JPS63280557A - Power receiving circuit - Google Patents

Abstract

PURPOSE:To reduce the power consumption by inserting a current variable means varying a current flowing to a loop to the loop. CONSTITUTION:In a power reception circuit 20 where it consists of a loop comprising e switch 60 connecting to an exchange or a PCM multiplexer 10, receiving a signaling signal from a telephone set to apply on/off operation, a current variable means 70 varying the current flowing to the loop is inserted to the loop. When the switch 60 is turned on by a signaling signal, a current flows to a loop comprising the current variable means 70 in the power reception circuit 20 connecting to a transmission line and the switch 60 and the current depends on the resistance of the transmission line. The current variable means 70 readjusts the current value to be a prescribed value, then the power consumption in the power reception circuit 20 is reduced.

Description

[Detailed Description of the Invention] [Summary] In a power receiving circuit such as a PCM multiplexer that processes information generated when dialing or on/off hooking a telephone, so-called signaling signals, an exchange and the power receiving circuit are connected via a transmission line. By inserting a circuit in which one or more resistors and electronic switches are connected in series or in parallel into the loop formed by the connection, the loop resistance in the power receiving circuit can be changed and the power consumption in the power receiving circuit can be reduced. It is designed to reduce the

(Industrial Application Field) The present invention relates to an improvement in a power receiving circuit that processes signaling signals in a PCM multiplexer or the like.

As shown in Figure 5, there is a line between the exchange and the PCM multiplexer that transmits voice signals from telephones and signaling signals generated when the handset of the telephone is lifted or lowered or when dialing. tied together.

It is desirable to have a circuit with a simple configuration that can reduce the power consumption in the power receiving circuit that transmits the signaling signal to the exchange as much as possible from the viewpoint of cost and the like.

(Prior Art) FIG. 4 is a block diagram showing the configuration of a power receiving circuit in a conventional PCM multiplexing device.

In FIG. 4, when the subscriber picks up the telephone (goes off-hook), a signaling signal is transmitted from the telephone to the exchange 5, the PCM multiplexer 4, and the transmission line to the PCM multiplexer 3 as shown in FIG. The power is sent to the power receiving circuit 2, and the electronic switch 6 is turned on.

As a result, the power supply and line in exchange 1 (the line resistance is R
LI, RL2), loop resistance R in the power receiving circuit 2
o and the electronic switch 6 form a closed loop, through which a current i flows.

The above-mentioned line resistances RLI and RL2 vary depending on the length of the line, and their maximum value is determined by the conditions under which the device is used (for example, 1.5Ω), and the minimum value is 0Ω. When the loop resistance Ro of the power receiving circuit is a constant value, the resistance value of Ro is selected such that a current of a constant value (for example, 20 mA) or more flows when the resistance values of the line resistances RL1 and RL2 are maximum.

[Problems to be Solved by the Invention] However, in the above-mentioned power receiving circuit, the resistance value of the line resistance decreases depending on the installed line line length, and even if it becomes 0Ω
Considering a case where the following occurs, there is a problem in that the current flowing through the loop in the power receiving circuit increases, and as a result, the power consumption in the power receiving circuit increases.

[Means for solving problems]

As shown in FIG. 1, the above problem arises from a loop including a switch 60 that is connected to an exchange or PCM multiplexer 10 via a transmission line and performs on/off operations by receiving signaling signals from telephones. This problem is solved by the power receiving circuit of the present invention, in which a current variable means 70 capable of varying the current flowing through the loop is inserted into the power receiving circuit 20 of the present invention.

[Effect]

In FIG. 1, a signaling signal causes switch 60 to
When turned on, the power receiving circuit 20 connected to the transmission line
A current flows through a loop formed by the current variable means 70 and the switch 60 inside. This current value changes depending on the resistance value of the transmission line.

Now switchboard 10. Assuming that the resistance value of the transmission line becomes 0Ω due to changes in the installation of the PCM multiplexing device 30, etc.
A large current flows through this loop.

The power consumed in the loop within the power receiving circuit 20 is proportional to the square of the flowing current.

Therefore, by resetting this current value to a predetermined value using the current variable means 7o, the power consumption in the power receiving circuit 20 can be reduced.

〔Example〕

FIG. 2 is a power receiving circuit diagram of the first embodiment of the present invention.

FIG. 3 is a power receiving circuit diagram of a second embodiment of the present invention.

The same reference numerals refer to the same objects throughout the design.

First, a first embodiment will be described with reference to FIG.

The line resistance RL3 of the line connecting the exchanger and the power receiving circuit 2,
Assume that the values of RL4 are both 450Ω. Also, Ro-
100Ω, R1=300Ω, R2=600Ω.

In addition, the power supply to this loop provided in the exchange 1 is
Set it to 0V.

First, the electronic switch SWI provided at both ends of R1 and R2,
When SW2 is turned on and both ends of R1 and R2 are shorted, the current l flowing through the loop of power receiving circuit 2 is: i = 50V/(2x450 +100)Ω-50m
A, and the power Po consumed by Ro is Po= i”
・Ro= (50・ICf'')2X100 =0.
It becomes 25 watts.

Now, suppose that the distance between the exchange 1 and the PCM multiplexer 3 has been shortened due to reconstruction of the transmission system, and the line resistance has become close to 0Ω. At this time, the current i flowing in the loop of the power receiving circuit 2 is i = 50V/100Ω = 0.5Am
p.

becomes. Therefore, the power PO consumed by Ro is P
o= i" ・Ro= (0,5)' ・100 = 2
5 watts, which is 100 times larger.

Therefore, when electronic switches SWI and SW2 are turned off, the total resistance of the loop is 100 + 300 + 600
=1000Ω. At this time, the current i flowing in the loop is
i = 50V/1000Ω-50m8, and the power Po consumed by the total resistance R of the loop is Po = i' ・R
= (50·1O-3)" x 1000 = 2.5 watts, which can be suppressed to about 10 times at most.

Next, a second embodiment shown in FIG. 3 will be described.

Also in Fig. 3, Ro = 100Ω, RL3, RL
4 are both 450Ω. Also, R3 and R4 are both 2Ω
shall be.

As in the case of the first embodiment, the line resistances RL3, RL
Suppose that both 4 and 4 change to 0Ω. At this time, turn off the electronic switch SW5 that was on until now, and at the same time turn off the electronic switch SW3.
, SW4 are both turned on.

As a result, the current i that was flowing in the loop before the line resistance value changed becomes i = 50V/1000Ω = 50mA, as in the case of the first embodiment, and after turning on SW3 and SW4 after the change. The current i in the loop is: i =50V/(100+1000)Ω=45.5
mA, and the power Po consumed by the total resistance R of the loop is Po = (45,5・10°")' ・100 + (
45,5/2 ・10°1) 1 ・2000X2=
It becomes 2.3 watts, which is about 10 times lower than before the change.

[Effects of the Invention] As described above, according to the present invention, power consumption in the power receiving circuit can be reduced with a simple circuit configuration.

[Brief explanation of drawings]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a power receiving circuit diagram of the first embodiment of the present invention, Fig. 3 is a power receiving circuit diagram of the second embodiment of the present invention, and Fig. 4 is a conventional example. FIG. 5 is a block diagram showing the configuration of an example telephone communication system. In the figure, 10 is an exchange or a PCM multiplexer, 20 is a power receiving circuit, 30 is a PCM multiplexer or exchange, 60 is a switch, and 70 is a current variable means. Figure 2 Figure 3

Claims (3)

[Claims] (1) A switch or a PCM multiplexer (1) via a transmission line.
0), and includes a switch (60) that receives a signaling signal from a telephone and performs an on/off operation. 70) is inserted into the loop. (2) The current variable means (70) is characterized by comprising one or more resistors connected in series and contacts of switches connected in parallel to each of the resistors and capable of switching on/off. A power receiving circuit according to claim 1. (3) The current variable means (70) is characterized by having a configuration in which one or more resistors and a set of contacts of a switch connected in series to the resistors and capable of switching on/off are connected in parallel. A power receiving circuit according to claim 1.