SU902312A1 - Device for power supply of telephonic lines - Google Patents

Description

(54) TELEPHONE POWER SUPPLY DEVICE

I

The invention relates to telephony and can be used in automatic telephone exchanges (PBX).

A device for powering telephone lines is known, which contains a station power source, the first output of which is connected to the first input of a stabilizer. current, as well as the feedback element ij.

However, in the known device the inverse dependence of the supply current on the line length takes place, which significantly reduces the communication range.

The goal of the acquisition is to ensure the variation of the supply current with the length of the line.

This goal is achieved by introducing a series-connected high-frequency inverter and a direct converter into the known power supply of telephone lines, the inputs of the high-frequency inverter being connected to the corresponding outputs of the current stabilizer, the second output of the stationary power source, and the feedback element

connected between the outputs of the high-frequency inverter and the additional inputs of the current stabilizer.

FIG. 1 shows a structural electrical circuit; in fig. 2 - a hygienic circuit of the proposed device.

The telephone line power supply device contains a station source 1, power supply (Fig. 1), a current stabilizer 2, a high frequency inverter 3, a rectifier 4, a feedback element 5, a telephone line 6.

Telephone line 6 via rectifier 4, transformer 7 (winding 8),

ts transistors 9 and resistor 10 are connected to station source 1 (Fig. 2). Transformer 7 with transistors 9 ob-circuit of the transistor high-frequency inverter 3, which in this

Claims (1)

20, the case is excited from a station generator (not shown) through transistors 11. The emitters of transistors 9 include a negative current feedback resistor 10, and the bases of transistors 9 through transistors 11 and a diode bridge 12 are connected to a zener diode 13. The feedback element 5 consists from the feedback coil 14, the diagonal of which is connected between the Zener diode 13 and the bases of the transistors 9 through the transistors 11. The current stabilizer 2 is connected to the transistors 9, the resistor Yu is connected to the emitter circuit, and the bases of the transistors 9 are connected of transistors 11 and 12 to the diode bridge stabilitro well 13. Thus, transistors 9, first ly, are part of the inverter 3 and, on the other hand - part 2 of the current stabilizer. The device works as follows. Under the influence of exciting pulses coming from the station generator to the bases of the transistors 11, the bases of the transistors 9 are alternately connected to the zener diode 13 via the bridge 12. As a result, one of the transistors 9 goes into active mode and the other is locked. The collector current of the transistor 9, which is in active mode, is approximately equal to the stabilization voltage of the Zener diode 13 divided by the resistance of the resistor 10, and does not depend on the supply voltage and resistance included in the collector of the transistor 9. Thus, the transistors 9 operate in the stabilization mode current in their collectors, as a result of which, under certain assumptions, it can be assumed that the current in the winding 8 of the transformer 7, and hence the rectified current in line 6, will be independent of both the source voltage 1 and the resistance Yeni-line 6. This is true in the case where the feedback through the winding 14 of the transformer 7 is not activated (interrupted). If the OFAT connection is activated, the voltage from the diode bridge 12 is added to the voltage of the Zener diode 13, which accordingly leads to an increase in the collector current of transistor 9 and, consequently, the current in line 6. Because the voltage is not winding 14 is directly proportional to the resistance of line 6 then the increase in current in line 6 becomes proportional to resistance. With an increase in the length of the latter, the current increases. As a result, on the one hand, as the subscriber moves away from the PBX, the power of the microphone of the telephone apparatus increases, and on the other hand, the variable signal is amplified. As a result of the action of both these factors, it is possible to increase the communication distance without changing the cross section of the wires and without additional installation of additional devices and amplifying devices in the line. The invention The power supply device of telephone lines, containing a station power source, the first output of which is connected to the first input of a current stabilizer, as well as a feedback element, characterized in that, in order to ensure the variation of the supply current on the length of the line, a series-connected high-frequency inverter and rectifier, the inputs of the high-frequency inverter are connected to the corresponding outputs of the current regulator, the second output of the station power source is connected to the second input stabilizer and a current, and a feedback element is connected between the outputs of the high-frequency inverter and the additional inputs of the current stabilizer. Sources of information taken into account in the examination 1. French patent number 2279237, cl. H 04 M 19/00, published. 1976 (prototype). five -w-f (Xj stp -CZD (paz.i one t ( // 7Si3 I f