JP3282309B2 - Power supply - Google Patents

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 used for various electronic devices.

[0002]

2. Description of the Related Art Conventionally, this type of power supply device has a configuration as shown in FIG . In FIG. 2 , reference numerals 21 and 31 denote an AC power supply,
Reference numerals 22 and 32 denote transformers, each of which has a primary winding 22a,
32a and secondary windings 22b and 32b. 2
Reference numerals 3 and 33 are rectifying diodes, 24 and 34 are smoothing capacitors, 25 and 35 are discharge resistors, and 26 is a relay for switching polarity.

The operation of the power supply having such a circuit configuration is as follows. AC power supply 2 as AC input
1 and 31 are applied to the primary windings 22a and 32a, an AC voltage is generated in the secondary windings 22b and 32b, and
Is positively rectified by the diode 33 and negatively rectified by the diode 33.
The resistors 25 and 35, which are smoothed by the reference numerals 4 and 34 and generate positive and negative DC voltages, respectively, are discharge resistors. The polarity is selected by a relay 26 for outputting either the positive or negative DC voltage.

[0004]

In such a conventional circuit configuration, transformers 22 and 32 and a rectifier circuit are required for positive and negative, respectively, and a relay 26 for switching the polarity is also required. It was larger and the price was higher. There is also a disadvantage that the reliability is poor because the relay 26 is used.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a highly reliable power supply having a simple structure by eliminating the above-mentioned conventional disadvantages.

[0006]

In order to solve the above-mentioned problems, the present invention has a primary winding to which an AC input is applied.
A rectifier circuit is connected to the secondary winding of the transformer.
From one end to ground via the first impedance element
Connect the other end to ground via the first constant voltage element
And a second constant voltage element and a second
The voltage is divided by an impedance element and the output is taken out .

[0007]

According to this structure, the alternating current can be varied.
Output can be continuously changed from negative to positive
Things.

[0008]

FIG . 1 is a circuit diagram of a power supply unit according to an embodiment of the present invention.
, And the by controlling the AC power of the primary side, Ru circuit der for varying the negative output from positive. In FIG. 1 , 1 is an AC power supply, 2 is a transformer, and primary windings 2a and 2a.
A secondary winding 2b is provided. 3 is a diode for rectifying the AC generated in the secondary winding 2b, 4 is a smoothing capacitor, 1
7 is a Zener diode as a second constant voltage element, 1
Reference numeral 8 denotes a resistor as a second impedance element, which is output from a connection point between the Zener diode 17 and the resistor 18. 19 is connected to ground from the other end of the rectifier circuit
A zener diode 20 as a first constant voltage element, and a resistor 20 as a first impedance element connected from one end of the rectifier circuit to the ground.

The operation of FIG . 1 is as follows. First, the voltage of the AC power supply 1 is applied to the primary winding 2a, and an AC voltage is generated in the secondary winding 2b. This AC voltage is rectified and smoothed by the diode 3 and the capacitor 4 and converted to DC. Assuming that the DC voltage is 600 V and the Zener voltages of the Zener diodes 17 and 19 are 500 V, a positive 100 V is generated at one end of the rectifier circuit and a negative 500 V is generated at the other end. This voltage is applied to Zener diode 17 and resistor 18
, That is, a negative 400 V lower than the positive 100 V generated at one end of the rectifier circuit by the Zener voltage of the Zener diode 17 by 500 V.

Next, assuming that the DC voltage is 1000 V, the following is obtained. A positive 500 V is generated at one end of the rectifier circuit and a negative 500 V is generated at the other end. From this positive 500V,
A value of 0 V which is lower by the Zener voltage is output.

Next, assuming that the DC voltage is 2000 V, the following is obtained. A positive 1500V at one end of the rectifier circuit,
A negative 500 V is generated at the other end. A positive 1000 V lower than the positive 1500 V by the Zener voltage is generated.

As described above, by varying the AC power supply, it is possible to continuously change the output from negative to positive.

[0013]

As described above, according to the present invention,
What used to require two power supplies in the past can be configured with one power supply, so that the circuit can be simplified, downsized, and reduced in cost. In addition, since the positive / negative switching is performed by a relay using a semiconductor switch or by changing the input power supply, the reliability is improved. Since the switching of the electronic devices is easy, the range of application to various electronic devices is widened.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a power supply device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional power supply device.

[Explanation of symbols]

Reference Signs List 1 AC power supply 2 Transformer 2a Primary winding 2b Secondary winding 3 Diode 4 Capacitor 17 Zener diode (second constant voltage element) 18 Resistance (second impedance element) 19 Zener diode (first constant voltage element) 20 Resistance (first impedance element)

Claims (1)

(57) [Claims] 1. A primary winding to which an AC input is applied.
A rectifier circuit is connected to the secondary winding of the transformer.
From one end to ground via the first impedance element
Connect the other end to ground via the first constant voltage element
And a second constant voltage element and a second
Divide the voltage with an impedance element and take out the output.
Power supply.