CN203399102U - Transceiver circuit - Google Patents
Transceiver circuit Download PDFInfo
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- CN203399102U CN203399102U CN201320364826.7U CN201320364826U CN203399102U CN 203399102 U CN203399102 U CN 203399102U CN 201320364826 U CN201320364826 U CN 201320364826U CN 203399102 U CN203399102 U CN 203399102U
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- transceiver circuit
- discharge tube
- resistor
- resistor network
- resistance
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Abstract
The utility model provides a transceiver circuit which is especially suitable for an outdoor industrial control instrument to use. The transceiver circuit comprises an RS-485 transceiver chip. A and B ends of the communication interface are connected with a voltage division shunt resistor network. The resistor network is composed of three resistors. Two resistors are respectively connected in series with A and B ends. One resistor is connected in parallel with A and B ends. The A end is connected with VCC through a pull-up resistor. The B end is grounded through a pull-down resistor. A and B ends are connected in parallel with a zener diode and a discharge tube. Insurances are between the zener diode and the discharge tube. The transceiver circuit provided by the utility model has the advantages that the voltage division shunt resistor network and the zener diode play the role of protection before the insurances fail to play the role of protection first; a path is provided for transient current; and through dual protection of the ceramic gas discharge tube and the insurances, a device can reliably run in a harsh transient high voltage impact environment.
Description
Technical field
The utility model belongs to field of power electronics, especially relates to a kind of transceiver circuit.
Background technology
According to the standard code of RS-485, the receiving sensitivity of receiver is ± 200mV, while this means the be more than or equal to+200mV of differential voltage when receiving terminal, receiver is output as high level, during be less than or equal to-200mV, be output as low level, between between ± 200mV time, receiver is output as nondeterministic statement.When bus free time and transmission line open circuit or short trouble, if do not take special measure, receiver may be exported high level or low level.Once the receiver of certain node produces low level, will make serial received device (UART) can not find start bit, thereby cause communication abnormality.
RS-485 interface chip damages being all likely subject to electrostatic impact in transit of use, welding or equipment.At transmission line, be set up in outdoor use occasion, interface chip and even whole system also likely suffer the high pressure that external interference (thunderbolt, surge, static) produces to damage RS-485 port, so RS-485 communication interface is also provided with external protective circuit.
Be generally at A and B end and access respectively two thermistors, thermistor generates heat the increase because of electric current, and the resistance of thermistor also will increase, thereby guarantees that chip input is not damaged by high pressure, the effective lightning protection effect of a discharge tube in parallel.Above-mentioned protective circuit in most of the cases makes RS-485 interface obtain better must protection, still often has the impaired situation of RS-485 interface to occur, can not make equipment can be in more harsh high voltage transient shock environment reliability service.
Summary of the invention
Problem to be solved in the utility model is to provide a kind of simple in structure, and cost is low, and transceiver circuit is especially applicable to outdoor Industry Control instrument and uses.
For solving the problems of the technologies described above; the utility model transceiver circuit comprises RS-485 transponder chip; the A of its communication interface, B end connects a dividing potential drop dividing current resistor network; described resistor network is comprised of three resistance; two resistance are serially connected in respectively A, B end; a resistance is in parallel with A, B end; A end accesses VCC by pull-up resistor; B end is by pull down resistor ground connection; A, B end parallel voltage-stabilizing diode and discharge tube; between voltage stabilizing didoe and discharge tube, respectively there is an insurance, adopt multi-stage protection measure.
Preferably, the VCC of RS-485 transponder chip end is also connected with a filter capacitor.
Preferably, described discharge tube is selected three utmost point chip ceramic gas discharge tubes.
Preferably, described voltage stabilizing didoe is P6KE6.5CA diode.
Preferably, the A of described RS-485 transponder chip, B end is by socket place in circuit
Advantage and the good effect that the utlity model has are: dividing potential drop dividing current resistor network and voltage stabilizing didoe first play the effect of protection when insurance does not also play a protective role, for transient current provides path, make telecommunication circuit can because of overvoltage, not puncture or exceed the quata electric current and overheated burning, the duplicate protection of ceramic gas discharge tube and insurance, make equipment can be in more harsh high voltage transient shock environment reliability service, prime is selected three utmost point chip ceramic gas discharge tubes, even under large surge voltage, RS-485 communication interface also has insurance that overload overcurrent protection is provided.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present utility model.
Embodiment
As shown in Figure 1, the utility model serial ports protective circuit comprises RS-485 transceiver U11, the enable pin DE of U11 and RE are by pull-up resistor R34 ground connection, its A, B holds respectively connect a current-limiting resistance R36 and R37, after current-limiting resistance R36, A end is by pull-up resistor R8 access VCC, current-limiting resistance R37B end is by pull down resistor R7 ground connection, parallel resistance R37 and voltage stabilizing didoe D1, described voltage stabilizing didoe D1 is P6KE6.5CA diode, A after voltage stabilizing didoe D1, B end respectively connects one from recovering insurance BX3 and BX4, rear and connect same discharge tube D26, its model is selected three utmost point chip ceramic gas discharge tube LT-B3D090L, rear A, B termination enters a socket, the UART mouth of its RO and DI termination single-chip microcomputer, its VCC termination power, is also connected with a filter capacitor C1.
RS-485 transponder chip is selected the MAX3483 chip of Maxim, operating voltage 3.3V, half-duplex, restriction conversion speed is to guarantee error-free data transmission, power down electric current 2Na, message transmission rate can reach 250kbps, and common-mode input voltage range is-7.0～+ 12V.
The course of work of this example: when circuit has instantaneous overvoltage to scurry into, dividing potential drop dividing current resistor network and voltage stabilizing didoe D1, P6KE6.5CA voltage stabilizing didoe D1 wherein, operation voltage is 6.5V, if input voltage is greater than 6.5V, in short circuit conducting state, when also not playing a protective role, insurance first plays the effect of protection, for transient current provides path, make telecommunication circuit can because of overvoltage, not puncture or exceed the quata electric current and overheated burning; From recovering insurance BX3 and BX4, in high-impedance state, make power circuit in off state, after overvoltage surge disappears, certainly recover insurance BX3 and BX4 and automatically return to low resistance state, circuit recovers normal operation; Three utmost point chip ceramic gas discharge tube D26 are breakdown, and impedance declines rapidly, is almost short-circuit condition, large electric current is released by line-to-ground or loop, also by limiting voltage at electronegative potential, thereby protected circuit and equipment; The high-voltage signal that such 485 mouthfuls of arrival ends apply just can not be added on 485 communication lines, thereby has protected RS485 communication port.The present embodiment improves Product Safety greatly, reliability, make equipment can be in more harsh high voltage transient shock environment reliability service.
Above an embodiment of the present utility model is had been described in detail, but described content is only preferred embodiment of the present utility model, can not be considered to for limiting practical range of the present utility model.All equalization variations of doing according to the utility model application range and improvement etc., within all should still belonging to patent covering scope of the present utility model.
Claims (5)
1. a transceiver circuit, comprise RS-485 transponder chip, it is characterized in that: the A of its communication interface, B end connects a dividing potential drop dividing current resistor network, described resistor network is comprised of three resistance, and two resistance are serially connected in respectively A, B end, and a resistance is in parallel with A, B end, A end accesses VCC by pull-up resistor, B end is by pull down resistor ground connection, and A, B end parallel voltage-stabilizing diode and discharge tube, respectively have an insurance between voltage stabilizing didoe and discharge tube.
2. transceiver circuit according to claim 1, is characterized in that: the VCC end of described RS-485 transponder chip is also connected with a filter capacitor.
3. transceiver circuit according to claim 1, is characterized in that: described discharge tube is selected three utmost point chip ceramic gas discharge tubes.
4. transceiver circuit according to claim 1, is characterized in that: described voltage stabilizing didoe is P6KE6.5CA diode
5. transceiver circuit according to claim 1, is characterized in that: the A of described RS-485 transponder chip, B end is by socket place in circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320364826.7U CN203399102U (en) | 2013-06-24 | 2013-06-24 | Transceiver circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320364826.7U CN203399102U (en) | 2013-06-24 | 2013-06-24 | Transceiver circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203399102U true CN203399102U (en) | 2014-01-15 |
Family
ID=49910598
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320364826.7U Expired - Lifetime CN203399102U (en) | 2013-06-24 | 2013-06-24 | Transceiver circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203399102U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106950890A (en) * | 2017-04-28 | 2017-07-14 | 南京搜新智能科技有限公司 | Intelligent switching circuit based on double 485 communications |
| CN107634510A (en) * | 2017-09-30 | 2018-01-26 | 深圳市艾特智能科技有限公司 | Chip interface circuit |
| US10901443B2 (en) | 2018-01-03 | 2021-01-26 | Synopsys, Inc. | Connection and disconnection differential surge limiter circuit for AC coupled transceiver |
| CN112803387A (en) * | 2021-03-17 | 2021-05-14 | 南通大学 | Lightning protection circuit suitable for twisted pair communication and working method thereof |
-
2013
- 2013-06-24 CN CN201320364826.7U patent/CN203399102U/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106950890A (en) * | 2017-04-28 | 2017-07-14 | 南京搜新智能科技有限公司 | Intelligent switching circuit based on double 485 communications |
| CN107634510A (en) * | 2017-09-30 | 2018-01-26 | 深圳市艾特智能科技有限公司 | Chip interface circuit |
| US10901443B2 (en) | 2018-01-03 | 2021-01-26 | Synopsys, Inc. | Connection and disconnection differential surge limiter circuit for AC coupled transceiver |
| CN112803387A (en) * | 2021-03-17 | 2021-05-14 | 南通大学 | Lightning protection circuit suitable for twisted pair communication and working method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20190829 Address after: Room 207, M1, Haitai Green Industry Base, No. 6 Haitai Development Road, Huayuan Industrial Zone, Tianjin Binhai New Area, 300384 Patentee after: Tianjin Anjie Wulian Science and Technology Co.,Ltd. Address before: 300384 Haitai Green Industrial Base M1, No. 6 Haitai Development Six Road, Huayuan Industrial Zone, Nankai District, Tianjin (Tianjin Haitian Quantum Technology Development Co., Ltd.) Patentee before: TIANJIN S.QUANTUM TECHNOLOGY DEVELOPMENT Co.,Ltd. |
|
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140115 |