| 摘要 |
A firing circuit for deploying a pair of air bags comprises two circuit legs (12,14) connected in parallel across a voltage supply (16). Each circuit leg comprises in series a safing sensor (30,38), a squib (32,40), and a crash sensor (34,42) with each sensor being shunted by a like resistor (36,44) having a nominal resistance substantially greater than the nominal resistance of the squibs. A first diode bridge (46) comprising a pair of oppositely-biased diodes (48) extends between a first pair of junctions (50,52) on the circuit legs located between the safing sensors and the squibs thereof. A second diode bridge (54) comprising a pair of oppositely- biased diodes (56) extends between a second pair of junctions (58,60) on the circuit legs located between the squibs and the crash sensors thereof. A third diode bridge (62) comprising oppositely-biased diodes (68) connected in series also extends between the latter pair of junctions (64,66) on the circuit legs. A third crash sensor (70) connects a junction (72) on the third diode bridge between the diodes thereof with both circuit legs, respectively, so as to be placed in parallel with the crash sensors thereof. The diode bridges provide multiple firing paths for both squibs (32,40) to ensure deployment of both air bags upon simultaneous closure of either safing sensor (30,38) and any crash sensor (34,42,70). Full circuit diagnosability is achieved through a comparison of the voltages achieved about the circuit and the effects thereon of incrementing the supply voltage and/or the operation of a plurality of current drains connected about the circuit.
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