JP2853468B2 - Battery backup DC 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 DC power supply, and more particularly to a DC power supply which converts external AC power into DC power and outputs the DC power to two or more DC output loads. Battery backup DC power supply for backing up a battery with a battery.

[0002]

2. Description of the Related Art A conventional battery backup DC power supply of this type receives an external AC power supply as input and converts the AC / DC converter into DC power having a desired voltage.
One DC / DC converter connected to the output side of the C / DC converter and outputting DC power converted to a predetermined voltage, and a voltage connected to the output side of the AC / DC converter and falling below a specific voltage Circuit for limiting the maximum output current to a certain value or less, and the above-described AC through the charging circuit.
And a battery that is charged by the DC output of the / DC converter. When the external AC power is cut off, the DC / DC converter is operated by the battery for a certain period of time to supply DC power to the load. .

[0003]

In the above-mentioned conventional battery backup DC power supply, when the load connected thereto is, for example, an information processing device, the information processing device performs a series of normal operations. In the state, the consumption of DC power is large, but the operation of information processing is stopped,
If the state immediately before the stop is stored in the storage unit and DC power is supplied only to the part holding the storage state, the power required for the part holding the storage state is small, but the load is small. Since there is only one DC / DC converter for supplying DC power to the power supply, a portion for maintaining the above-described storage state for the load and a portion for performing normal information processing and consuming a large amount of power are collectively provided. Since the DC power is supplied, when the external AC power supply is cut off, the time during which the power can be supplied from the battery to the load is, for example, about several minutes. Within.

Therefore, if the external power supply is cut off for a long time, for example, in the above case, for about several minutes or more, the output of the battery decreases, and it is necessary to stop the backup operation by the battery. However, since the storage state in the storage unit that stores the operation state up to that time is also lost, the supply of the external AC power is not performed for such a program that is being processed at the time when the external AC power is cut off. When it is restarted, it has the disadvantage that data processing according to this program must be restarted from the beginning.

[0005] An object of the present invention is to reduce such power consumption when the external AC power supply is cut off and the load device interrupts normal operation and becomes in a state that requires little power consumption. A first DC / DC converter capable of maintaining an unnecessary state and supplying power for a long time only to a part necessary for returning to a normal state when the supply of the external AC power is resumed; A second DC that operates only for a short period of time required after the external AC power supply is cut off until the normal operation state is interrupted as described above.
Provided is a battery backup DC power supply device having a simple circuit configuration having a DC / DC converter and a battery for supplying backup power to the first and second DC / DC converters, and for effectively using the battery capacity. It is in.

[0006]

SUMMARY OF THE INVENTION A battery-backed DC power supply according to the present invention has an AC / DC converter for inputting AC power and outputting DC and a first voltage for receiving an output of the AC / DC converter as input. A first DC / DC converter that outputs the first DC power converted into a DC power, and a forward series connected between one of an output side of the AC / DC converter and an input side of the first DC / DC converter. A first diode inserted into the AC / DC converter, and an input side connected to a portion closer to the output of the AC / DC converter than the first diode on the output side of the AC / DC converter, and ON / OFF applied from outside. A second DC / D that outputs DC power having a second voltage when the ON / OFF signal is ON and DC power is output from the AC / DC converter under the control of a signal.
A C converter, a relay having a drive unit connected in parallel to the output side of the second DC / DC converter and having normally open contacts, and one of two terminals on the output side of the AC / DC converter A charging circuit for connecting one end of the charging circuit to maintain the output voltage at or below a predetermined constant value and restricting the output current to a predetermined value or less; and a forward direction with respect to the current flowing through the charging circuit at the other end of the charging circuit. A second diode having one end connected to the other end of the second diode, and one end connected to the other end of the second diode, and the other end in the forward direction between the other end of the two terminals on the output side of the AC / DC converter. And the battery connected to
The normally open contact having one terminal connected to the one end on the output side of the C / DC converter, and the first DC / DC among the other terminal of the normally open contact and the terminal of the first diode A third diode connected in a direction opposite to a direction in which a current of the battery flows, between a terminal on the converter side and an end of the both ends of the battery to which the second diode is connected. I have.

[0007]

FIG. 1 is a block diagram showing an example of a battery backup DC power supply according to the present invention.

The battery backup DC power supply of the present invention shown in FIG. 1 has an AC / DC converter 1 which receives an external AC power supply and converts it into DC power having a predetermined voltage, and this AC / DC converter. 1 or an output of a battery 6 to be described later, and a first DC / DC converter 2 which always outputs a DC power having a desired voltage even when an external AC power supply is cut off, Is controlled by the ON / OFF signal of AC / DC.
A second DC / DC converter 3 is provided which receives an output of the converter 1 or a battery 6 described later as input and outputs DC power having a desired voltage only when necessary.

The battery backup DC power supply shown in FIG. 1 has one end connected to the battery 6 and the positive electrode of the output of the AC / DC converter 1, and the other end connected to a second diode (to be described later). A charging circuit 4 connected to the positive electrode side for charging the battery 6 at the time of charging to maintain the voltage applied to the battery 6 at a certain voltage or less and for maintaining the current at the time of charging and discharging the battery 6 at a predetermined current value or less; , The second DC /
A driving unit is connected in parallel to the output side of the DC converter 3,
A relay 5 having a normally open contact (a contact that is opened when no current flows through the drive unit) 5A.

Further, the battery backup DC power supply shown in FIG. 1 has a positive terminal connected to the output side of the AC / DC converter 1 and a negative terminal connected to the input side of the first DC / DC converter 2. A first diode 7 whose side is connected, the above-mentioned normally open contact 5A connected in parallel to the positive electrode and the negative electrode of the above-mentioned first diode 7,
And a third diode 8 whose positive electrode is connected to the positive electrode side of the battery 6 described above.

One end of the charging circuit 4 is connected to AC /
The positive terminal of the DC converter 1 is connected to the positive terminal of the first diode 7, and the negative terminal of the second diode 9 is connected to the positive terminal of the battery 6. Further, the negative side of the battery 6 is connected to the negative side of the output side of the AC / DC converter 1.

The input-side negative terminals of the first and second DC / DC converters 2 and 3 are connected to the output-side negative terminal of the AC / DC converter 1.

Next, the operation of the battery backup DC power supply of the present invention will be described in detail with reference to the embodiment of FIG. When AC power is normally input to the AC / DC converter 1, DC power having a predetermined voltage is output from the output of the AC / DC converter 1. Since the DC voltage _VDC is set higher than the voltage of the battery 6, the battery 6 is charged by the charging circuit 4 to the second diode 9.
, And at this time, the output of the AC / DC converter 1 is supplied to the first DC / DC converter 2 through the diode 7.

The second DC / DC converter 3 also has A
The output of the C / DC converter 1 is supplied directly. Therefore the first
The first DC power which is the output of the DC / DC converter 2 is output to a load, and the second DC power which is the output of the second DC / DC converter 3 is, for example, the load of this DC power supply. Is controlled by an ON / OFF signal output from an information processing device that is not
If the FF signal is ON, the second DC / DC converter 3
Outputs the second DC power, and turns ON / OFF as described above.
When the signal is OFF, the second DC power is not output from the second DC / DC converter 3.

When the ON / OFF signal is ON, the second DC power is output, so that the normally open contact 5A of the electromagnetic relay 5 is closed. Here, when the AC input decreases or stops, the DC output of the AC / DC converter 1 decreases, and finally falls below the voltage of the battery 6. In such a state, the first DC / DC converter 2 from the battery 6 via the third diode 8 and the second DC / DC converter 2 via the normally open contact 5A
/ DC converter 3 is supplied with battery power, and enters a battery backup state.

The first and second DC / DC converters 2 and 3 continue to output normally until the battery voltage falls to a predetermined voltage. On the other hand, if the above-described ON / OFF signal is OFF while the external AC power is being supplied to the AC / DC converter 1, the second DC / DC converter 3 does not operate, so the second No DC power is output, and the normally open contact 5A is open. In such a situation, if the external exchange drops or stops,
The output of the battery 6 is supplied to only the first DC / DC converter 2 without being supplied to the second DC / DC converter 3, so that the first DC power that is always output from the first DC / DC converter 2 Only the battery is backed up by the battery, and in such a state, the ON signal becomes the second DC
/ DC converter 3, the second DC / DC
The second DC power from converter 3 is not output.

The first DC / DC converter 2 is connected to, for example, a state storage unit necessary for storing information processed by the information processing apparatus, while the second DC / DC converter 2 is connected to the first DC / DC converter 2.
A part required when the above-mentioned information processing apparatus operates when executing the normal information processing other than such a state storage unit is connected to the converter 3 as a load. During the operation of (1), the AC / DC converter 1 is operated by the power from the external AC power supply, and an ON signal is applied from the information processing device to the second DC / DC converter 3, and the first and second DC / DC converters 3 are turned on. The / DC converters 2 and 3 supply first and second DC power to an information processing device (not shown), which is a load, and charge the battery 6 in advance.

As described above, while the information processing apparatus is operating,
When the external AC power supplied to the / DC converter 1 is interrupted, the information processing device detects the disconnection of the external AC power in a portion (not shown), and the external AC power is interrupted. At the time, after an appropriate time has elapsed, the information processing apparatus described above outputs an OFF signal to the second DC / DC converter 3.
In addition, the operation of the second DC / DC converter 3 is stopped, and thereafter, only the first DC power is supplied by the first DC / DC converter 2 by the battery 6 until the supply of the external AC power is resumed. Supply.

As described above, the power required to store the operation state of the information processing device is very small compared to the power required for the information processing device to perform other information processing. By the above-described operation, the first DC / DC converter 2 can be operated by the battery 6 for a long time.

In addition, during the period from when the information processing apparatus detects the disconnection of the external AC power supply to when the OFF signal is output,
If the normal information processing operation is stopped and the state of the previous operation is stored, when the supply of the external AC power is restarted, the normal operation is performed based on the stored operation state. Processing can be resumed.

[0021]

As described above, the AC / DC converter 1
Is divided and supplied to the first and second DC / DC converters 2 and 3 in addition to the battery 6, and the first DC / DC converter
A converter having a smaller power consumption than the load connected to the second DC / DC converter 3 is connected to the converter 2, and when the external AC power supply is cut off, the first and second DC / DC converters are briefly connected. The DC converters 2 and 3 are both operated, and thereafter, the normally open contact of the relay 5 is opened so that only the first DC / DC converter 2 is driven by the battery 6. This makes it possible to supply necessary DC power by the battery backup operation for a long time.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 AC / DC converter 2 First DC / DC converter 3 Second DC / DC converter 4 Charging circuit 5 Relay 6 Battery 7 First diode 8 Third diode 9 Second diode

Claims (1)

(57) [Claims] 1. An AC which receives an AC power supply as input and outputs DC.
A DC / DC converter, and a first DC / DC converter that receives an output of the AC / DC converter and outputs a first DC power converted to a first voltage.
A DC / DC converter, and a first diode inserted in series in a forward direction between one of an output side of the AC / DC converter and an input side of the first DC / DC converter,
The input side is connected to a portion closer to the output of the AC / DC converter than the first diode on the output side of the AC / DC converter, and the ON / OFF signal is controlled by an externally applied ON / OFF signal. ON and the AC /
A second DC / DC converter that outputs DC power having a second voltage when DC power is being output from the DC converter, and a driving unit connected in parallel to an output side of the second DC / DC converter And a relay having a normally open contact, and one end connected to one of two terminals on the output side of the AC / DC converter to maintain an output voltage at a predetermined constant value or less and output a current. A charging circuit for limiting the current to a certain value or less, a second diode having one end connected in a forward direction to a current flowing through the charging circuit at the other end of the charging circuit, and one end connected to the other end of the second diode. The above A
A battery having the other end connected in the forward direction between the other end of the two terminals on the output side of the C / DC converter;
The normally open contact having one terminal connected to the one end on the output side of the converter, and the other terminal of the normally open contact and the terminal of the first DC / DC converter among the terminals of the first diode. A battery backup comprising: a terminal and a third diode connected in a direction opposite to a direction in which a current of the battery flows, between an end of the battery and both ends of the battery to which the second diode is connected. DC power supply.