CN2160174Y

CN2160174Y - Transistor switch for electronic key controlled telephone system

Info

Publication number: CN2160174Y
Application number: CN 93225218
Authority: CN
Inventors: 谢国河
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-02-24
Filing date: 1993-02-24
Publication date: 1994-03-30
Anticipated expiration: 2003-02-24

Abstract

The utility model relates to a transistor switch for an electronic key controlled telephone system, which has the advantages of little power consumption, small distortion, convenience for circuit integration, etc., compared with a relay switch. The utility model is composed of a polarity holding circuit 1, a charging circuit 2, a starting or holding circuit 3, a talking equivalent circuit 4 and a switch circuit 5. The utility model is characterized in that a light coupler is used for starting a high-voltage resistant transistor in the switch circuit 5, and the holding circuit composed of another transistor causes the voltage resistant transistor to be in saturation state, and the switch is completely on.

Description

Transistor switch for electronic key controlled telephone system

The utility model relates to the transistor type switching device of a kind of electronic keying telephone system (EKTS) usefulness.

For a long time, key telephone system (KTS) provides many convenience for office communicates by letter with family.Though it's a pity that KTS is electronic, still continue to use mechanical switchs such as relay, magnetic red device among the EKTS.The relay resistance generally is not more than 1000 Ω, and the current sinking amount is big, increases the complexity of power circuit, the cost height, and cause the transmission signals distortion easily, directly influence the reliability of EKTS.In addition, the cost of relay is not low, and volume is big again, is unfavorable for the integrated of circuit.

The purpose of this utility model provides the transistor switch device of an alternative above-mentioned relay, to improve reliability, reduces power consumption, reduces cost, and is convenient to make integrated circuit, promotes EKTS to produce in batches.

The utility model is to realize like this.

The utility model is made up of utmost point electric protection circuit, switching circuit, charging circuit, startup/holding circuit and conversation equivalent electric circuit.Two high pressure resistant transistors of switching circuit are connected to the impact that circuit moment surge and ringing-current voltage can be born in the two ends of outside line by polar protective circuit; Polar protective circuit is used for guaranteeing that the negative terminal of diode D1 is a positive voltage; Charging circuit is made of resistance, electric capacity, and resistance value is greater than 10M Ω, and the outside line voltage of 48V charges to electric capacity by resistance at ordinary times, for startup/holding circuit provides power supply; Be subjected to the startup/holding circuit of CPU (CPU) control, its optical coupler and transistor are respectively as starting and the usefulness of maintenance.As everyone knows, the intercom system that EKTS system is made up of the telephone set of tape swap function, and comprise speech channel unit and CPU two large divisions.The utility model only relates to the switching device of speech channel part, and adopts the common known signal bus to be connected with CPU.

The utility model advantage is to adopt transistor as switching device, and its power consumption stream is 1% of relay, and distorted signals is little, and cost is low, is convenient to integrated.

Below in conjunction with drawings and Examples the utility model is further described.

Fig. 1 is the utility model block diagram.

Fig. 2 is the utility model circuit diagram.

Accompanying drawing number is:

1-polar protective circuit D1, D2-diode

2-charging circuit R1, R2-resistance C1-electric capacity

3-startup/holding circuit Q3-transistor PH-optical coupler R4, R5-resistance

4-conversation equivalent electric circuit L1-inductance C2-electric capacity

5-switching circuit Q1, Q2-transistor R3-resistance

Embodiment: the utility model is made up of polar protective circuit 1, charging circuit 2, startup/holding circuit 3, conversation equivalent electric circuit 4 and switching circuit 5.Polar protective circuit is the bridge circuit that 4 diodes constitute, and cross-over connection is on exchange line LA, LB, and diode D1 negative terminal is a positive potential;

Switching circuit 5 is made of transistor Q1, Q2 and resistance R 3, Q1, Q2 are connected across the output of above-mentioned bridge circuit, when the Q1 base stage is taken positive bias, Q1, Q2 conducting, (LA → diode → D1 → Q1 emitter, base stage → Q2 collector electrode, emitter → resistance R 3 → ground → diode D2 → LB) also form ac circuit (LA → D1 → Q1 emitter, collector electrode → inductance L 1 → capacitor C 2 → ground → D2 → LB), provide the conversation equivalent electric circuit of mainly being made up of L1 and C2 of native system simultaneously to form DC loop;

Charging circuit 2 is made of resistance R 1, R2 and capacitor C 1, and the R1 resistance value is greater than 10M Ω.

Startup/holding circuit 3 is by transistor Q3, optical coupler PH, resistance R 4, R5 constitutes, as the optical coupler that starts usefulness, its diode end (PH-D) receives the control signal of known EKTS CPU by the common known signal bus, when EKTS need form direct current (or interchange) loop, just make (PH-D) conducting, thereby make the also conducting of transistor (PH-Q) that triggers among the PH, fill the positive voltage deposited through R2 → R4 → PH-Q collector electrode → PH-Q emitter → transistor Q2 base stage by outside line when making capacitor C 1 flat, discharge, start transistor Q2, Q1, because R1 is greater than 10M Ω, C1 institute charging voltage is little, above-mentioned discharging current is very little, so Q1, Q2 is conducting fully not, just be activated, but Q1 one starts, the positive voltage of diode D1 negative terminal is just via the Q1 emitter, collector electrode → L1 → R5, be added to the emitter of transistor Q3, the Q3 conducting, and R5 is less than 10M Ω, and the Q1 electric current is very big so flow through this moment, Q1, the complete conducting of Q2, Q1, Q2 has the characteristic of the above high pressure of anti-150V, because surge and ringing-current can appear in exchange line.

Claims

1, a kind of transistor type switching device that is applied to the electronic keying telephone system is made up of polar protective circuit (1), charging circuit (2), startup/holding circuit (3), conversation equivalent electric circuit (4) and switching circuit (5), it is characterized in that:

(a) polar protective circuit (1) is that 4 diodes constitute bridge circuit, and cross-over connection is on exchange line LA, LB, and diode D1 negative terminal is a positive potential;

(b) switching circuit (5) is made of transistor Q1, Q2 and resistance R 3, Q1, Q2 cross-over connection are in the output of above-mentioned bridge circuit, when the Q1 base stage is taken positive bias, Q1, Q2 conducting, (LA → diode D1 → Q1 emitter, base stage → Q2 collector electrode, emitter → resistance R 3 → ground → diode D2 → LB) also form ac circuit (LA → D1 → Q1 emitter, collector electrode → inductance L 1 → capacitor C 1 → ground → D2 → LB) of native system simultaneously to form DC loop;

(c) charging circuit (2) is made of resistance R 1, R2 and capacitor C 1, and the R1 resistance value is greater than 10M Ω;

(d) startup/holding circuit (3) is by transistor Q3, optical coupler PH, resistance R 4, R5 constitutes, as the optical coupler that starts usefulness, its diode end (PH-D) receives the control signal of known EKTS CPU by the common known signal bus, when EKTS need form direct current (or interchange) loop, just make (PH-D) conducting, thereby trigger the also conducting of transistor (PH-D) among the PH, fill the positive voltage deposited through the emitter → transistor Q2 base stage of the collector electrode of R2 → R4 → (PH-D) → (PH-D) by outside line when making capacitor C 1 flat, discharge, start transistor Q2, Q1, this moment Q1, Q2 just is activated, Q1 one starts, the positive voltage of diode D1 negative terminal is just via the Q1 emitter, collector electrode → L1 → R5 is added to the emitter of transistor Q3, Q3 conducting, select R5 less than 10M Ω, this moment, the Q1 electric current was very big, Q1, the complete conducting of Q2, Q1, Q2 has the characteristic of the above high pressure of anti-150V.