JPH0675645A - Electric power unit - Google Patents

Abstract

PURPOSE:To efficiently change combinations of output voltages and current values without varying the total capacity of secondary sides of a transformer by switching and stabilizing the outputs of plural systems of the transformer to one or plural independent systems which are connected in series by changeover switches. CONSTITUTION:The secondary-side outputs of the transformer 10 which has plural secondary-side output systems are rectified by rectifying circuits 13 and 14 respectively and then smoothed by smoothing circuits 15 and 16. The smoothed outputs are inputted to a stabilizing circuit 17 by the changeover switches 11 and 12 for switching to one system or individually independent systems which are connected in series, and stabilized in voltage and outputted. Thus, the two secondary-side outputs of the transformer 10 are switched by the changeover switches 11 and 12 and inputted to the stabilizing circuit 17, and then combinations of output voltages and current values are efficiently changed without varying the total capacity of the transformer 10, thereby enabling wider application.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device, and more particularly to a series regulator capable of efficiently changing the combination of output voltage / current value without changing the total capacity (VA) on the secondary side of the transformer. System power supply device.

[0002]

2. Description of the Related Art FIG. 3 shows a connection diagram of a conventional series regulator type power supply device. 1 is a transformer, AC1
This is to obtain the voltage required to generate the output voltage Vcc from 00V. The secondary side output of the transformer 1 is rectified by the diode bridge 2, smoothed by the capacitor 3, and input to the stabilizing circuit 4. In the stabilizing circuit 4, the error amplifier 8 is arranged so that the value obtained by dividing the output voltage Vcc by the voltage dividing circuit formed by the resistors 5 and 6 is equal to the reference voltage source 7.
Controls the transistor 9 to stabilize the output voltage Vcc.

When such a series regulator system is used, for example, if the output of the power supply is 30V / 1A,
The output range is as shown in FIG. By the way, in the case of considering the output range as shown in FIG.
It suffices to change the value of the voltage dividing circuit formed in, but for the current, it is necessary to prepare a transformer capable of handling 30V / 2A.

[0004]

However, this is shown in FIG.
A power source that can cover the range of (c) is created, and a useless part is generated. Also, the capacity (VA) of the transformer
Increase in size, weight, and price is disadvantageous in the case of the application shown in FIG. 4 (b).

This problem can be solved by adopting an efficient switching type power source, but the switching type power source has a drawback in that it has a lot of noise. Therefore, for example, in order to obtain a low noise power amplifier, a series regulator type power supply must be adopted. As another method, as shown in FIGS.
By preparing two sets of output systems on the secondary side of 0 and switching the changeover switches 11 and 12 to connect these output systems in series or in parallel, the output voltage / output voltage can be changed without changing the total capacity of the transformer 10. The combination of currents can be changed. In the case of FIG. 5, the changeover switches 11 and 12 are set to NC.
By switching to the (normally open) side, they are connected in series and NO
Switching to the (normally closed) side enables parallel connection. In addition, in (a), the changeover switches 11 and 12 are connected to the secondary side winding of the transformer 10 to perform switching at the AC stage,
In (b), the changeover switches 11 and 12 are connected to the output terminals of the diode bridges 13 and 14, and the changeover is performed at the DC stage.

Here, there is no problem in the case of series connection, but in the case of parallel connection, the currents output by each differ depending on the voltage variations. For example, if two sets of 18V / 1A output secondary windings are connected in parallel to obtain an output current of 1.5A, there is a margin in the current capacity, so there is no problem, but an output current of 2A 2 if you want to get
There is a possibility that a load of 1 A or more may be applied to one side due to the variation in the secondary voltage, which is unsatisfactory. As described above, in order to efficiently obtain the voltage / current from the determined transformer, the circuit configuration shown in FIG. 5 is insufficient.

The present invention solves such a problem, and an object thereof is to provide a total capacitance (V) on the secondary side of the transformer.
It is to realize a series regulator type power supply device capable of efficiently changing the combination of the output voltage / current value without changing A).

[0008]

In order to solve such problems, the present invention provides a transformer having a plurality of secondary side output systems and a plurality of rectifying circuits for rectifying the secondary side outputs of the transformers. And a plurality of smoothing circuits for smoothing the output of each rectifier circuit, a plurality of changeover switches for outputting the output of each smoothing circuit by switching to one system connected in series or a plurality of independently independent systems, and these changeover switches A stabilizing circuit that stabilizes the voltage output from one system to a plurality of systems and outputs the stabilized voltage to the outside is provided.

[0009]

The outputs of the plurality of systems of the transformer are switched to one system connected in series by the changeover switch or a plurality of systems independently independent and input to the stabilizing circuit, respectively stabilized and output to the outside. As a result, the stabilizing circuit can individually stabilize the outputs of a plurality of systems of the transformer, so that a power supply device that can efficiently change the output range without changing the output capacity of the transformer can be obtained.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a basic circuit diagram of an essential part of the present invention, and parts common to those in FIG. In FIG. 1, the COM contact of the changeover switch 11 is connected to the negative side output terminal of the smoothing circuit 15 that smoothes the output of the rectifier circuit 13, and the NC contact is the positive side of the smoothing circuit 16 that smoothes the output of the rectifier circuit 14. The NO contact is connected to the output terminal, and is connected to the negative output terminal of the smoothing circuit 16 and the ground line GND of the stabilizing circuit 17. The COM contact of the changeover switch 12 is connected to one input terminal of the stabilizing circuit 17, the NC contact is connected to the positive output terminal of the smoothing circuit 15 and the other input terminal of the stabilizing circuit 17, and the NO contact is smooth. It is connected to the positive output terminal of the circuit 16.

FIG. 2 is a circuit diagram showing a concrete example of FIG.
The same parts as those in FIG. 1 are designated by the same reference numerals. In the stabilization circuit 17 of FIG. 2, the collector of the transistor 18 is connected to the NC contact of the changeover switch 12 and the positive output terminal of the smoothing circuit 15, and the collector of the transistor 19 is connected to the COM contact of the changeover switch 12. ing. The emitters of the transistors 18 and 19 are commonly connected via the protective resistors 20 and 21 and serve as the output of this power supply circuit. The output voltage Vcc is connected to the COM contact of the changeover switch 22 and the inverting input terminal of the error amplifier 27 via the resistance 23, the NC contact of the changeover switch 22 is connected to the ground GND via the resistance 24, and the NO contact is the resistance. It is connected to the ground GND via 25.
The reference voltage source 26 is connected to the non-inverting input terminal of the error amplifier 27, and the output of the error amplifier 27 is connected to the bases of the transistors 18 and 19.

The operation of the circuit thus configured will be described. First, for example, the secondary side output capacity of the transformer 10 is set to 18V / 1A and the target power supply output is set to 30V / 1A. At this time, the COM contacts of the changeover switches 11, 12, 22 are connected to the NC side as shown in FIG. In this case, from the viewpoint of the stabilizing circuit 17, the output becomes the secondary side of the transformer of 36V / 1A, and the value obtained by dividing the output voltage by the voltage dividing circuit formed by the resistors 23 and 24 is equal to the output voltage of the reference voltage source 26. The error amplifier 27 controls the transistors 18 and 19 so that the target value of 30 V is output. Here, the transistors 18 and 19 are connected in parallel, and the resistors 20 and 21 make the collector currents flowing through the transistors 18 and 19 substantially equal. That is, when 1 A is taken as the output of the power supply, the currents flowing through the transistors 18 and 19 are about 0.5 A, respectively.

Next, when the target power supply output is set to 15V / 2A, the COM contacts of the changeover switches 11, 12, 22 are NO.
Connect to the side. In this case, 2 from the viewpoint of the stabilizing circuit 17.
The outputs are the secondary side outputs of the transformers of 18V / 1A, and are respectively connected to the collectors of the transistors 18 and 19. The output voltage can be changed by switching the resistors 24 and 25. In this case as well, the output voltage is set to the resistance 23,
The value divided by the voltage dividing circuit formed by 25 and the reference voltage source 2
The error amplifier 27 controls the transistors 18 and 19 so that the output voltages of 6 become equal, and the target value of 15 V is output. Here, since the transistors 18 and 19 have the same base potential and the emitters are commonly connected via the resistors 20 and 21, the collector currents flowing through the transistors 18 and 19 are almost the same even if the collector potentials are slightly different. Will be equal. Therefore, when 2A is taken as the output of the power supply,
The current flowing through the transistors 18 and 19 is about 1 A each.
Becomes

As described above, the two sets of the secondary side outputs of the transformer 10 are switched by the changeover switches 11 and 12 to one system output connected in series and two independent systems independently.
By setting the stabilizing circuit 17 to 2 inputs, the transformer 1
Efficiently without changing the total capacity (VA) of 0
The output ranges of (a) and (b) can be realized. In addition, with the same series regulator method, for example, 18V
By using 4 sets of transformer secondary side outputs of / 1A and using a 4-input stabilizing circuit, 18V / 4A, 36V / 2 is seen from the stabilizing circuit.
A, 72V / 1A transformer secondary side output can be handled equivalently. Therefore, without changing the total capacity of the transformer, the output of the final power supply is 15V / 4A, 30V / 2A,
It is possible to switch about 60V / 1A.

A dual tracking power supply can be obtained by implementing the same circuit on the negative power supply side.

[0016]

As described above, according to the present invention,
In the series regulator type power supply, transformer 2
It is possible to efficiently change the combination of the voltage / current value to be output without changing the total capacity (VA) on the secondary side, and it is possible to support a wider range of applications.

[Brief description of drawings]

FIG. 1 is a basic circuit diagram of a main part of the present invention.

FIG. 2 is a circuit diagram of the specific example of FIG.

FIG. 3 is a connection diagram of an example of a conventional series regulator type power supply device.

FIG. 4 is an explanatory diagram of a combination of output voltage and output current.

FIG. 5 is a connection diagram of another example of a conventional series regulator type power supply device.

[Explanation of symbols]

 10 transformer 11,12 changeover switch 13,14 rectifier circuit 15,16 smoothing circuit 17 stabilizing circuit

Claims (1)

[Claims] 1. A transformer having a plurality of secondary-side output systems, a plurality of rectifying circuits for rectifying the secondary-side outputs of the transformers, a plurality of smoothing circuits for respectively smoothing the outputs of the respective rectifying circuits, and respective smoothing circuits. A plurality of changeover switches for switching and outputting the output of the circuit to one system connected in series or a plurality of individually independent systems, and to stabilize and output the voltage output from these changeover switches to one system or plural systems to the outside. A power supply device comprising a stabilizing circuit.