JPS61247271A - Chopper type dc-dc converter - Google Patents

Abstract

PURPOSE:To improve output stability in high efficiency, by providing a saturable reactor connected to a control circuit, between a switch element and an output rectification circuit. CONSTITUTION:The switch element 2 of a chopper type DC-DC converter is turned on and off by an oscillator 17, and between the switch element 2 and output rectification circuits 23, 24, a saturable reactor 20 is provided. According to the detected value of output V03, by a control circuit 29, reset current is made to flow from an output smoothing condenser 26 to the control winding 22 of the saturable reactor 20, and the saturable reactor 20 is arranged to be magnetized. After the switch element 2 is turned ON and input voltage is checked for a specified period, the saturable reactor 20 is saturated, and to the cathode side of a diode 23, the voltage of pulse width with the regular value of the output voltage V03 is fed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a chopper converter, and particularly relates to a chopper m DC-DC converter that stabilizes the output using a saturable reactor. It is something.

(Conventional technology)? W y pa! ! In the IIDC-DC converter, as shown in FIG. 4, changes in the output voltage η caused by fluctuations in the load current fttIOI are detected, and the control circuit 9 controls the opening and closing of the switch element 2 to control the output voltage. A method for stabilizing is known. Also, a multi-output taper W-DC that obtains multiple outputs with one switch element.
- As a DC converter, the one shown in Fig. 5 is known, and in the figure, the output v08 is stabilized by controlling the opening and closing of the switch element 2 by the control circuit 9, and the output vo2 is A three-terminal regulator 13 is used to stabilize the output.

(Problem to be solved by the invention) However, in the circuit system shown in Fig. 4, the load current I0
1 becomes smaller, the current flowing through the smooth chic coil 4 becomes discontinuous, and the voltage across both temperatures of the smooth chic coil 4 decreases during the ON period of the switch element 20, causing the output to drop.
Since the voltage of the switching element 2 tends to rise, the on-period of the switching element 2 is reduced by the control circuit 9, and in some cases, intermittent excavation occurs.

For this reason, a multi-output chip type ■-DC as shown in Figure 95
Converter! When this happens, the load current I0° at the output ends becomes small.For the above reason, the pulse width of the voltage input to the smoothing circuit 11 at the output end becomes small, so the load current I0
When the warehouse becomes large, a problem arises in which the voltage drops below the specified value. Therefore, the inductance of the smoothing circuit coil 4 is increased, and a dummy resistor 50 is provided between the output terminals 6 and 7. Measures have been taken to prevent the current flowing through the smooth check coil 4 from becoming discontinuous even when Ios#' is zero. However, such a measure causes the problem of increasing the size of the smooth check coil 4 and lowering the efficiency. Furthermore, since the three-terminal regulator 13 is used to stabilize the output, there is also the problem of large losses.

(Means for Solving Intergroup Points) In order to solve the above problems, in the present invention, one or more output rectifier circuits are connected to at least one or more switch elements directly connected to a DC power supply. In a converter that takes out one or more outputs, a control circuit configured to flow a predetermined current depending on at least one of the outputs between the switch element and the output rectifier circuit is composed of a saturable reactor. It is characterized in that it is connected to the saturable reactor to stabilize the output.

(Example) Hereinafter, the present invention will be explained with reference to examples.

FIG. 1 shows an embodiment of a chip-type DC-DC converter based on the 8AK of the present invention, and shows the basic circuit configuration. In the figure, since the switch element 2 is opened and closed by the oscillator 17, the load current I during the opening and closing period of the switch element 2 is
The configuration is such that it is not affected by n. The control circuit 29 outputs a reset current according to the detected value of the output end of the positive terminal of the smoothing capacitor 26.

Control circuit 29. Diode 30. Saturable reactor 20
0 control volume @22. The saturable reactor 20 flowing through the load path of the output smoothing capacitor 26 is magnetized to the opposite polarity to the black circle shown in the figure. When the switch element 2 is turned on, the saturable reactor 20 is magnetized to the polarity of the black circle and the magnetic flux density can change. The saturation reactor 2o is saturated after blocking the input voltage for a predetermined period of time, and as a result, the cathode side of the diode 230 is supplied with a voltage having a pulse width such that the output voltage - is the specified value. When the switch element 2 is turned off, the energy stored in the saturable reactor 20 is transferred to the load winding 21 of the saturable reactor 20. diode 25
゜Output smoothing coil 25. Output smoothing capacitor 2
6. Resistance 19. Diode 18. Saturable reactor 20
Current flows through the path of the load winding 21 and is consumed by the resistor 19. Therefore, the control circuit 29 can reset the saturable reactor 20 with a small current. (For details on the operation, please refer to the IEEJ Magnetics Study Group material MAG-84-
24) Here, the load winding 21 and the control winding are used as the saturable reactor 20. Although we have taken as an example the one equipped with m22, it goes without saying that the present invention is also effective in cases where there is no control winding @22 and only the load winding 21 is used. In this case, KW! is connected between the load winding @21 and the diode 23 from the control circuit 29 via the diode SO! Continued.

FIG. 2 shows an embodiment in which a multi-output power converter is constructed by combining the control method of the present invention with a power converter type DC-DC converter whose output is stabilized by a switch element 2. In the conventional circuit shown in FIG. 5, the output 27.7 is configured according to the present invention. Note that the operation is the same as in the first embodiment, so a description thereof will be omitted. Note that the switching element does not require an independent root generator, and is directly feedback-controlled from 7 to the output. By using this system, it is possible to greatly increase efficiency compared to the configuration shown in FIG. 5, which is combined with the conventional series dropper system. FIG. 3 shows another embodiment in which the present invention is applied to a multi-output chopper type DC-DC converter, in which the present invention is applied to an output of 27.7. With this configuration, both outputs can be independently controlled from no load to maximum output without increasing the inductance of the output smoothing first coil 25 or increasing the output dummy resistance. A multi-output chip DC-DC converter can be constructed.

(Effects of the Invention) As explained above, the present invention makes it possible to obtain a multi-output chip W DC-DC converter with high efficiency and excellent output stability.

[Brief explanation of the drawing]

FIG. 1 is a basic circuit configuration diagram showing one embodiment of the present invention, and FIG. It is. Figure 4 is a circuit configuration diagram of a conventional Chitsubahoshi DC-DC converter that uses a switching element to stabilize the output, and Figure 5 shows the output that is stabilized using a conventional deaf switching element and a series dropper. FIG. 2 is a circuit configuration diagram of a multi-output chopper-type to-X converter having an output for stabilizing the output. 1: DC power supply, 2: Switch element, 20: Saturable reactor, 21: Load winding weight of saturable reactor + TjA) $z month: 56 Qin 48 Figure 5 Procedure correction type

Claims (1)

[Scope of Claims] 1) In a DC-DC converter in which one or more output rectifier circuits are connected to at least one switch element connected in series with a DC power source to take out one or more outputs, the switch element and an output rectifier circuit, a control circuit that causes a predetermined current to flow in at least one of the outputs according to the output, and a load winding of a saturable reactor consisting of a saturable reactor and a rectifier diode are connected in series. , a chopper type DC-DC converter characterized by stabilizing the output. 2) A control winding is wound around the same iron core of the saturable reactor and is connected in series with the control circuit in addition to the load winding, and the winding is accumulated in the saturable reactor during the ON period of the switch element. The output energy is consumed by a diode and a resistor connected between the input terminal of the load winding of the saturable reactor and the GND line during the off period of the switch element, and the output of the saturable reactor is stabilized if possible. A chopper type DC-DC converter that is characterized by being closed. 3) DC-, in which one or more rectifier circuits are connected to each of at least one switching element connected in series with a DC power source, and two or more outputs are taken out from at least one of the switching elements. A chopper type DC converter characterized by having the following parts:
-DC converter. (a) A load winding of a saturable reactor inserted and connected between the switch element and the output rectifier circuit. (b) A control circuit that detects an output voltage and flows a predetermined current through a saturable reactor according to the output voltage to stabilize the output voltage. (c) A control winding wound around the same iron core of the saturable reactor and having one end connected to the control circuit via a diode and the other end connected to the negative electrode of the DC electrode. 4) Output of at least one of the two or more outputs is stabilized by the switch element, and at least one other output is stabilized by the circuit having the saturable reactor and the control circuit. The chopper type DC-DC converter according to claim 3, characterized in that the chopper type DC-DC converter is configured to perform the following.