Siemens Aktiengesellschaft

Reinhard Weber

Jurgen Eigler

Marten Swart

Richard Vogt

Circuit arrangement for triggering a vehicle passenger protection system, having a plurality of triggers (ZP1, ZP2, ZP3), through which (ZP1, ZP2, ZP3) in the event of a sufficiently serious accident a current impulse is conducted in each case, which for its part is intended to trigger the protection, one or more triggering switches (SS in FIGS. 1 and 2), the switching path of which (SS) in each case is non-conductive before the accident, and in the event of a sufficiently serious accident makes the transition to its conductive state and thus causes the current impulse through the triggers (ZP1, ZP2, ZP3), a plurality of current branches (ZP1/C2, ZP2/C5, ZP3/C9), which in each case contain at least one of the triggers, for example a primer capsule (ZP1, ZP2, ZP3), and a capacitor (C2, C5, C9), and a parallel circuit which is formed by the parallel circuit of the current branches (ZP1/C2, ZP2/C5, ZP3/C9). Before the accident the capacitor (C2, C5, C9) of each of the current branches (ZP1/C2, ZP2/C5, ZP3/C9) is connected during the journey to a voltage source (VCC30, GND according to FIG. 3 ), and thus is charged before the accident to an ignition voltage (approximately 30 V). The capacitor (C2, C5, C9) of each of the current branches (ZP1/C2, ZP2/C5, ZP3/C9) has both so high a self-capacitance (270.mu.F) and, before the accident, so high an ignition voltage (approximately 30 V), that during the accident it (C2, C5, C9) delivers the current impulse with reliably sufficient energy in each case to trigger the trigger/triggers (ZP1, ZP2, ZP3) of the relevant current branch (ZP1/C2, ZP2/C5, ZP3/C9) despite any additional energy losses (in D2, D 8, D11, Q6, Q9, Q13, Q16, R41, R42, R56).

Circuit arrangement for triggering a vehicle passenger protection system

A control unit for a passenger restraint and/or protection system for vehicles includes a sensor for generating an electronic analog output signal corresponding to accelerations or decelerations. An evaluation circuit determines if threshold values are exceeded. A tripping circuit trips a passenger-protection component if a threshold value is exceeded. Each sensor output signal is subjected to evaluations by supplying the signal to the evaluation circuit. Each evaluation circuit evaluates a temporal course by different criteria and by differently defined threshold values. The evaluation circuit uses typical characteristics of the temporal course and a definition of the threshold value to distinguish between accidents of at least two different types. The evaluation circuit ascertains the severity of the type of accident individually assigned to it from typical characteristics of the temporal course and from a definition for a threshold value. A logical linkage element links applicable evaluation outcomes and supplies a linkage outcome to the tripping circuit. The linkage element has a logical linking function tripping the system only if evaluations by the criteria show a defined type of accident, and that the threshold value having been specifically assigned to the applicable type of accident has been exceeded. The evaluation circuit ascertains an optimal tripping instant, differing from an instant at which exceeding of the tripping threshold value is ascertained.

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Wuppertal, Germany

Jurgen Eigler