Method and firing circuit for triggering a vehicle occupant protection system
AssigneeSiemens Aktiengesellschaft
InventorStefan Hermann
Life of this patent
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Abstract
To fire a firing cap of a vehicle occupant protection system of a motor vehicle, at least two firing capacitors are provided which initially remain connected in parallel at the start of a firing process and are connected in series after expiry of a time interval from the start of the firing process. It is ensured that a firing current which flows across the firing cap is always of a sufficient magnitude and at the same time initial power losses are avoided.
Claims11
A method for firing a vehicle occupant protection system, which comprises:
- activating a firing circuit having a firing cap and a firing switch connected in series with the firing cap and the firing switch activated by a firing pulse, the firing circuit further having at least two firing capacitors connected in parallel with one another before a firing process, the firing capacitors can be charged by one of a voltage source and a current source and discharge a stored charge simultaneously into the firing cap in response to the firing pulse;
- and
- maintaining the firing capacitors to remain connected in parallel at a start of the firing pulse and connected in series after a time delay after the start of the firing pulse.
In combination with a vehicle occupant protection system of a motor vehicle, a firing circuit for the vehicle occupant protection system, the firing circuit comprising:
- a firing cap;
- a firing switch connected in series with said firing cap and said firing switch receiving and activated by a firing pulse;
- at least two firing capacitors to be charged by one of a voltage source and a current source;
- a control circuit connected to said firing switch and generating the firing pulse and a switch-over pulsed;
- and
- a changeover switch connected to said firing capacitors for switching over said firing capacitors between a parallel connection of said firing capacitors and a series connection of said capacitors, and in an event requiring firing of said firing cap said control circuit initially generating the firing pulse for simultaneously discharging said firing capacitors and only applying after a time delay the switch-over pulse to said changeover switch to switch over said firing capacitors from said parallel connection to said series connection.
Dependencies are inferred from the claim text.