JPH0782401B2 - DC high voltage power supply - Google Patents

Description

Description: A. Field of Industrial Application The present invention relates to a DC high-voltage power supply device, and is particularly required for applying a high voltage pulse to a cell suspension in a cell fusion device or a gene transfer device. The present invention relates to a power supply device that supplies a high DC voltage.

B. Conventional Technology In recent years, in the field of biotechnology, a technique for applying a high voltage pulse to a cell suspension for cell fusion or gene transfer has been studied and developed.

Such cell fusion is performed as follows, for example. An alternating voltage is applied to a cell suspension in which two types of cells are suspended to bring the cells close to each other, and then a high voltage pulse is applied to fuse the two types of cells. For gene transfer, a cell suspension in which one type of cells and a gene (DNA) are suspended is used, and the gene is transferred in the same procedure as the above-mentioned cell fusion.

A device for performing such cell fusion or gene transfer is equipped with a DC high voltage power supply device necessary for generating a high voltage pulse.

The outline of this DC high-voltage power supply device will be described below with reference to FIG.

In the figure, reference numeral 40 denotes a DC high-voltage power supply device, and 50 denotes an electrode tank containing a cell suspension.

The DC high-voltage power supply device 40 includes a DC high-voltage power supply E, a resistor R connected in series to the DC high-voltage power supply E, a charging capacitor C, and a changeover switch for switching charging / discharging of the charging capacitor C.
It is composed of SW, etc. The output terminal of the DC high-voltage power supply device 40 is connected to the positive electrode 51 and the negative electrode 52 of the electrode tank 50 containing the cell suspension, respectively.

FIG. 5 is an external perspective view showing an example of the electrode tank 50.
The electrode tank 50 is composed of a rod-shaped positive electrode 51 located at the center of the shaft, and a cylindrical negative electrode 52 concentrically arranged with the positive electrode 51. The cell suspension 60 is housed between the positive electrode 51 and the negative electrode 51.

The operation for outputting the high voltage pulse will be described below.

First, the switch SW is connected to the contact T ₁ . This allows
The charging capacitor C is charged from the DC high voltage power supply E via the resistor R. Change the charging voltage of the charging capacitor C
It is shown in FIG. When the charging of the charging capacitor C is completed, the switch SW can be switched to the contact T ₂ side. Then, the electric charge accumulated in the charging capacitor C is discharged toward the electrode tank 50, and the high voltage pulse as shown in FIG. 6B is applied to the cell suspension 60 in the electrode tank 50.

By the way, in performing cell fusion or gene transfer by applying a high voltage pulse, for example, a means for applying a single pulse of a very high voltage level of about 10 kV, as well as a voltage lower than that (for example, 1000 V or less) It is known that cell fusion and the like can be performed even when pulses are continuously applied.

If a power supply device that generates a too high voltage is used, it is necessary to take various safety measures such as sufficient insulation of the device. Therefore, conventionally, a means of applying a plurality of relatively low voltage pulses has been used. It is often done.

C. Problems to be Solved by the Invention However, according to the above-described conventional device, since the charging capacitor C is charged by the DC high-voltage power source E, a relatively large current flows at the beginning of the charging period. As the charging voltage of the charging capacitor C increases, the charging current gradually decreases, and a predetermined voltage level (in this case,
There is a problem that the charging time until the voltage value of the DC high-voltage power source E) is reached becomes long. Therefore, according to the conventional device, it takes a long time to apply the continuous pulse.

On the other hand, the switch SW provided in the DC high-voltage power supply device 40
It is also conceivable to continuously generate a pulse having a short pulse period by continuously switching the pulse. However, the charging time of the conventional device is longer than that of the discharging time, so that FIG.
As shown in, there arises a problem that the voltage level of the continuous pulse gradually decreases.

Therefore, if a power supply device capable of supplying a large current is used in order to shorten the charging time, there arises a problem that the device becomes large.

Furthermore, in the future, it may be possible to study the mechanism of cell fusion and gene transfer by applying pulses of different voltage levels to the cell suspension. However, according to the conventional device, it is difficult to change the voltage level due to its configuration. Even if a variable voltage power supply is used to change the voltage level, it takes a long time to change it to a predetermined voltage level because of the long charging time, resulting in poor workability. is there.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a small DC high-voltage power supply device that has a relatively short charging time and can quickly change the charging voltage. Has an aim.

D. Means for Solving the Problems FIG. 1 is a block diagram showing the configuration of the DC high-voltage power supply device according to the present invention.

The DC high-voltage power supply device according to the present invention comprises a control element 1 to which an unstable voltage is applied, a charging capacitor C to which the output of the control element 1 is applied, and a voltage setting means 2 for setting the charging voltage of the charging capacitor C. When the charging voltage is lower than the set voltage based on the comparison between the voltage (set voltage) set by the voltage setting means 2 and the charging voltage, the control element 1 is operated at a constant DC voltage. When the charging voltage reaches near the set voltage, the charging voltage becomes equal to the set voltage,
Operation switching means 3 for operating the control element 1 at a constant DC voltage, and discharging means 4 for discharging the charging capacitor C.
And discharge control means 5 for driving the discharge means 4 when the set voltage is set lower than the charge voltage.

E. Operation When the charging voltage of the charging capacitor C is lower than the set voltage, the control element 1 operates in direct current constant current, so that the charging capacitor C is quickly charged by the constant current. When the charging voltage reaches close to the set voltage, the control element 1 is switched to the DC constant voltage operation, and the charging voltage is maintained at the set voltage.

On the other hand, when the set voltage is set lower than the charging voltage of the charging capacitor C, the discharging means is driven and the electric charge stored in the charging capacitor C is discharged. When the charging voltage becomes equal to or lower than the new setting voltage, the above-described DC constant current operation and DC constant voltage operation are performed, and the charging voltage is maintained at the new setting voltage.

F. Embodiment FIG. 2 is a block diagram showing a schematic configuration of a DC high voltage power supply device according to an embodiment of the present invention.

In the figure, reference numeral 10 is a DC high-voltage power supply device according to this embodiment, and 30 is a pulse generation circuit for switching a DC high-voltage voltage output from the DC high-voltage power supply device 10 to generate continuous pulses.

The configuration of the DC high-voltage power supply device 10 will be described below.

The AC voltage AC is rectified by the rectifier circuit 11 and the smoothing circuit 12.
It is converted into an unstable DC voltage and given to the collector of the control transistor Tr. The emitter output of the control transistor Tr is given to the charging capacitor C via the current detection resistor R ₁ and the backflow prevention diode Di. Control transistor Tr
A resistor R ₂ is connected between the collector and base of. The base of the control transistor Tr is connected to the output terminals of the differential amplifiers 13 and 14.

The differential amplifier 13 is configured to amplify the error between the voltage drop value of the current detection resistor R ₁ and the reference voltage V _REF . On the other hand, the differential amplifier 14 amplifies an error between the charging voltage V ₀ of the charging capacitor C divided by the resistors R ₃ and R ₄ and the set voltage V _SET set by the charging voltage setter 15. It is configured.

The charging voltage setting device 15 is composed of a microcomputer, a digital switch or the like, and sets the charging voltage of the charging capacitor C as a digital value. The setting output of the charging voltage setting device 15 is given to a digital-analog converter (D / A converter) 17 via an isolation 16 such as a photocoupler. The set voltage V _SET converted into an analog signal by the D / A converter 17 is given as one input of the differential amplifier 14 as described above. The output of the charging voltage setting unit 15 is given to the D / A converter 19 via the isolation 18. The set voltage V _SET output from the D / A converter 19 is given as one input of the comparator 20.

The comparator 20 controls the operation of the discharge circuit composed of the resistor R ₅ and the switching circuit 21, and is supplied with the charging voltage divided by the resistors R ₆ and R ₇ as the other input.
The switching circuit 21 is composed of a switching element or a relay.

Next, the operation of the embodiment having the above configuration will be described.

(I) Constant Current Operation First, the operator operates the charging voltage setting device 15 to set the charging voltage of the charging capacitor C. This set value is L ₁ . By setting the set value L ₁ ,
The set voltage V _SET1 corresponding to the set value L ₁ is applied to the differential amplifier 14.

When the power supply device 10 starts, the base current is supplied to the base of the control transistor Tr via the resistor R ₂ . As a result, the output current I ₀ flows from the collector of the control transistor Tr, causing a voltage drop in the current detection resistor R ₁ . At this time, the voltage drop (V ₁ −V ₀ = I ₀ · R ₁ ) due to the current detection resistor R ₁ becomes larger than the reference voltage V _REF , and the differential amplifier 13 becomes one of the base currents supplied to the control transistor Tr. Pull in the department.
Then, the differential amplifier 13 performs constant current operation (I ₀ = V _REF / R ₁ ) so that the voltage drop I ₀ · R _{1 at} the current detection resistor R ₁ and the reference voltage V _REF become equal. , Fig. 3 (a)
As shown in, the charging voltage of the charging capacitor C increases almost linearly and approaches the set value L ₁ .

On the other hand, the level of the charging voltage V ₀ divided by the resistors R ₃ and R ₄ is lower than the setting voltage V _SET1 which is set by the charging voltage setting unit 15 and is applied to one input of the differential amplifier 14. Therefore, the differential amplifier 14 tries to raise the charging voltage V ₀ by supplying the base current to the control transistor Tr. However, since the differential amplifier 13 is performing the pull-in operation as described above,
The current output from the differential amplifier 14 is sucked into the differential amplifier 13. In other words, the constant voltage operation by the differential amplifier 14 is prohibited while the control transistor Tr ₁ is in the constant current operation.

(II) Constant voltage operation When the charging voltage V ₀ of the charging capacitor C approaches the set value L ₁ , the output current I ₀ decreases, and the suction of the differential amplifier 13 decreases, so that the output current I ₀ decreases. It gradually becomes zero, and thereafter, the constant voltage operation by the differential amplifier 14 causes the charging voltage.
V ₀ is maintained at the set value L ₁ .

(III) Discharging Operation Next, it is assumed that the operator operates the charging voltage setting unit 15 to set the set value L ₂ at a level lower than the current set value L ₁ . Then, the level of the charging voltage divided by the resistors R ₆ and R ₇ becomes higher than the set voltage V _SET2 provided as one input of the comparator 20, so that the output of the comparator 20 is inverted. As a result, the switch circuit 21
In the ON state, the charge accumulated in the charging capacitor C is discharged through the resistor R ₅ and the switch circuit 21, and the charging voltage of the charging capacitor C gradually decreases as shown in FIG. 3 (a).

When the charging voltage becomes lower than the set value L ₂ , the control transistor Tr operates in constant current as described above, and the charging voltage is set to the set value.
I try to get closer to L ₂ . When the charging voltage reaches the set value L ₂ , the voltage value is maintained by the constant voltage operation of the control transistor Tr.

The high-voltage DC voltage output from the DC high-voltage power supply device 10 as described above is given to the pulse generation circuit 30. The pulse generation circuit 30 switches based on a pulse cycle control signal from a microcomputer (not shown) or the like to output a high voltage pulse of a predetermined cycle as shown in FIG. 3 (b). With high voltage pulse output,
If the charging voltage fluctuates, the control transistor Tr described above
Due to the constant current operation and the constant voltage operation, the charging voltage is quickly maintained at the set voltage.

In the above-described embodiment, the AC voltage AC is rectified / smoothed and supplied to the control transistor Tr, but the smoothing circuit 12 is not always necessary. That is, the pulsating voltage output from the rectifier circuit 11 may be directly supplied to the control transistor Tr. In this case, the charging time for the charging capacitor C becomes slightly longer, but the device can be configured in a simple form.

When a microcomputer is used as the charging voltage setter 15, the charging voltage can be sequentially changed by a program, so that high voltage pulses with different voltage levels are continuously applied to the cell suspension for cell fusion or It is convenient for studying the mechanism of gene transfer.

G. Effects of the Invention As is clear from the above description, the DC high-voltage power supply device according to the present invention operates the control element at a constant current during the charging period of the charging capacitor, and the charging voltage reaches the set value. After that, since the charging voltage is maintained at the set value by operating the control element at a constant voltage, the charging time becomes shorter than that of the conventional device that is charged by the voltage source. Therefore, the DC high-voltage power supply device according to the present invention,
It is very suitable as a power source for outputting a high voltage pulse when cell fusion etc. are performed by continuously applying a high voltage pulse.

Also, if you try to shorten the charging time by the voltage source,
Since a large current needs to flow, the power supply becomes larger,
According to the present invention, since charging is performed with a constant current, the charging time can be shortened even with a relatively small power supply device.

Further, in the device according to the present invention, when the set value of the charging voltage is set to a value lower than the current charging voltage, the discharging means is driven to discharge the charging capacitor, so that the charging voltage becomes lower than the new setting value. When it becomes low, the charging voltage is raised by the constant current operation, and thereafter, the charging voltage is maintained at the setting value by the constant voltage operation, so that the setting value of the charging voltage can be changed quickly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a DC high voltage power supply device according to the present invention, FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 3 is an operation waveform diagram of the embodiment, FIG. 4 is a circuit diagram showing a schematic configuration of a conventional power supply device, and FIG. 5 is a perspective view of an example of an electrode tank containing a cell suspension.
FIG. 6 is an operation waveform diagram of the conventional device. 1 ... Control element 2 ... Charging voltage setting means 3 ... Operation switching means 4 ... Discharging means 5 ... Discharge control means C ... Charging capacitor 10 ... DC high-voltage power supply device 13, 14 ... Differential amplifier 15 ...... Charging voltage setter 20 …… Comparator 21 …… Switch circuit Tr …… Control transistor R ₁ …… Current detection resistance 30 …… Pulse generation circuit 50 …… Electrode cell 60 …… Cell suspension

Claims (1)

[Claims] 1. A control element to which an unstable voltage is applied, a charging capacitor to which the output of the control element is applied, a voltage setting means for setting a charging voltage of the charging capacitor, and a voltage set by the voltage setting means. When the charging voltage is lower than the setting voltage based on the comparison between the (setting voltage) and the charging voltage, the control element is operated with a constant DC current, and the charging voltage reaches near the setting voltage. In this case, the operation switching means for operating the control element in the direct current constant voltage mode, the discharging means for discharging the charging capacitor, and the setting voltage being higher than the charging voltage so that the charging voltage becomes equal to the setting voltage. A DC high-voltage power supply device comprising: a discharge control unit that drives the discharge unit when the discharge voltage is set low.