JP2905955B2 - Power supply circuit for terminal attachment device - Google Patents

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 additional device for supplying power from a station power supply to an additional device connected to a telephone terminal device such as a telephone for restricting dial transmission. Things.

[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 power supply circuit operated by a dry battery or a commercial power supply is often used, but a power supply circuit operated by using a station power supply is used. It may be done. In the case of using the station power supply, a voltage extracting circuit is connected in parallel to the line terminal of the terminal device and a parallel configuration using the output voltage of this circuit is used. There is a series configuration in which an extraction circuit is inserted in series and a voltage drop of this circuit is used.

[0003]

However, in the case of the above-described circuit having a parallel configuration, if the dial is closed when the terminal device operates the dial or the like, the voltage extracting circuit is short-circuited and the additional device is connected. Disadvantages include critical issues such as interruption of power supply.

In the case of the above-mentioned circuit having a series configuration,
Due to the voltage drop by the circuit inserted in series, the current supplied to the terminal device becomes insufficient and the operation of the device becomes unstable, or if the dial is opened and the current to the terminal device is cut off, the above There is a disadvantage that the voltage drop of the circuit is eliminated.

In addition, when a call arrives at the terminal device, the incoming call signal current is supplied to the circuit inserted in series, which causes a problem that the power supply may malfunction. For this reason, a dry battery is often used without using the station power supply, but in this case, there is a problem in maintenance such as replacement of the battery.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and solves the problems of a power supply circuit of a series configuration and a parallel configuration using a station power supply. It is an object of the present invention to obtain a power supply circuit of a terminal additional device that supplies stable power to a terminal.

[0007]

In order to achieve the above object, a first aspect of the present invention is to provide a power supply circuit for an additional device of a telephone line terminal device, the terminal on the side to which the telephone line is connected. A series circuit of the first directional conduction element circuit and the light emitting element section of the photocoupler, which is inserted in one of the current paths connecting the terminal and the terminal to which the terminal device such as a telephone is connected, and connected in parallel to this series circuit The second direction conducting element circuit having a polarity opposite to that of the first direction conducting element circuit and the time constant circuit are controlled by the operation of the time constant circuit, and the input electrode is connected to the telephone line connection terminal to supply the station power. A station power supply control circuit comprising a transistor circuit to be connected, and first and second power supply lines connected to the output electrode of the transistor circuit of the station power supply control circuit and connected in parallel. By times A power supply control circuit for supplying the station power through the transistor circuit using the second power supply line when the loop is open, and using the first power supply line when the line loop is closed; And a power output circuit that is supplied with power through a power supply control circuit and supplies power to the terminal additional device. In a second aspect of the present invention, the first power supply path is a low resistance circuit including a light receiving element controlled by a light emitting element of a photocoupler, and the second power supply path is a high resistance circuit such as a constant current diode. It is characterized by being comprised in.

[0008]

When the terminal device such as a telephone is in an on-hook state in a normal state, the station power supply control circuit is in an off state, but when the terminal device is off-hook and a line loop is created,
The station power supply control circuit is operated. Then, the station power is supplied to the power output circuit through the first power supply line. In this case, although the voltage of the station power supply is not high, a sufficient current is supplied because the first power supply line has low resistance. 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 cut in a pulse manner by a dial or the like, the light emitting element of the photocoupler is turned off, the light receiving element is also turned off, and the first power supply path is cut off. However, since the station power supply control circuit keeps its ON state by the delay operation function, the station power is supplied to the power supply control circuit. At this time, the voltage of the station power supply is approximately equal to the station power supply voltage, so that 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 intermittent pulses, and can output stable power to the additional device. When the line is disconnected due to the on-hook, the station power supply control circuit is restored with the disappearance of the timed function, and the circuit returns to normal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail 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. It is.

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

Reference numeral 12 denotes a second one-way conductive element circuit, which is connected in parallel to the series circuit of the first one-way conductive element circuit 11 and the light emitting diode unit 13 with opposite polarities.
After the other party responds, it is used to stop the control operation of this power supply circuit.

The capacitor 14 and the resistors 15, 16, 17
Constitutes a time constant circuit, and charges the capacitor 14 when the first one-way conduction element circuit 11 conducts.
The operation of the transistor circuit 18 is controlled by delaying both operations of discharging the capacitor 14 when the first one-way conductive element circuit 11 is turned off by a dial pulse or the like. That is, the transistor circuit 18 is turned on by being controlled by the delay operation function at the time of charge when the first one-way conduction element circuit 11 is turned on, and is delayed by the delay operation function at the time of discharge when the power supply is cut off. Becomes Due to this delay operation function, even if the first one-way conductive element circuit 11 is turned off in a pulsed manner, the transistor circuit 18 does not turn off but keeps on.

The delay operation during charging of the time constant circuit is such that the incoming call signal is transmitted to the first and second one-way conductive element circuits 1.
1 and 12, 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 from the station power supply to the power output circuit 3 when the transistor circuit 18 of the power supply control circuit 1 is on. The first power supply line 21 is used in response to a state in which the terminal device is energizing the first one-way conductive element circuit 11, and is connected to the power output circuit 3 by the local power supply output from the transistor circuit 18.
This is a power supply path for supplying power to the power supply. Therefore, the voltage applied to the first power supply path 21 is the station power supply voltage output from the transistor circuit 18 because it is used in accordance with the state in which the first one-way conductive element circuit 11 is energized. Since the voltage is a low voltage close to the terminal voltage when the terminal device is off-hook, the transistor circuit 18 corresponding to the light emitting diode unit 13 of the photocoupler is used as the first power supply line 21, and a low resistance circuit is used. is there.

On the other hand, the second power supply path 22 is used in response to a pulse-like interruption of the current supply to the first one-way conductive 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 is a terminal voltage when the terminal device is turned off and has a high value close to the station power supply voltage. Therefore, a high-resistance circuit such as a constant current diode is provided in the second power supply line 22. Is illustrated.

The power output circuit 3 is supplied with power through the first or second power supply path 21 or 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 controlling Zener diode. Reference numeral 4 denotes an additional device for the terminal device, which controls dialing of the terminal device. VDD is a positive pole input power supply terminal and indicates a specified value of about 5 volts.

The apparatus according to the present invention has the above-described configuration, 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, 12
Because there is no current, the light-emitting diode 1 of the photocoupler
3. The first power supply line 21 is off, and all the power supply circuits are in a normal state.

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

In this state, when the line current is intermittently turned on and off by the dial, when the pulse is turned off, the first one-way conductive element circuit 11 and the light emitting diode 13 are also turned off. Accordingly, the first power supply path 21 that operates correspondingly is also turned off, and the power supply to the power output circuit 3 by this circuit is stopped.

On the other hand, the transistor circuit 18 continues to be turned on by the delay operation function at the time of discharging of the time constant circuit, so that the output of the station power supply to the power supply 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 received power from the power supply from the power supply 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 operation function at the time of charging of the time constant circuit allows the transistor circuit to respond to the ringing signal current at the time of incoming by using the terminal voltage generated in the first one-way conductive element circuit 11. 18 is prevented from operating. Further, the terminal voltage of the one-way conductive element circuit may be a voltage value enough to operate the base / emitter of the transistor circuit. Therefore, this voltage can be sufficiently reduced, and the one-way conductive element circuit is inserted in series. However, the influence of the operating voltage of the terminal device due to the voltage drop can be reduced. There are two types of dial impulse speeds used in ordinary dial-type telephones, 10 pps and 20 pps. For each of them, the allowable range of the speed and the ratio of the impulse contact (make) and break (break) times (impulse make) It is known that the rate is determined. Makeup rate of impulse = (contact time / (contact time + interruption time)) × 100 (%) Impulse speed Makeup rate 10 pps 10 ± 0.8 pps 33 ± 3% 20 pps 20 ± 1.6 pps 33 ± 3% Thus, if the example is taken at 10 pps, the loop break time will be 70-64 milliseconds.

[0023]

As described above, according to the present invention,
The circuit for supplying power only when the terminal device goes off-hook is in operation, and when the terminal device is in the on-hook state, there is an effect that the station power supply does not consume current.

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

When the pulse is cut off, for example, when a dial operation is performed, the station power is supplied to the power output circuit via the constant current diode circuit serving as the second power supply path. Has the effect of preventing interruption of the power supply to the station.

Further, according to the present invention, the time constant circuits operating at the time of charging and at the time of discharging, respectively, are used, so that the station power supply control circuit not only performs a predetermined operation even during pulse transmission, but also generates a call signal current at the time of incoming call. Therefore, there is an advantage that malfunction of the station power supply control circuit due to the above can be prevented.

Since the terminal voltage of the one-way conductive element circuit may be a voltage value enough to operate the base / emitter of the transistor circuit, this voltage can be sufficiently reduced, and the one-way conductive 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, since the light emitting element portion of the photocoupler is inserted into the line and the light receiving element portion is used as the first power supply line, the correspondence between the presence or absence of the line current and the power supply line to be used is determined. Operation is obtained.

[Brief description of the drawings]

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 station power supply control circuit 2 power supply control circuit 3 power output circuit 4 additional device for terminal device 13 light emitting diode part of photocoupler 18 transistor circuit 21 first power supply path (light receiving element part) 22 second power supply path

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Hoshi 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Ikuko Shimada 1-16-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan (56) References JP-A-4-200141 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04M 19/00-19/08 H04M 1/00 H04M 1/66

Claims (2)

(57) [Claims] In a power supply circuit of an additional device of a telephone line terminal device, a power supply circuit for connecting a terminal to which a telephone line is connected to a terminal to which a terminal device such as a telephone is connected is connected to one of the current paths. A series circuit of a first direction conducting element circuit and a light emitting element portion of a photocoupler, a second direction conducting element circuit having a polarity opposite to that of the first direction conducting element circuit connected in parallel to the series circuit, and a time constant; A station power supply control circuit comprising a transistor circuit controlled by the operation of the circuit and the time constant circuit, the input electrode being connected to the telephone line connection terminal and being supplied with station power, and a transistor circuit of the station power supply control circuit The first and second power supply lines are connected in parallel to each other, and the second power supply line is provided when the line loop is opened by the dial of the terminal device, and when the line loop is closed. Is the first A power supply control circuit to which the station power is supplied through the transistor circuit by using the power supply path, and a power output circuit that is supplied with power through the power supply control circuit and supplies power to the terminal additional device. Characteristic power supply circuit of terminal addition device. 2. The first power supply path is configured as a low resistance circuit including a light receiving element controlled by a light emitting element of a photocoupler, and the second power supply path is configured as a high resistance circuit such as a constant current diode. The power supply circuit according to claim 1, wherein: