Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-03-08
2001-04-17
Fleming, Fritz (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C340S438000, C280S735000
Reexamination Certificate
active
06218739
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a procedure for the functional testing of a vehicle occupant protection system having plural separate ignition circuits for triggering the igniters of plural occupant protection devices as well as a test circuit for implementing this procedure.
BACKGROUND INFORMATION
German Utility Model DE 92 17 359 U1 contains a circuit layout for the functional testing of a multistage transistor circuit as used in the ignition circuits of vehicle occupant protection systems. Their use in airbag trigger circuits is explicitly mentioned.
In addition, there are a large number of vehicle occupant protection systems available in the market where a central processing unit, or possibly even several output stages distributed within the vehicle, each trigger several ignition circuits for the ignitors of vehicle occupant protection systems, in particular pyrotechnic ignitors of airbag or belt tensioning gas generators. The output stages are usually integrated as Application Specific Integrated Circuits (ASICs) and feature the corresponding switching means for the ignition circuits to be controlled. Via connection lines, the proper ignitors will then be connected. DE 92 17 359 U1 contains a test circuit which, in the ignition circuit, will test the ignition circuit, in particular the switching means within such a circuit, by means of test currents which are very low when compared with actual trigger currents. The test is carried out by comparing any occurring changes in voltage potential with threshold values.
However, short-circuiting of components in or across parallel ignition circuits will so far not be detected. This type of short-circuiting may occur either within the ASIC—caused by damaged insulation areas between the various individual switching means—or by insulation defects in the connection lines from the functional unit, e.g. ASIC, to the ignitors.
SUMMARY OF THE INVENTION
The invention provides a procedure for the functional testing of a vehicle occupant protection system as well as a suitable test circuit by means of which even a short-circuiting of components in or across the parallel ignition circuits of an output stage will be detected.
Accordingly, in each ignition circuit, a predefined position of the switching means will be generated; and it will then be tested in the other ignition circuits as to whether these also show changes in voltage potential. This test is extremely easy to implement and does not require any great circuitry. Moreover, this test will determine whether an improper coupling, e.g. a short-circuit, between respective ignition circuits exists and causes an improper voltage change in a non-energized second ignition circuit when a first ignition circuit parallel thereto is energized.
REFERENCES:
patent: 3863208 (1975-01-01), Balban
patent: 4163268 (1979-07-01), Spies et al.
patent: 5187465 (1993-02-01), Stonerook et al.
patent: 5446442 (1995-08-01), Swart et al.
patent: 5596497 (1997-01-01), Honda
patent: 5621326 (1997-04-01), Watanabe et al.
patent: 2614491 (1977-10-01), None
patent: 9001803 U (1990-06-01), None
patent: 9217359 (1993-04-01), None
patent: 4408382A1 (1995-09-01), None
patent: 0494859 (1992-07-01), None
patent: 0806323 (1997-11-01), None
patent: WO98/12569 (1998-03-01), None
Daimler-Chrysler AG
Fasse W. F.
Fasse W. G.
Fleming Fritz
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