Airbag energy storage voltage

What is a typical airbag application circuit?

Fig 1 shows a typical airbag application circuit. The supply voltage is usually 25 V to 35 V, which is provided by a boost converter operating from the 12 V car battery. The squib firing voltage is usually 15 to 20 V, which is controlled by the IC controller, this means the MOSFET drain to source voltage V DS is 10 V to 15 V.

Why do airbags have energy reserve capacitors?

The energy reserve capacitors used in the ACU (Airbag Control Unit) are provided so that once a crash event occurs and Loss of Battery (LOB) occurs in turn, the airbags can still be powered with their help as an emergency supply system.

Do airbag squib drivers have a high firing voltage?

I have been looking at several airbag squib drivers lately and I found that most of the squib drivers on the market (such as MC33797 or L9659) have quite large firing voltage range, roughly from 7 to 35 V. I would guess that most of them are suited for 12 V cars so I am wondering why is there this tendency to support such high voltage?

Are airbag control units safe in case of a crash?

Airbag control units are safe in case of a crash Electronics are providing functional safety -> ASIL D Mandatory data has to be stored even when the battery is cut off (autarky) Storage is not continuous but in discrete sections which increases storage time. The sections can only be recorded sequentially (see below)* *Diagram not to scale.

Can you put airbags on a 12 volt car?

You would not want the airbags to deploy when a mechanic disconnects the battery after forgetting to turn the engine off. So most of the car electronics that are powered from 12 V have to be able to cope with 35 V or more, at least for a short time.

What is a typical airbag squib application circuit?

Airbag Squib typical application circuit Fig 1 shows a typical airbag application circuit. The supply voltage is usually 25 V to 35 V, which is provided by a boost converter operating from the 12 V car battery.