Patent ID: 7111870
Filing Date: 2006-09-26
Classification: B60R

Abstract:
1. An airbag system for a car comprising: airbag inflatable with gas; an inflator for producing gas for the airbag; a squib for firing the inflator; a firing circuit including a high-side switch and a low-side switch for allowing a firing current to flow or preventing the current from flowing through the squib, on the high-voltage and low-voltage sides, respectively, of the squib; the firing circuit further including a switch driving means for switching the two switches; a first motion detecting circuit including a first motion sensor for outputting an electric signal representing a motion of the car; a second motion detecting circuit including a second motion sensor for outputting an electric signal representing a motion of the car; a first collision determining circuit; and a second collision determining circuit independent of the first collision determining circuit; the first and the second collision determining circuits being adapted to determine on the basis of the electric signals from the first and the second motion detecting circuits, respectively, whether the car has collided or not; the two collision determining circuits being further adapted to output firing signals to the switch driving means of the firing circuit when the car collides, wherein the airbag is inflated when the car collides, the first collision determining circuit comprising a comparator for comparing the electric signal from the first motion detecting circuit with a reference value.