit value determined by the setting characteristics of the magnetic switch AL1, the magnetic switch AL1 saturates at this time point t3 to have a low inductance. As a result, a current pulse i1 flows through the loop of the capacitor C1, the capacitor C2, and the magnetic switch AL1. The current pulse i1 becomes 0 at time t4 after a predetermined transfer time δ1 determined by the capacitance of the capacitors C1 and C2 and the inductance after saturation of the magnetic switch AL1.

When the time product S2 of the voltage VC2 of the capacitor C2 reaches a limit value determined by the setting characteristics of the magnetic switch AL2, the magnetic switch AL2 saturates at this time t5, whereby the capacitor C2, the peaking capacitor CP, A current pulse i2 flows through the loop of the magnetic switch AL2.

Thereafter, the voltage VCp of the peaking capacitor Cp rises with the progress of charging, and when this voltage VCp reaches a predetermined main discharge starting voltage, at time t6, the laser gas between the main electrodes 10 is broken down and the main discharge is started. Is started. The laser medium is excited by the main discharge, and a laser beam is generated after several nsec.

[0011] Thereafter, the voltage of the peaking capacitor Cp rapidly decreases due to the main discharge, and returns to the state before the start of charging after a predetermined time has elapsed.

[0012] Such a discharging operation is repeatedly performed by the switching operation of the main switch SW in synchronization with the trigger signal TR, whereby pulse laser oscillation is performed at a predetermined repetition frequency (pulse oscillation frequency).

In this case, since the inductance of the charge transfer circuit of each stage composed of the magnetic switch and the capacitor is set to decrease as it goes to the subsequent stage, the peak values of the current pulses i0 to i2 become higher sequentially. In addition, a pulse compression operation is performed such that the width of the current supply becomes gradually narrower, and as a result, a strong discharge can be obtained between the main electrodes 6 in a short time.

If the pulse compression ratio is too high by the magnetic pulse compression as described above, a pulse laser beam having a short pulse width and a large peak output can be obtained, but a pulse laser beam having a short pulse width and a high output can be obtained.・ The durability of the optical components provided in the laser resonator is deteriorated. ・ The number of round trips (the number of round trips of the laser light in the resonator) is reduced. Various problems such as a decrease in the number of times of incidence and a decrease in the efficiency of band narrowing occur. Therefore, in recent years, on the contrary, a pulse laser beam whose pulse width is not too short and peak output is not too large is often demanded. Since the pulse width is increased even though the peak output of the pulse laser light is reduced, the energy per laser pulse does not become smaller than that of the pulse laser light having a short pulse width and a large peak output.

However, in the above prior art, the capacitor C
From 2 to the peaking capacitor Cp, all charges are transferred at a time as a current pulse i2, so that the emission intensity and emission time of the pulse laser light are uniquely determined by the charge transfer time and the peak value of only the current pulse i2. It is difficult to fine-tune this. Further, in the above-described prior art, most of the electric charge transferred from the capacitor C2 to the peaking capacitor Cp is consumed by the discharge, and the electric charge is not transferred to the peaking capacitor Cp even after the start of laser emission. However, there is a natural limitation in terms of circuit in increasing the pulse width of the laser pulse.

The present invention has been made in view of such circumstances, and provides a pulse laser power supply device capable of obtaining pulse laser light having a pulse width not too short and a peak output not too large with a simple configuration. The purpose is to do.

[0017]

According to the first aspect of the present invention, there is provided a pulse laser discharge electrode provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a peaking capacitor. It has a saturable reactor connected in parallel with the capacitor and a series circuit of the transfer source capacitor, and transfers the electric charge charged in the transfer source capacitor to the peaking capacitor by utilizing the magnetic saturation phenomenon of the saturable reactor. In a pulse laser power supply device that generates a pulse laser by exciting a laser medium by performing pulse discharge between electrodes, a series circuit of the saturable reactor and a transfer source capacitor is connected in parallel to the peaking capacitor. Along with the magnetic coupling of the plurality of supersaturated reactors,
Further, a saturable reactor for finely adjusting the transfer start time is connected in series to each of the plurality of saturable reactors.

According to the first aspect of the present invention, the plurality of saturable reactors connected in parallel included in the final-stage charge transfer circuit for transferring charges from the transfer source capacitor to the peaking capacitor are magnetically coupled. The saturation timings of the plurality of magnetically coupled saturable reactors coincide. That is, since a plurality of saturable reactors connected in parallel are magnetically coupled, before the saturable reactor saturates due to various variation factors, it is assumed that there is some variation in the change in the current flowing through each saturable reactor. Also, the saturation timings of the plurality of saturable reactors match, and the timing of the start of charge transfer with the plurality of saturable reactors can be aligned.
According to the first aspect of the invention, a saturable reactor for finely adjusting the transfer start time is connected to each of the plurality of magnetically coupled saturable reactors in series. The plurality of saturable reactors for fine adjustment of the transfer start time connected in series are not magnetically coupled.

Therefore, according to the first aspect of the invention, the charge transfer start timing in a plurality of circuit routes from a plurality of transfer source capacitors to a peaking capacitor is finely adjusted and delayed by a saturable reactor for fine adjustment of a transfer start time. In addition, the inductance in each circuit route is increased by the plurality of saturable reactors for fine adjustment of the transfer start time, so that the charge transfer time in each circuit route can be finely adjusted to be long.

Thus, according to the first aspect of the present invention,
The charge transfer start timing for charge transfer from multiple transfer source capacitors to the peaking capacitor is delayed, and the charge transfer time can be adjusted longer, so that the laser light emission time can be extended and the unit time can be increased. Per light emission intensity can be reduced. Therefore, according to the present invention, a pulse laser beam whose pulse width is not too short and peak output is not too large can be obtained with a simple configuration. According to the first aspect of the present invention, the saturable reactor having a small inductance for fine adjustment is provided separately from the saturable reactor having a large inductance which is magnetically coupled, and the transfer is started by the saturable reactor for fine adjustment. Since the timing and the charge transfer time are adjusted, the adjustment accuracy can be improved as compared with the case where the saturable reactor having a large inductance is adjusted.

According to a second aspect of the present invention, in the first aspect of the present invention, the assist times of the plurality of transfer start time fine adjustment saturable reactors are made different.

In the second aspect of the present invention, the assist times of the plurality of saturable reactors for fine adjustment are made different, so that the saturation timings of the plurality of saturable reactors for fine adjustment become different. Accordingly, the start timings of the charge transfer from the plurality of transfer source capacitors to the peaking capacitors are different from each other. Therefore, charge transfer to the peaking capacitor is performed at different start timings through a plurality of circuit routes, whereby the peaking capacitor is charged relatively slowly. Therefore, in the present invention, the emission time of the laser light can be further extended and the emission intensity per unit time can be reduced as compared with the first aspect of the invention. In this case, since the charge transfer of each circuit route is performed at a different start timing, the discharge is started by the charge transferred to the peaking capacitor, and the peaking is performed from another circuit route while the laser light is being emitted. A phenomenon in which charges are transferred to the capacitor occurs, and the emission time of the laser light can be extended.

According to a third aspect of the present invention, in the first aspect of the invention, the plurality of magnetically coupled saturable reactors have different inductances after saturation.

According to the third aspect of the present invention, since the inductances of the plurality of magnetically coupled saturable reactors after saturation are made different, the charges of the plurality of charge transfer routes from the plurality of transfer source capacitors to the peaking capacitor are changed. The transfer start timings are the same, but the charge transfer times are different. Therefore, in the present invention,
Compared with the first aspect of the invention, the emission time of the laser beam can be further extended, and the emission intensity per unit time can be reduced. Also, in this case, since the charge transfer time of each circuit route is different, the discharge is started by the charge transferred to the peaking capacitor, and the peaking capacitor is transferred from another circuit route while the laser light is emitted. A phenomenon that charges are transferred to the substrate occurs, and the emission time of the laser beam can be extended.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the plurality of magnetically coupled saturable reactors have different inductances after saturation.

In other words, according to the fourth aspect of the present invention, the post-saturation inductances of the plurality of magnetically coupled saturable reactors are made different, and the assist times of the plurality of transfer start time fine adjustment saturable reactors are made different. Therefore, the charge transfer start timings of the plurality of charge transfer routes from the plurality of transfer source capacitors to the peaking capacitor are different, and the charge transfer times thereof are different. Therefore, in the present invention, the emission time of the laser light can be further extended and the emission intensity per unit time can be reduced as compared with the first aspect of the invention. In this case, since the charge transfer start timing and the charge transfer time of each circuit route are different from each other, the discharge is started by the charge transferred to the peaking capacitor, and the other light is emitted while the laser light is being emitted. A phenomenon in which charges are transferred from the circuit route to the peaking capacitor occurs, and the emission time of the laser light can be extended.

According to a fifth aspect of the present invention, there is provided a pulse laser discharge electrode provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a saturable reactor connected in parallel to the peaking capacitor. A pulse discharge is performed between the discharge electrodes by transferring a charge charged in the transfer source capacitor to a peaking capacitor by utilizing a magnetic saturation phenomenon of the saturable reactor, thereby forming a laser. In a pulse laser power supply device that generates a pulse laser by exciting a medium, the saturable reactor is divided into a plurality of parallel circuits of magnetically coupled saturable reactors, and each of the plurality of saturable reactors is connected in series to the plurality of saturable reactors. The fact that a saturable reactor for fine adjustment of the transfer start time is connected It is a symptom.

According to the fifth aspect of the present invention, in the magnetic pulse compression circuit, a series circuit of a saturable reactor and a plurality of saturable reactors in the series circuit of the saturable reactor and the transfer source capacitor included in the charge transfer circuit of the last stage is used. And a plurality of these saturable reactors are magnetically coupled, and a saturable reactor for fine-tuning the transfer start time is connected in series to each of the plurality of magnetically coupled saturable reactors.

That is, in the case of the present invention, there is one transfer source capacitor.

Therefore, according to the fifth aspect of the present invention, similarly to the first aspect of the present invention, the charge in the plurality of circuit routes from the plurality of transfer source capacitors to the peaking capacitor by the saturable reactor for fine adjustment of the transfer start time. The transfer start timing can be finely adjusted to be delayed, and the inductance in each circuit route is increased by the plurality of saturable reactors for fine adjustment of the transfer start time, so that the charge transfer time in each circuit route is lengthened. Fine adjustment can be made, so that in the present invention, the emission time of the laser beam can be extended and the emission intensity per unit time can be reduced. Further, in the present invention, the transfer start timing and the charge transfer time are adjusted by the saturable reactor for fine adjustment, so that the adjustment accuracy can be improved as compared with the case of adjusting the saturable reactor having a large inductance. .

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the assist times of the plurality of saturable reactors for fine adjustment are made different.

According to the sixth aspect of the present invention, since the assist times of the plurality of saturable reactors for fine adjustment are made different, the saturation timings of the plurality of saturable reactors for fine adjustment become different. Accordingly, the start timings of the charge transfer from the plurality of transfer source capacitors to the peaking capacitors are different from each other. Therefore, charge transfer to the peaking capacitor is performed at different start timings through a plurality of circuit routes, whereby the peaking capacitor is charged relatively slowly. Therefore, in the present invention, the emission time of the laser light can be further extended and the emission intensity per unit time can be reduced as compared with the invention of the fifth aspect. In addition, a phenomenon occurs in which electric charges are transferred to the peaking capacitor from another circuit route while the laser beam is being emitted while discharging is started by the charges transferred to the peaking capacitor,
It is possible to extend the emission time of the laser light.

According to a seventh aspect of the present invention, in the fifth aspect of the invention, the plurality of magnetically coupled saturable reactors have different inductances after saturation.

According to the seventh aspect of the present invention, the inductances of the plurality of magnetically coupled saturable reactors after saturation are made different, so that the charges of the plurality of charge transfer routes from the plurality of transfer source capacitors to the peaking capacitor are changed. The transfer start timings are the same, but the charge transfer times are different. Therefore, in the present invention,
The emission time of the laser beam can be further extended and the emission intensity per unit time can be reduced as compared with the invention of claim 5. In addition, a phenomenon occurs in which discharge is started by the electric charge transferred to the peaking capacitor and the electric charge is transferred from another circuit route to the peaking capacitor while the laser light is being emitted. It is also possible to extend the light emission time.

According to an eighth aspect of the present invention, in the sixth aspect of the invention, the plurality of magnetically coupled saturable reactors have different inductances after saturation.

According to the eighth aspect of the invention, the plurality of magnetically coupled saturable reactors have different inductances after saturation, and the plurality of transfer start time fine adjustment saturable reactors have different assist times. Therefore, the charge transfer start timings of the plurality of charge transfer routes from the plurality of transfer source capacitors to the peaking capacitor are different, and the charge transfer times are different. Therefore, in the present invention, the emission time of the laser light can be further extended and the emission intensity per unit time can be reduced as compared with the invention of the fifth aspect. In this case, since the charge transfer start timing and the charge transfer time of each circuit route are different from each other, the discharge is started by the charge transferred to the peaking capacitor, and the other light is emitted while the laser light is being emitted. A phenomenon in which charges are transferred from the circuit route to the peaking capacitor occurs, and the emission time of the laser light can be extended.

According to the ninth aspect of the present invention, a pulse laser discharge electrode provided in the laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a plurality of transfer starters connected in parallel to the peaking capacitor. A final stage charge transfer circuit having a series circuit of a saturable reactor for time fine adjustment and a first capacitor; and a plurality of saturable reactors and a second capacitor connected to each of the plurality of first capacitors. And a charge transfer circuit one stage before the last stage having a series circuit of: a plurality of the first capacitors using a magnetic saturation phenomenon of a saturable reactor to transfer the charges charged in the plurality of second capacitors. By performing pulse discharge between the discharge electrodes by transferring to a peaking capacitor through the A pulse laser power supply device for generating a plurality of saturable reactors of a charge transfer circuit one stage before the last stage by magnetic coupling, and a plurality of transfer start times included in the last stage charge transfer circuit. It is characterized in that the saturation timing of the saturable reactor for adjustment is made different.

According to the ninth aspect of the present invention, the charge transfer circuit one stage before the final stage connects a plurality of series circuits of the saturable reactor and the second capacitor in parallel, and connects the plurality of saturable reactors to the magnetic field. Join. The charge transfer circuit at the final stage connects a series circuit of a saturable reactor for fine adjustment of the transfer start time and a first capacitor to a plurality of peaking capacitors in parallel. The saturation timing of the saturable reactor for finely adjusting the transfer time included in the charge transfer circuit in the final stage is made different. That is, according to the ninth aspect of the present invention, a plurality of series circuits of the saturable reactor for fine adjustment of the transfer start time and the first capacitor are provided in order to make the transfer start timings of the plurality of charge transfer routes to the peaking capacitor different. The charge transfer circuits connected in parallel are added to the last stage. In other words, the stage immediately before the final stage magnetically couples a plurality of saturable reactors so that the charge transfer start timings of the stages immediately before the final stage match, and the final stage has the charge transfer route of each charge transfer route. The charge transfer start timing is made different.

As described above, according to the present invention, charge transfer to the peaking capacitor is performed at different start timings through a plurality of circuit routes, so that the peaking capacitor can be compared with the case where charges are collectively transferred simultaneously. It will be charged slowly. Therefore, the emission time of the laser beam can be extended, and the emission intensity per unit time can be reduced.
In addition, the phenomenon that charges are transferred from other circuit routes to the peaking capacitor occurs even when the laser light is emitted after the discharge is started, making it possible to extend the laser light emission time. Become.

According to a tenth aspect of the present invention, in the ninth aspect of the invention, the post-saturation inductances of the plurality of saturable reactors of the charge transfer circuit one stage before the magnetically coupled last stage are made different.

According to the tenth aspect of the present invention, the post-saturation inductances of the plurality of saturable reactors of the charge transfer circuit one stage before the last stage magnetically coupled are made different, so that the stage one stage before the last stage. Of the plurality of charge transfer routes in the charge transfer circuit of FIG. Therefore, according to the present invention, charges having different charge transfer times are transferred with different charge transfer start timings to the peaking capacitor via a plurality of charge transfer routes, thereby further extending the laser light emission time. And the emission intensity per unit time can be reduced.

According to an eleventh aspect of the present invention, in the ninth aspect of the present invention, the post-saturation inductances of the plurality of saturable reactors for finely adjusting the transfer start time included in the last-stage charge transfer circuit are made different. It is characterized by.

In the eleventh aspect of the present invention, the saturation timing and the post-saturation inductance of the plurality of finely-adjustable saturable reactors in the charge transfer circuit in the final stage are made different from each other. The charge transfer start timing of the charge transfer route and the charge transfer time are different. Therefore, according to the present invention, charges having different charge transfer times are transferred to the peaking capacitor at different charge transfer start timings through a plurality of charge transfer routes, thereby making it possible to extend the laser light emission time. Also, the emission intensity per unit time can be reduced.

According to a twelfth aspect of the present invention, a discharge electrode for a pulse laser provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a plurality of transfer starters connected in parallel to the peaking capacitor A final-stage charge transfer circuit having a series circuit of a saturable reactor for time fine adjustment and a first capacitor; a plurality of saturable reactors connected in series to each of the plurality of first capacitors; A charge transfer circuit one stage before the last stage having one second capacitor connected in parallel with the saturable reactor, and using the magnetic saturation phenomenon of the saturable reactor to transfer the charge charged in the second capacitor. A pulse discharge can be performed between the discharge electrodes by transferring to a peaking capacitor via the plurality of first capacitors. A pulse laser power supply for exciting a laser medium to generate a pulsed laser, wherein a plurality of saturable reactors of a charge transfer circuit one stage before the last stage are magnetically coupled, and the charge of the last stage is The saturation timing of a plurality of saturable reactors for fine adjustment of the transfer start time included in the transfer circuit is made different.

According to the twelfth aspect of the present invention, one step from the last stage.
The preceding charge transfer circuit includes one second capacitor,
It is composed of a plurality of saturable reactors connected in parallel to the second capacitor. Also, the final stage charge transfer circuit
A series circuit of a saturable reactor for fine adjustment of the transfer start time and a first capacitor is connected in parallel to a plurality of peaking capacitors. Then, the saturation timing of the saturable reactor for finely adjusting the transfer time included in the charge transfer circuit of the final stage is made different.

According to the twelfth aspect of the present invention, a series circuit of a saturable reactor for finely adjusting the transfer start time and the first capacitor is provided so as to make the start timings of the charge transfer of the plurality of charge transfer routes to the peaking capacitor different. A plurality of charge transfer circuits connected in parallel are added to the final stage. That is, the twelfth aspect of the present invention is different from the ninth aspect of the present invention in that only one capacitor is included in the charge transfer circuit immediately before the last stage.

Therefore, also in the twelfth aspect of the present invention, the stage immediately before the final stage is magnetically coupled with a plurality of saturable reactors, so that the charge transfer start timing of the stage immediately before the final stage is achieved. And the charge transfer start timing of each charge transfer route is made different at the final stage.

In the twelfth aspect of the present invention as well, charge transfer to the peaking capacitor is performed at different start timings via a plurality of circuit routes. In comparison, it will be charged relatively slowly. Therefore, the emission time of the laser beam can be extended, and the emission intensity per unit time can be reduced. In addition, the phenomenon that charges are transferred from other circuit routes to the peaking capacitor occurs even when the laser light is emitted after the discharge is started, making it possible to extend the laser light emission time. Become.

According to a thirteenth aspect of the present invention, in the twelfth aspect, the post-saturation inductances of the plurality of saturable reactors of the charge transfer circuit one stage before the last stage magnetically coupled are made different.

According to the thirteenth aspect of the present invention, the post-saturation inductances of the plurality of saturable reactors of the charge transfer circuits one stage before the last stage magnetically coupled are made different, so that one stage before the last stage. Of the plurality of charge transfer routes in the charge transfer circuit of FIG. Therefore, according to the present invention, charges having different charge transfer times are transferred with different charge transfer start timings to the peaking capacitor via a plurality of charge transfer routes, thereby further extending the laser light emission time. And the emission intensity per unit time can be reduced.

According to a fourteenth aspect, in the twelfth aspect, the post-saturation inductances of the plurality of saturable reactors for finely adjusting the transfer start time included in the last-stage charge transfer circuit are made different. .

According to the fourteenth aspect of the present invention, the saturation timing and the post-saturation inductance of the plurality of finely-adjustable saturable reactors in the charge transfer circuit in the final stage are made different from each other. The charge transfer start timing of the charge transfer route and the charge transfer time are different. Therefore, according to the present invention, charges having different charge transfer times are transferred to the peaking capacitor at different charge transfer start timings through a plurality of charge transfer routes, thereby making it possible to extend the laser light emission time. Also, the emission intensity per unit time can be reduced.

[0053]

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

FIG. 1 is an equivalent circuit diagram showing an embodiment of the present invention. FIG. 1 shows only the last stage compression circuit circuit portion in the magnetic pulse compression circuit.
This magnetic pulse compression circuit is used as a power supply circuit for applying a high voltage to a discharge electrode of a pulse gas laser such as an excimer laser.

In this embodiment, a peaking capacitor Cp is connected to the discharge electrode 10 in parallel.
A series circuit of a saturable reactor ALn1, a transfer time fine adjustment saturable reactor (hereinafter simply referred to as a fine adjustment saturable reactor) BLn1 and a transfer source capacitor Cn1, and a saturable reactor ALn2
And a series circuit of a saturable reactor BLn2 for fine adjustment and a transfer source capacitor Cn2 are connected in parallel. The two transfer source capacitors Cn1 and Cn2 transfer charges to the peaking capacitor Cp, and these capacitors Cn1 and Cn2
And Cn2, charges are simultaneously transferred from a preceding capacitor (not shown). That is, the voltages of the transfer source capacitors Cn1 and Cn2 change in exactly the same manner. The transfer source capacitors Cn1 and Cn2 have the same capacitance.

On the other hand, the two saturable reactors ALn1 and ALn2 connected in parallel are densely magnetically coupled, so that their saturation timings are simultaneous.

As a method of magnetic coupling, for example, as shown in FIG. 2, two saturable reactors ALn1 and ALn2 are used.
Are wound around one common core 13.

In the saturable reactor, even if a voltage is applied to the saturable reactor, the core has a very high magnetic permeability at first, and the inductance of the winding is sufficiently large. Therefore, the current flowing through the winding increases very slowly. Go. When the magnetic flux generated by the current exceeds the saturation magnetic flux density of the core, the core is saturated, whereby the magnetic permeability of the core rapidly decreases, and the current flowing through the winding increases at a stretch.
This point is the saturation point (ON point) of the saturable reactor.

In this embodiment, since a plurality of saturable reactors of the same stage are formed by using the same core 13, before the core is saturated due to various dispersion factors,
Even if there is some variation in the change in the current flowing through the windings 11 and 12, the saturation timings of the saturable reactors at the same stage coincide, and the charge transfer of the saturable reactors ALn1 and ALn2 intervenes. Start timing can be aligned.

As another method of magnetic coupling, there is a method as shown in FIG.

In the case of FIG. 3, four saturable reactors are magnetically coupled. That is, in this method, a plurality of (in this case, four) cores 20 to 23 are used,
Of each saturable reactor across two cores 25-2
8 is wound. Of the arrows shown in FIG. 3, the arrows shown in parallel to the windings indicate the direction of the current, and the arrows shown in each of the cores 20 to 23 indicate the directions of the magnetic field created by the windings. I have. Here, it is necessary to adjust the winding direction of the coil and the direction of the current so that the directions of these magnetic fields are reversed in units of one such as counterclockwise → clockwise → counterclockwise. Also, in order to realize a reverse magnetic field in such a unit,
The number of cores needs to be even.

In FIG. 3, when a voltage is applied to each of the windings 25 to 28, a voltage is generated in each of the windings of each of the cores 20 to 23 so as to cancel the current flowing through each of the windings. Suppress the increase. At first, since the magnetic permeability of each of the cores 20 to 23 is extremely large, the inductance of the winding is sufficiently large, so that the current flowing through the winding increases very slowly. Due to this increase in current, the magnetic flux density of each of the cores 20 to 23 also increases, and approaches the saturation similarly. The core is saturated when the magnetic flux generated by the current exceeds the saturation magnetic flux density of the core.

Assuming that one core 20 has reached saturation, the windings 25 and 2 wound on this core 20
The current flowing through 8 increases sharply. Due to these current increases, the magnetic flux densities of the cores 21 and 23 adjacent to the core 20 also increase sharply.
Also saturates immediately.

As a result, the current flowing through the windings 26 and 27 wound around the cores 21 and 23 sharply increases.

Then, the core 22 remaining due to these current increases is immediately saturated.

In this way, even if any of the four cores is saturated first, the remaining three cores are immediately saturated, and the saturation timings of these four saturable reactors are matched. It becomes possible.

Next, in FIG. 1, the magnetically coupled 2
Saturable reactors BLn1 and BLn2 for fine adjustment are connected in series to the two saturable reactors ALn1 and ALn2. These saturable reactors BLn for fine adjustment
1 and BLn2 are not magnetically coupled.

That is, saturable reactor BL for fine adjustment
The post-saturation inductances of n1 and BLn2 are smaller and smaller than the post-saturation inductances of the two magnetically coupled saturable reactors ALn1 and ALn2. Improve adjustment accuracy. That is, the saturable reactors ALn1, ALn having a large inductance
Rather than adjusting the inductance of n2, the adjustment accuracy is improved by adjusting the inductance of the saturable reactors BLn1 and BLn2 for fine adjustment separately provided.

(1) First, as a first example in the circuit of FIG. 1, two saturable reactors BLn1 and BLn2
Are set so that their assist times (that is, the time required from the start of voltage application to the saturable reactor to the saturation of the saturable reactor) are different. The two saturable reactors ALn1 and ALn2 that are magnetically coupled have the same inductance after saturation.

With this setting, the charge transfer from the transfer source capacitors Cn1 and Cn2 to the peaking capacitor Cp is as shown in FIG. In FIG. 4, Vc1 is the voltage of the transfer source capacitor Cn1, Vc2 is the voltage of the transfer source capacitor Cn2, Vb1 is the terminal voltage of the saturable reactor BLn1 for fine adjustment, Vb2 is the terminal voltage of the saturable reactor BLn2 for fine adjustment, and Vcp is The current pulse I1 is the transfer current from the transfer source capacitor Cn1 to the peaking capacitor Cp, and the current pulse I2 is the transfer current from the transfer source capacitor Cn2 to the peaking capacitor Cp.

In the first state on the time axis of FIG. 4, the two magnetically coupled saturable reactors ALn1 and ALn2 are already saturated as can be seen from the states of the voltages Vc1 and Vc2. Although not shown in this waveform diagram, since the saturable reactors ALn1 and ALn2 are magnetically coupled, their saturation timings coincide. Further, since the saturable reactors ALn1 and ALn2 have the same inductance after saturation, the voltages Vc1 and Vc2 are set to the fine adjustment saturable reactor BL.
The same changes until n1 and BLn2 are saturated.

Magnetically Coupled Saturable Reactor AL
After the saturation of n1 and ALn2, the voltages Vb1 and Vb2 of the saturable reactors BLn1 and BLn2 for fine adjustment are changed from 0V to -EV.
Changes to In this case, the saturable reactor BL for fine adjustment
Each saturable reactor B such that the assist time of n1 is shorter than the assist time of saturable reactor BLn2 for fine adjustment.
The saturation characteristics of Ln1 and BLn2 are set. Therefore,
The saturable reactor for fine adjustment BLn1 reaches saturation first, and at this time, the charge of the transfer source capacitor Cn1 is changed to the current pulse I1.
Is transferred to the peaking capacitor Cp.

After that, the voltage-time product applied to the saturable reactor BLn2 for fine adjustment is changed to the saturable reactor BLn2.
When the saturation limit of n2 is reached, the saturable reactor BLn2 reaches saturation, at which point the charge of the transfer source capacitor Cn2 is transferred to the peaking capacitor Cp as a current pulse I2.

Thereafter, the voltage VCp of the peaking capacitor Cp rises, and when this voltage VCp reaches a predetermined discharge starting voltage, at this time, the laser gas between the main electrodes 10 is broken down and discharge is started. This discharge excites the laser medium and generates laser light.

As described above, in the first example, since the assist times of the plurality of saturable reactors for fine adjustment BLn1 and BLn2 are made different, the saturation timings of the saturable reactors for fine adjustment are different. As a result, the start timing of the charge transfer from the transfer source capacitors Cn1 and Cn2 to the peaking capacitor Cp becomes different. Therefore, charge transfer to the peaking capacitor Cp is performed at different start timings through a plurality of circuit routes, whereby the peaking capacitor Cp is charged for a relatively long time as shown in FIG. Will be.

Therefore, a phenomenon occurs in which electric charges are further transferred to the peaking capacitor during the start of the discharge and the emission of the laser light, and the emission time of the laser light can be extended. The light emission intensity per unit time can be reduced.

(2) Next, as a second example in the circuit of FIG. 1, two magnetically coupled saturable reactors AL
The inductances La1 and La2 after saturation of n1 and ALn2 are made different. For example, La1 <La2. However, 2
The two fine adjustment saturable reactors BLn1 and BLn2 have the same assist time. That is, the saturation timing of the saturable reactors BLn1 and BLn2 for fine adjustment is the same.

With this setting, the charge transfer from the transfer source capacitors Cn1 and Cn2 to the peaking capacitor Cp is as shown in FIG.

In the second example, the saturable reactors for fine adjustment BLn1 and BLn2 are set such that the assist times are the same, and therefore the saturable reactor for fine adjustment BLn
1 and BLn2 have the same saturation timing. Therefore, at the time of saturation of the fine-tunable saturable reactors BLn1 and BLn2, charge transfer (I1) from the transfer source capacitor Cn1 to the peaking capacitor Cp and transfer source capacitor Cp
Charge transfer (I2) from n2 to the peaking capacitor Cp is started at the same time.

However, in the second example, the inductances La1, La after saturation of the two magnetically coupled saturable reactors ALn1, ALn2 are set to La1 <La2.
As shown in FIG. 5, the charge transfer time of the current pulse I2 is longer than that of the current pulse I1.

As described above, in the second example, the saturable reactors BLn1 and BLn2 for fine adjustment are connected to the magnetically coupled saturable reactors ALn1 and ALn2, respectively, so that the final stage charge transfer is performed. The start timing can be delayed. Further, the post-saturation inductance La1, of the magnetically coupled saturable reactors ALn1, ALn2,
La2 is made different. Therefore, the start timing of the charge transfer (I1) from the transfer source capacitor Cn1 to the peaking capacitor Cp and the start timing of the charge transfer (I2) from the transfer source capacitor Cn2 to the peaking capacitor Cp coincide, but the charge transfer times are different. Become like Therefore, as shown in FIG. 4, the peaking capacitor Cp is charged for a relatively long time. Therefore, a phenomenon occurs in which electric charge is further transferred to the peaking capacitor during the start of discharge and emission of laser light, and the emission time of laser light can be extended, and the time per unit time can be increased. Can be reduced.

(3) Next, as a third example in the circuit of FIG. 1, two magnetically coupled saturable reactors AL
After saturation of n1 and ALn2, the inductances La1 and La2 are made different (for example, La1 <La2), and the assist times of the two fine adjustment saturable reactors BLn1 and BLn2 are made different.

With this setting, the charge transfer from the transfer source capacitors Cn1 and Cn2 to the peaking capacitor Cp is as shown in FIG.

In the third example, since the inductances La1 and La2 after saturation of the two magnetically coupled saturable reactors ALn1 and ALn2 are different (La1 <La2),
As shown in FIG. 6, the charge transfer time of the current pulse I2 is longer than that of the current pulse I1. In addition, since the assist times of the two saturable reactors for fine adjustment BLn1 and BLn2 are made different (reactor B in the case of FIG. 6).
The assist time of Ln1 is shorter than the reactor BLn2), and the charge transfer start timing of the current pulse I1 is changed to the current pulse I2.
Charge transfer start timing.

As described above, in the third example, the start timing of the charge transfer (I1) from the transfer source capacitor Cn1 to the peaking capacitor Cp and the start timing of the charge transfer (I2) from the transfer source capacitor Cn2 to the peaking capacitor Cp and Since the charge transfer time is made different, the peaking capacitor Cp is charged for a relatively long time as shown in FIG. Therefore, a phenomenon occurs in which electric charge is further transferred to the peaking capacitor during the start of discharge and emission of laser light, and the emission time of laser light can be extended, and the time per unit time can be increased. Can be reduced.

(4) Next, as a fourth example in the circuit of FIG. 1, two magnetically coupled saturable reactors AL
The inductance after saturation of n1 and ALn2 is the same, and the assist time of the two saturable reactors for fine adjustment BLn1 and BLn2 is also the same.

With this setting, the charge transfer from the transfer source capacitors Cn1 and Cn2 to the peaking capacitor Cp is as shown in FIG.

That is, in this case, the assist times of the fine adjustment saturable reactors BLn1 and BLn2 are the same, so that the transfer start times of the current pulses I1 and I2 do not differ. BLn1,
The charge transfer start timing of the current pulses I1 and I2 is delayed by an amount corresponding to the insertion of BLn2 as compared with the case where BLn2 is not inserted. In addition, these saturable reactors BLn1, Bn for fine adjustment
As a result of the insertion of Ln2, the reactance after saturation of each circuit increases, and the charge transfer time of the current pulses I1 and I2 also increases.

As described above, in the fourth example, according to the saturable reactors BLn1 and BLn2 for fine adjustment, a plurality of transfer source capacitors Cn1 and Cn2 are used to remove the peaking capacitor Cn1.
The charge transfer start timing in charge transfer to p is delayed, and the charge transfer time can be adjusted longer, so that the laser light emission time can be extended and the light emission intensity per unit time can be reduced. be able to.

FIG. 8 is an equivalent circuit diagram showing another embodiment of the present invention.

In this embodiment, the magnetically coupled saturable reactors ALn1 and ALn1 in the last stage charge transfer circuit
Only Ln2 and two saturable reactors BLn1 and BLn2 for fine adjustment connected in series to them are connected in parallel to the peaking capacitor Cp, and one transfer source capacitor Cn remains as before. That is, the circuit of FIG. 8 differs from the circuit of FIG. 1 only in that one transfer source capacitor Cn is left as in the related art.

In the circuit of FIG. 8, there is one transfer source capacitor Cn, but there are a plurality of charge transfer routes to the peaking capacitor Cp as in the circuit of FIG. 1, and via these plurality of routes. By performing the charge transfer, it is possible to obtain substantially the same effect as the circuit of FIG.
However, in the case of the circuit of FIG. 8, when the charge transfer of one of the two charge transfer routes is started, the voltage of the transfer source capacitor Cn drops, so that the charge transfer of the other route is started. Sometimes, the charge transfer must be performed in a state where the transfer charge amount of the transfer source capacitor Cn is reduced.
Various circuit adjustment operations are complicated as compared with the circuit of FIG.

As described above, also in the circuit configuration of FIG. 8, the adjustment of the charge transfer start timing or the charge transfer time shown in the first to fourth examples in the circuit of FIG. 1 can be applied.

That is, in the first example in the circuit of FIG. 8, the assist times of the two fine-adjustment saturable reactors BLn1 and BLn2 are set to be different.

In the second example of the circuit shown in FIG.
Two magnetically coupled saturable reactors ALn1 and ALn2
After saturation, the inductances La1 and La2 are made different, and two fine-adjustable saturable reactors BLn1 and BLn2 are used.
Are set so that the assist times of the two are the same.

In the third example of the circuit shown in FIG.
Two magnetically coupled saturable reactors ALn1 and ALn2
After saturation, the inductances La1 and La2 are made different, and two fine-adjustable saturable reactors BLn1 and BLn2 are used.
To make the assist time different.

In the fourth example of the circuit shown in FIG.
Two magnetically coupled saturable reactors ALn1 and ALn2
And the assist times of the two fine-adjustable saturable reactors BLn1 and BLn2 are the same.

In the embodiment shown in FIG. 8, almost the same charge transfer state as that shown in FIG. 1 can be generated, whereby the emission time of laser light can be extended, and the unit time per unit time can be increased. Emission intensity can be reduced.

FIG. 9 shows still another embodiment of the present invention.

In the embodiment shown in FIG. 9, the saturable reactors BLn1 and BLn2 for fine adjustment are not inserted into the charge transfer circuit at the final stage as in the embodiments shown in FIGS. , Saturable reactor for fine adjustment BLn1, BL
A charge transfer circuit comprising n2 and transfer source capacitors C (n + 1) 1, C (n + 1) 2 is added to the last stage.

In FIG. 9, a charge transfer circuit one stage before the last stage includes capacitors Cn1 and Cn2 and saturable reactors ALn1 and ALn1 connected in series to these capacitors, respectively.
ALn2. Saturable reactor ALn1, AL
n2 is magnetically coupled.

The final stage charge transfer circuit includes a capacitor C (n
+1) 1, C (n + 1) 2, and fine adjustment saturable reactors BLn1, BLn2 connected in series to these capacitors, respectively. Saturable reactor for fine adjustment BLn1, BLn2
Is not magnetically coupled. These saturable reactors for fine adjustment BLn1 and BLn have different saturation timings by making their assist times different.

In the circuit of FIG. 9, basically, the saturable reactors ALn1 and ALn2 of the preceding charge transfer circuit are magnetically coupled to change the capacitors C (n + 1) 1 and C (n) from the capacitors Cn1 and Cn2. +1) 2, the start timings of the charge transfer of the plurality of charge transfer routes are aligned, and the capacitors C (n + 1) 1, C (n +) are adjusted by the fine adjustment saturable reactors BLn1, BLn2 of the final stage charge transfer circuit. 1) Peaking capacitor Cp from 2
The start timing of the charge transfer of a plurality of charge transfer routes to the charge transfer route is made different to obtain the same effect as in the previous embodiment. That is, if the inductances of the magnetically coupled saturable reactors ALn1 and ALn2 after saturation are the same, substantially the same operation and effect as the first example can be obtained.

Various settings can be made for the post-saturation inductance of each saturable reactor as described above.

For example, in the circuit of FIG. 9, if the inductances of the magnetically coupled saturable reactors ALn1 and ALn2 after saturation are made different, the capacitors Cn1 and Cn1
The charge transfer time of a plurality of charge transfer routes from n2 to the capacitors C (n + 1) 1 and C (n + 1) 2 can be made different. Therefore, in this case, the capacitors C (n + 1) 1, C (n + 1) 2
Timing of charge transfer of a plurality of charge transfer routes from the capacitor Cp to the peaking capacitor Cp,
The charge transfer time of a plurality of charge transfer routes from n2 to the capacitors C (n + 1) 1 and C (n + 1) 2 is different from each other, so that when transferring the charge to the peaking capacitor Cp, The transfer start timing and the charge transfer time for each transfer route can be made different.

Further, in the circuit of FIG. 9, the post-saturation inductances of the fine adjustment saturable reactors BLn1 and BLn2 which are not magnetically coupled may be made different. In this way, the charge transfer start timings and charge transfer times of the plurality of charge transfer routes from the capacitors C (n + 1) 1, C (n + 1) 2 to the peaking capacitor Cp can be made different. .

With the circuit configuration shown in FIG. 9 as well, the emission time of laser light can be extended, and the emission intensity per unit time can be reduced.

FIG. 10 is an equivalent circuit diagram showing still another embodiment of the present invention.

In this embodiment, the number of the capacitors Cn included in the charge transfer circuit immediately before the last stage is one as in the conventional case. The other points are the same as those of the circuit shown in FIG.

That is, also in the embodiment shown in FIG. 10, the saturable reactors ALn1 and ALn2 of the previous stage charge transfer circuit are magnetically coupled, and the saturation timing of the fine adjustment saturable reactors BLn1 and BLn of the last stage charge transfer circuit is also set. Are different.

Also in this case, the inductances after saturation of the magnetically coupled saturable reactors ALn1 and ALn2 may be made different, or the inductances after saturation of the fine adjustment saturable reactors BLn1 and BLn may be made different. It may be.

With the circuit configuration shown in FIG. 10, the emission time of laser light can be extended, and the emission intensity per unit time can be reduced.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing one method of magnetic coupling.

FIG. 3 is a diagram showing another method of magnetic coupling.

FIG. 4 is a time chart of current and voltage in the first example of the embodiment in FIG. 1;

FIG. 5 is a time chart of current and voltage in a second example of the embodiment of FIG. 1;

FIG. 6 is a time chart of current and voltage in a third example of the embodiment in FIG. 1;

FIG. 7 is a time chart of current and voltage of a fourth example of the embodiment in FIG. 1;

FIG. 8 is an equivalent circuit diagram showing another embodiment of the present invention.

FIG. 9 is an equivalent circuit diagram showing another embodiment of the present invention.

FIG. 10 is an equivalent circuit diagram showing another embodiment of the present invention.

FIG. 11 is an equivalent circuit diagram showing a conventional technique.

FIG. 12 is a time chart of current, voltage, and the like according to the related art.

[Explanation of symbols]

 C1-C2, Cn, Cn1-Cn2 ... Capacitor Cp ... Peaking capacitor HV ... Charge power supply SW ... Main switch AL1, AL2, ALn1, ALn2 ... Saturable reactor BLn1, BLn2 ... Fine adjustment saturable reactor 10 ... Discharge electrode 11, 12, 25 to 28 ... winding 13, 20 to 23 ... core

Claims (14)

[Claims] 1. A discharge electrode for a pulse laser provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a series connection of a saturable reactor connected in parallel to the peaking capacitor and a transfer source capacitor. A pulse discharge between the discharge electrodes by transferring the charge charged in the transfer source capacitor to the peaking capacitor using the magnetic saturation phenomenon of the saturable reactor, thereby exciting the laser medium. In a pulse laser power supply device that generates a pulse laser, a plurality of series circuits of the saturable reactor and the transfer source capacitor are connected in parallel to the peaking capacitor, and the plurality of supersaturated reactors are magnetically coupled, and the plurality of Possible to fine-tune the transfer start time in series with each saturable reactor. Pulsed laser power source device being characterized in that so as to connect the sum reactor. 2. The pulse laser power supply device according to claim 1, wherein assist times of said plurality of transfer start time fine adjustment saturable reactors are made different. 3. The pulse laser power supply device according to claim 1, wherein said plurality of magnetically coupled saturable reactors have different inductances after saturation. 4. The pulse laser power supply device according to claim 2, wherein said plurality of magnetically coupled saturable reactors have different inductances after saturation. 5. A discharge electrode for a pulse laser provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a series of a saturable reactor connected in parallel to the peaking capacitor and a transfer source capacitor. A pulse discharge between the discharge electrodes by transferring the charge charged in the transfer source capacitor to the peaking capacitor using the magnetic saturation phenomenon of the saturable reactor, thereby exciting the laser medium. In a pulse laser power supply device that generates a pulse laser, the saturable reactor is divided into a plurality of parallel circuits of magnetically coupled saturable reactors, and fine adjustment of transfer start time is performed in series with each of the plurality of saturable reactors. Characterized by connecting a saturable reactor for The power supply for the. 6. The pulse laser power supply device according to claim 5, wherein assist times of said plurality of transfer start time fine adjustment saturable reactors are made different. 7. The pulse laser power supply device according to claim 5, wherein said plurality of magnetically coupled saturable reactors have different inductances after saturation. 8. The pulse laser power supply device according to claim 6, wherein said plurality of magnetically coupled saturable reactors have different inductances after saturation. 9. A pulse laser discharge electrode provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a plurality of transfer start time fine adjustments connected in parallel to the peaking capacitor. A final stage charge transfer circuit having a series circuit of a saturable reactor and a first capacitor; and a plurality of series circuits of a saturable reactor and a second capacitor connected to each of the plurality of first capacitors. A charge transfer circuit one stage before the last stage having the charge transfer circuit, and peaking the charge charged in the plurality of second capacitors through the plurality of first capacitors using the magnetic saturation phenomenon of the saturable reactor. A pulse that excites the laser medium and generates a pulse laser by performing a pulse discharge between the discharge electrodes by transferring the pulse to a capacitor A laser power supply device for magnetically coupling a plurality of saturable reactors of a charge transfer circuit one stage before the last stage, and for finely adjusting a plurality of transfer start times included in the last stage charge transfer circuit. A pulse laser power supply device wherein the saturation timing of a saturable reactor is made different. 10. The pulse laser power supply according to claim 9, wherein the post-saturation inductances of the plurality of saturable reactors of the charge transfer circuit one stage before the last stage magnetically coupled are made different. apparatus. 11. The pulse laser according to claim 9, wherein the post-saturation inductances of the plurality of saturable reactors for fine-tuning the transfer start time included in the last stage charge transfer circuit are made different. Power supply. 12. A pulse laser discharge electrode provided in a laser medium, a peaking capacitor connected in parallel to the discharge electrode, and a plurality of transfer start time fine adjustments connected in parallel to the peaking capacitor. A final stage charge transfer circuit having a series circuit of a saturable reactor and a first capacitor; a plurality of saturable reactors connected in series to each of the plurality of first capacitors; and a plurality of the saturable reactors in parallel. And a charge transfer circuit one stage before the final stage having one second capacitor to be connected, wherein the charge stored in the second capacitor is transferred using the magnetic saturation phenomenon of the saturable reactor. By performing pulse discharge between the discharge electrodes by transferring to the peaking capacitor via the capacitor 1, the laser medium And a pulse laser power supply device for generating a pulse laser by exciting a plurality of saturable reactors of the charge transfer circuit one stage before the last stage and including the saturable reactors in the last stage charge transfer circuit. A power supply device for a pulse laser, wherein the saturation timings of the plurality of saturable reactors for fine adjustment of the transfer start time are varied. 13. The pulse laser power supply according to claim 12, wherein the post-saturation inductances of the plurality of saturable reactors of the charge transfer circuit one stage before the last stage magnetically coupled are made different. apparatus. 14. The pulse laser according to claim 12, wherein the post-saturation inductances of the plurality of saturable reactors for fine-tuning the transfer start time included in the last-stage charge transfer circuit are made different. Power supply.