JPS63240374A - Voltage multiplying circuit for capacitor diode - Google Patents

Abstract

PURPOSE:To reduce rush current and make the title circuit highly efficient, by connecting a diode to a capacitor to be connected to the diode through a resistor. CONSTITUTION:In a Cockcroft-Walton type voltage multiplying circuit having 4 multiplying stages, the connecting points b'-j' of diodes D1-D8 and the connecting points b-j of capacitors C1-C8 are connected through respective resistors R1-R9 (the value of resistance of all resistors is same). According to this constitution, an overcurrent (rush current) upon alternating an input voltage may be suppressed perfectly and, further, the regulation of an output voltage may be effected in some degree by the selection of the value of resistance. Currents flowing through the diodes D1-D8 are minimized; therefore, a comparatively inexpensive diode allowable current is small may be employed.

Description

[Detailed description of the invention] [Object of the invention] (Field of industrial application) What is this invention? ! f of two or more capacitors and diodes
By adjusting f11, the DC high voltage is reduced by 1q from the AC input voltage.
The present invention relates to a capacitor/diode voltage multiplier circuit, and particularly relates to reducing rush current and increasing efficiency when the AC input voltage is a rectangular wave.

(Prior Art) As is well known, various types of capacitor-diode voltage distribution circuits have been developed, but the most basic circuit is the Cottcroft-Luton type lightning voltage distribution circuit. For example, this circuit is explained by showing a four-stage multiplication circuit in FIG. It has a second capacitor circuit in which C5 to C8 are connected in series. Capacitor 01~C4
Each output terminal c, e, g, i, is connected to a diode D2.
．． D4. D6. It is connected to each output terminal d, f, h, j of the capacitors C5 to C8 through D8, and the capacitors 05 to 05
Each input terminal S, d, f of C8.

h are respective diodes I)1. D3. D5. Each output c, e of the capacitors C1-C4 via D7.

q, connected to i. The diodes D1 to D8 are connected in series between the input and output terminals 1 and 1 of the second capacitor circuit so that their rectifying directions are the same.

A rectangular wave AC power supply Pc is connected between input terminals a and b of the first and second capacitor circuits, the input terminal of the second capacitor circuit is grounded, and the input and output terminals of the second capacitor circuit are grounded. A load resistor RL is connected between the terminals 3 and 3.

In other words, this voltage multiplier circuit uses diodes D1 to D8 to charge the capacitors in the order of CI, C5, C2°, etc. by changing the charging path of the capacitor every time the output of the AC power supply PC is reversed. . At this time, each capacitor is charged using the output voltage of the AC power supply PC (EtcV!). Finally, C1 becomes HHv3, and c2 to C8 become 2E[V]
Therefore, the output voltage of this circuit is 8Ei [V]. In other words, the output voltage of this circuit is the AC input voltage multiplied by twice the number of multiplication stages.

Since its development in 1932, the voltage converter circuit represented by the Kotscroft-Truton type has mainly used a sine wave input. In this case, there were few problems because the current flowing through the input power supply system and each diode was relatively slow. However, in recent years, converter technology has taken off, and the number of converter circuits being used for input power supplies has dramatically increased.In this case, the power supply output waveform is generally a rectangular wave. If the input voltage is a rectangular wave, an excessive current (rush current) will be generated between each capacitor at the moment of voltage alternation.This will also cause various problems in the converter circuit system that becomes zB. In addition, during the transient rise of the input voltage, the instantaneous current of the voltage alternation becomes extremely large, which may damage the diode, so it is necessary to use a diode with a relatively large allowable current value.For this reason, in the past, the power supply Excessive current is limited by methods such as taking measures to round the waveform in the system or adding a resistor in series with only the diode closest to the circuit input terminal to a degree that does not affect the output voltage.

However, the method of blunting the power supply output waveform as described above causes the problem of complicating the power supply circuit (11) and further reducing the efficiency.Also, in order to protect the diode, a resistor is connected in series with the diode. There are ways, but
Low resistances in the range of several ohms to several tens of ohms have been used in consideration of loss due to resistance, but very effective effects have not been obtained.

(Problems to be Solved by the Invention) This invention was made in consideration of the fact that in the past, when the AC input was a rectangular wave voltage, there was no effective means for dealing with the rush current that occurs during voltage alternation. Even if the AC input is a square wave voltage, the rush current can be sufficiently reduced with a simple 4-component configuration, allowing the use of diodes with a small allowable current value, and a highly efficient capacitor-diode voltage multiplier circuit. The purpose is to provide.

[Structure of the Invention] (Means for Solving the Problems) The capacitor/diode voltage layer A8 circuit according to the present invention connects a diode and a capacitor to be connected to the diode through a resistor. This is a characteristic feature.

(Function) The capacitor/diode voltage:1 multiplier circuit with the above configuration can extremely reduce the current flowing through the diode by using a resistor connected in series with the diode, completely suppressing excessive current when the input voltage is alternating. Furthermore, it is possible to simplify the power supply circuit and improve its efficiency.

(Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2. However, in FIG. 1, the same parts as in FIG. 10 are denoted by the same reference numerals, and only the different parts will be described here.

FIG. 1 shows a configuration in which the present invention is applied to the Cotscroft-Luton type voltage switching circuit having four stages of multiplication circuit B shown in FIG. This circuit consists of the connecting points of the diodes D1 to D8 and the capacitors C1 to C.
8 connection points b-j are connected via resistors R1 to R9 (all have the same resistance value).

That is, all the diodes D1 in the circuit shown in FIG.
~ Connecting D8 and capacitors C1 to C8 via resistors does not necessarily cause a decrease in output voltage;
Experiments have revealed that when the resistance 1n increases to a certain extent, the output voltage actually increases, and that the output voltage changes depending on the resistance value.

The above experimental results are shown in FIG. Figure 2 shows capacitor 0
The color of 1 to C8 is 0.1 [μ''], and the load resistance RL is 10.
[MΩ], wave height of square wave AC input voltage 1a1000[V
], the frequency is 50 [Hz] (period 20 [mS])
, is a characteristic diagram showing changes in output voltage with respect to changes in resistance values of resistors R1 to R7 when rise and fall times are set to 0.2 [msl]. In this case, the output voltage increases rapidly from a resistance value of about IQO [Ω], and reaches a maximum of 1 voltage around 1.8 [kΩ]. The effective range of the larger resistance value is 1 less and wider than 50 [kΩ], and an output voltage 1q larger than the normal output is produced.

Furthermore, as a result of experiments and operational analysis, it has become clear that the output voltage of the 0-stage Cotscroft-Walton type voltage multiplier B circuit can be maximized by satisfying the following equation.

r=anb <n+1) etr/2Ei-=(1) However, the time constant, a, is determined by the product of the capacitance of the component capacitor and the resistance value connected in series with the diode.

b is a constant determined by experiment, a = 3 x 10'2 to 5 x 10 m, b = 2.7 to 3.3, e = I10 - f' (I is load current, C is 8 capacitors) , f is the input voltage frequency), Ei is the input voltage, is the rise time of the input voltage [i, and n is the number of multiplication stages, which is half the number of diodes. The effective range is also extremely wide, and τ is 10
It has become clear that the range ranges from [μS] to about half the period of the input voltage [i. However, when the number of ports was 1, the effect of increasing the voltage was not obtained.

From the above, the Kotscroft-Walton voltage multiplier circuit in which resistors are inserted and connected in series with all diodes as described above can completely suppress excessive current, that is, rush current, when the input voltage is alternated. It is also possible to adjust the output voltage by selecting the resistance value.

Since the current flowing through the diode becomes miserable and small, a relatively inexpensive diode with a small allowable current value can be used. Furthermore, when viewed from the power supply side, this voltage multiplier circuit can be regarded as almost a pure resistance, so there is no need to provide the power supply circuit with any means for preventing rush current output. Therefore, the power supply circuit can be simplified and the rectangular wave can be input as is, resulting in extremely high efficiency.

Furthermore, since the output voltage is higher than in the conventional case, if the load current is constant, the voltage drop will be reduced. This means that the output impedance has become lower.

Furthermore, when the power supply output was a sine wave, almost no increase in the output voltage was observed, but even if the output voltage was the same, the effect of significantly reducing the current flowing through the diode was 1 g.
It will be done.

Furthermore, the present invention is not limited to the above-mentioned embodiment, and can be similarly implemented with other capacitor/diode voltage 3% multiplier circuits as shown in FIGS. 3 and 4, for example.

In other words, the voltage ">'14 multiplier circuit shown in FIG. 3 connects diodes D11 to D19 in series, and
Connect one end of capacitors 011 to C19 to CI 1,014. Connect C17 in series, C12, C
15, C18 are connected in series, C13, CI6, 019 are connected in series, connection point a is grounded, and a load resistance R is connected between a and 1.
Connect the first capacitor C12 between the other end of the capacitor C12 and the ground.
A second AC power source P is connected between the other end of the capacitor C11 and the contact Jlj1. For the voltage multiplier circuit with 2 connected, disconnect the connection points between each diode and capacitor, and connect resistors R11 to R19 between each point a to h on the capacitor side and each point a to h- on the diode side. This is what I did. In addition, the first and second rectangular wave AC power supplies P
c 1 and Pc 2 are outputs in the same phase, and can be configured, for example, by connecting a transformer to one AC power source, providing an intermediate tap in its secondary winding, and covering this with ground. On voltage in this case? The effect is the same as in the case of FIG. 1, and in order to maximize the output voltage, n=(no-load output voltage)/2Ei, and formula (1) is satisfied.

FIG. 4 shows a conjunctive state when the present invention is applied to a circuit called a double-wave rectifier Cockcroft-Walton circuit. This circuit consists of capacitors C21 and C2, respectively.
2, C23, C24°C25,026, C27, C28
, C29, and diodes D21-D26, D27-D32, respectively.
It has a first and second diode series circuit consisting of. Then, the first and second capacitor series circuits and the first diode series circuit form a positive-side Kotscroft-Two Luton circuit using the first AC power source Pc1 as an input power source. and each diode of a double-wave rectifier Cockcroft-Walton circuit, which is configured with a third capacitor series circuit and a second diode series circuit to form a Cockcroft-Walton circuit on the four negative pole sides using the second AC power source Pc2 as an input power source. The connection point of the capacitor and the connection point of each capacitor are connected through resistors R21 to R34, respectively. The conditional expression that maximizes the output voltage of this circuit is n
=<JiW shipping output voltage 2 If it is set to 1, it will match equation (1), but if the constant a is 0.7x10'2~1°3x10
It has been confirmed through experiments and operation analysis that −2 can be determined more accurately.

FIG. 6 shows a case where the method shown in FIG. 1 is applied only to one side. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals.

In this case as well, sufficient effects can be obtained.

(7) PA In equation (1), a is 6×101 to 10×1
If it is set to 0″2, it will hold true as an experimental formula.

FIG. 7 is also applied to only a part of FIG. 3. In this figure, the same parts as in FIG. 3 are designated by the same reference numerals.

In this case as well, sufficient effects can be obtained.

Equation (1) also holds if n=(no-load output voltage)/2Ei, a=6×10′2 to 10×10″2.

FIG. 8 is applied only to a part of FIG. 4. In this figure, the same parts as in FIG. 4 are designated by the same reference numerals.

In this case as well, sufficient effects can be obtained.

In this case as well, equation (1) is n = (no-load output horn voltage)/2E
iT'a=1.5x10゛2~2.5X104.

FIGS. 9 and 10 are the first embodiment of the circuits shown in FIGS. 6 and 7, respectively, in which the scope of application is further narrowed and the resistance connections are made at two locations. In FIGS. 9 and 10, the same parts as in FIGS. 6 and 7 are denoted by the same reference numerals.In this case as well, it can be expected that the rush current will be reduced to the extent that the output voltage will rise to some extent.

However, if it is applied to only one place, little effect can be expected.

From the above, it is believed that the present invention is effective in various content-1-Giode voltage multiplier circuits.

[Effect of the Invention 1 As described above, according to the present invention, even if the AC input is a rectangular wave voltage, it is easy to use. The rush current can be sufficiently reduced with a simple configuration, a diode with a small permissible current value can be used, and a highly efficient capacitor/guiode voltage multiplier circuit can be provided.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of an 18 capacitor/guiode voltage source circuit according to the present invention. Figure 1S2 (characteristic diagram showing the experimental results of the same example; Figures 3 to 9 are circuit configuration diagrams showing other examples according to the present invention, respectively;
FIG. 10 is a circuit diagram showing the configuration of a typical Kotscroft-Rilton type circuit as a conventional capacitor/guiode voltage multiplier circuit. C1-C8, C11-C19, C21-G29... Capacitor, D1-D8. D11~D19゜021~D3
2...Diode, R1-R8°R11-R19,R
21~R32---Resistance, PClPc1, Pc
2...Square wave AC power supply, RL...Load resistance. Applicant's representative Patent attorney Takeru Suzue Figure 2 Summary of resistance values Figure 4 Figure 5 Figure 6 Figure 9

Claims (1)

[Claims] A capacitor that generates DC multiplied voltage from AC input voltage by connecting multiple capacitors and diodes in combination.
A capacitor/diode voltage multiplier circuit, characterized in that the diode and the capacitor to be connected to the diode are connected via resistors at at least two places.