JPS62290328A - Battery backup circuit for communication equipment - 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 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention relates to a battery backup circuit for a communication device.

(Prior Art) Conventionally, this type of circuit has been designed to prevent backflow of current in one line 22 of the power supply lines 22 and 23 connecting the main power supply unit 21 and the communication device, as shown in FIG. 2, for example. A diode 24 is inserted in the power supply line 22.
23, a diode 25 for preventing current backflow, a battery power supply section 26 connected in series with the diode 25, and a resistor 27 connected in parallel with the diode 25.

By the way, in the above battery backup circuit, the battery power supply section 26 starts from the time when the main power supply section 21 stops supplying power.
However, this backup continues indefinitely regardless of whether the communication device is used or not until power supply by the main power supply unit 21 is resumed. If it lasted for a long time, the battery power supply section 26 would be extremely consumed. For this reason, the battery power supply unit 26
However, if a rechargeable secondary battery is used, which is expensive, or a primary battery is used, the battery must be replaced frequently. The use of expensive secondary batteries and the frequent replacement of primary batteries have resulted in an increase in the overall cost of the communication device.

(Problems to be Solved by the Invention) As described above, in the conventional circuit, it is necessary to use an expensive secondary battery or to frequently replace the primary battery.
There is a problem in that the overall cost of the communication device increases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a battery backup circuit for a communication device that can use an inexpensive primary battery, does not require replacement every time there is a power outage, and has a low overall cost.

[Structure of the Invention] (Means for Solving the Problems) The battery backup circuit of the present invention provides a normally open contact between a battery power supply section and a communication device, and prevents the main power supply section from contacting the communication device during communication. The normally open contact is closed for a preset predetermined time from the time when the power supply is stopped, and when the communication ends, the normally open contact is opened even during the predetermined time. .

(Function) According to the battery backup circuit of the present invention, when a power outage occurs during communication, the battery backup time performed by the battery power supply unit is regulated within the predetermined time, so that the battery Even if a primary battery is used in the power supply section, consumption is low and the frequency of replacement can be reduced.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the battery backup circuit of the present invention.

In the figure, the main power supply section 2 of the communication device 1 is connected to an AC plug 3.
, a transformer 4, a diode bridge 5, and a smoothing capacitor 6. A diode 8 is connected between the power supply line 7 of the communication device 1 and the ground to prevent current from flowing backward, and the battery is connected to the battery via the contact 10 of the first relay 9. Power supply units 11 are connected in series.

For example, when a voltage of AClooV is applied to the AC plug 3 and power is being supplied by the main power supply unit 2, the second relay 12 connected in parallel to the primary side of the transformer 4 is operated, and its contact 13 is closed. Therefore, the power supply voltage from the power supply line 7 is input to the transistor 14 and the input port 16 of the CPU 15 through the contact 13 of the second relay 12, and the transistor 14 is turned on and the level of the current input to the input port 16 becomes "H#
become.

At the same time, the CPU 15 detects whether or not the communication device 1 is communicating. If the communication device 1 is communicating, the CPU 15 sets the level of the current output from the output port 17 to "H" and the transistor 18 is turned on, and when communication is not in progress, the level of the current output from the output port is set to "L" and the transistor 18 is turned off.

If power is being supplied by the main power supply unit 2 and the contact 13 of the second relay 12 is closed, the transistor 14 is turned on, so the base side of the transistor 19 is grounded via the transistor 14. be done. Therefore, since the transistor 19 is turned off and the contact 10 of the first relay 9 is maintained in an open state, power is not supplied from the battery power supply section 11 to the power supply line 7.

Next, the moment AClooV is no longer applied to the AC plug 3 due to a power outage, the contact 13 of the second relay 12 is opened. At this time, the base side of the transistor 14 is grounded via the pull-down resistor 20 and turned off, and the CPU
I5 indicates that the level of current input to input port 16 is “
The CPU 15 starts counting a predetermined period of time at the same time as the signal goes to "L". At this time, if the CPU 15 detects that the communication device 1 is communicating, the CPU 15 changes the level of the current output from the output port 17. “Ho” and transistor 18
turn on. Therefore, the voltage of the power supply line 7 is applied to the base side of the transistor 19, the transistor 19 is turned on, and as the contact 10 of the first relay 9 is opened, the power supply from the battery power supply section 11 to the power supply line 7 is stopped. will be started.

If this series of operations is sufficiently short for the discharge time of the capacitor 6, the voltage supplied from the battery power supply section 11 is also input to the transistor 19 via the transistor 18, so that the first relay 9 Since the contact 10 is kept open, the power supply to the communication device 1 is continuously switched from the main power supply to the backup power supply.

In this way, power supply from the main power supply section 2 is stopped due to a power outage,
In a state where the battery power supply unit 11 is supplying power, that is, backup is being performed, the CPU 15 starts counting a predetermined period of time from the point in time when the main power supply unit 2 stops supplying power, and determines whether the count of the predetermined period of time increments. Alternatively, when it is detected that the communication by the communication device 1 has ended within the predetermined time, the level of the voltage applied from the output port 17 is set to "Ho" and the transistor 18 is turned off. In such a state, the transistor 19 is turned off. is turned off and the contact 10 of the first relay 9 is opened, so that backup by the battery power supply section 11 is no longer performed.

Therefore, at the longest, the backup by the battery power supply section 11 ends within the time from when the main power supply section 2 stops supplying power until the aforementioned predetermined time is counted up. Further, when the communication of the communication device 1 ends within the predetermined time, the backup by the battery power supply section 11 ends immediately.

Note that if the main power supply section 2 is restored before the level of the voltage output from the output port 17 of the CPU 15 becomes "L", the contact 13 of the second relay 12 is closed and the transistor 14 is turned on. Along with this, transistor 1
9 is turned off, backup by the battery power supply unit 11 is no longer performed. Furthermore, even if the power supply from the main power supply unit 2 is stopped, if communication is not in progress, the level of the voltage output from the output port 17 of the CPU 15 is "L", the transistor 18 is turned off, and the transistor 19 is kept off. Therefore, backup by the battery power supply unit 11 is not performed.

Although the CPU 15 is provided separately from the communication device 1 in this embodiment, the CPU within the communication device 1 may be used.

[Effects of the Invention] As explained above, according to the battery backup circuit of the communication device of the present invention, the backup by the battery power supply unit is performed for a predetermined period of time from the time when the power supply by the main power supply unit is stopped during communication. If communication is completed within a predetermined time, the backup is stopped at that point, so the battery power supply unit is less consumed.

Therefore, even if a primary battery is used in the battery power supply section, there is no need to frequently replace the battery, and the overall cost of the communication device can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the battery backup circuit of the present invention, and FIG. 2 is a circuit diagram showing a conventional battery backup circuit. DESCRIPTION OF SYMBOLS 1... Communication device, 2... Main power supply part, 3... AC plug, 4... Transformer transformer, 5... Diode bridge, 6... Smoothing capacitor, 7... Power supply line,
8...Diode, 9...First relay, 10...
・Contact point of first relay 9, 11...battery power supply section,
12...Second relay, 13...Second relay 12
Contact, 14°18.19... Transistor, 15.
CPU, 16...Input port, 17...Output port, 2o...Pull-down resistor.

Claims (1)

[Scope of Claims] A normally open contact provided between a battery power supply unit and a communication device, a communication detection means for detecting whether or not communication is in progress, and a control unit for supplying power to the communication device by a main power supply unit. If communication is detected by the power supply stop detection means that detects a stop, the timer that measures a preset predetermined time, and the communication detection means, the time when the power supply stop is detected. the normally open contact is closed until the predetermined time measured by the timer, and if the communication detection means detects that no communication is in progress, the normally open contact is opened even during the predetermined time. A battery backup circuit for a communication device, comprising means.