JPS58224564A - Switching regulator - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a switching regulator and to improve the responsiveness and the reliability of the regulator by connecting an inductance element or an inductance element and a resistor to a line, through which only the control current of a control circuit for maintaining the output voltage constant is mainly flowed. CONSTITUTION:A pulsating voltage is induced at the seconary coil 4 of a main transformer 2 by the ON and OFF of a switching element 1 which is connected to the primary coil 3, to which a DC voltage is applied. This voltage is presentedas a DC voltage via a saturable reactor 5 through a rectifier 6 to output terminals 8a, 8b. The control current of the reactor 5 is controlled by a control circuit 7, and the output is set to the prescribed value. An inductance element 11 or a series circuit having an inductance element 11 and a resistor 9 is connected in series with a line, to which only the control current in the contol circuit 7 is mainly flowed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the characteristics of a magnetic amplifier system as one of constant voltage systems for switching regulators.

An example of this type of switching regulator is shown in FIG. In the figure, 1 is a switching element, 2 is a main transformer, and 3 and 4 are a primary winding and a secondary winding of the main transformer. 5 is a saturable reactor, 6 is a rectifier circuit, 7 is a constant voltage control circuit, and 8a.

8b is a DC output terminal.

Next, the operation of this circuit will be explained.

A pulse-like voltage is induced in the secondary winding 4 of the main lance 2 by turning on and off the switching element 1 connected to the primary winding 3 to which a DC voltage is applied.

This voltage passes through a saturable reactor 5 and a rectifier circuit 6.
The voltage appears as a DC voltage at the output terminals 8a and 8b. At this time, the saturable reactor 5 reaches the saturation point A in FIG. 8 due to the positive pulse current i, and returns to point 3r when 11 becomes zero. The negative pulse current 12 is changed by the control circuit 7 in substantially inverse proportion to the set value of the output DC voltage. That is, the negative pulse current 12 is a control current, and as this value increases, the reset operation gradually shifts from point B to point C in FIG. 8. When 12 becomes large and the operation between points 0 and A is repeated, the impedance of the saturable reactor is at its maximum and the voltage drop is at its maximum at 4T. In this way, the magnetic amplifier system is a system in which the voltage drop due to the saturable reactor 1- is changed by the control current 19 and the output DC voltage is kept constant.

The problem in the design of the above system is the problem of disturbance in the control of the magnetic amplifier system. For example, when the output load current changes drastically instantaneously as shown in FIG. 5, the larger the difference between l max and l min, the more likely the control system of this method will fall into disorder.

In other words, the conditions are most severe when 1m1n=0 and when the full load is 1 max! It is 1.

Figure 6 shows the main switching 1-transistor 1 at this time.
This shows the locus of the envelope of the vector current IC,
It is clearly seen from the figure that after several Ill S OC after the change from l max to I min, the collector current IC is abnormally added II'l, and a so-called whisker current 12 is observed. This abnormal current is more likely to occur as the gain of the control system is higher, that is, in a power supply having an I-line system with excellent responsiveness. Because of this, we sacrifice some responsiveness to
It is unavoidable to lengthen the life of the main switching transistor (1) and to direct the entire Shinto exit (1). In the prior art shown in FIG. 1, for this purpose, current limiting resistors 9 are inserted in series in a circuit in which only the control current I mainly flows.

However, this method not only (1) impairs the response of the control system, but also (2) increases the loss of the control system, and as a result, the overall characteristics including the temperature characteristics of the switching power supply This is undesirable as it causes deterioration.

SUMMARY OF THE INVENTION An object of the present invention is to compensate for the above-mentioned drawbacks of the prior art and provide a switching regulator using a reliable magnetic amplifier that has high efficiency, excellent responsiveness, and no disturbance.

In order to achieve the above object, the switching regulator of the present invention is connected in series with the primary winding of the transformer,
a periodically intermittent switching cable, a saturable reactor connected in series to the secondary winding of the output of the transformer, a rectifier circuit connected in series to the saturable reactor; , in a switching regulator using a magnetic amplifier method in which the control current of the saturable reactor I is controlled by a control circuit for keeping the DC voltage at the output end of the rectifier circuit constant, only the control current of the control circuit is It is characterized in that an inductance element or a series circuit consisting of an inductance element and a resistance element is connected in series to the main line.

The present invention will be described in detail below based on examples.

FIG. 3 is a diagram showing an embodiment of the present invention.

An inductance element 11 is connected in series to a line through which only a control current 12 mainly flows. This inductance element 11 has the effect of smoothing the waveform of the control current 12. In other words, J51 is added to the conventional circuit shown in FIG.
As shown in FIG. 2, the control current 12
In the process of discovering the present invention, it became clear that the presence of a whisker current of 10 in the current of 1 h adversely affects the reliability and stability of the control circuit 7.

Various means can be considered to suppress such a sink current 10, but as a result of study, it has been found that connecting an inductance element in series is the most effective. Figure 4 shows
FIG. 3, which is a circuit diagram of an embodiment of the present invention, shows the waveform of the control current 12.

As is clear from this figure, the whisker current 10 is no longer observed, and the waveform has a smooth triangular shape. In this condition, when the full load is released ((max→(min
FIG. 7 shows the envelope of the collector current of the main transistor when the load current is instantaneously and suddenly changed as shown in FIG. As is clear from this figure, the whisker current 12, which is a similar collector current, also disappeared, and the reliability of the main transistor was significantly improved.

In this embodiment, the inductance cord 11 and the resistance element 9 are used together in series, but the presence of the resistance element 9 is not a necessary condition. The effects of the present invention shown in FIGS. 4 and 7 can be fully achieved by using the inductance element 11. The characteristics are low loss,
It has high magnetic permeability and low squareness ratio. In particular, the last low square ratio is the strip 9 that is necessary because the usage condition is a state in which direct current is superimposed.

As described above in detail using the embodiments, according to the present invention, it is possible to reduce the loss caused by the resistor element 9.
It is clear that this has the great effect of suppressing disturbances in the magnetic amplifier type control system without increasing the loss of the control system, and significantly improving the overall reliability.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of the conventional technology, Fig. 2 and Fig. 6 are diagrams showing waveforms of various parts of the conventional technology, Fig. 5 is a diagram showing changes in load current, and Fig. 3 is a diagram showing the circuit diagram of the present invention. The circuit diagram of the embodiment, FIG. 4 and FIG. 7 are diagrams showing waveforms of various parts showing the effects of the present invention, and FIG. 8 is a characteristic diagram of a supersaturated reactor. 7- E 1 Mouth and teeth 4 Notes t°2 years old 8 Person amending Patent Application No. 107461 of 1982 Relationship with A↑ 18 Applicant
-It Location: 1-2 Marunouchi Tai-chome, Chiyoda-ku, Tokyo
Saena (U: t5oal 1) Ritsumeikan Co., Ltd. Representative Norio Kono Osamu Person Residence Location Chiyoda-ku, Tokyo, Marunouchi Division, Lower Division, No. 1-2 Specification subject to amendment

Claims (1)

[Claims] A switching element connected in series to the primary winding of the transformer and periodically surrounding it; a saturable reactor connected in series to the secondary winding of the output of the transformer; A magnetic amplifier system is used in which the control current of the saturable reactor is controlled by a rectifier circuit connected in series with the saturable reactor, and a control circuit for keeping the DC voltage at the output end of the rectifier circuit constant. A switching regulator characterized in that an inductance element is connected in series to a line through which only a control current of the control circuit mainly flows. 2. A switching regulator according to claim 1, characterized in that a resistance element is connected in series with the inductance element.