JPS61116939A - No-break power supply backup device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an uninterrupted power backup device used in a small capacity power supply device, and in particular, to a device that maintains a predetermined DC voltage regardless of power outage types with different power outage times. The present invention relates to an uninterrupted power backup device that makes it possible to

[Conventional technology]

Generally, when a power outage occurs, industrial electronic equipment
As a result, the system stops functioning and is required to continue operating.

A conventional uninterruptible power supply backup device of this type is described in Japanese Patent Application Laid-open No. 72223/1983.

As shown in FIG. 4, during normal operation when no power outage occurs, the input terminal is connected to the output voltage detection terminal 7, which is the same as the power supply output terminal, through the transformer 1, the rectifier 2, and the series controller 3. The output voltage is supplied to the At this time, the smoothing capacitor of the rectifier 2 is charged to a predetermined voltage ■, as shown in FIG. has been done.

When a power outage occurs in this normal state, the output voltage decreases from the predetermined voltage 1, and when it decreases to a power outage detection level voltage U lower than the predetermined voltage V1 determined by the Zener voltage of the rectified voltage comparison and detection section 4, the output voltage decreases from the predetermined voltage The output transistor of converts from an off state to an on state. Therefore, the transistor of the switching section 6 changes from the off state to the on state, and the predetermined voltage V2 charged in the charging capacitor of the rectifying section 5 changes to the switching section 6. Since the voltage is supplied to the output voltage detection terminal 7 via the series control section 3, the voltage at the output voltage detection terminal 7 rises from the power failure detection level voltage U to the predetermined voltage Vz.

Thereafter, by discharging the charging capacitor of the rectifier 5, the voltage at the output voltage detection terminal 7 changes from the predetermined voltage v2 to the predetermined voltage V and the detection level voltage U, as shown in FIG. The minimum value of rectification voltage v that guarantees the operation of
(v<u) is reached.

Therefore, according to the above-mentioned uninterrupted power supply backup device, the rectifier section 5 includes a small capacitance capacitor, the rectifier voltage comparison detection section 4. Added switching section 6! By doing so, it becomes possible to maintain the output voltage, which could not be maintained until time T, for an extended period until time T2.

[Problem that the invention seeks to solve]

However, in the conventional uninterrupted power supply backup device described above, since the output voltage holding time is determined by the discharging time of the charging capacitor, there is a certain limit to making the power outage time relatively long. Its application is limited to industrial electronic equipment where the power outage time is relatively short, such as power supplies for nodes on optical data highways, which must maintain output voltage even after a long power outage lasting several hours. However, there was a problem in that the capacitance of the charging capacitor had to be increased, making it impossible to put it into practical use.

In addition, a rectified voltage comparison and detection section is required, and a winding for the rectifier section 5 must be added to the transformer, which complicates the circuit configuration and increases the number of parts, resulting in higher costs and lower reliability. However, there was also the problem of an increase in the mounting space.

Therefore, this invention makes it possible to maintain the output voltage even after a power outage lasting several hours with a simple circuit configuration, thereby reducing costs, improving reliability, and reducing mounting space. The purpose of the present invention is to provide an uninterrupted power backup device that is capable of providing uninterrupted power supply.

[Means for solving problems]

In order to solve the above problems, the present invention provides a differential switching unit having a differential amplifier circuit configuration in which a small-capacity main power supply and a backup power supply with a predetermined voltage lower than the predetermined voltage of the cough main power supply are connected to the input side. The differential switching unit compares the main power supply voltage and the backup power supply voltage, selects and outputs the main power supply voltage when the former is higher than the latter, and selects the backup power supply voltage when it is lower. It is characterized by being configured to output.

[Effect]

In the present invention, during normal operation when there is no power outage in the main power source, the voltage of the main power source exceeds the voltage of the backup power source, so the differential switching section selects the main power source and outputs the selected voltage.

Furthermore, when the main power supply is in a power outage state, the voltage of the main power supply becomes lower than the voltage of the backup power supply, so the differential switching section selects the power supply for the backup amplifier and outputs that voltage.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing a schematic configuration of the present invention, and FIG. 2 is a circuit diagram showing a specific configuration thereof.

First, the configuration will be explained. In FIG. 1, 1 is a transformer, 2 is a rectifier, IO is a differential switching section, and 11 is an output section. A backup power source 12 is connected to the input side of the differential switching section 10.

As shown in FIG. 2, the specific configuration of each of the above parts is as follows: The transformer 1 includes a primary winding l connected to AC power supply terminals 1a and 1b, and a primary winding l wound around this through an iron core. It has a next winding E2.

The rectifier 2 also includes diodes D, , D, whose anodes are connected to both ends of the secondary winding 12 of the transformer l, respectively.
A device comprising a smoothing capacitor C connected between a connection point where their cathodes are connected to each other and an intermediate tap of the secondary winding "JAβ2" of the transformer 1. , 2 constituting a differential amplifier circuit
It has two transistors T+ and Tz.

The transistor T is a resistor RI whose collector is connected to one output side of the rectifier 2, its emitter is connected to the output side, and its base is connected in parallel with the smoothing capacitor C of the rectifier 2.
and R2 are connected to the connection midpoints of a voltage dividing circuit 14a in which R2 is connected in series.

The transistor T2 is a voltage dividing circuit in which the collector is connected to the backup power supply connection terminal 10a, the emitter is connected to the emitter of the transistor T, and the base is connected in series with the resistors R3 and R4 between the backup power supply terminals 10a and 10b. 14b, respectively. Here, the resistance values of the resistors R1 and R1 and the resistance values of the resistors R2 and R4 are respectively selected to be equal. Also, between the backup power supply terminal 10b and the resistor R4 of the voltage dividing circuit 14b)
A contact point is connected to the other output side of the rectifying section 2, and is also connected to the external output terminal 11b. Further, a series circuit including a resistor R3 and a diode D is connected between one output side of the rectifier 2 and the backup power supply terminal 10a. This resistor R1 is for determining the charging current value as a backup source, and the diode D.

is provided to prevent leakage from the backup power supply side to the rectifier 2 side.

Further, the backup power supply 12 connected to the backup power supply terminals 10a and 10b is a rechargeable battery such as an alkaline battery, and the battery voltage E0 is higher than the DC charging voltage E+ between both ends of the smoothing capacitor C. A low value is selected.

Further, the output section 11 has three terminals that suppress the value of the output voltage connected to the output side of the differential switching section 10 within a certain fluctuation range from a certain constant value, and the output current value is about 0.1 to 1A. It is composed of a regulator 13, and external output terminals 11a and llb are led out from the output side thereof.

Next, the effect will be explained. Now, the AC power supply that will be the main power source is connected to the AC input terminals 1a and 1b of the transformer 1.
are connected to the backup power terminals 10a and 10b.
It is assumed that a backup power supply 12 consisting of an alkaline battery is connected to the AC power supply, and in this state, a normal AC output with a rated voltage value of 1 is supplied from the AC power supply to the primary winding A of the transformer 1. It is assumed that there is In this state, the AC output from the main power supply is connected to the transformer 1 and the diode D+ of the rectifier 2.
, Dz, and a DC charging voltage E+ is applied between both terminals of the smoothing capacitor C of the rectifier 2.

On the other hand, the backup power terminals 10a and 1°b have
A backup power source 12 consisting of a battery is connected,
The battery voltage is the DC charging voltage E, the lower voltage E0
has been selected.

Therefore, in the normal state of the AC output, the differential switching section 1
As shown in Figure 3, which shows the relationship between input voltage and collector current, a differential amplifier composed of a resistor R1-Ra of 0 and transistors T1 and T2 operates in such a way that the transistor T1 is in the on state and the transistor T2 is in the off state. It has become.

Therefore, the DC charging voltage E1 across the smoothing capacitor C is almost 3.
It is applied to the input side of the terminal regulator 13, and a desired stabilized DC voltage is output from its output side.

Then, if a power outage occurs in the main power supply from the above normal state,
The main power supply voltage Vl decreases, and the DC charging voltage across the smoothing capacitor C decreases from El to a value smaller than the battery voltage E0. At this time, as shown in FIG. 3, the two transistors TI and T2 constituting the differential amplifier both pass through the unsaturated region as the DC charging voltage E1 decreases, and the transistor T1 shifts to the off state. At the same time, the transistor T2 is turned on. Therefore, most of the battery voltage E0 of the backup power supply 12 except for the collector-emitter voltage drop is applied to the input side of the three-terminal regulator 13 through the on-state transistor T2.
A desired stabilized voltage is output on its output side.

In this way, in the event of a main power outage, the backup amplifier power supply 12
Since the battery voltage E0 from the main power source is continuously outputted, a stable DC output voltage can be obtained even if the main power supply continues to be out of service for a long time. In addition, in this example,
Since a battery is used as a power source for the back-up amplifier, the maximum value of the DC output voltage retention time during a power outage is selected at the time of design, taking into consideration the battery's nominal capacity, charge/discharge characteristics, cycle life characteristics, etc.

Furthermore, when the main power supply is restored from a power outage state, the DC charging voltage El is applied across the smoothing capacitor C of the rectifying section 2, so that the transistor T of the differential switching section 10, turns on again, the DC charging voltage E is applied to the three-terminal regulator 13 through this transistor T, and a desired stabilized DC voltage is output from its output side.

In addition, in the above example, the case where a battery is used as a backup power source will be explained.
However, it is not limited to this, and a DC/DC converter can also be used. In this case, even if the main power supply is out of power for a long time, the DC output voltage can be maintained in an uninterrupted state. There is an advantage that it can be done.

Further, in the above embodiments, the case where the main power source is an AC power source has been described, but it goes without saying that a DC power source can be used instead.

Furthermore, in the above embodiment, the output current of about 0.5 to IA is targeted, but the resistors R1 to Ra.

By selecting the characteristics of the transistors T, . . . Tg to predetermined values, it is possible to make the output current several amperes. However, in this case, it is necessary to add several resistors and transistors outside the three-terminal regulator 13 to make the output section for high output current.

〔Effect of the invention〕

As explained above, according to the present invention, the main power supply and the power supply for the back amplifier are connected to the input side of the differential switching section, and the differential switching section has both the voltage comparison detection function and the switching function. With this configuration, any power source such as a battery or DC/DC converter can be connected as a backup power source, resulting in instantaneous power outages lasting from a few cycles to a few seconds to long-term power outages lasting from ten minutes to several hours. It becomes possible to maintain the DC output voltage even if any type of power outage occurs. In addition, since the differential switching section has a voltage comparison detection function and a switching function, the overall circuit configuration is simple and the number of parts is small, thereby reducing costs, improving reliability, and reducing mounting space. Effects such as being able to do this can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an outline of an embodiment of the present invention;
FIG. 2 is a circuit diagram showing a specific configuration of an embodiment of the present invention, FIG. 3 is an explanatory diagram providing a detailed explanation of the invention, and FIG.
The figure is a block diagram showing a conventional example, and FIG. 5 is an explanatory diagram for explaining the operation of the conventional example. In the figure, 1 is a transformer, 2 is a rectifier, 10 is a differential switching unit, 1
1 is the output section, 12 is the backup power supply, D+, I)z
is a diode, T+, Tz is a transistor, R1-R
4 is a resistor, and 13 is a three-terminal regulator. 1b Komizu (V)

Claims (1)

[Claims] The differential switching unit has a differential amplifier circuit configuration in which a small-capacity main power supply and a backup power supply with a predetermined voltage lower than the predetermined voltage of the main power supply are connected to the input side, and the differential switching unit is connected to the main power supply. The main power supply voltage is compared with the backup power supply voltage, and when the former is higher than the latter, the main power supply voltage is selectively output, and when the latter is lower, the backup power supply voltage is selectively output. Uninterrupted power backup device.