CN102681960A - Serial communication port circuit and computer - Google Patents
Serial communication port circuit and computer Download PDFInfo
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- CN102681960A CN102681960A CN2011100558461A CN201110055846A CN102681960A CN 102681960 A CN102681960 A CN 102681960A CN 2011100558461 A CN2011100558461 A CN 2011100558461A CN 201110055846 A CN201110055846 A CN 201110055846A CN 102681960 A CN102681960 A CN 102681960A
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- tvs pipe
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- isolator
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Abstract
The invention is applicable to the field of computer port circuits and provides a serial communication port circuit and a computer. The serial communication port circuit comprises a serial communication port, four protection circuits and an energy release circuit, and each protection circuit comprises a clamping unit, a limiting unit and a filtering unit. According to the invention, when high-voltage lighting interference and static high voltage interference influences the serial communication port, the clamping unit performs clamping on high voltage, and the energy release circuit releases residual voltage, thereby realizing the effects of static prevention and lighting prevention; simultaneously, as a high-voltage capacitor has a high voltage isolation effect, the serial communication ports meets the requirements on insulation resistance and dielectric strength; and as the resistance value is very large and does not influence the requirements of the product on the insulation resistance and the dielectric strength, charges accumulated on the ground due to isolation can be released by virtue of an access of the resistance when the port is interfered by virtue of lighting and static signals.
Description
Technical field
The invention belongs to the computer port circuit field, relate in particular to a kind of COM circuit and computing machine.
Background technology
Be that motherboard circuit perhaps insulate greatly with casing ground on electric functionally floatingly, suspend with respect to the earth.Floating ground equipment is meant that reference ground does not have the equipment that directly links to each other with the earth.More and more to the product of industries such as electric power, subway design in recent years, these industries need satisfy the requirement of insulation resistance, dielectric strength, design so all need adopt floatingly.
In floating ground design proposal; Electromagnetic compatibility (EMC) is anti-interference to be a unmanageable relatively technical matters; Because ground connection is the key point of protection COM (COM), and EMC protection device can't directly connect casing ground, the very first time with the energy the earth of releasing.Especially the interference of static and thunderbolt can have a strong impact on the transmission of COM port signal, even destroys the function of COM port.So in electric power and subway industry, need on floating ground design basis, design lightning protection, the electrostatic prevention scheme of COM port, reach the purpose of protection COM port.
As shown in Figure 1, existing C OM port electrostatic prevention, lightning protection scheme are to adopt every signal wire through TVS pipe ground connection, thereby reach the effect of lightning protection, electrostatic prevention.Above-mentioned prior art has adopted non-high pressure resistant device directly to connect casing ground on signal protection; Though reach the effect of electrostatic prevention, lightning protection immunity to interference; But ignored the requirement of insulation resistance, dielectric voltage withstand and dielectric strength in the industry, promptly can't realize the floating ground requirement of equipment.
Summary of the invention
The purpose of the embodiment of the invention is to provide a kind of COM circuit, is intended to solve existing COM and has the problem that can't satisfy the requirement of insulation resistance and dielectric strength when satisfying electrostatic prevention, lightning protection immunity to interference.
The embodiment of the invention is to realize like this; A kind of COM circuit; Said COM circuit comprises a serial communication port, four tunnel holding circuits and an energy release circuit; The ground wire terminal of said COM connects isolator; The reception data terminal of said COM, send data terminal, terminal is sent in request and the data carrier detection terminal connects four tunnel holding circuits respectively, said each road holding circuit includes clamp units, current limliting unit and filter unit, said COM, clamp units, current limliting unit link to each other with filter unit successively; Said clamp units and filter unit connect isolator; The public connecting end of said current limliting unit and filter unit connects isolator through energy release circuit, the rs 232 serial interface signal end on another termination mainboard of said filter unit, said high-voltage capacitance through parallel connection isolator and the resistance shell ground of meeting sb. at the airport.
The purpose of the embodiment of the invention is to provide a kind of computing machine, and said computing machine comprises above-mentioned COM circuit.
In embodiments of the present invention, when high voltage thunderbolt interference and electrostatic high-pressure interference entering COM, clamp units can be carried out clamp to high pressure; Energy release circuit discharges residual voltage, plays the effect of electrostatic prevention, lightning protection, simultaneously; High-voltage capacitance plays the effect that high pressure is isolated; Make COM satisfy the requirement of insulation resistance and dielectric strength, resistance is very big, does not influence insulation resistance, the dielectric strength requirement of product; After serial ports received thunderbolt and electrostatic signal interference, the electric charge of going up accumulation isolator can discharge electric charge through this path of resistance.
Description of drawings
Fig. 1 is the structural drawing of existing COM circuit;
Fig. 2 is the schematic block circuit diagram of the COM circuit that provides of the embodiment of the invention;
Fig. 3 is the exemplary circuit figure of the COM circuit that provides of the embodiment of the invention.
Embodiment
In order to make the object of the invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
Fig. 2 shows the schematic block circuit diagram of the COM circuit that the embodiment of the invention provides.
The COM circuit comprises a serial communication port one 00, four tunnel holding circuits and an energy release circuit 200; The ground wire terminal SG of COM 100 connects isolator; The reception data terminal RXD of COM 100, send data terminal TXD, terminal RTS is sent in request and data carrier detection terminal DTR connects four tunnel holding circuits respectively; Each road holding circuit includes clamp units 300, current limliting unit 400 and filter unit 500; COM 100, clamp units 300, current limliting unit 400 and filter unit 500 link to each other successively, and clamp units 300 connects isolator with filter unit 500, and the public connecting end of current limliting unit 400 and filter unit 500 connects isolator through energy release circuit 200; Rs 232 serial interface signal end on another termination mainboard of filter unit 500; Specifically comprise receive data terminal RXD1, send data terminal TXD1, request sends terminal RTS1 and data carrier detection terminal DTR1, high-voltage capacitance C1 through parallel connection and the resistance R 1 shell ground of meeting sb. at the airport isolator, high-voltage capacitance C1 adopts withstand voltage electric capacity greater than AC500V; The resistance of resistance R 1 is that power is more than 0.5W more than the 20M Ω.Circuit also comprises fixed screw holes MH34, the fixed screw holes MH34 shell ground of meeting sb. at the airport.
Fig. 3 shows the exemplary circuit structure of the COM circuit that the embodiment of the invention provides.
As one embodiment of the invention; With first via holding circuit is that example describes; Clamp units 300 comprises a two-way TVS pipe D1; The reception data terminal RXD of the first terminated serial PORT COM 100 of two-way TVS pipe D1 and the public connecting end of current limliting unit 400, second termination of two-way TVS pipe D1 isolator.
As one embodiment of the invention, current limliting unit 400 adopts resettable fuse F1, first end of the two-way TVS pipe of first termination of resettable fuse F1 D1.
As one embodiment of the invention, filter unit 500 comprises a capacitor C 2, second end of the first termination resettable fuse F1 of capacitor C 2, and second termination of capacitor C 2 is isolator.
Other three tunnel holding circuits connect respectively COM 1 00 send data terminal TXD, terminal RTS and data carrier detection terminal DTR are sent in request, its structure is the same with the structure of above-mentioned holding circuit, repeats no more here.
As one embodiment of the invention, energy release circuit 200 adopts TVS pipe combinational circuit U1, and first end of TVS pipe combinational circuit U1 connects second end of the resettable fuse in four tunnel holding circuits respectively, and second termination of TVS pipe combinational circuit U1 isolator.TVS pipe combinational circuit U1 comprises TVS pipe D2, TVS pipe D3, TVS pipe D4, TVS pipe D5 and TVS pipe D6; The anode of TVS pipe D2, TVS pipe D3, TVS pipe D4 and TVS pipe D5 connects second end of the resettable fuse F1 in four tunnel holding circuits respectively; The negative electrode of four TVS pipes connects the negative electrode of TVS pipe D6 simultaneously, and the anode of TVS pipe D6 connects isolator.
The embodiment of the invention also provides a kind of computing machine, and computing machine comprises above-mentioned COM circuit.
Principle of work is:
1, disturb when getting into COM 100 when high voltage thunderbolt, at first two-way TVS pipe carries out clamp to high pressure, and voltage is stabilized in the maximum clamping voltage of two-way TVS pipe, and (the maximum clamping voltage of the two-way TVS pipe of selecting in the present embodiment is 16.7V; In different circuits,, then need select different TVS pipes if the ceiling voltage of claimed serial port chip is different; The maximum clamping voltage of different TV S pipe is also different), two-way TVS pipe is when moment punctures, and the signal wire electric current also can increase; Make resettable fuse generate heat; Resistance moment increase, with the circuit instantaneous trip, the circuit of protection back is without prejudice.After electric current diminishes and disappears, resettable fuse conducting operate as normal.Part voltage is residual, and U1 discharges through the TVS of back pipe combinational circuit.
2, when electrostatic high-pressure disturbs entering COM 100; Two-way TVS pipe receives the high pressure clamp; And the characteristics of electrostatic interference be the time short, voltage is high, energy is little, this moment, the electric current of signal wire can not raise, not action of resettable fuse; The TVS pipe combinational circuit U1 of back discharges the residual voltage of static, reaches the purpose to COM 100 electrostatic protections thereby COM 100 is carried out second class protection.In addition, the components and parts in the circuit also can transform the electrostatic energy of a part.
Be connected to casing ground through withstand voltage capacitor C 1 greater than AC500V with resistance R 1 (more than the 20M Ω, power is more than 0.5W) isolator, its effect has 3 points:
I, this electric capacity are the high frequency path of releasing, and when high frequency interference appears in the COM circuit, can get into the earth through the electric capacity passage.
II, high-voltage capacitance C1 play the effect that high pressure is isolated, and satisfy the requirement of product insulation resistance, dielectric strength.For example, can reach among the GB-T 14598.300-2008 " microcomputer protection equipment for transformer general technical specifications " the insulation resistance of product and the requirement of dielectric strength.
III, resistance R 1 resistance are very big, do not influence insulation resistance, the dielectric strength requirement of product.After serial ports received thunderbolt and electrostatic signal interference, the electric charge of going up accumulation isolator can discharge electric charge through resistance R 1 this path.
In embodiments of the present invention, when high voltage thunderbolt interference and electrostatic high-pressure interference entering COM, clamp units can be carried out clamp to high pressure; Energy release circuit discharges residual voltage, plays the effect of electrostatic prevention, lightning protection, simultaneously; High-voltage capacitance plays the effect that high pressure is isolated; Make COM satisfy the requirement of insulation resistance and dielectric strength, resistance is very big, does not influence insulation resistance, the dielectric strength requirement of product; After serial ports received thunderbolt and electrostatic signal interference, the electric charge of going up accumulation isolator can discharge electric charge through this path of resistance.The above is merely preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of within spirit of the present invention and principle, being done, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.
Claims (8)
1. COM circuit; It is characterized in that; Said COM circuit comprises a serial communication port, four tunnel holding circuits and an energy release circuit; The ground wire terminal of said COM connects isolator; The reception data terminal of said COM, send data terminal, terminal is sent in request and the data carrier detection terminal connects four tunnel holding circuits respectively, said each road holding circuit includes clamp units, current limliting unit and filter unit, said COM, clamp units, current limliting unit link to each other with filter unit successively; Said clamp units and filter unit connect isolator; The public connecting end of said current limliting unit and filter unit connects isolator through energy release circuit, the rs 232 serial interface signal end on another termination mainboard of said filter unit, said high-voltage capacitance through parallel connection isolator and the resistance shell ground of meeting sb. at the airport.
2. COM circuit as claimed in claim 1; It is characterized in that; Said clamp units comprises a two-way TVS pipe, the said COM of first termination of said two-way TVS pipe and the public connecting end of current limliting unit, and second termination of said two-way TVS pipe is isolator.
3. COM circuit as claimed in claim 2 is characterized in that, said current limliting unit adopts resettable fuse, first end of the two-way TVS pipe of first termination of said resettable fuse.
4. COM circuit as claimed in claim 3 is characterized in that said filter unit comprises an electric capacity, second end of the first termination resettable fuse of said electric capacity, and second termination of said electric capacity is isolator.
5. COM circuit as claimed in claim 4; It is characterized in that; Said energy release circuit adopts TVS pipe combinational circuit; First end of said TVS pipe combinational circuit connects second end of the resettable fuse in four tunnel holding circuits respectively, and second termination of said TVS pipe combinational circuit isolator.
6. COM circuit as claimed in claim 5; It is characterized in that; Said TVS pipe combinational circuit comprises TVS pipe D2, TVS pipe D3, TVS pipe D4, TVS pipe D5 and TVS pipe D6; The anode of said TVS pipe D2, TVS pipe D3, TVS pipe D4 and TVS pipe D5 connects second end of the resettable fuse in four tunnel holding circuits respectively, and the negative electrode of said TVS pipe D2, TVS pipe D3, TVS pipe D4, TVS pipe D5 connects the negative electrode of TVS pipe D6 simultaneously, and the anode of said TVS pipe D6 connects isolator.
7. COM circuit as claimed in claim 1 is characterized in that, said high-voltage capacitance adopts withstand voltage electric capacity greater than AC500V, and the resistance of said resistance is that power is more than 0.5W more than the 20M Ω.
8. a computing machine is characterized in that, said computing machine comprises each described COM circuit like claim 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100558461A CN102681960A (en) | 2011-03-09 | 2011-03-09 | Serial communication port circuit and computer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011100558461A CN102681960A (en) | 2011-03-09 | 2011-03-09 | Serial communication port circuit and computer |
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| CN102681960A true CN102681960A (en) | 2012-09-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011100558461A Pending CN102681960A (en) | 2011-03-09 | 2011-03-09 | Serial communication port circuit and computer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105790856A (en) * | 2014-12-25 | 2016-07-20 | 研祥智能科技股份有限公司 | EMC protection system for automatic train control system host |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100239119B1 (en) * | 1996-11-29 | 2000-01-15 | 구자홍 | The communication of monitor and pc |
| CN1359182A (en) * | 2001-12-31 | 2002-07-17 | 深圳安圣电气有限公司 | Signal lightning protector |
| CN1790303A (en) * | 2004-12-17 | 2006-06-21 | 鸿富锦精密工业（深圳）有限公司 | Signal conversion circuit |
| CN101162847A (en) * | 2006-10-10 | 2008-04-16 | 伍占禧 | Automatic equalization charging equipment charged by series storage battery |
| CN201207707Y (en) * | 2008-05-15 | 2009-03-11 | 青岛海信移动通信技术股份有限公司 | Mobile terminal having touch screen |
| CN101488666A (en) * | 2008-01-18 | 2009-07-22 | 研祥智能科技股份有限公司 | Network port lightning preventing circuit and RJ45 interface apparatus thereof |
| CN101626586A (en) * | 2008-07-08 | 2010-01-13 | 深圳富泰宏精密工业有限公司 | System and method for preventing over-current damage in mobile phone tests |
| CN201466706U (en) * | 2009-06-09 | 2010-05-12 | 上海臻和防雷电气技术有限责任公司 | Anti-lightning protection circuit of RS485 serial communication interface |
-
2011
- 2011-03-09 CN CN2011100558461A patent/CN102681960A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100239119B1 (en) * | 1996-11-29 | 2000-01-15 | 구자홍 | The communication of monitor and pc |
| CN1359182A (en) * | 2001-12-31 | 2002-07-17 | 深圳安圣电气有限公司 | Signal lightning protector |
| CN1790303A (en) * | 2004-12-17 | 2006-06-21 | 鸿富锦精密工业（深圳）有限公司 | Signal conversion circuit |
| CN101162847A (en) * | 2006-10-10 | 2008-04-16 | 伍占禧 | Automatic equalization charging equipment charged by series storage battery |
| CN101488666A (en) * | 2008-01-18 | 2009-07-22 | 研祥智能科技股份有限公司 | Network port lightning preventing circuit and RJ45 interface apparatus thereof |
| CN201207707Y (en) * | 2008-05-15 | 2009-03-11 | 青岛海信移动通信技术股份有限公司 | Mobile terminal having touch screen |
| CN101626586A (en) * | 2008-07-08 | 2010-01-13 | 深圳富泰宏精密工业有限公司 | System and method for preventing over-current damage in mobile phone tests |
| CN201466706U (en) * | 2009-06-09 | 2010-05-12 | 上海臻和防雷电气技术有限责任公司 | Anti-lightning protection circuit of RS485 serial communication interface |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105790856A (en) * | 2014-12-25 | 2016-07-20 | 研祥智能科技股份有限公司 | EMC protection system for automatic train control system host |
| CN105790856B (en) * | 2014-12-25 | 2020-04-24 | 研祥智能科技股份有限公司 | EMC protection system of automatic train control system host |
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Application publication date: 20120919 |