JPH06152804A - Power supply circuit for terminal adaptor - Google Patents

Abstract

PURPOSE:To supply power stably to an adaptor of a terminal equipment such as a telephone set. CONSTITUTION:A line power supply control circuit 1 is connected between terminals L1, L2 to which a telephone line is connected and terminals TL1, TL2 to which a terminal equipment such as a telephone set is connected. A series circuit comprising a 1st one-way conduction element circuit 11 of the control circuit 1 and a light emitting diode section 13 of a photocoupler is inserted to a line between the terminals L1 and TL1. The series circuit is connected between a base and an emitter of a transistor(TR) circuit 18 and its collector is connected to an input terminal of a power output circuit 3 via 1st and 2nd feeding lines 21, 22 of a feeding control circuit 2. The 1st feeding line 21 is made up of a light receiving element section of a photocoupler. An output terminal of the power output circuit 3 is connected to an adaptor 4 of a terminal equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit of a terminal addition device for supplying power from a station power supply to an addition device connected to a telephone terminal device such as a telephone for regulating dial transmission. It is a thing.

[0002]

2. Description of the Related Art As a power supply circuit for supplying power to an additional device or the like connected to a terminal device such as a telephone, a battery or a commercial power supply is often used, but a power supply circuit operated by using a local power supply is used. It may be done. In the case of using this station power supply, a circuit for voltage extraction is connected in parallel to the line terminal of the terminal device and the output voltage of this circuit is used in parallel, and the voltage circuit There is a series configuration in which an extraction circuit is inserted in series and the voltage drop of this circuit is utilized.

[0003]

However, in the case of the above-mentioned circuit having the parallel structure, when the dial is closed when the terminal device operates the dial or the like, the voltage extracting circuit is short-circuited to the additional device. There are drawbacks, including the critical problem of power interruptions.

Further, in the case of the circuit having the above series configuration,
Due to the voltage drop due to the circuit inserted in series, the current supplied to the terminal device becomes insufficient and the operation of the device becomes unstable, or the dial is opened and the current to the terminal device is cut off. There is a drawback that the voltage drop of the circuit disappears.

Further, when a call arrives at the terminal device, an incoming call signal current is applied to a circuit inserted in series, which causes a problem that the power supply may malfunction. For this reason, dry batteries are often used without using the local power source, but in this case, there is a problem in maintenance such as battery replacement.

The present invention has been made in view of the above circumstances, solves the problems of the power supply circuits of the serial configuration and the parallel configuration using the station power source, and is an additional device for a terminal device such as a telephone. It is an object of the present invention to obtain a power supply circuit of a terminal addition device that supplies stable power supply to

[0007]

In order to achieve the above-mentioned object, the present invention provides a terminal having a terminal to which a telephone line is connected and a terminal to which a terminal device such as a telephone is connected. It is connected between them and is turned on / off when the line loop is open / closed, and when the line loop is interrupted by a dial etc., the on state is maintained even when the line loop is interrupted. Power supply control circuit for controlling the supply of power, and power supply having first and second power supply lines connected to the station power supply control circuit and supplied with power in response to the on / off state of the line loop. It is characterized by comprising a control circuit and a power output circuit which is supplied with power through the power supply control circuit and supplies power to the terminal addition device.
According to a second aspect of the present invention, a light emitting element section of a photocoupler is provided in a station power supply control circuit, and the light emitting element section is provided with a terminal on the side to which a telephone line is connected and a terminal on the side to which a terminal device such as a telephone is connected. It is characterized in that the light receiving element portion of the photocoupler is used as the first power feeding path of the power feeding control circuit by being inserted in series to one of the lines between the two. A third aspect of the invention is characterized in that the first power feeding path is a low resistance circuit and the second power feeding path is a high resistance circuit.

[0008]

In normal times when the terminal device such as the telephone is on-hook, the station power supply control circuit is off, but when the terminal device off-hooks to create a loop of the line,
The station power supply control circuit is operated. Then, the station power supply is supplied to the power output circuit through the first power supply path. In this case, the voltage of the station power supply is not high, but the first power supply path has a low resistance, so that a sufficient current is supplied. At this time, since the second power supply path has a high resistance, it is masked by the first power supply path and does not operate.

On the other hand, when the line loop is disconnected in a pulsed manner by the dial or the like, the light emitting element portion of the photocoupler is turned off, so that the light receiving element portion is also turned off and the first power feeding path is disconnected. However, since the station power supply control circuit maintains its ON state by the delay operation function, the station power supply is supplied to the power supply control circuit. Since the voltage of the station power supply at this time is approximately the same as the voltage of the station power supply, a predetermined current is supplied to the power supply path even if the resistance value of the second power supply path is large. Therefore, the power output circuit is supplied with a predetermined power even during pulse interruption, and can output stable power to the additional device. When the line is disconnected due to on-hook, the station power supply control circuit is restored with the disappearance of its timed function, and the circuit returns to normal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a power supply circuit showing an embodiment of the present invention including an additional device. L1 and L2 are terminals for connecting a telephone line, and TL1 and TL2 are terminals for connecting a terminal device such as a telephone. Is.

Reference numeral 1 denotes a station power supply control circuit, which forms a station power supply path by turning on / off a hook switch and dialing. Reference numeral 11 denotes a first one-way conducting element circuit, which is connected in series to the light emitting diode section 13 of the photocoupler and has the same polarity as the light emitting diode section 13. A resistor 19 is connected in parallel to the light emitting diode section 13. This resistor 1
Reference numeral 9 is for stabilizing the operation of the light emitting diode section 13.

Reference numeral 12 is a second one-way conducting element circuit, which is connected in parallel and opposite polarity to the series circuit of the first one-way conducting element circuit 11 and the light emitting diode section 13, and in the case of a telephone,
It is used to stop the control operation of this power supply circuit after the other party responds.

Capacitor 14 and resistors 15, 16, 17
Is a time constant circuit, and charges the capacitor 14 when the first one-way conducting element circuit 11 is conducting,
The transistor circuit 18 is controlled by delaying both operations of discharging the capacitor 14 when the first unidirectional conducting element circuit 11 is de-energized by a dial pulse or the like. That is, the transistor circuit 18 is controlled to be turned on by the delay operation function at the time of charging when the first one-way conduction element circuit 11 is in the conductive state, and is turned off after a delay operation function at the time of discharging when the current is cut off. Becomes With this delay operation function, even if the energization of the first one-way conduction element circuit 11 is interrupted in a pulsed manner, the transistor circuit 18 does not turn off but remains on.

In the delay operation of the time constant circuit during charging, the incoming call signal is the first and second one-way conducting element circuit 1.
Even if the currents 1 and 12 are alternately energized, the transistor circuit 18
Is controlled so as not to malfunction.

Reference numeral 2 denotes a power supply control circuit, which constitutes a path for supplying power to the power output circuit 3 from the station power supply when the transistor circuit 18 of the station power supply control circuit 1 is in the ON state. The first power supply path 21 is used corresponding to the state where the terminal device is energizing the first one-way conduction element circuit 11, and the power output circuit 3 is provided by the station power source output by the transistor circuit 18.
Is a power supply path for supplying power to. Therefore, since the voltage is applied to the first one-way conducting element circuit 11 corresponding to the state in which the circuit is energized, the voltage applied to the first power feeding path 21 is the local power supply voltage output by the transistor circuit 18. Since the voltage is a low voltage close to the terminal voltage when the terminal device is off-hook, the first power feeding path 21 uses the transistor circuit 18 corresponding to the light emitting diode section 13 of the photocoupler, and is used as a low resistance circuit. is there.

On the other hand, the second power supply path 22 is used in response to a pulse-like interruption of the energization of the first one-way conducting element circuit 11, and is a power supply path for supplying power to the power output circuit 3. is there. In this case, the first power supply path 21 is turned off,
The station power supply voltage output from the transistor circuit 18 becomes a terminal voltage when the terminal device is in a disconnected state and has a high value close to the voltage of the station power supply. Therefore, a high resistance circuit such as a constant current diode is provided in the second power supply path 22. It is illustrated.

The power output circuit 3 is supplied with power via the first or second power supply paths 21 and 22, and outputs a predetermined power to the additional device. Although the detailed circuit configuration is not shown,
It is configured as a general circuit by circuit components such as a smoothing capacitor and an output voltage control Zener diode. Reference numeral 4 denotes an additional device for the terminal device, which controls the dialing of the terminal device. VDD is a positive pole input power supply terminal and displays a specified value of about 5 volts.

The apparatus of the present invention has the above-mentioned structure, and its operation will be described below. When the terminal device is in the on-hook state, the first and second one-way conducting element circuits 11 and 12
Since there is no power supply to the photocoupler, the light emitting diode 1 of the photocoupler
3. The first power supply path 21 is off, and the power supply circuits are all in the normal state.

When the terminal device goes off-hook to energize the first one-way conducting element circuit 11 and the light emitting diode 13,
The capacitor 14 is charged with this terminal voltage. The voltage of the capacitor 14 is
Since the voltage is applied to the emitter, the transistor circuit 18 is turned on when this voltage reaches a predetermined value. In this case, since the light emitting diode section 13 of the photocoupler is operating, the station power supply supplies power to the power output circuit 3 via the first power supply path 21.

In this state, when the line current is intermittently pulsed by the dial, when the pulse is interrupted, the energization of the first one-way conduction element circuit 11 and the light emitting diode 13 is also interrupted. Therefore, the first power supply path 21 that operates in response to this is also turned off, and the power supply to the power output circuit 3 by this circuit is stopped.

On the other hand, since the transistor circuit 18 continues to be in the ON state by the delay operation function at the time of discharging of the time constant circuit, the output of the local power source to the power feeding control circuit 2 is continued. Therefore, the power supply to the power output circuit 3 by the station power supply is performed by the second power supply path 22 instead of the first power supply path 21.

The power output circuit 3, which has been fed with the local power from the power feeding control circuit 2, supplies stable power to the additional device of the terminal device. Further, in the station power supply control circuit 1, the delay time function of the time constant circuit at the time of charging causes the transistor circuit by the terminal voltage generated in the first one-way conducting element circuit 11 even for the ringing signal current at the time of incoming. 18 is prevented from operating. Furthermore, the terminal voltage of the one-way conducting element circuit may be a voltage value that operates the base and emitter of the transistor circuit, so this voltage can be made sufficiently small, and the one-way conducting element circuit can be inserted in series. Even so, the influence of the operating voltage of the terminal device due to this voltage drop can be reduced.

[0023]

As described above, according to the present invention,
The circuit that supplies power only when the terminal device goes off-hook is in an operating state, and when the terminal device is on-hook, there is an effect that current consumption of the station power supply does not occur.

When the terminal device is in the off-hook state, the station power source supplies power to the power output circuit through the light receiving element portion of the photocoupler, which is the first power feeding path, so that the current value can be increased, and therefore, There is also an advantage that the output voltage of the power output circuit can be rapidly raised.

Further, when a pulse operation is interrupted, such as when a dial operation is performed, the station power supply is supplied to the power output circuit via the constant current diode circuit which is the second power supply path. There is an effect that it is possible to prevent interruption of the power supply to the station.

Further, according to the present invention, since the time constant circuit that operates during charging and discharging is used, the station power supply control circuit not only performs a predetermined operation during pulse transmission, but also calls the call signal current when receiving a call. There is an advantage that it is possible to prevent the malfunction of the station power supply control circuit due to.

Since the terminal voltage of the one-way conducting element circuit may be a voltage value for operating the base / emitter of the transistor circuit, this voltage can be made sufficiently small, and the one-way conducting element circuit is inserted in series. Even so, the influence of the operating voltage of the terminal device due to this voltage drop can be reduced.

Further, by inserting the light emitting element portion of the photocoupler into the line and using the light receiving element portion in the first power feeding path, the correspondence between the presence / absence of the line current and the power feeding path to be used is determined, which is stable. The motion is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a power supply circuit including an addition device of the present invention.

[Explanation of symbols]

 1 Station Power Supply Control Circuit 2 Power Supply Control Circuit 3 Power Output Circuit 4 Terminal Device Addition Device 13 Photocoupler Light Emitting Diode Part 18 Transistor Circuit 21 First Power Supply Path (Light-Receiving Element Section) 22 Second Power Supply Path

Front page continuation (72) Inventor Satoshi Hoshi 1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Ikuko Shimada 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph Phone Co., Ltd.

Claims (3)

[Claims] 1. A power circuit of an additional device for a telephone line terminal device, wherein a line loop is connected between a terminal on a side to which a telephone line is connected and a terminal on a side to which a terminal device such as a telephone is connected. Station power supply that controls the supply of station power by turning on / off when open / closed and maintaining the on state even when the line loop is interrupted by a dial etc. Connected to the control circuit and this station power supply control circuit, the station power is turned on / off in the line loop.
A power supply control circuit having first and second power supply paths for supplying power corresponding to the off state; and a power output circuit for supplying power to the terminal addition device by being supplied with power through the power supply control circuit. Power supply circuit for terminal addition device. 2. A light emitting element section of a photocoupler is provided in the station power supply control circuit, and the light emitting element section is connected to a terminal to which a telephone line is connected and a terminal to which a terminal device such as a telephone is connected. The power supply circuit of the terminal addition device according to claim 1, wherein the power supply circuit of the terminal addition device is inserted in one of the lines between the two in series, and the light receiving element portion of the photocoupler is used as a first power supply path of the power supply control circuit. 3. A low resistance circuit for the first power feeding path and a second power feeding path for the second power feeding path.
2. The power supply circuit of the terminal addition device according to claim 1, wherein the power feeding path of is a high resistance circuit.