JPH0145270Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a DC power supply, and more particularly to a DC power supply capable of providing equal constant voltage output to a plurality of loads.

2. Description of the Related Art Conventionally, as a DC power supply device capable of providing an equal constant voltage output to a plurality of loads, there has been one having a circuit configuration shown in FIGS. 1 and 2.

Referring to FIG. 1, an AC power supply 1 is pressure-reduced by a pressure reducing transformer 2, rectified by a full-wave rectifier circuit 3, and provided with a smoothed output by a smoothing capacitor 4. The output is then given to the first load 6 as a constant voltage output via an output voltage adjustment circuit 5 consisting of a regulator transistor 51 and a constant voltage source 52.

Further, for another second load 3, another regulator transistor 71 connected to the smoothed output
The voltage is applied to the second load 8 via another output voltage adjustment circuit 7 consisting of another constant voltage source 72 .

Furthermore, another regulator transistor 7
A switch 9 is connected in parallel between 1 and another constant voltage source 72, and the regulator transistor 71 is turned on/off by opening/closing the switch 9. It is possible to control the power supply to.

By the way, when the voltages applied to the first and second loads 6 and 8 must be constant voltage outputs that are equal to each other, in the conventional DC power supply device having the circuit configuration as described above, a plurality of constant voltage sources are used. 5
2 and 72, it was difficult to make the voltages supplied to the loads 6 and 8 completely equal due to variations in the voltages of the constant voltage sources 52 and 72.

Therefore, as shown in FIG. 2, the output voltage adjustment circuit 5
An apparatus is used having a circuit configuration in which two loads 6 and 8 are connected in parallel to the output of the circuit, and a relay 10 is inserted between the load 8 and the voltage adjustment circuit 5. In the case of this circuit configuration, the voltages applied to the loads 6 and 8 are equal, and the power supply to the load 8 can also be controlled to be interrupted by the relay 10. however,
In this circuit device, the relay 10 is expensive;
In addition, in order to supply power to multiple loads 6 and 8,
There were problems such as an increased burden on the output voltage adjustment circuit 5.

Therefore, the object of this invention is to provide a DC power supply device that eliminates the drawbacks of the above-mentioned conventional examples and can provide completely equal constant voltage outputs to a plurality of loads.

The DC power supply device according to this invention includes a rectifier that outputs a DC voltage by rectifying a given AC voltage, and a first regulator connected between the output of the rectifier and a first load. a transistor, a constant voltage source that supplies a predetermined DC constant voltage to the base electrode of the first regulator transistor, and a second regulator transistor connected between the output of the rectifier and the second load. is connected between the output of the first regulator transistor and the first load to compensate for a voltage corresponding to the voltage drop that occurs between the base electrode of the second regulator transistor and its output. and voltage compensation means. The second regulator transistor has its base electrode connected to the output of the first regulator transistor.

In operation, the second regulator transistor outputs a voltage at a constant level in response to the voltage output from the first regulator transistor. Since the output voltage of the first regulator transistor is applied to the first load via the voltage compensation means, the same level of DC voltage is supplied to the first and second loads.

The above objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 3 is a circuit diagram of an embodiment of this invention. The configuration, operation, and features of this embodiment will be explained with reference to FIG.

First, in the configuration, a full-wave rectifier circuit 3 composed of four diodes 31 is connected to an AC power supply 1 via a pressure reducing transformer 2. An output voltage adjustment circuit 5 is connected to the output side of the full-wave rectifier circuit 3 via a smoothing capacitor 4 . Output voltage adjustment circuit 5 includes a regulator transistor 51 and a constant voltage source 52 connected to the base of transistor 51. The output of the output voltage adjustment circuit 5 is connected to a load 6 via a diode 12.

Further, a transistor 11 is connected in series to the output side of the smoothing capacitor 4, and its output is connected to a load 8. The base of the transistor 11 is connected via the changeover switch 9 to the output terminal of the above-mentioned output voltage adjustment circuit 5, that is, to the emitter terminal of the regulator transistor 51. This is one of the features of the configuration of this embodiment.

In operation, the AC power source 1 is reduced in pressure by the pressure reducing transformer 2, rectified by the full-wave rectifier circuit 3, and provided with a smoothed output by the smoothing capacitor 4. This output is made into a constant voltage output by the output voltage adjustment circuit 5, and the diode 1
2 to the load 6. Further, a rectified and smoothed output output from the rectifier circuit 3 via the smoothing capacitor 4 is given to the second load 8 via the transistor 11. At this time, the transistor 11
The output voltage of the regulator transistor 51 is applied to the base of the regulator transistor 51 via the switch 9. In other words, the constant voltage output defined by the single constant voltage source 52 is
is applied to the load 6, and the transistor 1
It is also applied to the base of 1. Therefore, the output voltage of the regulator transistor 5 and the output voltage of the transistor 11 are completely equal constant voltage outputs without variations.

Note that the diode 12 inserted between the regulator transistor 5 and the load 6 is a diode for compensating for a voltage drop in the base-emitter voltage (V _BE ) of the transistor 11.

Further, in the above embodiment, the power supply to the load 8 can be arbitrarily controlled by opening and closing the changeover switch 9, but if there is no need to control the power supply to the load 8, the changeover switch 9 is omitted. You can also do that.

Furthermore, in the above embodiment, two loads 6, 8
Although a case has been described in which a constant voltage output equal to 2 is supplied, if the load is 3 or more, this can be handled by connecting additional transistors in parallel to the transistor connected to the output side of the smoothing capacitor 4.

As described above, according to this invention, since multiple transistors are controlled by a single constant voltage source,
It is possible to provide a DC power supply device that is ideal for providing equal constant voltage output to a plurality of loads without causing variations in the output voltage output from each transistor. Further, the circuit configuration of the power supply device can be configured simply and at low cost.

[Brief explanation of the drawing]

FIG. 1 is a configuration circuit diagram of a conventional DC power supply device, which is of interest as a background to this invention. FIG. 2 is another configuration circuit diagram of a conventional DC power supply device. FIG. 3 is a configuration circuit diagram of an embodiment of this invention. In the figure, 1 is an AC power supply, 3 is a full-wave rectifier circuit, 4 is a smoothing capacitor, 5 is an output voltage adjustment circuit, 51 is a regulator transistor, 52 is a constant voltage source, 6 is a first load, and 8 is a first load. 2 is a load, 9 is a changeover switch, 11 is another transistor, and 12 is a diode.

Claims (1)

[Claims for Utility Model Registration] (1) A DC power supply device for supplying equal DC voltage to at least first and second loads, which outputs DC voltage by rectifying the applied AC voltage. rectifying means; a first regulator transistor having a base electrode connected between the output of the rectifying means and the first load; and a predetermined electrode connected to the base electrode of the first regulator transistor. a constant voltage source that supplies a constant DC voltage; and a second regulator transistor having a base electrode connected between the output of the rectifying means and the second load, the second regulator transistor having a base electrode. The regulator transistor has a base electrode connected to the output of the first regulator transistor, a base electrode connected between the output of the first regulator transistor and the first load, and a base electrode connected to the output of the first regulator transistor and the first load.
DC power supply device comprising voltage compensation means for compensating a voltage corresponding to the voltage drop occurring between the base electrode of the regulator transistor and its output. (2) The DC power supply device according to claim 1, wherein the voltage compensation means includes a diode connected between the output of the first regulator transistor and the first load. . (3) The DC power supply device further includes switching means connected between the output of the first regulator transistor and the base electrode of the second regulator transistor. The DC power supply device according to item 1 or 2.