JPH03136451A - Power supply device for terminal use network controller - Google Patents

Abstract

PURPOSE:To attain sure charging when a power voltage is dropped by detecting the decrease in the wavelength power supply voltage and applying charging through a DC/DC converter from a telephone line. CONSTITUTION:When a voltage of a battery 9 is dropped to a specified value or below, a battery voltage detection circuit 10 operates a current limit circuit 7 of a DC/DC converter 6 to supply a current to the DC/DC converter 6 from a telephone line 1. The DC/DC converter 6 converts a high voltage (48V) to a prescribed low voltage and the battery 9 is charged by the output of the DC/DC converter 8 through a charging circuit 8. Thus, the battery voltage decreasing to the specified value or below is prevented and the equipment power supply is charged easily with simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device for a terminal network control device used for remote meter reading using a telephone line.

[Conventional technology]

Conventional power supply methods for this type of network control equipment for terminals include:
There are several known methods: (1) using a commercial power supply; (2) reducing the power of the device and supplying power only with current from the telephone line; and (2) using a battery as a power source for the device.

[Problem to be solved by the invention]

The above-mentioned method (■) using a commercial power source has the problem that it cannot be used in places where commercial power cannot be physically supplied, and the device cannot function in the event of a power outage. Although it can solve problems caused by commercial power, the current that can be supplied from the exchange is generally about 20mA to 100mA for subscriber lines, and about 81118mA for answering calls on non-linking lines, which is insufficient power when adding additional functions to the equipment. The problem is that For this reason, the method (2) in which batteries are used together is used, but in this case there is a problem that the batteries must be replaced periodically. In order to save the trouble of battery replacement, the exchange is equipped with a power supply circuit for charging the storage terminal, and when the terminal is not in use, the exchange and the terminal communicate with each other, so that the terminal makes a charging request to the exchange, and the exchange then charges the stored terminal. There is also a method of charging using a circuit, but in this case a charging circuit or the like is required in the exchange, which has the disadvantage that it cannot be implemented with a general subscriber line or the like and requires special exchange equipment.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the conventional device, to supply power to the power source for the device in the network control device for the terminal using the subscriber telephone line of -a, and to easily supply the power source for the device with a simple configuration. An object of the present invention is to provide a power supply device for a terminal network control device that can be charged.

[Means to solve the problem]

The present invention, as a first form to achieve the above-mentioned object, includes a rectifier circuit connected to a telephone line, and a DC/DC converter with a current limiting circuit that uses human power to convert the rectified output voltage of the rectifier circuit into a predetermined output voltage. converter and this DC/DCC
A device power source connected between the output terminals of the DC/DCC device, a charging circuit connected between this device power source and the DC/DCC device, and a voltage of the device power source connected to a specified value. There is a power supply voltage detection circuit for the device which outputs an output when the voltage falls below the voltage, and the output of the power supply voltage detection circuit for the device makes the current limiting circuit of the DC/DC converter conductive, and the DC/D is output from the telephone line.
The present invention is characterized in that it includes a control unit that charges the power supply for the device via the CC/type controller and notifies the center side of a drop in the power supply voltage for the device by making a call.

Further, as a second embodiment of the present invention, there is provided a rectifying circuit connected to a telephone line, a charging capacitor connected via a high resistance between the rectifying output terminals of this rectifying circuit, and a voltage between the terminals of this charging capacitor. a comparator that compares the voltage with a specified voltage, a switch means that is controlled on and off by the output of this comparator, and the charging capacitor is connected to the primary winding through this switch means, and the power supply for the device is supplied to the secondary winding. and a transformer connected to the charging capacitor, and when the voltage between the terminals of the charging capacitor exceeds the specified voltage of the comparator, the switching means is turned on to discharge the charge stored in the charging capacitor to the primary winding of the transformer, The present invention is characterized in that a device power source connected to the secondary winding of the transformer is charged.

[For production]

In the first embodiment of the network-controlled TJ packing device power supply device for terminals according to the present invention, when the battery voltage drops below a specified value, the battery voltage detection circuit activates the DC/DCC/type current limiting circuit. Supply current to the DCC/type controller from the telephone line. The DC/DC converter converts the high voltage (48V) of the telephone line into a predetermined low voltage and outputs it. The battery is charged via the charging circuit by the output of the DC/DCC/equator, and as a result, it is possible to prevent the battery voltage from falling below a specified value.

Further, in the second embodiment of the present invention, when the comparator detects that the voltage of the charging capacitor charged by the minute current supplied from the telephone line has reached the specified voltage, the comparator activates the switching means. Turn on and connect the capacitor to the primary winding of the transformer. The device power source of the terminal network control device connected to the secondary winding of the transformer is charged by the discharge energy of the charging capacitor via the transformer. As a result, even if the current supplied from the telephone line is minute, the device power source of the terminal network control device is constantly charged.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention.

In FIG. 1, a rectifier circuit 5 is connected to a telephone line 1 via a surge absorber 2 and a current monitor circuit 3, and the output of the current monitor circuit 3 is input to a CPU 4. The output of the rectifier circuit 5 is an IIC/
It is connected to the input terminal of the DC converter 6, and this DC
/DCC/Formula-A resistor R and diode D are connected to the output terminal of
A battery 9 serving as a power source for the device is connected via a charging circuit 8 consisting of 1. The output of battery 9 is used as a power source for the device and is connected to a comparator 10 which acts as a battery voltage detection circuit. The output of the comparator IO is connected to one input terminal of the OR circuit 11 and is also input to the CPU 4. The output of the CPU 4 is connected to the other input terminal of the OR circuit 11.

A polarity inversion circuit 12 is connected to the telephone line 1 via a current monitor circuit 3, and a loop forming circuit 13 and a dial circuit 14 are connected to this polarity inversion circuit 12 via a diode D2. A transformer 15 is connected to the dial circuit 14 via a DC blocking capacitor C, and a modem 16 connected to the CPU 4 is connected to the transformer 15.
is connected. Note that IMF indicates an amplifier.

When the voltage of the battery 9 is higher than the specified value, the output of the comparator 10 is at a low level (hereinafter referred to as L).
The CPU 4 is in a standby state, and the OR circuit 11 is also outputting DC/DCC/Equation-ta 6.
Since the current limiting circuit 7 is in an off state, the DC/DC converter 6 is disconnected from the telephone line l.

Next, a case where the battery voltage decreases will be explained using FIG. 2.

Now, when the voltage of the battery 9 falls below the specified value (at time t1 in Figure 2), the output of the comparator 10 becomes high level (hereinafter referred to as H), which causes the DC/D [+ converter 6 is turned on, and the DC/DO converter 6 is connected to the telephone line 1. Further, the output of the comparator 10 is output from the CPU 4
, and the CPU 4 enters the operating state.

When the CPU 4 enters the operating state, it outputs a current limit output signal 41, and this current limit output signal 41 maintains the current limit circuit 7 in the on state via the OR circuit 11. cpu4
outputs the current limit output signal 41 and turns on the loop forming circuit 13 to connect the telephone line 1 to the dial circuit 14 and the transformer 15 (at time t2 in Fig. 2). When the loop forming circuit 13 turns on, it connects the telephone line 1 to the center. A current of t is supplied from the side, and charging of the battery 9 via the DC/DO converter 6 is started. The CPU 4 activates the dial circuit 14 to dial the center side and makes a call (
When the charging of the battery 9 progresses and the battery voltage rises and reaches the specified voltage (time t3 in Figure 2), the output of the comparator 10 becomes L, but the current limiting circuit 7 4 is turned on by the current limit output signal 41, and charging of the battery 9 is thereby continued. CPU
When the dialing circuit 14 is activated by the dialing circuit 4 and the connection with the center side is completed after dialing, the polarity of the telephone line 1 is reversed. This polarity reversal is detected by the polarity reversal detection circuit 12 and input to the CPU 4. When the connection with the center side is confirmed by the output from the calling polarity reversing circuit 12, the CPU 4 outputs an FSK signal to the telephone line l via the modem 16, AMP, and transformer 15, and the battery voltage is changed to the center side. When the CPU 4 finishes transmitting the FSX signal that notifies the center side of the battery voltage drop (time t5 in Figure 2), the CPU 4 outputs the current limit output signal 4.
1 is turned off and goes into standby mode.

In this way, the battery 9 is charged via the DC/DD converter 6, and the center side is notified of the decrease in battery voltage.

FIG. 3 shows a different embodiment of the present invention, and in FIG. 3, the same parts as in the embodiment shown in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

The differences in FIG. 3 from the embodiment shown in FIG. 1 are as follows:
A charging capacitor 102 is connected between the rectifier output terminals of the rectifier circuit 5 via a high-resistance resistor 101, and a Zener diode 103 and a resistor 105 are connected between the terminals of the capacitor 102, and the emitter-collector path of the transistor 107. The connection point between the Zener diode 103 and the resistor 105 is connected to the inverting input terminal of a comparator 104 which operates using the charge charged in the capacitor as a power source, and the non-inverting input of the comparator 104 is connected to the primary winding of the transformer 108. A resistor 106 is connected to the terminal, and a diode 1 is connected to the secondary winding of the transformer 108.
A capacitor 110 as a power source for the device is connected through the capacitor 09, and a Zener diode 111 is connected in parallel to the capacitor 110.

The charging capacitor 102 connected between the rectifier output terminals of the rectifier circuit 5 is insulated from the telephone line 1 by a high resistance value resistor 101, but a minute current flows from the telephone line 1 through the rectifier circuit 5 and the resistor 101. Charging is being performed. The transistor 107 is turned off because the output of the comparator 104 is at a low level during a period when the voltage across the terminals of the capacitor 102 is lower than the Zener voltage of the Zener diode 103. When the charging of the capacitor 102 progresses and the voltage between the terminals of the capacitor 102 exceeds the Zener voltage of the Zener diode 103, the comparator
104 is inverted, its output becomes high level, and transistor 107 is turned on. When the transistor 107 is turned on, the charge in the capacitor 102 flows through the transistor 107 to the primary winding of the transformer 108 and is discharged.

When the charge in the capacitor 102 is discharged and the voltage between the terminals of the capacitor 102 becomes lower than the Zener voltage of the Zener diode 103, the comparator 104 is inverted again, the transistor 107 is turned off, and the transformer 10 is turned off.
The current flowing through the primary winding of 8 is interrupted. At this time, a voltage is induced in the secondary winding of the transformer 108 and the diode 1
A capacitor 110 is charged via 09. By repeating charging and discharging of the charging capacitor 102 supplied with power from the telephone line 1 in this manner, the capacitor 110 serving as a power source for the device is constantly charged.

〔Effect of the invention〕

As explained above, according to the first embodiment of the present invention, by detecting a drop in the device power supply voltage and performing charging via the DC/DC converter, it is possible to reliably charge the device when the power supply voltage decreases. This has the effect that even if a DC/DC converter uses a power source with a different voltage value depending on the terminal, charging can be performed appropriately according to the voltage value. Furthermore, when a battery is used as a power source for the device, by detecting a drop in battery voltage and notifying the center, the center can determine the battery life.

According to the second aspect of the present invention, the terminal network control device is configured to charge the device power source via the transformer when the voltage of the capacitor charged by the minute II current from the telephone line reaches a specified voltage. Since the power supply device is configured, the device @ source of the terminal network control device is always charged, and by constantly charging the device power source in this way, it is possible to use a capacitor as the device power source. It has the advantage that there is no need to use a commercial power source or battery as an ITA for the device. Furthermore, a transformer is placed between the telephone line and the equipment power supply, which insulates the terminal network control equipment circuit from the telephone line. This has the effect that it does not add any additional noise and does not have any adverse effect on the telephone line.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a power supply device of a terminal network control device showing one embodiment of the present invention, FIG. 2 is a waveform diagram of the main part of FIG. 1, and FIG. FIG. 2 is a block diagram of a power supply device of a network control device for terminals showing an embodiment. l: Telephone line, 4: CPU, 5: Rectifier circuit, 6: DC/
DC converter, 8: Charging circuit, 9: Battery, lO: Comparator, 12: Polarity reversal detection circuit, 13: Loop formation circuit, 14: Dial circuit, 15 Nidorance, 16
; Modem, 101: Resistor, 102: Charging capacitor, 103: Zener diode, 104: Comparator, 107: Transistor, 108: ) Lance, 11
0: Conden 5 Honja light time chart

Claims (1)

[Scope of Claims] 1) A rectifier circuit connected to a telephone line, a DC/DC converter with a current limiting circuit that receives the rectified output voltage of this rectifier circuit and converts it into a predetermined output voltage, and this DC/DC converter.
A device power source connected between the output terminals of the converter, a charging circuit connected between the device power source and the DC/DC converter, and an output when the voltage of the device power source falls below a specified value. The device power supply voltage detection circuit and the output of this device power supply voltage detection circuit conduct the current limiting circuit of the DC/DC converter to allow DC/DC from the telephone line.
A power supply device for a terminal network control device, comprising a control unit that charges a power source for the device via a DC converter and notifies a center side of a drop in power source voltage for the device by making a call. 2) A rectifier circuit connected to the telephone line, a charging capacitor connected via a high resistance between the rectified output terminals of this rectifier circuit, and a comparator that compares the voltage between the terminals of this charging capacitor with a specified voltage. , comprising a switch means controlled on and off by the output of the comparator, and a transformer in which the charging capacitor is connected to the primary winding and the device power supply is connected to the secondary winding via the switch means, When the voltage across the terminals of the charging capacitor exceeds the specified voltage of the comparator, the switch means is turned on, discharging the charge stored in the charging capacitor to the primary winding of the transformer, and discharging the charge stored in the charging capacitor to the secondary winding of the transformer. A power supply device for a network control device for a terminal, characterized in that it charges a power source for a connected device.