JPS61239684A - Discharge circuit for laser - Google Patents

Abstract

PURPOSE:To obtain voltage required for starting laser discharge at low cost by overlapping the charging voltage of a capacitor to supply voltage, applying the voltage to a laser discharge section and applying high voltage higher than supply voltage to the laser discharge section. CONSTITUTION:A diode B is inserted in series between a power supply E and a laser discharge section D. A series circuit of a switch S and a capacitor C is inserted in parallel with the diode B. When the power supply E is turned ON under the state in which the switch S is at OFF, voltage E is divided by voltage-dividing resistors R1, R2, and the capacitor C is charged. When the switch S is closed, the capacitor C is regarded as the power supply of voltage E.R2/(R1+R2) in a short time because the capacitor C instantaneously starts discharge. Consequently, a power supply in which the capacitor power supply is connected in series wit the power supply E is formed, and high output voltage can be extracted. Accordingly, discharge can be started in the discharge section D even when voltage E is lower than discharge-starting voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Technical Field of the Invention The present invention relates to a discharge circuit used in a power supply for a laser oscillator [Technical Problems of the Invention] '1.

Conventionally, a laser discharge circuit generally has a configuration shown in Example 8.
are connected in series. The voltage versus current characteristic curve of such a laser discharge circuit is as shown in FIG. In Figure 9, the operating point is current ■a, voltage V
If you want to set point A of a, first set the voltage of power supply E to ■1 which is higher than the discharge starting voltage VS, draw a straight line L1 passing through point A from that voltage V1, and set the intersection with the current axis to 11.
□゛ru. The value of the stabilizing resistor R is determined by R-V+/r+. In this manner, the voltage V1 of the power source E and the value of the stabilizing resistor R were determined, a circuit was constructed using the determined voltages and resistances, and the circuit was operated so as to maintain the discharge state at point A after the start of discharge.

However, in the case of such a conventional laser discharge circuit, the voltage (V+ - Va ) is not applied to the stabilizing resistor R, so the voltage (V+ - Va ) is not applied to the stabilizing resistor R.
・Loss of la is occurring. This 161. ') In order to keep the loss low, the value of the stabilizing resistor R is made small, and R2=V
2/12), the loss in the stabilizing resistor R is (V
2-Va)・la, which becomes smaller. However, in this case, the voltage V2 of the power source E becomes lower than the discharge starting voltage Vs, so that it becomes impossible to start the discharge.

Therefore, the voltage applied to the laser discharge section is set higher than the starting voltage Vs until the discharge starts, and after the discharge starts, the voltage of the power supply E is lowered to V2 to keep the loss in the stabilizing resistor R low. It is advisable to cover it. However, if a variable voltage power source is used to start the discharge (ly), it will be disadvantageous in terms of cost. Therefore, it is desirable to have a lightning discharge circuit for lightning that can obtain a high voltage until the start of discharge without changing the voltage of the power supply.
Purpose of the Invention The present invention has been made in view of the above-mentioned problems in the prior art. The purpose is to provide circuits.

[Structure of the invention]

In this invention, a diode is inserted in series in a discharge current path between a laser discharge section and a power supply, a series circuit of a switch and a capacitor is inserted in parallel with this diode, and a voltage dividing resistor is connected in parallel to the laser discharge section. and a voltage dividing point of the voltage dividing resistor is connected to the capacitor, the laser discharge circuit comprising: a voltage dividing point of the voltage dividing resistor connected to the capacitor; the charging voltage of the capacitor is superimposed on the power supply voltage by closing a switch in the series circuit; A high voltage higher than the power supply voltage is applied to the laser discharge section at the start of discharge.

[Embodiments of the invention]

FIG. 1 shows a circuit according to an embodiment of the present invention, in which a diode B is inserted in series with a discharge current path consisting of a power source E, a discharge section D, and a stabilizing resistor R. Further, a series circuit of a switch S and a capacitor C is inserted in parallel with this diode B. Furthermore, a voltage dividing resistor R+ is connected in parallel to the discharge section.

R2 is connected to the voltage dividing resistor R+, and a capacitor C is connected to the voltage dividing point of the voltage dividing resistor R+ and R2.

The operation of the laser discharge circuit having the above configuration will be described next. When the power supply E is turned on with the switch S in the OFF state, the power supply voltage [ is divided by the voltage dividing resistors R+ and R2, and the capacitor C is charged.

When the switch S is closed, the capacitor C starts discharging instantaneously.
can now be regarded as a power source with a voltage [.R2/(R1+R2), and an equivalent circuit as shown in FIG. 2 will be constructed.

The equivalent circuit shown in Fig. 2 is a power supply in which a capacitor power supply EC is connected in series with a power supply [,
+ and R2, it is possible to obtain an output voltage in the range of E≦output voltage≦2F. Therefore, if E<VS/2 with respect to the discharge starting voltage VS, the power supply voltage E becomes the discharge starting voltage V
-4-,':gjf, which is lower than s, can also start discharge at the discharge section.

Note that the diode B provides a path for current from the power source E to the discharge section after the charge stored in the capacitor C is discharged.

FIG. 3 shows another embodiment of the present invention, in which a thyristor Th is used as the switch. Therefore, the power source F1, diode B1, discharge section D, stabilizing resistor R1, voltage dividing resistor R+, R2, and capacitor C have the same configuration as the embodiment shown in FIG. 1, and a thyristor Th is inserted in series with the capacitor C as a switch. They are different in what they did. In this embodiment, when the thyristor Th is turned on by a trigger circuit not shown in the figure when the capacitor C is fully charged, the electric charge of the capacitor C is discharged, and as in the equivalent circuit shown in FIG. By applying an applied voltage higher than the discharge starting voltage VS to the cell, discharge can be started.

In this embodiment, when the charge in the capacitor C has finished discharging, the thyristor Th is turned off, and after that, current flows from the power source E through the diode B to the discharge section.

In the embodiments shown in FIGS. 1 and 3, the J: voltage vs. current f1 curves shown in FIG. 4 are obtained, respectively. A straight line L connecting the two points between the operating point A and the power supply voltage H on the voltage axis
2 is the load line.

However, at the start of discharge, the power supply voltage has risen to a level where the load line becomes B3 and the operating point shifts to B. Therefore, the current at the start of discharge increases, and harmful discharge may occur.

Therefore, a discharge circuit is desired in which the power supply voltage remains negative but the current does not increase. FIG. 5 shows an embodiment that meets these requirements.

In FIG. 5, power source F1 diode B1 discharge section D,
A stabilizing resistor R is connected in series to form a discharge current path, and voltage dividing resistors R+ and R2 are connected to a discharge current path.
j1m in parallel A 8 : I'L T &) 8・1'
In addition to the capacitor C and the switch S, a resistor R3 is inserted into the series circuit connected in parallel to the node 8.

The operation of the laser discharge circuit with the above configuration will be explained below.
When the electric current mE is turned on with the switch S in the OFF state, a capacitor is applied by the voltage dividing resistors R+ and R2.

The sensor C is charged with electric charge.

When the capacitor C is charged, the switch S
When turned on, the capacitor C instantly closes and starts discharging. A voltage versus current characteristic curve at this time is obtained as shown in FIG. During normal operation, the switch S is OFF, so the resistor R3 does not work, and the power supply voltage F is directly applied to the discharge section through the diode B, and the load line becomes Ll.

However, when the switch S is turned on and the charge in the capacitor C is discharged, the stabilizing resistance in the discharge current path becomes (R+R3), the load line becomes B4, and the current does not increase. As a result, it is possible to reliably prevent the occurrence of bad discharge at the start of discharge.

FIG. 7 shows still another embodiment, in which series circuits are combined in multiple stages in order to generate an even higher discharge starting voltage. In other words, a first diode B+ and a second diode B2 are inserted in series with the discharge current path of the power source E1 discharge section D1 stabilizing resistor R, and the respective diodes B+,
A series circuit of resistor R3, switch S1, and capacitor C1, and a series circuit of resistor R4, switch S2, and capacitor C2 are inserted in parallel with B2. and each capacitor C
＋.

C2 is connected to the voltage dividing point of voltage dividing resistors R+ and R2 via diodes B3 and B4, respectively.

The operation of the laser discharge circuit having multiple stages of series circuits having the above configuration will be described below. Switch S+, S
When the power supply E is turned on while R2 is OFF, the voltage dividing resistor R1
, R2, respectively, to charge the capacitors C+ and C2.

When the capacitors C+ and C2 are in a charged state, i
If you turn on switches S+ and S2 at the same time, '1', 6. Wow, 2 pieces. 1 o□□ force becomes 3.-6°, and the voltage applied to the discharge section increases, making it possible to apply a higher discharge starting voltage than in each of the embodiments described above.

In the embodiment shown in FIG. 7 above, the diode B3
, B4 are used in order to separate the two stages of series circuits so that the voltage dividing resistors R+ and R2 can be shared. However, a voltage dividing resistor may be individually connected to each capacitor C1, C2, in which case the isolation diodes B3, B4 are not used.

(Effects of the Invention) This invention inserts a diode in series with a discharge current path consisting of a power supply discharge section and a stabilizing resistor, and inserts a series circuit consisting of a switch and a capacitor in parallel to the diode. The configuration is such that the capacitor is charged by the same power source. Therefore, by turning on the switch, the charging voltage of the capacitor is superimposed on the power supply, and a discharge starting voltage higher than the original power supply voltage can be applied to the discharge section. Therefore, there is an advantage that the voltage required to start the laser discharge can be easily generated at a low cost of 1~.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a schematic diagram of the start of discharge, etc. of the above embodiment, Fig. 3 is a circuit diagram of an additional embodiment of the invention, and Fig. 4 is a schematic diagram of the first embodiment of the invention. FIG. 5 is a circuit diagram of another embodiment of the present invention, FIG. 6 is an operating characteristic curve diagram of the above embodiment, and FIG. 7 is a diagram of still another embodiment of the present invention. FIG. 8 is a circuit diagram of a conventional example, and FIG. 9 is an operating characteristic curve diagram of a conventional example. E...Power supply D...Laser discharge section R...
・Stabilizing resistor B...Diode S...Switch C...Capacitor R+, R2...Voltage dividing resistor Th...Sirisk Figure 1 Figure 2 Figure 3 Figure 10

Claims (4)

[Claims] (1) Insert a diode in series in the discharge current path between the laser discharge section and the power supply, insert a series circuit of a switch and a capacitor in parallel to this diode, and connect a voltage dividing resistor in parallel to the laser discharge section. A discharge circuit for a laser, characterized in that the voltage dividing point of the voltage dividing resistor is connected to the capacitor. (2) The laser discharge circuit according to claim 1, wherein the switch is formed of a thyristor. (3) A discharge circuit for a laser according to claim 1 or 2, characterized in that a plurality of parallel circuits of the diode and a series circuit are provided. (4) The laser discharge circuit according to claim 1, 2, or 3, wherein the series circuit includes a resistor.