JPH04364331A - Battery backup system - Google Patents

Abstract

PURPOSE:To provide a highly economic battery backup system by reducing loss in the discharge circuit of battery. CONSTITUTION:A load 3 is normally fed with a constant voltage through a rectifying circuit 5 and a voltage stabilizing circuit 6 and a battery is charged through a charging circuit 7. Upon power interruption, the load 3 is fed with power from a battery 4 through a primary discharge path circuit 9 comprising a coupling diode 8 and the voltage stabilizing circuit. Upon voltage drop of the battery 4, the load 3 is fed with power through a secondary discharge path circuit 10 comprising a transistor Q1 interposed between the battery 4 and the output of the voltage stabilizing circuit 6 in place of the primary discharge path circuit 9.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery backup device for backing up a load such as a communication control device using a battery during a power outage.

0002

[Prior Art] Figure 2 shows, for example, "Yasuo Harada, 'Communication Power Supply' Revised 2nd Edition (April 1, 1972), Ohmsha, p16.
4-165'' is a block diagram showing an example of a configuration of a conventional battery backup device (SID method) for a communication control device. In FIG. 2, constant voltage rectifier 1
charges the storage battery 4 and supplies a constant voltage to the load 3 via the silicon dropper 2. However, since the silicon dropper 2 shown in FIG. 2 uses a diode as a voltage control element, it is not possible to precisely set the output voltage.

FIG. 3 is a block diagram of a small-capacity battery backup device that allows minute output voltage settings. In FIG. 3, a voltage stabilizing circuit 6 is inserted between the rectifier circuit 5 and the load 3 to enable fine output voltage settings, and a dedicated charging circuit 7 is provided for the storage battery 4. ing. In the event of a power outage, power is supplied from the storage battery 4 to the load 3 via a primary discharge path circuit 9 consisting of a coupling diode 8 and a voltage stabilizing circuit 6.

0004

However, in the battery backup device shown in FIG. 3, since there is a voltage drop due to the minimum control voltage of the voltage stabilizing circuit 6 and the coupling diode 8, it is necessary to increase the voltage of the storage battery 4 or There was a problem in that it was necessary to increase the capacity, and the number of cells or the cell capacity had to be increased. The present invention was made in order to solve the problem of increasing the number of cells or the capacity of a storage battery, and provides a highly economical battery backup device that reduces loss in the discharge circuit of a storage battery. The purpose is to

[0005]

[Means for Solving the Problems] The battery backup device of the present invention supplies a constant voltage to a load through a rectifier circuit and a voltage stabilization circuit, charges a storage battery through a charging circuit, and connects a coupling diode in the event of a power outage. In a battery backup device that supplies power from a storage battery to a load via a primary discharge path circuit consisting of a storage battery and a voltage stabilization circuit, the battery backup device is provided between the storage battery and the output of the voltage stabilization circuit so that the voltage of the storage battery reaches a predetermined level. When the voltage decreases to 1, the voltage stabilizing circuit is replaced by a secondary discharge path circuit including a transistor that supplies the discharge current of the storage battery to the load.

[0006]

[Operation] In the present invention, a constant voltage is constantly supplied to the load via the rectifier circuit and the voltage stabilization circuit, and the storage battery is charged via the charging circuit. In the event of a power outage, the discharge current from the storage battery is supplied to the load via the primary discharge path circuit. The primary discharge path circuit at this time includes a coupling diode and a voltage stabilization circuit, and the voltage drop is relatively large, and when the storage battery continues to discharge and the voltage of the storage battery decreases, the voltage stabilization circuit The output voltage of the secondary discharge path circuit decreases or does not function properly, but at this time, the emitter of the transistor in the secondary discharge path circuit is pulled to the negative side, and the discharge current from the storage battery is transferred to the load through the secondary discharge path circuit. Supplied. In this way,
Initially, discharge from the storage battery was performed through the primary discharge path circuit, and as the voltage of the storage battery decreased, the discharge was performed through the secondary discharge path circuit, so even if the voltage of the storage battery dropped, power was still supplied to the load. can do.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a battery backup device according to an embodiment of the present invention. In this embodiment, a secondary discharge path circuit 10 is added between the storage battery 4 and the output of the voltage stabilization circuit 6 to the conventional battery backup device of FIG. This secondary discharge path circuit 10 includes a transistor Q1 and a zener diode D4 as shown in the figure.
and a resistor R4.

FIG. 4 is a circuit diagram of FIG. 1. The rectifier circuit 5 is composed of a series circuit of a diode D1 and a resistor R1,
The charging circuit 7 is composed of a diode D2. Coupling diode 8 is composed of diode D3. The input terminal T1 for charging the storage battery is connected to the storage battery 4 via the diode D1 and the resistor R1, and the input terminal T2 for the stabilizing circuit is connected to the diode D2 and the voltage stabilizing circuit 6.
The diode D3 of the primary discharge path circuit 9 is connected to the storage battery 4 and the input section of the voltage stabilization circuit 6. Furthermore, as the secondary discharge path circuit 10, the positive terminal of the storage battery 4 and the transistor Q
1 and one end of the resistor R2 are connected, the emitter of the transistor Q1 is connected to one end of the load 3, the base of the transistor Q1 is connected to the other end of the resistor R2 and the cathode side of the Zener diode D4, The anode of the Zener diode D4 is connected to the input terminal T3 and the other end of the load 3.

Next, the operation will be explained. (1) During normal operation (when there is no power outage), the AC voltage supplied between input terminals T1 and T3 is rectified by diode D1 and converted to DC voltage, and then properly charges the storage battery 4 via resistor R1. do. The AC voltage supplied to the input terminals T2 and T3 is rectified by the diode D2 and converted into a DC voltage, and then supplied to the load 3 as a stable DC voltage with less ripple via the voltage stabilization circuit 6. At this time, the zener voltage of the zener diode D4 is selected so that the voltage appearing at the emitter of the transistor Q1 is lower than the output voltage of the voltage stabilizing circuit 6. The output of the voltage stabilizing circuit 6 takes priority, and power is supplied from the voltage stabilizing circuit 6 to the load 3 as described above.

(2) During a power outage During a power outage, a discharge current initially flows through the primary discharge path circuit 9. That is, the discharge current from the storage battery 4 is supplied to the load 3 via the diode D3 and the voltage stabilization circuit 6. Voltage stabilization circuit 6 and transistor Q at this time
The relationship with 1 is the same as in the normal case described above. Then, as the power supply by the primary discharge path circuit 9 continues and the voltage of the storage battery 4 decreases, the output voltage of the voltage stabilization circuit 6 also decreases or does not operate properly, and the primary discharge path circuit 9 is replaced. The secondary discharge path circuit 10 operates accordingly. In other words,
When the output voltage of the voltage stabilizing circuit 6 decreases or does not operate properly, the emitter of the transistor Q1 of the secondary discharge path circuit 10 connected to the output side of the voltage stabilizing circuit 6 is pulled to the negative side, Power is supplied from the storage battery 4 to the load 3 via the secondary discharge path circuit 10.

FIG. 5 is a circuit diagram of a battery backup device according to another embodiment of the present invention. This embodiment is an applied embodiment for a load in which the discharge current of the storage battery is minute, and a light emitting diode D5 is inserted on the collector side of the transistor Q1. With such a configuration, the operation of the secondary discharge path circuit 10 can be displayed as a voltage drop alarm of the storage battery 4.

0012

As described above, according to the present invention, the discharge of the storage battery is controlled by the first
This is done via the secondary discharge path circuit, and if the voltage of the storage battery drops, it is performed via the secondary discharge path circuit with less loss in the discharge circuit, so even if the voltage of the storage battery drops, power is supplied to the load. Therefore, there is no need to increase the voltage of the storage battery or increase its capacity, and a reduction in the number of cells or cell capacity of the storage battery can be expected. Further, the secondary discharge path circuit can be expected to operate as a redundant system against failure modes of the coupling diode and voltage stabilizing circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a battery backup device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional battery backup device.

FIG. 3 is a block diagram of another conventional battery backup device.

FIG. 4 is a circuit diagram of the battery backup device of FIG. 1;

FIG. 5 is a circuit diagram of a battery backup device according to another embodiment of the present invention.

[Explanation of symbols]

3 Load 4 Storage battery 5 Rectifier circuit 6 Voltage stabilization circuit 7 Charging circuit 8 Coupling diode 9 Primary discharge path circuit 10 Secondary discharge path circuit

Claims (1)

[Claims] Claim 1: During normal operation, a constant voltage is supplied to the load via a rectifier circuit and a voltage stabilizing circuit, and a storage battery is charged via a charging circuit, and during a power outage, the voltage stabilizing circuit is comprised of a coupling diode and the voltage stabilizing circuit. In a battery backup device that supplies power from a storage battery to a load via a primary discharge path circuit, the voltage is A battery backup device characterized by having a secondary discharge path circuit including a transistor that supplies discharge current of a storage battery to a load instead of a stabilizing circuit.