JPH0815292B2 - Line switching unit drive - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line switching device for switching a line terminal device connected to a public telephone line and a telephone device.

2. Description of the Related Art As shown in FIG. 4, a conventional line switching device of this type has a wiring line switching unit 4 for connecting a telephone device 1 and a line terminal device 2 to a public telephone line 3. I was through. That is, the operation of the line switching unit 4 selects the device connected to the telephone line. The switching unit 4 is configured by switching a normal type small relay contact,
The relay coil 5 includes a switching unit 6 for coil operation.
Works by. Reference numeral 7 is a relay drive signal control unit that sends a signal to the switching unit. Reference numeral 8 denotes a constant voltage power supply unit, which receives power from a commercial power supply 10 via a power transformer 9. Reference numeral 11 surrounded by a chain line indicates a line switching device.

Problems to be Solved by the Invention However, in the above-mentioned configuration, since the relay is normally used, it is not necessary to continue to receive the predetermined power from the constant voltage power supply unit 8 and to hold the line switching unit 4 There was a connection working condition that should not occur. Therefore, there is a problem that a large voltage source capable of constantly supplying a power of a predetermined value or more is required as a power supply for operating the relay coil.

The present invention solves such a conventional problem, and an object of the present invention is to operate a line-switching relay with power-off to make the power source of the device as small as possible.

Means for Solving the Problems In order to solve the above problems, the line switching unit drive device of the present invention comprises a line switching unit of a switching contact of a self-holding type relay, and a line side of the switching unit. A rectifier that converts the polarity state of the line formed into a branched connection line to a constant value, a current limiting resistor that limits the current obtained from the public line to less than a specified value in both the on-hook state and the off-hook state, and the resistor. A constant-voltage element connected in series, a power supply section of a self-holding type relay composed of a capacitive element inserted in parallel with the constant-voltage element, and a switching section for applying a pulse signal of a predetermined width to a relay coil when the switching contact of the relay is operated. A relay drive signal control unit for sending a predetermined drive signal to the switching unit and a low voltage power supply for the control unit are provided.

With the above-described configuration, the present invention allows the coil power supply of the self-holding type relay that constitutes the line switching unit to have a current less than a predetermined value in order to satisfy the electrical regulation defined by the Telecommunications Business Act. It receives from the line through, and it is configured by charging the capacitive element. The constant voltage element connected in parallel with the capacitive element is for limiting the maximum voltage applied to the coil of the relay. In this way, the capacitive element is charged to a predetermined value, and the switching unit operates to supply current to the coil.
A relay contact, which is a line switching unit, is operated.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the components having the same numbers as those in FIG. 4 have the same functions. Reference numeral 12 is a coil of a self-holding type relay, the power source of which is a rectifier 13 for converting the polarity state of the line to a connection line branched at a and a ′ on the line side of the line switching unit 4 and the above-mentioned current. It is configured by charging the capacitive element 16 via the limiting resistor 14. The constant voltage element 15 is inserted in parallel with the capacitance element 16 and regulates the maximum value of charging. That is, the line voltage in the on-hook state is about 48 (V) in direct current, and if the impedance when the line is open is 1 (MΩ) or more, if it is less than about 48 (μA) even when open, the current from the line Since the power can be supplied, if the value of the 14 resistors is set to a predetermined value or more, it is possible to charge the capacitive element while satisfying the standard. Further, a constant voltage element is connected for the purpose of suppressing the voltage applied to the relay coil to a maximum allowable value or less.
A relay drive signal control unit 17 transmits a predetermined drive signal to the switching unit 6 to operate the coil 12. Reference numeral 18 denotes a low voltage power source for the control unit, and here, an example of a battery is shown. Since 12 is a self-holding type relay, when the drive signal control unit 17 outputs a pulse signal of a predetermined width to the switching unit 6, the switching unit 6 outputs a pulse current of a predetermined width to the relay coil in synchronization with this signal. To flow to 12,
The switching contact is activated. In other words, it is possible to carry out switching holding by only adding a short pulse signal at the time of switching, without power consumption thereafter, or with only a very small holding current. Here, when comparing the low-voltage power supply 18 and the relay power supply, the control unit of 17 is in the vicinity of 2 (V), and since it is possible to operate with a normal flow of several tens (μA), several ( It requires a very low voltage and a small capacity as compared with a relay power supply that does not operate unless it supplies dozens (mA) of V).

Further, even when the line is in the off-hook state, power can be supplied to the self-holding relay power supply by using the station power supply as described above.

Next, another embodiment of the present invention will be described with reference to FIG. In this figure, the connection lines after a and a'which are branched from FIG. 1 are shown, and the components having the same numbers as in FIG. 1 are the parts having the same function. Here, the relay is a latching type, and includes a set coil 19 and a reset coil 20. Reference numerals 21 and 22 are switching portions for coil operation when supplying an operating current to the coils 19 and 20, respectively,
It operates according to the instruction of the control unit 17 via the resistors 23 and 24. That is, in the structure in which the set side contact is connected to the line terminal device and the reset side contact is connected to the telephone device, the line is disconnected from the telephone device and 19 set coils are operated to connect to the line terminal device. Therefore, a signal having a predetermined pulse width is transmitted to the transistor 21, which is the switching unit.

The operation of each part in FIG. 2 will be described with reference to the timing chart in FIG. The horizontal axis represents time, and shows the case where the line connection is started from t = t ₀ . A is a voltage across the capacitive element 16, B is an output signal of the control unit 17 for operating the switching element 21, C is a pulse current supplied from the switching element 21 operated by B to the set coil 19 of the relay, D
Represents the state of the reset side contact, and E represents the state of the set side contact. From t = t _{0 to} t ₁ , it can be seen that the capacitive element is gradually charged to a predetermined voltage. The signal B is output between t = t _{1 and} t ₃ , a coil current having a waveform C is obtained by discharging the capacitive element 16, and the set side contact is in a conductive state as indicated by E. . t = t ₂ is the timing when the contact switches. As in A, the voltage of C decreases during the pulse signal application period, but is charged to a predetermined voltage again. In this way, the self-holding type relay can be operated by discharging the power source charged by the current supplied from the line only during the period of applying the pulse having the short predetermined width. Then, after switching once, the coil is not energized until it is time to actuate to the opposite contact side next time.

As described above, according to the line switching unit drive device of the present invention,
The following effects are obtained.

(1) In both the on-hook state and the off-hook state, the capacity element is charged with a current less than the specified value obtained from the public line to configure the power supply of the self-holding type relay, so that only the power of the control unit is supplied into the device. Only a small capacity low voltage power supply need be provided.

(2) Since the line switching unit is constituted by the contacts of the self-holding type relay, the power consumption is zero after switching and the line state can be maintained, which is economically very advantageous.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a line switching unit driving device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a relay coil driving unit of a device according to another embodiment of the present invention, and FIG. 3 is a self-holding type. FIG. 4 is a circuit block diagram of a conventional line switching device, which is a timing diagram showing driving of a relay. 1 ... telephone device, 2 ... line terminal device, 3 ... public line, 4 ... line switching unit, 6 ... coil operation switching unit, 12 ... self-holding relay coil, 13 ... rectifier, 14 ... Current limiting resistor, 15 ... Constant voltage element, 16 ...
… Capacitive element, 17 …… Relay drive signal controller, 18 …… Low-voltage power supply.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hosui Ikukawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-60-125052 (JP, A) Actually developed 54-140609 (JP, U)

Claims (1)

[Claims] 1. A line switching unit for connecting a telephone device or a line terminal device to a public line is composed of a switching contact of a self-holding type relay, and a connection line branched on the line side of the switching unit. A rectifier that converts the polarity state of the line to a constant, a current limiting resistor that is connected to the rectifier and limits the current obtained from the public line to less than a specified value in both the on-hook state and the off-hook state, and is connected in series with the resistor. Constant voltage element, a power supply section of a self-holding type relay consisting of a capacitance element inserted in parallel with the constant voltage element, a switching section for applying a pulse signal of a predetermined width to the relay coil when the switching contact of the relay is operated, A relay drive signal control unit for transmitting a predetermined drive signal to the switching unit,
A line switching unit driving device comprising the control unit low-voltage power supply.