CN201498984U - Lightning protection circuit of video monitoring equipment - Google Patents
Lightning protection circuit of video monitoring equipment Download PDFInfo
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- CN201498984U CN201498984U CN2009202095477U CN200920209547U CN201498984U CN 201498984 U CN201498984 U CN 201498984U CN 2009202095477 U CN2009202095477 U CN 2009202095477U CN 200920209547 U CN200920209547 U CN 200920209547U CN 201498984 U CN201498984 U CN 201498984U
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Abstract
The utility model relates to a lightning protection circuit of video monitoring equipment, which relates to the field of lightning protection. The utility model is characterized in that: the protection circuit adopts the three-level compound lightning protection; an input port adopts a gas discharge tube as a first-level lightning protection; the middle part of the protection circuit adopts a full-bridge rectifier and a transient voltage suppressor diode as a second-level lightning protection; an output port adopts diodes connected in series with each other as a third-level lightning protection; and wire-wound non-inductive resistances are connected in series among the first-level, second-level and third-level lightning protections as a gas discharge tube igniting resistance of the first-level lightning protection and a current-limiting resistance of the third-level lightning protection. The utility model has the advantages that: the lightning protection circuit adopts the three-level lightning protection; the output port utilizes low forward turn-on voltages of the diodes to clamp surge voltages as the third-level precision protection; the middle part adopts the full-bridge rectifier and the transient voltage suppressor diode as the second-level lightning protection to be matched with a third-level protection circuit; the input port adopts the gas discharge tube as the first-level lightning protection to discharge a large current; the resistances among all protections play a role of limiting the current and raising the pre-stage voltage.
Description
Technical field
The utility model relates to the lightning Protection field, specifically is a kind of lightning protection circuit of video monitoring equipment.
Background technology
Annual various communication control systems or computer network are of common occurrence because of the example that thunderbolt damages, and wherein safety defense monitoring system causes that because of being subjected to being struck by lightning device damage, automatically-monitored malfunctioning incident also take place often.In some Monitor And Control Subsystem, some front-end camera is installed in outdoor, and in the thunderstorm prone areas, these equipment are struck by lightning easily or induction lightening flows and cause damage, so the utmost point is necessary these equipment is carried out the emphasis lightning protection.When induction overvoltage that prevents the thunder and lightning generation and overcurrent, corresponding lightning arrester all should be installed at power line, the holding wire two ends of all watch-dogs turnover buildings.
General vision signal generally uses coaxial cable to transmit, its voltage magnitude is about 1V, adopting the A/D conversion chip at video terminal is digital signal with analog signal conversion, be example here with A/D chip ADV7181, its electric pressure such as Fig. 1, as seen the highest working voltage of its power supply is 4V, and analog signal is AGND-0.3 V to AVDD+0.3V to signal ground voltage (Analog Inputs to AGND), promptly analog input end range of signal over the ground at-0.3V between the 4.3V.And on the market the overwhelming majority at its voltage protection level of lightning protection device of video monitoring equipment all greater than 10V; when the digitizer of this low-work voltage of protection, low withstand voltage, general lightning protection device all can not be the overvoltage strangulation under digitizer be withstand voltage.So load onto such surge protector,, do not have protective effect for digitized video equipment.
Fig. 2 is traditional video interface lightning protection circuit, and adding the TVS pipe as the diode of final stage protection is can't reach even less than the voltage protection level of 4.3V.
The utility model content
The technical problem that the utility model solved is to provide a kind of employing three grades of lightning protections, with the voltage clamping on the video monitoring circuit below 4V, the lightning protection circuit of the video monitoring equipment that requires with the overvoltage protection that satisfies digitized video equipment.
The technical problem that the utility model solved realizes by the following technical solutions:
A kind of lightning protection circuit of video monitoring equipment; it is characterized in that: described protective circuit adopts three grades of compound lightning protections; input port adopts gas discharge tube as first order lightning protection; the middle full-bridge rectification that adopts adds transient voltage inhibition diode as second level lightning protection, and output port adopts the diode series connection as third level lightning protection.
Between described three grades of lightning protection, seal in the wire-wound noninductive resistance as the gas discharge tube igniting resistance of the first order and the current-limiting resistance of third level lightning protection.
Described video equipment is taked digitized overvoltage protection, so that the voltage protection level is less than 4V.
Described protective circuit is taked coaxial cable interface.
The beneficial effects of the utility model are to adopt three grades of lightning protections; utilize the low forward conduction voltage of diode to come the strangulation surge at output port; as the accurate protection of the third level; the middle full-bridge rectification that adopts adds transient voltage inhibition diode as second level lightning protection; to cooperate third level protective circuit; input port adopt gas discharge tube as first order lightning protection with the big electric current of releasing, the resistance between at different levels plays the effect of step voltage before current limliting and the lifting.
Description of drawings
Fig. 1 is typical video a/d chip ADV7181 electric pressure;
Fig. 2 is traditional video interface lightning protection circuit;
Fig. 3 is a video lightning protection circuit of the present utility model.
Embodiment
For technological means, creation characteristic that the utility model is realized, reach purpose and effect is easy to understand, below in conjunction with concrete diagram, further set forth the utility model.
As shown in Figure 3, the lightning protection circuit of video monitoring equipment, it adopts three grades of lightning protections, utilizes the low forward conduction voltage of diode to come the strangulation surge at output port, as the accurate protection of the third level; The middle full-bridge rectification that adopts adds transient voltage inhibition diode as second level lightning protection, to cooperate third level protective circuit; Input port adopt gas discharge tube as first order lightning protection with the big electric current of releasing.Resistance between at different levels plays the effect of current limliting and the preceding step voltage of lifting.
Circuit analysis such as Fig. 3 are example, when overvoltage produces, third level protection end by diode D5, D9, D10, D8 or D4, D9, D10, D7 with voltage limit below 4.3V.Resistance R 3 or R4 make TVS pipe and full-bridge rectification diode action with second level voltage lifting, flow through the electric current of the third level with restriction.TVS1 guarantees not produce high pressure between video signal cable (video) and the screen (shield), and TVS2 and TVS3 guarantee that video signal cable (video) and screen (shield) do not produce high pressure to lightning proof ground.Simultaneously, when current flowing resistance R1 or R2, will raise video signal cable (video) and screen (shield) voltage to earth, impel gas discharge tube G1 or G2 igniting conducting, thereby make main energy earial drainage from first order lightning protection of thunderbolt.
More than show and described basic principle of the present utility model and principal character and advantage of the present utility model.The technical staff of the industry should understand; the utility model is not restricted to the described embodiments; that describes in the foregoing description and the specification just illustrates principle of the present utility model; under the prerequisite that does not break away from the utility model spirit and scope; the utility model also has various changes and modifications, and these changes and improvements all fall in claimed the utility model scope.The claimed scope of the utility model is defined by appending claims and equivalent thereof.
Claims (4)
1. the lightning protection circuit of a video monitoring equipment; it is characterized in that: described protective circuit adopts three grades of compound lightning protections; input port adopts gas discharge tube as first order lightning protection; the middle full-bridge rectification that adopts adds transient voltage inhibition diode as second level lightning protection, and output port adopts the diode series connection as third level lightning protection.
2. according to the lightning protection circuit of the described video monitoring equipment of claim 1, it is characterized in that: seal in the wire-wound noninductive resistance between described three grades of lightning protection as the gas discharge tube igniting resistance of the first order and the current-limiting resistance of third level lightning protection.
3. according to the lightning protection circuit of the described video monitoring equipment of claim 1, it is characterized in that: described video equipment is taked digitized overvoltage protection, so that the voltage protection level is less than 4V.
4. according to the lightning protection circuit of the described video monitoring equipment of claim 1, it is characterized in that: described protective circuit is taked coaxial cable interface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202095477U CN201498984U (en) | 2009-09-11 | 2009-09-11 | Lightning protection circuit of video monitoring equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202095477U CN201498984U (en) | 2009-09-11 | 2009-09-11 | Lightning protection circuit of video monitoring equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201498984U true CN201498984U (en) | 2010-06-02 |
Family
ID=42442180
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009202095477U Expired - Fee Related CN201498984U (en) | 2009-09-11 | 2009-09-11 | Lightning protection circuit of video monitoring equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201498984U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110401181A (en) * | 2019-07-02 | 2019-11-01 | 浙江大华技术股份有限公司 | A kind of surging protection circuit |
| CN110401180A (en) * | 2019-07-02 | 2019-11-01 | 浙江大华技术股份有限公司 | A kind of surging protection circuit |
| WO2021000611A1 (en) * | 2019-07-02 | 2021-01-07 | Zhejiang Dahua Technology Co., Ltd. | Eletrical surge protection circuits |
-
2009
- 2009-09-11 CN CN2009202095477U patent/CN201498984U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110401181A (en) * | 2019-07-02 | 2019-11-01 | 浙江大华技术股份有限公司 | A kind of surging protection circuit |
| CN110401180A (en) * | 2019-07-02 | 2019-11-01 | 浙江大华技术股份有限公司 | A kind of surging protection circuit |
| WO2021000611A1 (en) * | 2019-07-02 | 2021-01-07 | Zhejiang Dahua Technology Co., Ltd. | Eletrical surge protection circuits |
| CN110401181B (en) * | 2019-07-02 | 2022-03-01 | 浙江大华技术股份有限公司 | Surge protection circuit |
| CN110401180B (en) * | 2019-07-02 | 2022-03-01 | 浙江大华技术股份有限公司 | Surge protection circuit |
| US11764569B2 (en) | 2019-07-02 | 2023-09-19 | Zhejiang Dahua Technology Co., Ltd. | Electrical surge protection circuits |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100602 Termination date: 20140911 |
|
| EXPY | Termination of patent right or utility model |