Hi,
I'm designing something to plug into a (nominal) +12V cigarette lighter socket in a vehicle.
Can someone please point me in the direction of STANDARDS which describe the electrical environment? I'm particularly interested in surges, overvoltages, etc.
BTW, I'm not really interested in knowing your circuit solution to automotive protection, but post anyway; there'll be others who might get something out of it.
Regards, Allan
Hi Allen,
type: iso 7637 level into google, altavista, webcrawler, etc and you find documents that refers to ISO 7637 test levels for EMC. The ISO standard is not free available.
Prepare yourself for heavy spikes. There is a difference in levels for equipment directly connected to the car battery and other means of connection.
When you download EN 301 489-3 (EMC for SRD equipment, free from the ETSI website) they also mention levels for 12 and 24 V board nets and refer to ISO 7637.
Regarding the DC level. A car generator should not charge the battery above 15V, however, some do.
Best regards,
Wim PA3DJS
National Semi also wrote an excellent ap note on the subject. It was a long time ago. So many years I'm embarrased to say (:
Hi Allen,
I forgot to mention
Best regards,
Wim PA3DJS
There's some good info here -
Also, google "alternator load dump" and/or "automotive transients" you should get at least a few links to $tandards.
Best regards, Ralph in NH
and this is the cure for insomnia
Martin
Old GE/Harris/Intersi/Littelfuse app note 9312
Military standards are pretty comprehensive, but are for 28V systems.
Ford describes surge waveforms and immunity levels expected in section
14 of EMC Spec ES-XW7T-1A278-AC.RL
Thanks to all who replied.
Allan
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