And electronic system is used in these numerous cars between, the car uses controller local area network interface of subsidiary channels in the human body through which vital energy (because CAN Bus) uses crewel to string together framework of the Chinese hackberrya that receive develop, can string together receive or receive aleatoric node unit, make wiring is reached not only those who safeguard is complex degree reduce considerably, can reduce wire and wiring cost along with all the others, because this is become,transmit interface with the system for the car of first selection.

 

 

The crewel differential that place of CAN Bus transmission interface uses (Two Wire Differential) transmits a technology, because break line or ground connection breakdown,be like line of mark of some differential question and cannot transmit question mark, still can change transmit mode for single-track question mark, accordingly but greatly communication of the system inside bring down car communicates undesirable machine to lead, promoted automobile body functional stability not only, the join means of its differential double skeining thread also is had fight in all modular electromagnetism disturbs ability. In addition CAN Bus is the framework with much lead plane condition conveys receive dispatch order, every lead plane all can give out communication actively to point to specific node, what because this can keep online,condition of the largest space handles vast data bulk is deferent receive, abounded automobile body function not only, if have trouble of node of either lead plane when also insusceptible, can escort the Emperor truly sail the person’s drive a vehicle experiences, reduce the risk that breakdown maintains.

 

The transmission speed of CAN Bus can have different choice, apply top demand to 1Mbps at present, and its transmit a distance farthermost can amount to 1000M, because this can satisfy application to differ within the car,subsystem transmits speed and the requirement of transmission distance to differring, developing the cost when level consequently, car weight is measured, below a lot of consideration on norms character, CAN Bus interface all can satisfy above requirement, as a result shows level to about the car of 70% already all used CAN Bus yesterday to transmit an interface to use for its.

 

And regard the car that contacts often with human body as the environment, electrostatic discharge incident (ESD) , electric overload incident (EOS) , and electric sex is fast instantaneous incident (EFT) often can appear in car moving process, this to travel medium car is a potential menace, and CAN sends and receive Lv of the unified exam when chip is being designed a few fight faze electrostaticly, but level far the requirement that level of short of system tests, reason becomes very important to the protective design of CAN communication interface.

 

Main component is the standard that at present car electron involves EMC to check 2 kinds:

 

1: In the light of the conduction of power source power supply instantaneous checks

2: The electrostatic, surge that is aimed at communication interface checks

 

The instantaneous incident that checks a bag to contain Pulse 1(a) to because power source cuts off generation,emulate inductance sex load in the light of power source, pulse 2(a) imitate bundle the inductance sex load of the line because electric current dash forward the instantaneous that breaks generation, the instantaneous that because locomotive power source moves to arise except place,air-blower of Pulse 2(b) imitate or rain brush motor, pulse 3(a)(b) is the instantaneous wave that imitate generates because of switch process, pulse 5 batteries drops report cast laden instantaneous wave.

 

What the article basically introduces is the test of electrostatic, surge of CAN interface.

 

Electrostatic test standard has the ISO10605 standard that the IEC61000-4-2 that place of international Electrotechnical Committee makes and international Organization for Standardization establish commonly, this both test model is same, specific the capacitance value that is in-house generator is different, and the test requirement that the product set car class to need to satisfy ISO10605 air 25KV.

 

 

If plan institute is shown, listed the energy signal that level tests individually in 2 standards, the 15KV test that the ability of 25KV electrostatic discharge that so car product tests provides than IEC is a lot of stricter.

 

Send and receive to protect CAN implement do not suffer above the influence of the voltage of abominable transient state such as mentioned ISO10605 ESD, diode of a TVS can be placed on CANH of bus line circuitry and CANL. This TVS diode regards a clamp down on as circuit, bring the high-energy pulse that any occurrence to ground connection, make its are far from send and receive implement. When choosing a diode, a bit want to notice, want to ask according to the design, make the rating of diode reachs predicting energy order and degree.

 

 

The two-way 24V that SMC24 of thunder the fourth of the twelve Earthly Branches encloses for SOT23 protects component.

 

The product of small electric capacity can satisfy CAN signal to speed is as high as the speed of 2Mbit/s and won’t lose a bag;

 

Low clamp when voltage also ensures transient state surge happens, back end chip bears lesser surge pressure;

 

ESD defends grade can amount to IEC61000-4-2 to contact discharge and 30kV of air space discharge, and EFT defends grade can amount to IEC61000-4-4 4kV, pass test and verify of reliability of AECQ101 car compasses, assure to operate temperature from microtherm – 55 degrees of C are supreme lukewarm 125 degrees of C, in order to ensure the high low temperature of the Yan Ke inside bodywork handles environmental application.

 

Of ESD parts of an apparatus decorate a proposal

 

A) stands by equipment input end or connector as far as possible.

B) is the smallest change equipment and suffer the method length between protective route.

C) retains collateral signal way in lowermost limit.

D) Avoid to run the conductor that gets protection and the conductor parallel connection that did not get protection.

E) is the smallest change all printed circuit board (PCB) electric return circuit, include power source and ground connection return.

F) is the smallest the transient state that changes pair of ground returns method length.

G) avoids to use the transient state that share to return method to be nodded to communal ground connection.

H) uses ground level as far as possible, multilayer printed circuit board, use ground via.