CN101320912A - Protective circuit - Google Patents
Protective circuit Download PDFInfo
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- CN101320912A CN101320912A CNA2008101416150A CN200810141615A CN101320912A CN 101320912 A CN101320912 A CN 101320912A CN A2008101416150 A CNA2008101416150 A CN A2008101416150A CN 200810141615 A CN200810141615 A CN 200810141615A CN 101320912 A CN101320912 A CN 101320912A
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- circuit
- protective circuit
- protection
- bridge circuit
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Abstract
The invention relates to a protection technology of a communication device, in particular a communication device protection circuit, which comprises an over-voltage protection component in parallel among port lines on the user side. The over-voltage protection component comprises a bridge circuit consisting of commutation diodes D2, D3, D5, and D6. Two balance points of the bridge circuit are connected with the port lines, and a thyristor T1 is connected between the other two balance points of the bridge circuit. The differences are that: a switch is respectively stringed on the external line side, wherein the switch is a normally closed switch; the commutation diode D4 is connected between the other two balance points of the bridge circuit and is in series with the thyristor T1; and the commutation diode D4 and the thyristor T1 are grounded via the commutation diodes D1 and D7. The protection circuit is characterized in rapid response, safety and stability, and economical cost. Moreover, the protection circuit can be widely applicable to broadband and narrow-band transmission.
Description
Technical field
The present invention relates to a kind of guard technology of communication equipment, particularly a kind of communication equipment protective circuit.
Background technology
In the communications field, main frame is the visual plant that connects subscriber's line and communication exchange equipment (PSTN or DSLAM).
Overvoltage, the overcurrent of the user side circuit that causes because of thunderbolt, surge, power line overlap joint, power induction etc. can be brought serious threat to the communication exchange equipment of equipment side and operating personnel's personal safety by main frame.Therefore, in main frame, need to be equipped with Security Unit (independent protection circuit part) with reply overvoltage, overcurrent phenomenon, the switching equipment of support equipment side and operating personnel's safety.At present, in main frame,, realize that different protective circuits achieve the above object by adopting different overvoltage, over-current protection device as crucial protective device.
The general thermistor mode of parallel connection in the line that adopts of over-current protection device, when big electric current reached the scope of setting, thermistor was high-impedance state, and from blocking passing through of overcurrent, reached the purpose of over-current protection.
Overvoltage protecting device then has multiple choices, and different overvoltage protecting devices has determined the design of different preventing protection circuit and the performance of protective circuit.
Many is selects gas discharge tube or the solid discharging tube protective circuit as overvoltage protecting device.Their common operation principle: when overvoltage reaches the scope of setting; gas discharge tube or the discharge of solid discharging tube shorted to earth are generated heat in the process of discharge simultaneously, and switch in the driver circuit or fuse disconnect; with the subscribers feeder shorted to earth, thereby realization is to the protection of equipment side.But, slow because of the response speed of flue protective circuit, do not have due protective effect for the fast rise waveform as the overvoltage of generations such as thunderbolt, the protection in the frequent area that should not be used to be struck by lightning; And the solid discharging tube protective circuit, because of its electric capacity is big, much larger than the 30pF that broadband transmission link requires, should not be as the contour protection of keeping pouring in lines of DSL circuit especially VDSL circuit.
Also there is the part occasion to adopt and selects IC as the overvoltage protecting device protective circuit, but there are a lot of defectives in IC as overvoltage protecting device: because the through-current capability of IC own is very little, need the other peripheral circuit of configuration, the circuit complexity when causing concrete the application, hidden danger increases, poor reliability; Electric capacity is also bigger, is not suitable for especially VDSL high frequency transmission circuit protection of DSL equally.Moreover, ripe not enough because the application time is not long, and cost is obviously higher.
On some products abroad, adopted protective circuit as shown in Figure 6.In this circuit, main what adopt is the bridge-type protective circuit, with bidirectional thyristor as main overvoltage protecting device.Wherein D1, D2, D3, D4, D5, D6, D7 are diode, and T1 is a bidirectional thyristor.The bridge circuit that D2, D3, D5, D6 form can be realized the isolation between a, the b line.When user side voltage was lower than setting range, thyristor T1 was high resistant and cuts off state, and protective circuit disconnects.When voltage reaches the scope of setting; thyristor T1 is conducting state; the protective circuit conducting; realize discharge over the ground; FUS1 in discharge process (fuse) issues thermal cut in the big function of current; excite protection mechanism to drive normal open switch K1, K2 closure, just a, b end overvoltage shorted to earth is realized overvoltage protection.In this circuit, driving switch K1, K2 adopt the open type setting, when overvoltage takes place, by Closing Switch K1, K2, realize the overvoltage shorted to earth.After FUS1 disconnected, T1 disconnected with circuit fully and loses protective effect, and after K1, the K2 action, electric current is with on the long time loading circuit, and protection device will be generated heat for a long time, easy initiation fire.
Summary of the invention
At above-mentioned the deficiencies in the prior art, the invention provides a kind of protective circuit, possess the characteristics of quick, safe and reliable, the cost economy of response, and can be widely used in wide, narrow band transmission.
For achieving the above object, the present invention adopts following technical scheme, a kind of protective circuit, comprise the overvoltage protecting device that is connected in parallel between the user-side port line, described overvoltage protecting device comprises the bridge circuit that rectifier diode D2, D3, D5, D6 form, two balance points of bridge circuit are connected with port lines, connect thyristor T1 between two other balance point; Its difference is, gone here and there a switch respectively in the outside line side, and described switch is a normally closed switch; Be connected with rectifier diode D4 between two other balance point of bridge circuit, T1 connects with thyristor, and rectifier diode D4, passes through rectifier diode D1, D7 ground connection with thyristor T1.
As to improvement of the technical scheme, between bridge-type protective circuit and equipment side port lines, be in series with over-current protection device, to strengthen overcurrent protection.
As to improvement of the technical scheme, can add Light-Emitting Diode LED and K switch 3, realize the protection alarm.
As to improvement of the technical scheme, can also between the user-side port line, set up the first class of protection circuit arrangement, form the two-stage protection scheme, further strengthen its overvoltage excess current protective function.
In the present invention, well user side, equipment side circuit are isolated, guaranteed good capacitance characteristic by the bridge circuit that D2, D3, D5, D6 form.When voltage during in normal range (NR); T1 is high-impedance state; when voltage reaches the scope of setting; thyristor T1 is the low-resistance conducting state; realization user side overvoltage, overcurrent are discharged over the ground; a large amount of heat drive K switch 1, K2 that protection mechanism utilizes thyristor T1 to send in discharge process disconnect and the K3 closure, and user side overvoltage and equipment side are disconnected, and have realized open-circuit-protection.Simultaneously, LED sends alarm signal, and alarm signal can be transferred to other warning systems.
Technical solution of the present invention is brought following beneficial effect: 1, low electric capacity is applicable to the especially contour lines that keeps pouring in of VDSL circuit of DSL circuit; 2, response fast, frequent regional protection is particularly useful for being struck by lightning; 3, open-circuit-protection can thoroughly disconnect overvoltage, the overcurrent of protection side and unprotect side, provides safer thoughtful protection to equipment side; 4, stable performance and cost economy, all devices are ripe device, steady quality, cost is lower.
Description of drawings
Shown in Figure 1 is the circuit theory diagrams of an exemplary embodiments of the present invention.
Shown in Figure 2 is an alternative embodiment of the invention circuit theory diagrams.
Shown in Figure 3 is an alternative embodiment of the invention circuit theory diagrams.
Shown in Figure 4 is an alternative embodiment of the invention circuit theory diagrams.
Shown in Figure 5 is an alternative embodiment of the invention circuit theory diagrams.
Shown in Figure 6 is the circuit theory diagrams of a prior art.
Embodiment
The present invention is further illustrated below in conjunction with accompanying drawing.
Shown in Figure 1 is the circuit theory diagrams of an exemplary embodiments of the present invention, and over-voltage protection function only is provided.Wherein, a, b are user side; also claim unprotect side or outside line side; a ', b ' are equipment side; also claim protection side or interior lines side, between user-side port line a, b, be parallel with the bridge circuit of rectifier diode D2, D3, D5, D6 composition, be in series with normally closed switch K1, K2 between two balance points of bridge circuit and user-side port line a, b; be connected with the rectifier diode D4 and the thyristor T1 of series connection between two other balance point of bridge circuit, both sides are then by rectifier diode D1, D7 ground connection.
When voltage during in normal range (NR); thyristor T1 is high-impedance state; when voltage reaches the scope of setting; thyristor T1 is the low-resistance conducting state; the a line discharges over the ground by D2-D4--T1-D7, D5-T1--D4-D1 route; the b line discharges over the ground by D3-D4-T1-D7, D6-T1-D4-D1 route; realization user side overvoltage is discharged over the ground; a large amount of heat drive normally closed switch K1, K2 that protection mechanism utilizes thyristor T1 to send in discharge process disconnect; user side overvoltage and equipment side are disconnected, realized protection equipment side equipment and operating personnel's person.
In the present invention, forming bridge circuit by D2, D3, D5, D6 well isolates a, b circuit, and D4 and two symmetric points that are connected to bridge circuit after T1 connects, be aided with D1, D7 and connect two symmetric points and ground respectively, can effectively realize a, the isolation over the ground of b line, reduce a, b line direct-to-ground capacitance, thereby guaranteed good low capacitance characteristic.
On this scheme basis, can increase different function elements, to satisfy the application of different actual conditions.Such as, K switch 1, K2 are replaced by fuse, then can simplify Application Design; Can increase over-current protection device at bridge circuit and equipment side, make entire circuit both be applicable to and use voltage protection, be applicable to overcurrent protection again; Can also between bridge circuit and ground, increase the alarm protective device.
Another embodiment circuit theory diagrams shown in Figure 2 have increased alarm function exactly on the scheme of Fig. 1, wherein LED is a Light-Emitting Diode, and K3 is a normal open switch, K1, K2, K3 parallel connection.During the protective circuit action, normal open switch K3 is with closure, and LED sends alarm signal, and S holds conducting over the ground simultaneously, alarm signal can be transferred to other warning systems.
Another embodiment circuit theory diagrams shown in Figure 3 then are to have increased over-current protection device PTC1, PTC2 on Fig. 2 scheme basis, and overvoltage, excess current protective function completely can be provided.Wherein, PTC1, PTC2 are thermistor.
The scheme that normally closed switch K1, K2 is replaced with fuse exactly on Fig. 1 scheme basis shown in Figure 4, same, Fig. 2, Fig. 3 scheme all can be replaced with fuse with normally closed switch K1, K2.
In order better to realize overvoltage, overcurrent protection to equipment side, can consider on technical scheme of the present invention basis, increase the first class of protection circuit.
Embodiment shown in Figure 5 has increased the first class of protection circuit arrangement exactly on the technical scheme basis of Fig. 1, form the scheme of two-stage protection.As shown in Figure 5; secondary gas discharge tube GDT1, GDT2 between normally closed switch K1, K2 and bridge-type protective circuit are connected on respectively between a, b line and the ground; form first order protective circuit with thermistor PTC1, PTC2, technical scheme originally (bridge circuit) becomes second level protective circuit.Certainly GDT1, GDT2 also can replace with three grades of gas discharge tubes.When overvoltage takes place, the overvoltage that speed is slow, electric current is bigger will realize that overvoltage unload over the ground by the GDT1 in the first class of protection, GDT2 shorted to earth, and speed faster waveform realize that by bridge-type protective circuit shorted to earth overvoltage unloads over the ground.Because PTC1, PTC2 can provide slack time for GDT1, the GDT2 of first class of protection to the iris action of electric current.In general, slow waveform is that the overvoltage such as the civil power that possess big current energy overlap, and speed faster waveform generally be to possess the overvoltage of small electric stream energy as thunderbolt.GDT1, GDT2 can send a large amount of heats in the process of discharge over the ground, excite protection mechanism to drive K1, K2 and disconnect, thereby disconnect outside line, and interlock exploitation K3 closure is sent alarm signal.Certainly, in Fig. 2, Fig. 3, several protective circuit embodiment shown in Figure 4, all can adopt aforesaid way to increase the first class of protection circuit arrangement.
In like manner, on the basis of the two-stage protection of mentioning in front, also can increase different function elements, to satisfy the application of different actual conditions.And protective circuit of the present invention both can design in main frame or other equipment, also can be designed to an external device.
More than be preferred forms of the present invention, according to content disclosed by the invention, some identical, replacement schemes that those of ordinary skill in the art can expect apparently all should fall into protection scope of the present invention.
Claims (7)
1, a kind of protective circuit, comprise the overvoltage protecting device that is connected in parallel between the user-side port line, described overvoltage protecting device comprises the bridge circuit that four rectifier diode D2, D3, D5, D6 form, two balance points of described bridge circuit are connected with described port lines, are connected with a thyristor T1 between two other balance point; It is characterized in that going here and there respectively between two balance points of described bridge circuit and described port lines has a normally closed switch K1, K2; Be connected with a rectifier diode D4 who connects with described thyristor T1 between two other balance point of described bridge circuit; Two other balance point two ends of described bridge circuit are respectively by rectifier diode D1, D7 ground connection.
2, protective circuit according to claim 1 is characterized in that, described protective circuit also is equipped with the Light-Emitting Diode LED and the K switch 3 of alarm usefulness.
3, protective circuit according to claim 1 is characterized in that, is in series with over-current protection device respectively between two balance points of described bridge circuit and equipment side port lines.
4, protective circuit according to claim 3 is characterized in that, described current protection device is thermistor PTC1, PTC2.
5, protective circuit according to claim 4 is characterized in that, described protective circuit also is equipped with the Light-Emitting Diode LED and the K switch 3 of alarm usefulness.
6. according to each described protective circuit among the claim 1-5, it is characterized in that between the user-side port line, also being provided with the first class of protection circuit arrangement; Described this grade protective circuit device installation is between normally closed switch K1, K2 and described bridge-type protective circuit, by being connected between the user port line and gas discharge tube GDT1, the GDT2 of ground connection and thermistor PTC1, the PTC2 that is connected in parallel on the user port line form.
7. protective circuit according to claim 6 is characterized in that, described normally closed switch K1, K2 can replace with fuse.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008101416150A CN101320912A (en) | 2008-07-16 | 2008-07-16 | Protective circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008101416150A CN101320912A (en) | 2008-07-16 | 2008-07-16 | Protective circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101320912A true CN101320912A (en) | 2008-12-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2008101416150A Pending CN101320912A (en) | 2008-07-16 | 2008-07-16 | Protective circuit |
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| CN (1) | CN101320912A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104518504A (en) * | 2013-09-30 | 2015-04-15 | 深圳市海洋王照明工程有限公司 | Anti-surge circuit and LED lighting system |
| CN109088404A (en) * | 2017-06-13 | 2018-12-25 | 神讯电脑(昆山)有限公司 | Electronic device with limitation output energy function |
| CN109155871A (en) * | 2016-04-26 | 2019-01-04 | 麦克赛尔株式会社 | Image output system, image output device and connection cables |
-
2008
- 2008-07-16 CN CNA2008101416150A patent/CN101320912A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104518504A (en) * | 2013-09-30 | 2015-04-15 | 深圳市海洋王照明工程有限公司 | Anti-surge circuit and LED lighting system |
| CN109155871A (en) * | 2016-04-26 | 2019-01-04 | 麦克赛尔株式会社 | Image output system, image output device and connection cables |
| CN109155871B (en) * | 2016-04-26 | 2020-11-13 | 麦克赛尔株式会社 | Image output system, image output device and connection cable |
| CN109088404A (en) * | 2017-06-13 | 2018-12-25 | 神讯电脑(昆山)有限公司 | Electronic device with limitation output energy function |
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| PB01 | Publication | ||
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Open date: 20081210 |