JPS58194455A - Feeding circuit for telephone circuit - Google Patents

Abstract

PURPOSE:To constitute a feeding circuit with use of a miniature transistor, by protecting the transistor which feeds a DC power supply when a telephone circuit is short-circuited. CONSTITUTION:First the base currents of transistors TR103 and 108 flow to turn on these TRs. Then a DC current is supplied to a telephone 1. While a transformer 5 transmits an AC signal. In this case, circuits 102 and 107 have no AC loss for their feeding circuits since they have high impedance in terms of AC. If a telephone circuit is short-circuited, the voltage generated across a resistance 109 increases. Then a signal of H level is transmitted from a comparator 12. This signal turns on a thyristor 113 and turns off the TR108 respectively. As a result, the current flowed out of a plus power supply is supplied to a minus power supply through the TR103, the telephone 1, a resistance 110 and the thyristor 113. Therefore the TR108 is turned off, and the resistance 110 of high resistance value is connected in series to the TR103. Thus both TRs can be protected.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The invention of C is a power supply for supplying direct current to a telephone liner.
Section 7 is related to circuits.

[Technical backbone of the invention J The characteristic of transmitting the father's flow code (data in audio No. 16) along with the reverse current is inferior to this, and the conventional circuit is It is constructed as shown in Figure 2.

In the 11th, 1 beats Kameiyu Iso. This ``Ayu ridge 1'' is connected between the lines 2a and 2b of the Den-Ayu fermentation. This line abbreviation 2a + 2b's parent machine - has an interflow I No. 6deni
Connectors 3a + Jb for n are connected to each other. Furthermore, a positive voltage is applied to the line 2& through the choke coil 4, and a negative voltage is applied to the line 2bKFi through the choke coil 4. As a result, the line 2a
A direct current is applied to the telephone line consisting of +2b.

Similarly to FIG. 1, in Figure 2, the telephone 1 is connected to the telephone line 2 * * 2 b. and,
Electric port to convey AC notes! l! 1 rim and transformer 5
is connected, and a positive voltage is applied to the secondary @41 wire 5a, 2
A negative voltage is applied to the next winding 5b.

[Background technology issues]

However, the above power supply [GL path is smaller.

``It is difficult to reduce the weight, and there has been a demand for a 1g1W6 power supply using transistors.

Therefore, a 1IN1!11 supply using a transistor has been proposed, but in such a supply route, it must be taken into consideration that a large current will flow through the transistor in the event of an electromagnetic circuit or a short circuit. In the end, it was necessary to use large transistors. In other words, even though transistors were used, it was not possible to reduce the size and weight of the power supply circuit.

[Purpose of the invention]

The present invention was developed in view of these circumstances.

Therefore, an object of the present invention is to reduce the size and weight of a friend power supply 1.
The goal is to provide a path.

[Summary of the invention]

Therefore, in the present invention, it is connected to one line of the telephone line (9) and supplies direct current through a transistor, and
A first line having a high impedance in terms of AC is connected to the other line of the surround line, and is supplied with DC 1 through a transistor, and.

a second circuit with high impedance in terms of alternating current;
Also, a detection means is connected to a predetermined position of the transistor of the Fi second circuit to detect that excess Xa has flowed to the transistor, and a bypass of the transistor to which this detection means is connected when an overcurrent flows. A switching element is connected to a resistor located in the route and connected in series with other transistors, and is operated by the overcurrent detection output from the detection means, forming a power supply circuit. achieved.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 shows a circuit diagram of an embodiment of the present invention. In this figure, the same components as in FIGS. 1 and 2 are given the same numbers, and their explanations will be omitted.

54 terminal of transformer 5 which is the third cause and 5. A condenser v101 for cutting direct current is connected between the terminals.

102 indicates the first circuit, this first circuit 1I61o
2 consists of a transistor 103, resistors 104 and 105, a capacitor 106, and a positive voltage source. transistor 1
The collector of the transistor 103 is connected to the line 2aK of the telephone line, the emitter of the transistor 103 is connected to the positive voltage source 7 through the resistor 104, and the base flaKa and the core fysu 106 of the positive voltage source transistor 103 are connected to the line 2aK of the telephone line.
is connected to the base of transistor 1030 and transformer 5
A resistor 105 is connected to the terminal 54. Of these, the resistor 104 and the capacitor 106 are relatively large and make the first path 102 high impedance in terms of alternating current.

The second circuit 107 includes a transistor 108% resistor 109, 110 . capacitor 1
11, consisting of a negative voltage source. The collector of the transistor 108 is connected to the line 2bK* of the telephone line, and the collector of the transistor 108 is connected to a negative voltage source via a resistor 109. 9. A capacitor 111 is connected between the negative voltage regulator and the base of the transistor 1080, and a capacitor 111 is connected between the base of the transistor 108 and the 5 of the transformer 5.
．． A resistor 110 is connected between the terminal and the terminal. Of these, the resistor 109 and the capacitor 111 are connected to the second (b)
This is to make the path 107 high impedance in terms of alternating current.

One input terminal of a comparator 112 serving as a detection means is connected to the emitter V of the transistor 108 of this second circuit 107.
n and comparison 1! The reference voltage ■1 is applied to the other input terminal of the circuit 112. This reference voltage v1 is gaF
It is assumed that the voltage is approximately equal to the voltage generated at the emitter of the transistor 108 during normal operation of approximately 1 of jA. Then, when the voltage supplied from the output terminal of the transistor 11 is the reference voltage (1), the ratio device 112 outputs a signal of H1gh level from the output terminal, and the other devices output a signal of H1gh level from the output terminal. , outputs a signal at a very high level.

Comparison @ Is the output signal of 112 Sunden? 111K
3! A switching element connected to the column is provided to a control terminal of a thyristor 1130. This thyristor 11
3 has its anode connected to a resistor of 110Kil, and its cathode connected to a negative voltage source 8, so that the cyrisk 11
3 is turned on, the resistor 110 and the iris 113 become a bypass route for the transistor 108 K], and the resistor 110 is connected in series with the transistor 103 K.

The operation of the nine power supply circuit constructed as described above will be explained.

First, the base current of transistors 103 and 108 flows through the pressure source → resistor 104 → emitter of transistor 103 → base of transistor 1030 → resistor 105 → transformer ROS4 terminal → 51 terminal of transformer 5 → line 2a
→ Telephone 1 → Line 2b → 56 terminal of transformer 5 → 5s terminal of transformer 5 → Resistor 110 → Transistor 10i4)
Pace → Construction of transistor 108 → Resistor 109 →
Flows through the route of the negative voltage source. As a result, transistors 103 and 108 are turned on and the telephone IKII
i, direct current is supplied.

On the other hand, although the transformer 5 transmits an alternating current signal, the first 1-path 102 and the second 1-path 107 have high impedance in terms of alternating current, so no loss occurs in alternating current due to this power supply circuit.

Next, suppose that a short circuit occurs on the %X talk line (fii path 2a+
2b), as a result of which the current in the entire circuit increases, the voltage generated across the resistor 1090 also increases, and a voltage greater than the reference voltage 1 is applied from the emitter of the transistor 108 to the comparator 112. Ru. Then, an output signal of H1gh level is sent from the comparator 112 and reaches the control terminal of the self-control thyristor 113. As a result, the current flowing out from the positive voltage source is as follows: Telephone l-+-M2b→Transformer 5
56 terminal of transformer 5 → 5s terminal of transformer 5 → resistor 110 → thyristor 111 C) Anode → thyristor 1130 cathode → negative voltage source.

Therefore, since the transistor 108 is in an off state, no electric power is applied to it, and since the resistor 110 having a high resistance value is connected in series to the transistor la&, the load tflL of the transistor 103 is significantly reduced. limited to.

In this embodiment, the current holding the thyristor 113 is limited to the current flowing through the short-circuited telephone [fc' via gllllill.
Thyristor 113 is turned off.

Ji4iim is a fake circuit diagram of the present invention.

In this embodiment, the resistor 105 of the embodiment of FIG. 3 is connected between the base of the transistor 103 and 11112m,
A resistor 110 is connected to the gate of transistor 108 and the threshold of line 2b. In this embodiment as well, the same operation as in the embodiment of FIG. 3 is performed.

19, Im*bfl+b cutkm<, II 1 c1m
Since mlo2 and 0i111107 are symmetrical,
Even if the comparator 112 and the SIRISK 113 of the 3-1 irises 41klO example are connected through the first path 102K, there is no problem.

〔Effect of the invention〕

As described above, according to the present invention, telephone-1jio
At the time of a disturbance, the transistor is protected by gA,
Since large currents do not flow through the transistors, the power supply circuit can be configured using Shosha's transistors. Circle 1,
If thyristor is used as a switching element, the start-up operation of the thyristor is fast, so it is possible to keep the transistor stable.
Since the time in bt is shortened and the pace resistors provided in the 11th and 2nd 1gl paths each have a high resistance value, Since only a small current flows through the transformer to avoid AC signal loss due to the magnetic saturation fAm of the transformer, it is possible to reduce the load current of the switching element (Sirisk) by making the transformer wrinkled. By controlling O, the switching element can be made small and have a small capacity.

Further Ks *In the example, the holding current to Hiro and Cyrisk flows only through the telephone line route, so after the short-circuit accident is restored,
The stone that opens the phone and the cyrisk turn off 9.
The power supply circuit becomes operational again. *It is convenient because the circuit can be normalized without having to go to the equipment (for example, the exchange) that is equipped with the power supply circuit.

[Brief explanation of drawings]

Fig. 2 is a circuit diagram of a conventional power supply circuit, Fig. 3 is a circuit diagram of an embodiment of the present invention, and Fig. 4 is a circuit diagram of another embodiment of the present invention!
Refer to the circuit diagram of the example. 1... Telephone 2m, 2b... Edge Road 10
2...Ill circuit 107...Second circuit 11
2... Comparator (detection means) 113... Thyristor (switching element) substitute
Patent Attorney Book 1) Fist Diagram 4

Claims (1)

[Scope of Claims] (1) One line connected to one line of a telephone line, directly supplying aXa via a transistor, and having high impedance in terms of alternating current. A circuit connected to the other l1FIl path of the electric pasting line 11al, to which direct current is supplied via the transformer 7, and which is high impedance in terms of alternating current, and the circuit connected to the i1o circle or the side 2 Predetermined position of transistor in circuit rc*
A detecting screw is connected to the terminal and detects that an overcurrent has flowed to the transistor, and a resistor is connected to the resistor located in the bypass route of the transistor to which this detecting means is connected and connected in series with other transistors. A telephone (9)-1, 0 power supply circuit comprising a switching element which is wired and operates based on the overcurrent detection output from the detection means. (2) The switching element is connected only when a self-holding current flows through the circuit.
. (4) %ll! where the switching element is a thyristor. F## Ice s Disciple 1 or Xie 2 Indication value V Kamewa Kaigan power supply Lc! circuit.