CN112803387A - Lightning protection circuit suitable for twisted pair communication and working method thereof - Google Patents
Lightning protection circuit suitable for twisted pair communication and working method thereof Download PDFInfo
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- CN112803387A CN112803387A CN202110287228.3A CN202110287228A CN112803387A CN 112803387 A CN112803387 A CN 112803387A CN 202110287228 A CN202110287228 A CN 202110287228A CN 112803387 A CN112803387 A CN 112803387A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
- H02H9/06—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage using spark-gap arresters
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Abstract
The invention provides a lightning protection circuit suitable for twisted pair communication and a working method thereof, wherein the lightning protection circuit comprises a direct current bias protection circuit, a first-stage lightning protection circuit, a second-stage lightning protection circuit and a third-stage lightning protection circuit which are connected to two signal wires of a twisted pair; the direct current bias protection circuit is used for providing bias voltage for the two signal lines, so that the idle signal state of the signal lines can be determined; the direct current bias protection circuit comprises a pull-up circuit and a pull-down circuit, and the first-stage lightning protection circuit consists of a first-stage ceramic discharge tube; the second-stage lightning protection circuit consists of two PPTC protection tubes and a TVS transient suppression diode; the third-stage lightning protection circuit is used for preventing secondary lightning, and consists of a rectifier bridge consisting of a quick rectifier tube, two piezoresistors and a GDT ceramic discharge tube. The lightning protection circuit of the invention provides a feasible and reliable lightning protection circuit design for twisted pair communication, so that the remote communication is safer through the twisted pair.
Description
Technical Field
The invention belongs to the technical field of communication, and particularly relates to a lightning protection circuit suitable for twisted pair communication and a working method thereof.
Background
Twisted pair is one of the most common transmission media in integrated wiring engineering, and has been fully utilized in long-distance communication due to its good suppression effect on signal interference. However, long-distance communication causes a problem that a signal line is struck by lightning, the instantaneous voltage can reach hundreds of millions of volts during the lightning strike, and a common chip cannot bear the high voltage, so that the front-stage circuit and the rear-stage circuit equipment can be damaged irreversibly, and a large amount of economic loss is caused.
Disclosure of Invention
The invention aims to provide a twisted pair lightning protection circuit suitable for long-distance and high-frequency communication and a working method thereof, so as to solve the problems of equipment damage and even fire caused by lightning stroke of a twisted pair in long-distance communication.
In order to achieve the above object, an embodiment of the present invention provides a lightning protection circuit suitable for twisted pair communication, which is characterized by including a dc bias protection circuit, a first stage lightning protection circuit, a second stage lightning protection circuit, and a third stage lightning protection circuit connected to two signal lines of a twisted pair;
the direct current bias protection circuit is used for providing bias voltage for the two signal lines, so that the idle signal state of the signal lines can be determined; the direct current bias protection circuit comprises a pull-up circuit and a pull-down circuit, wherein the pull-up circuit provides a pull-up signal for one signal line, the pull-down circuit provides a pull-down signal for the other signal line, the pull-up circuit comprises resistors R4 and R5 and a capacitor C2, and the capacitor C2 is connected with the resistors R4 and R5 and is grounded; the pull-up circuit is electrically connected with a voltage stabilizing diode and a PPTC thermal fuse, and the PPTC thermal fuse is electrically connected with a high-level bias power supply through a resistor R8; the pull-down circuit comprises resistors R1 and R2 and a capacitor C1; the capacitor C1 is connected with the resistors R1 and R2 and is grounded; the resistor R1 is connected with a ground signal; the two signal wires are directly connected in parallel with an adjustable matching resistor and are matched with the interruption resistor through an adjustable potentiometer;
the first-stage lightning protection circuit consists of a first-stage ceramic discharge tube;
the second-stage lightning protection circuit consists of two PPTC protection tubes which are respectively connected into two signal wires in series and 3 TVS transient suppression diodes; the TVS transient diode circuit provides clamping of common mode voltage for the two communication lines respectively and provides differential mode suppression between the two communication lines;
the third-level lightning protection circuit is used for preventing secondary lightning, and the third-level lightning protection circuit consists of a rectifier bridge consisting of a quick rectifier tube, two piezoresistors and a GDT ceramic discharge tube.
Furthermore, the resistance value of the adjustable matching resistor is 100-20.1K omega.
Furthermore, the voltage withstanding value of the voltage stabilizing diode is larger than the voltage value of the bias power supply.
Furthermore, the resistances of the resistors R1, R2, R4 and R5 are all 22K omega.
Further, the capacitance of the capacitors C1 and C2 is 104 F。
The embodiment of the invention also provides a working method of the lightning protection circuit suitable for twisted pair communication, which is characterized by comprising the following steps:
s1, the direct current bias protection circuit generates a pull-up signal and a pull-down signal, when lightning strike occurs, a voltage stabilizing diode and a capacitor in the pull-up signal generating circuit can provide buffering for a power module, and when short circuit occurs, the PPTC can rapidly cut off power supply;
s2, leading the current on the signal wire to the ground by the primary ceramic discharge tube of the primary lightning protection circuit, thereby greatly weakening the energy of lightning stroke and providing the first layer protection for the circuit;
s3, the TVS transient diode circuit in the second-stage lightning protection circuit provides clamping of common-mode voltage for the two communication lines respectively, and differential mode suppression is provided between the two signal lines; the instantaneous current of conduction can be very large, the voltage is clamped rapidly, meanwhile, the risk of short circuit is formed, once the short circuit occurs, the probability of fire is increased, and the PPTC heat protection tube can cut off a signal wire rapidly, so that the risk of fire is reduced;
s4, the third-stage lightning protection circuit is used for preventing secondary lightning, if lightning strikes occur again in the recovery process of the PPTC of the second-stage lightning protection circuit, the lightning strikes can be rectified quickly by the quick rectifying tube, the resistance value of the rear piezoresistor is reduced quickly, the ceramic tube is communicated with the ground, the lightning strikes are led into the ground, and the voltage of the signal line is reduced quickly.
The technical scheme of the invention has the following beneficial effects:
(1) aiming at the problems that the twisted pair has high communication frequency and two communication lines are wound, the following problems need to be considered when the lightning stroke problem is solved, the circuit design ensures the characteristic of high communication frequency of the twisted pair, and ensures normal communication and fire protection when the lightning stroke occurs; therefore, the lightning protection circuit design of the twisted pair is symmetrical as much as possible and has the characteristics of common mode and differential mode suppression.
(2) The lightning protection circuit suitable for twisted pair communication provides a feasible and reliable lightning protection circuit design for twisted pair communication, so that the remote communication is safer through the twisted pair. The risk of damage to the front-stage equipment circuit and the rear-stage equipment circuit is reduced, and economic loss is reduced.
(3) The invention is applicable to a plurality of conditions, fully retains the advantages of twisted pair communication, reduces the interference of communication on the basis, and increases the reliability of remote communication.
Drawings
Fig. 1 is a circuit diagram of a lightning protection circuit suitable for twisted pair communication according to the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
As shown in fig. 1, a lightning protection circuit suitable for twisted pair communication includes a dc bias protection circuit, a first stage lightning protection circuit, a second stage lightning protection circuit and a third stage lightning protection circuit connected to two signal lines of a twisted pair.
The direct current bias protection circuit is used for providing bias voltage for the two signal lines, so that the idle signal state of the signal lines can be determined; the direct current bias protection circuit comprises a pull-up circuit and a pull-down circuit, wherein the pull-up circuit provides a pull-up signal for one signal line, the pull-down circuit provides a pull-down signal for the other signal line, the pull-up circuit comprises resistors R4 and R5 and a capacitor C2, and the capacitor C2 is connected with the resistors R4 and R5 and is grounded; the pull-up circuit is electrically connected with a voltage stabilizing diode and a PPTC thermal fuse, and the PPTC thermal fuse is electrically connected with a high-level bias power supply through a resistor R8; the pull-down circuit comprises resistors R1 and R2 and a capacitor C1; the capacitor C1 is connected with the resistors R1 and R2 and is grounded; the resistor R1 is connected with a ground signal; the two signal wires are directly connected in parallel with an adjustable matching resistor and are matched with the interruption resistor through an adjustable potentiometer; preferably, said adjustment isThe resistance value of the matching resistor is 100-20.1K omega. Preferably, the voltage withstanding value of the zener diode is greater than the voltage value of the bias power supply. Preferably, the resistances of the resistors R1, R2, R4 and R5 are all 22K Ω. Preferably, the capacitance of the capacitors C1 and C2 is 104 F。
The first-stage lightning protection circuit consists of a first-stage ceramic discharge tube. Its advantage is quickly reducing surge voltage to zero. However, the method has the disadvantages that the response speed is slow, the general speed of the discharge tube is about 200ns, and the chip can be burnt out only by a few nanoseconds, so that the lightning protection by only the discharge tube is not enough.
The second-stage lightning protection circuit consists of two PPTC protection tubes which are respectively connected into two signal wires in series and 3 TVS transient suppression diodes; the TVS transient diode circuit provides clamping of common mode voltage for the two communication lines and differential mode rejection between the two communication lines, respectively. The TVS transient suppression diodes (D1, D2 and D3) are selected to be bidirectional transistors with slightly higher signal voltage peak values, and the rectifier bridge needs to select a fast rectifier with higher voltage withstanding value, such as BYV 26E.
The third-level lightning protection circuit is used for preventing secondary lightning, and the third-level lightning protection circuit consists of a rectifier bridge consisting of a quick rectifier tube, two piezoresistors and a GDT ceramic discharge tube.
An operating method of a lightning protection circuit suitable for twisted pair communication comprises the following processes:
s1, the direct current bias protection circuit generates a pull-up signal and a pull-down signal, when lightning strike occurs, a voltage stabilizing diode and a capacitor in the pull-up signal generating circuit can provide buffering for a power module, and when short circuit occurs, the PPTC can rapidly cut off power supply;
s2, leading the current on the signal wire to the ground by the primary ceramic discharge tube of the primary lightning protection circuit, thereby greatly weakening the energy of lightning stroke and providing the first layer protection for the circuit;
s3, the TVS transient diode circuit in the second-stage lightning protection circuit provides clamping of common-mode voltage for the two communication lines respectively, and differential mode suppression is provided between the two signal lines; the instantaneous current of conduction can be very large, the voltage is clamped rapidly, meanwhile, the risk of short circuit is formed, once the short circuit occurs, the probability of fire is increased, and the PPTC heat protection tube can cut off a signal wire rapidly, so that the risk of fire is reduced;
s4, the third-stage lightning protection circuit is used for preventing secondary lightning, if lightning strikes occur again in the recovery process of the PPTC of the second-stage lightning protection circuit, the lightning strikes can be rectified quickly by the quick rectifying tube, the resistance value of the rear piezoresistor is reduced quickly, the ceramic tube is communicated with the ground, the lightning strikes are led into the ground, and the voltage of the signal line is reduced quickly.
The lightning protection circuit can be used for 485/432 protocol communication between single chip microcomputer systems; lightning protection of the monitoring equipment circuit; lightning protection of video signal lines, etc.
When the lightning protection circuit is applied to serial port communication between single chip microcomputer systems, the obtained effect is best when the baud rate is 115200, and the packet loss rate of a data packet received by receiving equipment is not more than 1%. A baud rate of 224000 is supported at maximum.
In Multisim simulation software, 1000V high-frequency square waves are used for simulation tests, and the mean voltage of a signal line can be clamped to be about 20V. For a single pulse, it can be clamped to a lower potential, which is mainly related to the type selection of the TVS transient diode.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (6)
1. A lightning protection circuit suitable for twisted pair communication is characterized by comprising a direct current bias protection circuit, a first-stage lightning protection circuit, a second-stage lightning protection circuit and a third-stage lightning protection circuit, wherein the direct current bias protection circuit, the first-stage lightning protection circuit, the second-stage lightning protection circuit and the third-stage lightning protection circuit are connected to two signal wires of a twisted pair;
the direct current bias protection circuit is used for providing bias voltage for the two signal lines, so that the idle signal state of the signal lines can be determined; the direct current bias protection circuit comprises a pull-up circuit and a pull-down circuit, wherein the pull-up circuit provides a pull-up signal for one signal line, the pull-down circuit provides a pull-down signal for the other signal line, the pull-up circuit comprises resistors R4 and R5 and a capacitor C2, and the capacitor C2 is connected with the resistors R4 and R5 and is grounded; the pull-up circuit is electrically connected with a voltage stabilizing diode and a PPTC thermal fuse, and the PPTC thermal fuse is electrically connected with a high-level bias power supply through a resistor R8; the pull-down circuit comprises resistors R1 and R2 and a capacitor C1; the capacitor C1 is connected with the resistors R1 and R2 and is grounded; the resistor R1 is connected with a ground signal; the two signal wires are directly connected in parallel with an adjustable matching resistor and are matched with the interruption resistor through an adjustable potentiometer;
the first-stage lightning protection circuit consists of a first-stage ceramic discharge tube;
the second-stage lightning protection circuit consists of two PPTC protection tubes which are respectively connected into two signal wires in series and 3 TVS transient suppression diodes; the TVS transient diode circuit provides clamping of common mode voltage for the two communication lines respectively and provides differential mode suppression between the two communication lines;
the third-level lightning protection circuit is used for preventing secondary lightning, and the third-level lightning protection circuit consists of a rectifier bridge consisting of a quick rectifier tube, two piezoresistors and a GDT ceramic discharge tube.
2. The lightning protection circuit suitable for twisted pair communication according to claim 1, wherein the adjustable matching resistor has a resistance of 100 Ω -20.1K Ω.
3. The lightning protection circuit for twisted pair communication according to claim 1, wherein the voltage-withstanding value of the zener diode is greater than the voltage value of the bias power supply.
4. The lightning protection circuit for twisted pair communication according to claim 1, wherein the resistors R1, R2, R4 and R5 each have a resistance of 22K Ω.
5. The lightning protection circuit of claim 1, wherein the capacitors C1 and C2 have a capacitance of 104 F。
6. A method of operating a lightning protection circuit adapted for twisted pair communication according to claim 1, comprising the steps of:
s1, the direct current bias protection circuit generates a pull-up signal and a pull-down signal, when lightning strike occurs, a voltage stabilizing diode and a capacitor in the pull-up signal generating circuit can provide buffering for a power module, and when short circuit occurs, the PPTC can rapidly cut off power supply;
s2, leading the current on the signal wire to the ground by the primary ceramic discharge tube of the primary lightning protection circuit, thereby greatly weakening the energy of lightning stroke and providing the first layer protection for the circuit;
s3, the TVS transient diode circuit in the second-stage lightning protection circuit provides clamping of common-mode voltage for the two communication lines respectively, and differential mode suppression is provided between the two signal lines; the instantaneous current of conduction can be very large, the voltage is clamped rapidly, meanwhile, the risk of short circuit is formed, once the short circuit occurs, the probability of fire is increased, and the PPTC heat protection tube can cut off a signal wire rapidly, so that the risk of fire is reduced;
s4, the third-stage lightning protection circuit is used for preventing secondary lightning, if lightning strikes occur again in the recovery process of the PPTC of the second-stage lightning protection circuit, the lightning strikes can be rectified quickly by the quick rectifying tube, the resistance value of the rear piezoresistor is reduced quickly, the ceramic tube is communicated with the ground, the lightning strikes are led into the ground, and the voltage of the signal line is reduced quickly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110287228.3A CN112803387B (en) | 2021-03-17 | 2021-03-17 | Lightning protection circuit suitable for twisted pair communication and working method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110287228.3A CN112803387B (en) | 2021-03-17 | 2021-03-17 | Lightning protection circuit suitable for twisted pair communication and working method thereof |
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| CN112803387A true CN112803387A (en) | 2021-05-14 |
| CN112803387B CN112803387B (en) | 2022-07-22 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201417941Y (en) * | 2009-06-08 | 2010-03-03 | 杭州华三通信技术有限公司 | Interface protection circuit |
| CN203399102U (en) * | 2013-06-24 | 2014-01-15 | 天津市海天量子科技发展有限公司 | Transceiver circuit |
| CN206181051U (en) * | 2016-11-19 | 2017-05-17 | 杭州步聚信息科技有限公司 | RS485 communication circuit |
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2021
- 2021-03-17 CN CN202110287228.3A patent/CN112803387B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201417941Y (en) * | 2009-06-08 | 2010-03-03 | 杭州华三通信技术有限公司 | Interface protection circuit |
| CN203399102U (en) * | 2013-06-24 | 2014-01-15 | 天津市海天量子科技发展有限公司 | Transceiver circuit |
| CN206181051U (en) * | 2016-11-19 | 2017-05-17 | 杭州步聚信息科技有限公司 | RS485 communication circuit |
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| CN112803387B (en) | 2022-07-22 |
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