CN201504099U

CN201504099U - Protection circuit of signal port

Info

Publication number: CN201504099U
Application number: CN200920219883XU
Authority: CN
Inventors: 黄翔
Original assignee: Hangzhou H3C Technologies Co Ltd
Current assignee: New H3C Technologies Co Ltd
Priority date: 2009-10-22
Filing date: 2009-10-22
Publication date: 2010-06-09
Anticipated expiration: 2019-10-22

Abstract

The utility model discloses a protection circuit of a signal port, comprising the signal port, an AC coupling capacitor, an AC coupling circuit and a port IC chip, wherein the signal port is connected with the AC coupling capacitor which is connected with the AC coupling circuit connected with the port IC chip. By replacing a PTC used in the original protection circuit with the AC coupling capacitance, the protection circuit prevents strong current from damaging the signal port, and reduces the manufacturing cost of the protection circuit.

Description

A kind of protective circuit of signal port

Technical field

The utility model relates to communication technique field, relates in particular to a kind of protective circuit of signal port.

Background technology

At present, find that according to analysis and the field investigation to damage equipment for a long time the situation of the burning especially severe of some signal transmission port obviously is the damage that has forceful electric power (power) entering signal port to cause.By the reason of forceful electric power entering signal port is analyzed, find roughly can comprise following three kinds of situations:

(1) power induction: when signal cable was grown distance with the parallel cabling of power supply power line, signal cable can be subjected to the inductive interference of power line;

(2) power line touches: when power line and holding wire cause insulation layer fails because of long-term ageing, cause power line directly to snap on the holding wire;

(3) construction mistake: in the process of construction, the circuit mistake is taken with installing or being connected the improper power line that causes and is touched on the signal cable.

Though it is a basic principle that signal port mustn't insert power supply,, in product design, still be necessary to consider signal port is carried out protection aspect the over-voltage and over-current according to the applied environment of product in order to improve reliability of products and adaptive capacity.

For the signal port that needs carry out the protection of overcurrent overvoltage aspect, mainly be the scheme that adopts PTC (Positive Temperature Coefficient, the semistor) of in holding wire, connecting at present, its schematic diagram is as shown in Figure 1.Its principle is that when electric current is excessive, the temperature of PTC will raise, and causes the resistance of PTC to become big, thereby reduces the electric current in the circuit.But be in the prior art: use PTC to improve the manufacturing cost of circuit.

The utility model content

The utility model provides a kind of protective circuit of signal port, is used for signal port is protected, and prevents the damage of forceful electric power to signal port.

The utility model provides a kind of protective circuit of signal port, comprising: signal port, ac coupling capacitor, ac-coupled circuit and port IC chip;

Described signal port is connected with described ac coupling capacitor;

Described ac coupling capacitor is connected with described ac-coupled circuit;

Described ac-coupled circuit is connected with described port IC chip.

Wherein, described ac coupling capacitor is withstand voltage ac coupling capacitor.

Wherein, also there are second ac coupling capacitor in described ac-coupled circuit and described port IC chip chamber.

Wherein, described second ac coupling capacitor is withstand voltage ac coupling capacitor.

Compared with prior art, the utlity model has following advantage:

By using ac coupling capacitor to substitute the PTC that uses in original protective circuit, can prevent the damage of forceful electric power, and reduce the manufacturing cost of protective circuit signal port.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the signal port protective circuit schematic diagram that has used PTC in the prior art;

Fig. 2 is the signal port protective circuit schematic diagram that provides in the utility model;

Fig. 3 is the signal port protective circuit schematic diagram that provides in the utility model.

Embodiment

Below in conjunction with the accompanying drawing among the utility model embodiment, the technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.

In the signal port protective circuit that provides in the utility model; directly utilize " stopping direct current is logical to be exchanged " characteristic of ac coupling capacitor; by a side that in the circuit of signal port and port IC chip, the is connected coupling capacitance of increasing exchanges, realize protection to overcurrent overvoltage on the signal port (touching) as power induction, power line with signal port.

In the circuit of a lot of signal ports of prior art, for hot plug, reduce between power consumption, the varying level, the consideration of various factors such as interconnect between the different DC biased level, adopted ac-coupled circuit between a lot of occasion transmitting-receiving ports, the circuit form that one can be used as shown in Figure 1.

In the protective circuit of the signal port that the utility model provides, comprising: signal port, ac coupling capacitor, ac-coupled circuit and port IC chip;

Described signal port is connected with described ac coupling capacitor;

Described ac coupling capacitor is connected with described ac-coupled circuit;

Described ac-coupled circuit is connected with described port IC chip.

One concrete form of the protective circuit of the signal port that provides in the utility model comprises as shown in Figure 2: signal port 10, ac coupling capacitor 20, ac-coupled circuit 30 and port IC chip 40.Wherein, signal port 10 is connected with ac coupling capacitor 20, and ac coupling capacitor 20 is connected with ac-coupled circuit 30, and ac-coupled circuit 30 is connected with port IC chip 40.Compare with as shown in Figure 1 circuit structure in the prior art, use an ac coupling capacitor 20 to replace the PTC that uses at same position in the prior art in the utility model, can play the anti-overcurrent overvoltage function that the circuit that uses PTC up till now has equally.Need to prove that in order to play the function of anti-over-voltage and over-current, employed ac coupling capacitor 20 need be selected suitable withstand voltage electric capacity according to specification requirement.

In addition, as shown in Figure 3, on the basis of circuit structure shown in Figure 2, can also there be second ac coupling capacitor 50 between ac-coupled circuit 30 and the port IC chip 40, can realizes same effect.This moment, employed second ac coupling capacitor 50 need be selected suitable withstand voltage electric capacity according to specification requirement equally in order to play the function of anti-over-voltage and over-current.

In the utility model; by using ac coupling capacitor to substitute the PTC that uses in original protective circuit; can prevent the damage of forceful electric power to signal port; can effectively solve product install and the long-term work process in the power line that occurs touch the equipment burnout incident that holding wire causes; thereby reduce the probability of damage of on-line apparatus, reduced the manufacturing cost of protective circuit simultaneously.

It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, unit in the accompanying drawing or flow process might not be that enforcement the utility model is necessary.

Above-mentioned the utility model embodiment sequence number is not represented the quality of embodiment just to description.

Claims

1. the protective circuit of a signal port is characterized in that, comprising: signal port, ac coupling capacitor, ac-coupled circuit and port IC chip;

Described signal port is connected with described ac coupling capacitor;

Described ac coupling capacitor is connected with described ac-coupled circuit;

Described ac-coupled circuit is connected with described port IC chip.

2. protective circuit as claimed in claim 1 is characterized in that, described ac coupling capacitor is withstand voltage ac coupling capacitor.

3. protective circuit as claimed in claim 1 or 2 is characterized in that, also there are second ac coupling capacitor in described ac-coupled circuit and described port IC chip chamber.

4. protective circuit as claimed in claim 3 is characterized in that, described second ac coupling capacitor is withstand voltage ac coupling capacitor.