JPH0557808B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention rapidly discharges the electric charge charged in a capacitor by a charging circuit, and converts the discharge current as it is or into light, magnetism, etc. The present invention relates to a charging/discharging device used for

[Problems to be solved by conventional technology and invention]

In this type of device, especially when using a high-voltage, large-capacity capacitor, a paper capacitor or an electrolytic capacitor is usually used.

However, the former is expensive, and the latter has a withstand voltage limited to about 500V, so it is necessary to increase the withstand voltage by connecting them in series.

In this case, since the capacitance of the electrolytic capacitors varies widely, the charging voltage is not applied equally to each capacitor, so overvoltage may be applied to one capacitor, and during the process of discharging, the loss may be unbalanced even though the current is constant. , which accelerates the deterioration of capacitor characteristics and causes problems in terms of life. Therefore, as shown in Figure 2, two series-connected electrolytic capacitors C
In the charging/discharging device described at the beginning, in which 1 and C2 charge from the charging circuit 1 and discharge the charging voltage to the load 3 through the switch circuit 2, a voltage dividing resistor circuit R1 for 1/2 voltage division is connected to the electrolytic capacitors C1 and C2. ，
It is well known to connect R2 in parallel. However, when the voltage dividing resistance value is increased in order to reduce loss, the time constant becomes correspondingly large, and it takes a considerable amount of time to equalize the charging voltage according to the divided voltage.

Therefore, the present invention provides a charging/discharging device that uses two series-connected electrolytic capacitors and charges the electrolytic capacitors equally to 1/2 of the output voltage using a voltage dividing resistor circuit. The purpose is to perform the operation quickly while increasing the value of the voltage dividing resistor.

[Means for solving problems]

In order to achieve this object, the present invention provides an npn type and a
The collectors of the two pnp transistors Q11 and Q12 are connected to voltage dividing resistor circuits R11 and R12, respectively.
Electrolytic capacitor C11,
Connected in parallel to C12 with proper polarity. The common connection point 11 of these capacitors was connected to the emitter, and the 1/2 voltage dividing terminals 14a of the voltage dividing resistor circuits R11 and R12 were connected to the base.

Note that the symbols in parentheses refer to those in the embodiment described later.

[Effect]

When the voltage at the common connection point 11 is higher than the voltage at the 1/2 voltage terminal 14a, one transistor Q12 is turned on, and when the voltage is small, the electrolytic capacitor C12 on the side charged to a higher voltage passes through the collector resistor r12 which is turned on. While quickly discharging at a constant rate, the other electrolytic capacitor C11 is quickly charged and 1/
Transistor Q12 is turned off at the point in time when the voltage matches the voltage at voltage-dividing terminal 14a. Common connection point 11 is 1/
If the voltage is lower than 2, the highly charged electrolytic capacitor C11 is quickly discharged through the collector resistor r11, while the other C12 is charged.

This equal charging operation is always performed during both the charging process and the discharging process.

[Embodiments of the invention]

FIG. 1 shows a charging/discharging device according to an embodiment of the present invention, in which two series-connected electrolytic capacitors C11 and C12 are connected by a high voltage generating circuit 10 as a charging circuit, as in the case of FIG. , the positive output voltage Vo is divided and charged to 1/2 by a voltage dividing resistor circuit 14 composed of resistors R11 and R12, and the charged voltage is discharged to a load 13 through a switch circuit 12.

According to the present invention, the electrolytic capacitor C11,
Two complementary connected transistors Q11 and Q12 of npn type and pnp type, whose emitters and bases are connected to each other, are connected to C12 in parallel with normal polarity. That is, the collector on the npn side is connected to the electrolytic capacitor C11 on the positive voltage side through the collector resistor r11, and the collector on the pnp side is connected to the electrolytic capacitor C12 on the ground side through the collector resistor r12. Furthermore, the common connection point 11 of the electrolytic capacitors C11 and C12 is connected to the emitter, and the 1/2 voltage dividing terminal 14a of the voltage dividing resistor circuit 14 is connected to the base.

The resistors R11 and R12 are sufficiently large so as not to cause loss, and are set to exactly the same resistance value for 1/2 voltage division. Collector resistance r11,
r12 functions as a current limiting resistor for transistors Q11 and Q12, and also serves as a current limiting resistor for transistors Q11 and Q12, as well as for electrolytic capacitors C11 and
R1 to reduce the charging/discharging time constant of C12.
1, the resistance value is set to be sufficiently smaller than R12.

The operation of the charging/discharging device configured as described above is as follows.

At the end of charging the electrolytic capacitors C11 and C12 by the positive output voltage Vo of the high voltage generation circuit 10, or during the charging process, the voltage at the 1/2 voltage dividing terminal 14a becomes 1/2 Vo with high accuracy, but the capacitance Due to variations, the charging voltage may not be set accurately to 1/2Vo. As a result, if the voltage at the common connection point 11 becomes lower than 1/2Vo, the transistor Q11 turns on and the collector resistor r11
1/2Vo is reached by momentary discharging of electrolytic capacitor C11 and charging of C12 through. vice versa,
If the voltage at the common node 11 becomes higher than 1/2Vo, the transistor Q12 turns on and momentarily discharges the electrolytic capacitor C12 through the collector resistor r12 and charges C11 to 1/2Vo.
Reach 2Vo.

That is, even if the resistance value of the voltage dividing resistor circuit 14 is made sufficiently large, the voltage is instantly adjusted to 1/2Vo with a small time constant by the small resistors r11 and r12 due to the switching action of the transistors Q11 and Q12. In this state, transistors Q11 and Q12 are turned off, so almost no loss occurs after charging is completed.

When the switch circuit 12 is turned on in the charging completed state, a discharge current is supplied to the load 13 from the electrolytic capacitors C11 and C12. In this discharge process, a similar uniform discharge operation is performed, and no abnormal loss occurs in one of the electrolytic capacitors.

This charging/discharging device is configured as a biological stimulator that uses a coil as the load 13, a charging voltage of 1 kV, and a capacitance of each electrolytic capacitor of several thousand μF, which manually or automatically discharges at high speed through a switch circuit 12 and applies magnetic pulses to nerves. can do.

In the above-mentioned embodiment, when the output voltage Vo is negative, the connections between the transistors Q11 and Q12 are reversed so that the polarity becomes normal. The same applies when the common connection point 11 is grounded and the high voltage generation circuit 10 outputs positive and negative voltages +Vo and -Vo.

〔Effect of the invention〕

As described above, according to the present invention, by combining a voltage divider and a complementary transistor, the charging voltage of an electrolytic capacitor is made to be an equal divided voltage during the charging/discharging process and at the end of charging, regardless of the presence or absence of variations in the capacitance. Can be set quickly with a small time constant. That is, acceleration of deterioration of the electrolytic capacitor is avoided, and even when repeatedly discharging current is used, a normal charging voltage can be obtained immediately.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a circuit configuration of a charging/discharging device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a circuit configuration of a conventional charging/discharging device. 14...Voltage dividing resistor circuit, 14a...1/2 voltage dividing terminal.

Claims (1)

[Claims] 1. Two series-connected electrolytic capacitors with 1/2
A charging/discharging device in which voltage dividing resistor circuits for voltage division are connected in parallel, these capacitors are charged to 1/2 of their output voltage in a charging circuit, and the charged voltage is discharged to the load through a switch circuit. In the npn where the emitsuta comrade and the base comrade are connected
The collectors of two transistors, one type and one pnp type, are connected in parallel to the two capacitors with regular polarity through a resistor whose resistance value is sufficiently smaller than that of the voltage dividing resistor circuit, and the common connection point of these electrolytic capacitors is connected to the A charging/discharging device characterized in that the 1/2 voltage dividing terminal of the voltage dividing resistor circuit is connected to the base.