JPH1042488A - Power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply having means for detecting interruption of AC input instantaneously and utilized as a backup power supply. SOLUTION: The power supply comprises an AC input filter 1, an AC input smoothing circuit 2, a DC/DC converter 4 for transforming a DC power supply and an emergency power supply, i.e., a battery 7. When AC instantaneously interruption detecting circuits 5a, 5b for detecting the interruption of external power supply are inserted, respectively, between AND provided for the smoothing circuit 2 and a first line 3a connecting the AC input filter 1 and the smoothing circuit 2 and between GND provided for the smoothing circuit 2 and a second line 3b connecting the AC input filter 1 and the smoothing circuit 2, any one AC instantaneous interruption detecting circuit can detect the voltage with no effect from the discharge of a capacitor included in the AC input filter 1, upon the occurrence of instantaneous interruption of AC input. Consequently, the occurrence of instantaneous interruption of AC input can be detected with no time lag.

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 the purpose of preventing data loss of information equipment due to a power failure or the like. The present invention relates to a power supply device having the same.

[0002]

2. Description of the Related Art A conventional power supply device will be described with reference to FIG. As shown in the figure, an AC input filter 1 connected to an external power supply which is a source of AC input, a smoothing circuit 2 for smoothing the AC input supplied via the AC input filter 1, and a supply from a smoothing circuit 2 In addition to the DC-DC converter 4 for transforming the DC power supply, an AC instantaneous power failure detection circuit 5 for measuring the voltage of the AC input supplied to the smoothing circuit 2 is provided. In No. 5, when there was an instantaneous stop of the AC input due to a power failure or the like (hereinafter referred to as an instantaneous interruption of the AC input), it was detected instantaneously.

[0003] When the AC instantaneous power failure detection circuit 5 detects an AC input instantaneous power failure, the AC instantaneous power failure detection circuit 5 instantaneously sends a signal to turn on the switching means 6 and switches the power supply source to the battery 7.
, Power supply to the information device connected to the output of the power supply device is performed without interruption. Under normal conditions, the battery 7 is kept charged by the charging means 8. Although not shown, the AC input filter 1 includes a capacitor for reducing a voltage fluctuation caused by noise or the like entering from an external power supply.

[0004]

However, in the above-mentioned conventional configuration, when an instantaneous blackout of the AC input occurs, the voltage from the external power supply applied to the capacitor provided in the AC input filter is released. The stored charge is discharged. For this reason, even after the momentary interruption of the AC input, the voltage due to the discharge of the capacitor is applied to the smoothing circuit for a while. Therefore, this voltage is detected by the AC instantaneous power failure detection circuit, and it is determined that the power is normally supplied, so that the detection of the AC input instantaneous power failure may be delayed. Therefore, in the power supply device having the above configuration, when the detection of the instantaneous blackout of the AC input is delayed, the power supply from the battery to the device may be delayed.

The present invention has been made to solve the above-mentioned conventional problems, and it is possible to minimize the influence of the discharge of the capacitor constituting the AC input filter and detect the instantaneous interruption of the AC input without time delay. An object of the present invention is to provide a power supply device that can supply stable power to information devices connected to an output of the power supply device.

[0006]

In order to achieve the above-mentioned object, the present invention provides a method comprising the steps of: connecting a first line connecting an AC input filter and a smoothing circuit to a GND provided in the smoothing circuit; An AC momentary power failure detection circuit is provided between a second line connecting the filter and the smoothing circuit and a GND provided in the smoothing circuit, for detecting a stop of supply of external power. When an instantaneous blackout of AC input occurs in this configuration, any of the instantaneous blackout detection circuits can instantaneously detect a change in voltage without being affected by the discharge of the capacitor included in the AC input filter. It is possible to detect that a momentary stop has occurred without any time delay.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS.

In FIG. 1, since the basic configuration is the same as that of the conventional example, description thereof will be omitted, and only different points will be described. In the present invention, the AC instantaneous power failure detection circuit A5a is connected between the first line 3a, which is one of the lines connecting the AC input filter 1 and the smoothing circuit 2, and the GND provided in the smoothing circuit 2.
And an instantaneous blackout detection circuit B5b between the second line 3b, which is the other line connecting the AC input filter 1 and the smoothing circuit 2, and the GND provided in the smoothing circuit 2.

In FIG. 2, A used in the present embodiment
Explaining the configuration of the C instantaneous power failure detection circuit, both the AC instantaneous power failure detection circuits 5a and 5b have a rectifier diode 9 and a resistor 1 respectively.
0, Zener diode 11 and photocoupler 12
And a constant current circuit 13 composed of a transistor and a resistor
It is composed of In addition, since each of the photocouplers 12 is connected to the switching unit 6, when a momentary interruption of the AC input occurs and the current stops flowing to the photocoupler 12, the photocoupler 12 outputs a signal to the switching unit 6, and 6 is turned on.

When an instantaneous AC input interruption occurs in this configuration, one of the AC instantaneous interruption detection circuits 5a and 5b immediately detects a voltage of 0 V without being affected by the discharge of the capacitor included in the AC input filter 1. Therefore, no current flows through the photocoupler 12 included in the AC instantaneous power failure detection circuit that has detected the 0V voltage, whereby it is detected that an AC input instantaneous power failure has occurred, and the switching means 6 is turned off by the photocoupler 12.
By sending a signal indicating N, the power supply source is switched to the battery 7 without time delay. Under normal conditions, the battery 7 is kept charged by the charging means 8.

FIG. 3 shows a change in the voltage waveform before and after the momentary interruption of the AC input in this configuration. In FIG. 3, since an alternating current is applied between the AC input filter 1 and the smoothing circuit 2, an AC waveform as shown from a point A to a point D in FIG.
At this time, points A to B and C to D are shown in FIG.
The voltage is detected by the AC instantaneous power failure detection circuit A5a as shown in FIG. 3B, and the voltage is detected by the AC instantaneous power failure detection circuit B5b from the point B to the point C as shown in FIG. 3C. .

When a momentary blackout of AC input occurs at point D, A
As shown in FIG. 3 (a), the C input immediately goes to 0V at this point D.
Becomes At this time, the detection values after the point D of the AC instantaneous power failure detection circuit A5a during the voltage detection are as shown in FIG.
Under the influence of the discharge of the electric charge accumulated in the capacitor 6 included in the AC input filter 1, the voltage does not immediately become 0 V after the momentary interruption of the AC input, and the detected value of the voltage gradually decreases. Therefore, the AC instantaneous power failure detection circuit is replaced by the AC instantaneous power failure detection circuit A5.
In the configuration in which only the “a” is provided, the instantaneous interruption of AC input is detected by the AC instantaneous interruption detection circuit A5a only at the point F. However, the power supply device of the present invention is provided with the AC instantaneous power failure detection circuit B5b, so that the AC instantaneous power failure detection circuit B5b normally detects a voltage as shown in FIG.
It can be instantaneously detected that no voltage is generated after the point. Therefore, no current flows through the photocoupler in the AC instantaneous power failure detection circuit B5b, and it is possible to detect the AC input instantaneous power failure at this point E. As a result, the time required for detection can be reduced by half, and the time required for detecting an instantaneous blackout of the AC input can be reduced only to the time between DEs. For comparison,
The normal waveforms after the point D at which the instantaneous interruption of the AC input has occurred are also indicated by alternate long and short dash lines.

As described above, since the time required for detecting the instantaneous interruption of the AC input is shortened, there is almost no loss time until the power supply source is switched from the external power supply to the battery 7 by the switching means 6, and the power supply device Since the power supply to the information device connected to the output can be continued without interruption by the battery 7, inconveniences such as loss of data of the information device can be prevented.

In this embodiment, it is assumed that an AC input instantaneous power failure occurs at point D where the AC instantaneous power failure detection circuit A5a is detecting a voltage.
In the case where an instantaneous AC input interruption occurs between BCs whose voltage is being detected by b, the instantaneous interruption of the AC input can be detected by the AC instantaneous interruption detection circuit A5a at the point C, contrary to the above case. Needless to say, even if the instantaneous blackout of the AC input occurs at the timing, the time required for the detection can be shortened.

[0015]

As is clear from the above embodiment, according to the present invention, the first and second lines connecting the AC input filter and the smoothing circuit, and the GND provided in the smoothing circuit are provided.
The AC instantaneous power failure detection circuit between them reduces the influence of the discharge of the electric charge stored in the capacitor.
It is possible to provide a power supply device that can detect the instantaneous blackout of the C input without time delay and can avoid inconveniences such as loss of data in an information device that is a power output destination.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a power supply device of the present invention.

FIG. 2 is a configuration diagram of an AC momentary power failure detection circuit used in the present embodiment;

FIG. 3 is an operation waveform diagram of the power supply device of the present invention.

FIG. 4 is a schematic diagram of a conventional power supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC input filter 2 Smoothing circuit 3a 1st line 3b 2nd line 4 DC-DC converter 5a AC instantaneous interruption detection circuit A 5b AC instantaneous interruption detection circuit B 6 Switching means 7 Battery 8 Charging means

Claims (1)

[Claims] 1. An AC input filter connected to an external power supply, a smoothing circuit for smoothing an AC input, a DC-DC converter for transforming a DC power supply, a battery used as a power supply in an emergency or the like, In a power supply device having a switching unit for switching a supply source to an external power supply or a battery, a first device for connecting the AC input filter and the smoothing circuit is provided.
And the second line connecting the AC input filter and the smoothing circuit and the GND provided in the smoothing circuit. A power supply device provided with an AC momentary power failure detection circuit for detecting.