CN107611951A - A kind of protection circuit of automobile bus communication line - Google Patents
A kind of protection circuit of automobile bus communication line Download PDFInfo
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- CN107611951A CN107611951A CN201711002146.XA CN201711002146A CN107611951A CN 107611951 A CN107611951 A CN 107611951A CN 201711002146 A CN201711002146 A CN 201711002146A CN 107611951 A CN107611951 A CN 107611951A
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- communication interface
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- protection circuit
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Abstract
The invention discloses a kind of protection circuit of automobile bus communication line; including communication interface circuit, interface protective circuit and protocol configuration matrix circuit; the signal output part of the communication interface circuit is connected with the input of the communication interface protection circuit, and the output end of the communication interface protection circuit is connected with the input of the protocol configuration matrix circuit.The present invention provides a kind of protection circuit of automobile bus communication line; for real-time overcurrent protection; it is slow to avoid PTC reaction speeds; protect incomplete, halfway problem; compared with all using PTC on every circuit; the cost of several triodes and resistance almost can be ignored, while the PCB space taken also has diminution；The present invention has the advantages of circuit structure is simple, and device occupies little space, protection completely real-time, and cost is low.
Description
Technical field
The present invention relates to protection circuit technical field, more particularly to a kind of protection circuit of automobile bus communication line.
Background technology
Enter ECU (the Electronic Control Unit) control periods from automobile the 1980s, it is big with the U.S. three
Motor corporation begins to monitor automotive control system with ECU for the automaker of representative.But the ECU and fault diagnosis of each manufacturer
Equipment is each developed by each automaker, diagnoses interface and communication mode is different, it is impossible to be general mutually.
Thus various comprehensive diagnos equipment are developed in market after automobile, and it passes through each communication to automobile OBD-16 diagnosis seats
Pin carries out agreement scanning, and analysis judges the protocol type of the electric-control system of automobile, and then realizes various automatically controlled to more car systems
The self-service diagnosis of system.But because each automobile vendor OBD-16 diagnoses seat to the second generation with car self-diagnosable system (OBD-II)
Difference during each self-defined use of the undefined pin of (On-Board Diagnostic II) standard criterion, causes comprehensive diagnos
When equipment connects diagnosis with automobile OBD-16 diagnosis seats, the circuit that various electrical characteristics differ greatly inevitably has mutually
Connection, causes diagnostic device and ECU electric-control systems telecommunication circuit to have the damage risk of overcurrent-overvoltage, this requires that comprehensive diagnos is set
It must have reliable protection circuit during standby access automobile OBD-16 diagnosis seats to ensure the safety of equipment and automobile ECU, especially
It is the safety of automobile ECU.
Comprehensive diagnos equipment in the market, which is substantially on communication line on every communication line, uses PTC
(resettable fuse) and TVS (Transient Voltage Suppressor Transient Suppression Diodes) protection circuit.Thus
Bring following shortcoming.
1st, because PTC is temperature sensor, its reaction time is slower, therefore its protective effect is incomplete.
2nd, all high using PTC costs on every communication line, it is big to take the area of circuit board, and one is formed to device miniaturization
Determine obstacle.
The content of the invention
The purpose of the present invention is that to solve the above problems and provides a kind of protection electricity of automobile bus communication line
Road.
The present invention is achieved through the following technical solutions above-mentioned purpose：
The present invention includes communication interface circuit, interface protective circuit and protocol configuration matrix circuit, the communication interface electricity
The signal output part on road is connected with the input of the communication interface protection circuit, the output end of the communication interface protection circuit
It is connected with the input of the protocol configuration matrix circuit.
Currently preferred, the communication interface circuit clamps down on triode group and second including first and clamps down on triode group,
Described first, which clamps down on triode group, includes the first triode, the first current limliting isolation resistance and the first sample resistance, and the described 1st
First current limliting isolation resistance described in the base series of pole pipe, colelctor electrode series connection the first sampling electricity of first triode
Resistance, described second, which clamps down on triode group, includes the second triode, the second current limliting isolation resistance and the second sample resistance, and described second
Second current limliting isolation resistance described in the base series of triode, colelctor electrode series connection the second sampling electricity of second triode
Resistance.
It is currently preferred, the protection circuit of described automobile bus communication line, it is characterised in that：The communication interface
The LOGIC- ends of circuit and OBD-16 diagnosis seat ECU terminate into be low-impedance load, believe on the left of first sample resistance
Number it is high level, FET cut-off, the communication interface circuit LOGIC- ends pass through first resistor device and access low level, circuit
Safety is normal；When the first sample resistance left-side signal is low level, the FET saturation conduction, then described first take
Sample resistance upstream super-high-current, when electric current comes 110~120mA, the pressure drop on first sample resistance is 0.3V, described
First triode saturation conduction, the right side of the first current limliting isolation resistance is clamped down on ends for high level, the FET,
The electric current of the communication interface circuit is restricted to zero, ensures the safety of circuit devcie.
It is currently preferred, the protection circuit of described automobile bus communication line, it is characterised in that：The communication interface
The DTS ends of circuit and OBD-16 diagnosis seat ECU terminate into be Vbat；When the second current limliting isolation resistance left-side signal is low
High level, circuit peace are accessed in level, the cut-off of VMOS FETs, the DTS ends of the communication interface circuit by second resistance device
It is complete normal；When the second current limliting isolation resistance left-side signal is high level, the VMOS FETs saturation conduction is then described
Second sample resistance upstream super-high-current, when electric current comes about 120mA, the pressure drop on first sample resistance is about
0.6V, the second triode saturation conduction, the right side of the second current limliting isolation resistance are clamped down on as low level, the VMOS
FET ends, and the electric current on the communication interface circuit is restricted to zero, ensures the safety of circuit devcie.
The beneficial effects of the present invention are：
The present invention provides a kind of protection circuit of automobile bus communication line, is real-time overcurrent protection, avoids PTC reactions
It is slow-footed, protect incomplete, halfway problem, compared with all using PTC on every circuit, several triodes and resistance
Cost almost can be ignored, while the PCB space taken also has diminution；The present invention is simple with circuit structure, and device accounts for
With space is small, protection completely real-time, the advantages of cost is low.
Brief description of the drawings
Fig. 1 is the circuit block diagram of the protection circuit of automobile bus communication line of the present invention；
Fig. 2 is the circuit diagram of communication interface circuit of the present invention.
Embodiment
The invention will be further described below in conjunction with the accompanying drawings：
As shown in Figure 1：The present invention includes communication interface circuit, interface protective circuit, protocol configuration matrix circuit, and communication connects
The signal output part of mouth circuit and the signal input part of interface protective circuit are connected, and output end and the agreement of interface protective circuit are matched somebody with somebody
Put the signal input part connection of matrix circuit.
As shown in Fig. 2 the communication interface circuit clamps down on triode group and second including first clamps down on triode group, it is described
First, which clamps down on triode group, includes the first triode Q17, the first sample resistance R132 and the first current limliting isolation resistance R143, and first
Triode Q17 the first sample resistance of base series R132, the first triode Q17 colelctor electrode the first current limliting isolation resistance of series connection
R143, second, which clamps down on triode group, includes the second triode Q14, the second sample resistance R133 and the second current limliting isolation resistance
R138, the second triode Q14 the second sample resistance of base series R133, the second triode Q14 limit of colelctor electrode series connection second
Flow isolation resistance R138, the LOGIC- ends of communication interface circuit and OBD-16 diagnosis seat ECU terminate into be low-impedance load, when
First current limliting isolation resistance R143 left-side signals are high level, and FET U16 cut-offs, communication interface circuit LOGIC- ends pass through
First resistor device R144 accesses low level, and circuit safety is normal；When the first current limliting isolation resistance R143 left-side signals are low level,
FET U16 saturation conductions, then the first sample resistance R132 upstream super-high-current, when electric current comes 110~120mA,
Pressure drop on one sample resistance R132 is 0.3V, the first triode Q17 saturation conductions, the first current limliting isolation resistance R143 right side
Clamped down on and be restricted to zero for high level, FET U16 cut-offs, the electric current of communication interface circuit, ensure the peace of circuit devcie
Entirely, the DTS ends of communication interface circuit and OBD-16 diagnosis seat ECU terminate into be Vbat；When the second current limliting isolation resistance
R138 left-side signals are low level, and VMOS FETs U15 cut-offs, the DTS ends of the communication interface circuit pass through second resistance
Device R137 accesses high level, and circuit safety is normal；When the second current limliting isolation resistance R138 left-side signals are high level, VMOS fields are imitated
Should pipe U15 saturation conductions, then the second sample resistance R133 upstream super-high-current, when electric current comes about 120mA, the second sampling electricity
The pressure drop hindered on R133 is about 0.6V, and the second triode Q14 saturation conductions, the second current limliting isolation resistance R138 right side is clamped down on
For low level, VMOS FETs U15 ends, and the electric current on communication interface circuit is restricted to zero, ensures the peace of circuit devcie
Entirely.
In summary, the present invention provides a kind of protection circuit of automobile bus communication line, is real-time overcurrent protection, avoids
PTC reaction speeds are slow, protect incomplete, halfway problem, compared with all using PTC on every circuit, several three poles
The cost of pipe and resistance almost can be ignored, while the PCB space taken also has diminution；The present invention has circuit structure letter
The advantages of list, device occupies little space, protection completely real-time, and cost is low.
Those skilled in the art do not depart from the essence and spirit of the present invention, can have various deformation scheme to realize the present invention,
Preferably feasible embodiment of the invention is the foregoing is only, not thereby limits to the interest field of the present invention, it is all with this
The equivalent structure change that description of the invention and accompanying drawing content are made, is both contained within the interest field of the present invention.
Claims (4)
1. a kind of protection circuit of automobile bus communication line, it is characterised in that including communication interface circuit, interface protective circuit
With protocol configuration matrix circuit, the signal output part of the communication interface circuit and the input of the communication interface protection circuit
Connection, the output end of the communication interface protection circuit are connected with the input of the protocol configuration matrix circuit.
2. the protection circuit of automobile bus communication line according to claim 1, it is characterised in that：The communication interface electricity
Road clamps down on triode group and second including first and clamps down on triode group, described first clamp down on triode group include the first triode,
First current limliting isolation resistance and the first sample resistance, the first current limliting isolation resistance described in the base series of first triode,
Colelctor electrode series connection first sample resistance of first triode, described second, which clamps down on triode group, includes the two or three pole
Pipe, the second current limliting isolation resistance and the second sample resistance, the second current limliting isolation electricity described in the base series of second triode
Resistance, colelctor electrode series connection second sample resistance of second triode.
3. the protection circuit of automobile bus communication line according to claim 2, it is characterised in that：The communication interface electricity
The LOGIC- ends on road and OBD-16 diagnosis seat ECU terminate into be low-impedance load, when the first sample resistance left-side signal
For high level, FET cut-off, low level, circuit peace are accessed in the communication interface circuit LOGIC- ends by first resistor device
It is complete normal；When the first sample resistance left-side signal is low level, the FET saturation conduction, then first sampling
Resistance upstream super-high-current, when electric current comes 110~120mA, the pressure drop on first sample resistance is 0.3V, described
One triode saturation conduction, the right side of the first current limliting isolation resistance are clamped down on as high level, the FET cut-off, institute
The electric current for stating communication interface circuit is restricted to zero, ensures the safety of circuit devcie.
4. the protection circuit of automobile bus communication line according to claim 2, it is characterised in that：The communication interface electricity
The DTS ends on road and OBD-16 diagnosis seat ECU terminate into be Vbat；When the second current limliting isolation resistance left-side signal is low electricity
Flat, high level, circuit safety are accessed in VMOS FETs cut-off, the DTS ends of the communication interface circuit by second resistance device
Normally；When the second current limliting isolation resistance left-side signal is high level, the VMOS FETs saturation conduction, then described
Two sample resistance upstream super-high-currents, when electric current comes about 120mA, the pressure drop on first sample resistance is about 0.6V,
The second triode saturation conduction, the right side of the second current limliting isolation resistance are clamped down on as low level, the VMOS fields effect
Should pipe cut-off, the electric current on the communication interface circuit is restricted to zero, ensures the safety of circuit devcie.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711002146.XA CN107611951B (en) | 2017-10-24 | 2017-10-24 | Protection circuit of automobile bus communication line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711002146.XA CN107611951B (en) | 2017-10-24 | 2017-10-24 | Protection circuit of automobile bus communication line |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107611951A true CN107611951A (en) | 2018-01-19 |
| CN107611951B CN107611951B (en) | 2020-04-07 |
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ID=61079780
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711002146.XA Active CN107611951B (en) | 2017-10-24 | 2017-10-24 | Protection circuit of automobile bus communication line |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201315646Y (en) * | 2008-12-23 | 2009-09-23 | 深圳创维－Rgb电子有限公司 | Digital audio interface circuit for TV |
| DE102014107748A1 (en) * | 2013-06-03 | 2014-12-04 | Infineon Technologies Ag | Switch-off protection for bus line drivers |
| CN104660247A (en) * | 2015-03-10 | 2015-05-27 | 北京大恒图像视觉有限公司 | Two-way interface circuit |
| CN204720953U (en) * | 2015-06-18 | 2015-10-21 | 深圳市高科润电子有限公司 | Electric vehicle controller hardware current foldback circuit |
| CN105516076A (en) * | 2015-09-23 | 2016-04-20 | 广汽吉奥汽车有限公司 | Unified multi-protocol conversion device |
| CN205186049U (en) * | 2015-08-06 | 2016-04-27 | 四川九洲电器集团有限责任公司 | OBD automobile -mounted terminal |
| CN207339254U (en) * | 2017-10-24 | 2018-05-08 | 深圳市博诺技术有限公司 | A kind of protection circuit of automobile bus communication line |
-
2017
- 2017-10-24 CN CN201711002146.XA patent/CN107611951B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201315646Y (en) * | 2008-12-23 | 2009-09-23 | 深圳创维－Rgb电子有限公司 | Digital audio interface circuit for TV |
| DE102014107748A1 (en) * | 2013-06-03 | 2014-12-04 | Infineon Technologies Ag | Switch-off protection for bus line drivers |
| CN104660247A (en) * | 2015-03-10 | 2015-05-27 | 北京大恒图像视觉有限公司 | Two-way interface circuit |
| CN204720953U (en) * | 2015-06-18 | 2015-10-21 | 深圳市高科润电子有限公司 | Electric vehicle controller hardware current foldback circuit |
| CN205186049U (en) * | 2015-08-06 | 2016-04-27 | 四川九洲电器集团有限责任公司 | OBD automobile -mounted terminal |
| CN105516076A (en) * | 2015-09-23 | 2016-04-20 | 广汽吉奥汽车有限公司 | Unified multi-protocol conversion device |
| CN207339254U (en) * | 2017-10-24 | 2018-05-08 | 深圳市博诺技术有限公司 | A kind of protection circuit of automobile bus communication line |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107611951B (en) | 2020-04-07 |
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