JPS63213475A - Dc power source circuit - Google Patents

Abstract

PURPOSE:To enhance the economy of a DC power source circuit and to reduce the size and the weight of the power source by providing a switching element using a nonpolarized capacitor. CONSTITUTION:When a current flows from an AC power source 1 through a diode 3, the current flows to its output 7, and an electric energy is stored in a choke 4 and a capacitor 6 simultaneously. Thus, when an input voltage decreases or the current flows reversely to the diode 3, the current flows from the capacitor 6 to the output 7 to output a DC. In this case, the input current flowing through the diode 3 is arbitrarily controlled by utilizing a nonpolarized capacitor 2 and the diode 3. Thus, the magnitude of a resistor 8 determines the base current of a transistor 9, and the remaining charge of the capacitor 2 is determined by the corresponding collector current. As a result, the current amount flowing to the output is varied by the resistor 8, and the output voltage is also altered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to a DC power supply circuit that receives AC from an AC power source such as a commercial power supply or an inverter and obtains a constant voltage DC.

<Prior Art> As an example of the prior art, FIG. 7 shows a switching regulator using transistors. In Figure 7, l
is an AC input power source, which is converted to DC by the diode 2 and capacitor 3, and becomes the DC input of this switching regulator.

When the voltage of the DC output of 8 and the reference voltage 11 are compared by the comparator 10, and the output voltage of 8 becomes low.

Increase the amount of time transistor 4 is on.

Increase the power sent to the Conversely, when the output voltage of 8 is low, K shortens the on time of transistor 4 and reduces the power sent to choke 5. Then, it is smoothed by a choke 5, a diode 6, and a capacitor 7 to obtain a DC output 8.

Furthermore, another conventional example is shown in FIG. In FIG. 8, the switching transistor 1 of the DC/DC converter is turned on and off to excite the transformer 2 with alternating current, thereby producing an alternating current voltage in the output winding 3. This alternating current is rectified by a diode 5, and a flywheel diode 6
, filtered by choke 7° condenser 8, 9
DC output. Choke 4 has a saturable iron core.

When the iron core is saturated with current, the impedance becomes almost 0.
When K and t are not saturated, the impedance becomes extremely large. Then, the reference voltage 120 and the output voltage 9 are compared and amplified by the comparator 11, and the reset current flowing through the transistor IO is controlled to control the time for the choke 4 to become saturated and the impedance to be almost zero. Controls the power sent to and keeps the voltage at 9 constant. The circuit shown in FIG. 8 is commonly called a mag-amp circuit.

<Problems to be solved by the invention> However, although the circuit shown in FIG. A current several times higher than that during operation flows, which often results in damage, and as a countermeasure, many circuit parts are used, resulting in an increase in cost. More KIOA
Switching a large current such as 20A or 20A causes a semiconductor such as a transistor such as 4 to have a large switching loss at the moment it turns on and off, a large foredrop loss when it is turned on, and a decrease in efficiency.

Moreover, the mag-amp circuit shown in FIG. 8 is stable and strong, with the saturable iron core 4 not being damaged even in the event of the above-mentioned problems. However, for the saturable iron core (No. 4), the transformer material (No. 2) and the choke material (No. 7) are not as common, and the difference in magnetic permeability, which is the basis of impedance, must be large between saturated and unsaturated states. In addition to being expensive, most of the wires are ring-shaped, so the number of man-hours required for 9 windings is 2.In the EI type, which is commonly used for 2 transformers, the 2 winding frame is provided separately from the magnetic core. Compared to conventional models, there are many manual parts involved, and they are generally more expensive.

Furthermore, in order to miniaturize the DC power supply circuit, in a switching regulator that turns off the power at a high frequency such as several hundred kHz, the saturable iron core 4 shown in Fig. In this case, losses increase rapidly and efficiency decreases significantly. Also, the types of parts are special and difficult to obtain.

In order to solve the above-mentioned problems, the present invention uses a non-polar capacitor as a switching element that turns on and off current, and when on-current flows, the impedance of the capacitor to alternating current changes. In addition, the device resets by discharging the accumulated charge caused by the flow of on-current to the variable impedance element connected in parallel. In this way, it is possible to provide a switching regulator that is small, lightweight, and has high economical efficiency.

<Example> Two examples of the present invention will be described below with reference to the drawings. In order to simplify the explanation, the following embodiments will only include components 9 that are necessary for purposes other than the operation of the present invention, such as resistors between transistor pace emitters, series resistors and diodes for protecting transistors, etc.

It is omitted.

FIG. 1 is an embodiment showing the basic principle of the present invention. 1st
In the figure, capacitor 2. Transistor 9. resistance 8
The circuit without is a known circuit that converts alternating current to direct current. Its operation is as follows: When current flows through diode 3,
At the same time as the current flows to the output of the diode 7, electrical energy is stored in the choke 4 and the capacitor 6, and when the current direction is opposite to the diode 3 where the input voltage has become low, the current no longer flows from the input. Then, current flows from capacitor 6 to output of capacitor 7.

Since current continues to flow from the diode 4 to the output cuff through the diode 5, the output cuff is filtered and becomes a direct current.

In contrast to the rectifier filter circuit that operates in this way, 9 In the case of the circuit shown in Figure 1 of the present invention, the input current flowing through the diode 3 can be arbitrarily controlled using the capacitor 2 and the transistor 9. That is.

In Figure 1, 1. is an AC power source.

2 is a non-polar capacitor. The capacitor 2
is in the initial state, and when no charge is stored between the terminals 2-1 and 2-2, the electrode 1-1 of the AC power source l
When the electrode 1-2 becomes (→ at Choke 4, diode 5, and capacitor 6 form a DC outflow cuff.

When current flows through capacitor 2, terminal 2-1
is (→, terminal 2-2 becomes (→), and the electric charge accumulates, and the current that flows gradually decreases. On the other hand, the transistor 9, which is connected in parallel with the capacitor 2, has a voltage in the opposite direction to the pace and emitter. is applied, so it is in a cutoff state.Then, if the polarity of AC power supply 1 is reversed, -1
1-1 is (→.

When 1-2 becomes (→, the pace current of transistor 9 circulates from 1-2 through resistor 8 and capacitor 2 to 1-1. Then, a collector current flows in proportion to this pace current, and the current flows through the capacitor. The charge accumulated in the resistor 2 is discharged. Therefore, the amount of discharge can be varied by arbitrarily changing the value of the resistor 8.

Then, when the electrode 1-1 of the AC power source becomes (→) again, the potential of 1-1 becomes the potential between 2-1 and 2-2 due to the charge remaining in the capacitor 2, and the anode potential of the diode 3. When the sum exceeds the sum, current flows from the AC power source 1 through the capacitor 2 to the output.

The pace current of the transistor 9 is determined by the size of the resistor 8, and the amount of discharge and the amount of charge remaining in the capacitor 2 is determined by the corresponding collector current. That is, the amount of current flowing to the output can be varied by the resistor 8, and the output voltage can also be varied.

In order to describe the above matters in more detail, FIG. 2 shows the operation in FIG. 1 in terms of time and voltage at each part.

In FIG. 2, curve 1 is a curve showing the relationship between input AC power voltage and time. Straight line 2 shows the relationship between output voltage 7 and time in FIG.

Note that the straight line 2 is the line 4 in FIG.

The pull voltage and forward voltage of diode 3 are omitted. 3 in Figure 2 is the potential of capacitor 2 in Figure 1 and the terminal voltage of 2-1 and 2-2. 9. During the time 40 when the potential of 1-1 is (→), the curve 30 , the voltage increases.If the time of 4 is longer, this voltage will reach the maximum value of 1 (1#) as shown in curve 9.Then, when the potential of input 1 becomes reverse polarity for 50 hours, As mentioned above, the charges across the capacitor 2 in FIG. 1 are discharged by the transistor 9 in FIG. 1, and the voltage across the capacitor 2 decreases. When a large amount of pace current flows through the transistor 9, the collector current and discharge amount also increase, so the potential of the capacitor 2 becomes low as shown by curve 6 in Figure 1. The amount of current flowing from capacitor 2 in Figure 1 to the output can be increased, and the output voltage can be increased.

Conversely, when the resistance value 8 in FIG. 1 is large.

In the time after the first cycle 8, as shown by the curve 7 in FIG. 2, the amount of current flowing into the output decreases, and the output voltage decreases.

As described above, it is possible to vary the voltage at the output cuff by changing the size of the resistor 8 shown in FIG.

FIG. 3 shows an embodiment of the present invention for obtaining a constant voltage direct current by inputting the alternating current power from the main transformer 2 of the DC/DC converter. In FIG. 3, when the main transistor 1 is on, the primary current of the transformer 2 flows in the direction (13), and the secondary current flows from the output winding of the transformer 2 in the direction (14).

This AC output passes through a non-polar capacitor 3, is rectified by a diode 4, and is connected to a diode 5.

- is filtered by filter 6 and condenser 7, and becomes DC output 8. In the DC/DC converter shown in FIG. 3, instead of controlling transistor 9 using resistor 8 in FIG. 1, transistor 10 is controlled to change the collector current of transistor 9. As described above, the discharge amount of the capacitor 3 shown in FIG. 3 is adjusted.

In Figure 3, the pace current of transistor 9 is:

The main transistor of transformer 1 is turned off, and the secondary current of transformer 2 is (15) due to the flyback voltage of transformer 2.
(by trying to flow in the direction of).

From the output voltage 8, the transistor 10. capacitor 3
．． through the output winding of transformer 2.

On the other hand, the output voltage of 8 and the reference voltage of 12 are compared and amplified by a comparator 11, and when the output voltage 8 becomes high, the pace current of the transistor 10 is reduced.

This reduces the collector current of the transistor 10 and the collector current of the transistor 9 to reduce the amount of discharge of the capacitor 3, thereby reducing the current flowing into the output from the input and lowering the voltage.

Conversely, when the value of the output voltage becomes low, the pace current of transistor 10 is increased, the collector current of transistor 9 is increased, the amount of discharge of transistor 3 is increased, the amount of current flowing into the output from the input is increased, and the output voltage is increased. Try to increase it.

As described above, the operation can be controlled so that the output voltage of the circuit 8 is constant.

FIG. 4 shows an embodiment of the stabilized DC power supply of the present invention using a push/pull type DC/DC converter.

Capacitors 1 and 2 in FIG. 4 have the same function as capacitor 3 in FIG. 3, and transistors 3 and 4 in FIG. 4 discharge the charges in capacitors 1 and 2, respectively.

The operation of the transistors 3 and 4 is controlled by the transistor 5, and the operation of one circuit is the same as that shown in FIG.

FIG. 5 shows an embodiment of the present invention in a DC/DC converter called a flyback type.

In Figure 5, when the main transistor 1 is on, the primary current of the transformer 2 flows in the direction (9), and the secondary current flows in the direction (10), so the diode 4, it does not flow to the output and is accumulated in the transformer 2.

When the main transistor 1 is off, the accumulated flypack energy flows in the direction (11) and is output towards the output 4, and the transformer 2 also functions as the choke 4 in Figure 1. It also has the role of continuously passing current. Therefore, this is a circuit in which the circuit 4 in FIG. 1 and the choke 6 in FIG. 2 can be omitted.

In the circuit of FIG. 5 as well, as described above.

K when the output current of transformer 2 is in the forward direction where it does not flow to the output, that is, in the * (io) direction.

The electric charge of the capacitor 3 is discharged by the transistor 6. At this time, the pace current of transistor 6 is obtained from output 5 through transistor 7, and is superimposed on the current (10) of transformer 2 through capacitor 3. As described above, this current is controlled to keep the voltage of the output 5 constant, the amount of discharge of the capacitor 3 is determined, and the output current flowing in the (11) direction of the transformer 2 is controlled.

FIG. 6 shows a method in which the control current is not fed back from the output voltage. In this method, the pace current of the transistor 5 for discharging the non-polar capacitor 3 is generated only by the flyback current of the transformer 2 that flows when the transistor 1 is off. The amount of light emitted by the diode of photocoupler 6-2 is changed in proportion to the difference between output voltage 4 and reference voltage, and the current flowing through phototransistor 6-1 is changed to change transistor 5.
By changing the pace current of the transistor 5, the collector current of the transistor 5 is controlled, and the output voltage is kept constant. Since the control current does not pass through the output, this circuit operates more stably.

<Effect of the invention> As is clear from the above description, according to the present invention.

Since semiconductors such as transistors, which are vulnerable to high frequencies and large currents, are not used to turn on and off the main current, they are not rigid, and are relatively inexpensive, lightweight, and small capacitors are used, making them economical and efficient DC power supplies. I can do it.

Furthermore, at high frequencies such as several hundred kHz or MHz, capacitors are much smaller than transistors or saturable iron cores and can efficiently flow high-frequency large currents.2 The circuit of the present invention is also very economical. It is advantageous for

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first embodiment of the present invention. In Figure 1, 1 is an AC power supply, 2 is a non-polar capacitor, 3 and 5 are diodes, and 4 is a choke. 6 represents a capacitor regardless of polarity, 8 represents a resistor, and 9 represents a transistor. Figure 2 shows the relationship between voltage and time of each part to explain the operation of Figure 1, where l is the input AC voltage, 2 is the output voltage, 3 is the capacitor voltage, and 4 is the polarity of the AC. 5 indicates the time when the polarity of the alternating current is (→. FIG. 3 is a circuit diagram of the second embodiment of the present invention.
In the figure, 1, 9, and 10 are transistors, 2 is a transformer, and 3 is a non-polar capacitor. 4.5 is a diode, 6 is a diode, 7 is a capacitor regardless of polarity, 8 is an output, and 11 is a comparison. Control circuit for amplification etc., 12 is reference voltage. (13), (14), and (15) indicate the direction of current in the transformer 2, respectively. FIG. 4 is a circuit diagram of a third embodiment of the present invention. Fourth
In the figure, 1, 2 are non-polar capacitors, 3, 4 .
5 is a transistor. FIG. 5 is a circuit diagram of a fourth embodiment of the present invention. Fifth
In the figure, 1, 6.7 are transistors, 2 is a transformer, and 3 is a non-polar capacitor. 4 indicates a diode, and 5 indicates an output. FIG. 6 is a circuit diagram of a fifth embodiment of the present invention. 6th
In the figure, 1 and 5 are transistors. 2 is a transformer, 3 is a non-polar capacitor, 4 is an output,
6-1 and 6-2 indicate photocouplers. FIG. 7 is a circuit diagram of a switching regulator using conventional transistors. FIG. 8 is a circuit diagram of a conventional Maganzo circuit. Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. In a DC power supply circuit that receives AC from an AC power supply and obtains a constant voltage DC, a non-polar capacitor is connected in series between a rectifying diode of the DC power supply circuit and the AC power supply. and connect a variable impedance element such as a transistor, FET, or thyristor in parallel to the non-polar capacitor, and when the current of the AC power source has the opposite polarity to the polarity flowing to the DC output, the non-polar capacitor , and the amount of discharge is arbitrarily varied by varying the magnitude of the impedance of the variable impedance element, thereby changing the amount of current flowing from the AC input power source to the DC output, and arbitrarily adjusting the output voltage. A DC power supply circuit characterized by being variable. 2. In a DC power supply circuit that receives AC from an AC power supply and obtains a constant voltage DC, a non-polar capacitor is connected in series between the rectifying diode of the DC power supply circuit and the AC power supply. A variable impedance element such as a transistor, FET, or thyristor is connected in parallel to the capacitor, and the charge in the non-polar capacitor is discharged when the polarity of the current of the AC power source becomes opposite to the polarity flowing to the DC output, A DC power supply circuit that arbitrarily varies the discharge amount by varying the impedance of the variable impedance element, changes the amount of current flowing from the AC input power supply to the DC output, and arbitrarily varies the output voltage. Then, the output voltage is compared with an arbitrary reference voltage, and when the output voltage becomes high, the value of the variable impedance is increased to reduce the amount of discharge of the non-polar capacitor, thereby trying to lower the output voltage, or vice versa. 1. A DC power supply circuit characterized by having a circuit that stabilizes the output voltage to a constant voltage by increasing the amount of discharge and applying feedback to increase the output voltage when the output voltage becomes low.