Land vehicles – Wheeled – Attachment
Patent
1998-04-24
2000-05-30
Mai, Lanna
Land vehicles
Wheeled
Attachment
280735, B60R 2132
Patent
active
060682876
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an electronic device and a method for actuating passenger-protection systems.
BACKGROUND INFORMATION
Article No. 1141, Ingenieurs de l'Automobile No. 6 1982, pp. 69-77, and in particular FIG. 19 on page 74, describes a safety device for vehicle occupants. The safety device includes squibs, (i.e. firing pellets), which are actuated by a control unit. Upon actuation, the squibs activate a gas-producing propellant charge, which is operatively connected to an internal restraining device for vehicle occupants, such as, in particular, an airbag, and inflate said airbag. U.S. Pat. No. 3,911,391 describes a method for testing such squibs. In this context, the squibs to be tested receive a testing current supplied by a testing current source. The ensuing voltage drop is compared in a comparative circuit to the voltage supplied by a reference voltage source. The accuracy of such measurement is a function of the accuracy of the test current fed to the squib during the test. However, when working with integrated circuits, it is relatively difficult and expensive to provide a highly precise current source.
SUMMARY OF THE INVENTION
An electronic device and method according to the present invention have the advantage of a substantial overload protection for the control unit's output stage that actuates the squib, even when the squib's resistance value deviates markedly from its setpoint value, and particularly when it is considerably below said value. This allows to use an output stage with comparatively small dimensions, which, in an integrated design, requires only little chip surface. This, urn, leads to a cost reduction. A very flexible response to the squib's resistance fluctuations is possible, because the squib is actuated in timed cycles by a resistance value that deviates from its setpoint value, the current being measured at every cycle. The minimum energy required for activating the squib can advantageously be made available even when the resistance value of the squib deviates quite markedly from its setpoint value. Even in the event that the squib's resistance is short-circuited, the maximum energy required by the control unit is limited by the squib's timed fixed-cycle actuation. Furthermore, through a marked rise in the current amplitude and resultant scavenging of short-circuits and/or shunts, a reliable squib actuation can be achieved even under very difficult operating conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of an exemplary embodiment of an electronic device according to the present invention.
FIG. 2 shows a detailed block diagram of the electronic device with the squib being shown.
FIG. 3 shows a current profile plotted as a function of time.
FIG. 4 shows another current profile plotted as a function of time.
FIG. 5 shows yet another current profile plotted as a function of time.
FIG. 6 shows a further current profile plotted as a function of time.
FIG. 7 shows a flow chart according to the present invention.
FIG. 8 shows another exemplary embodiment of the electronic device including a plurality of output stages for triggering a plurality of squibs.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a simplified block diagram of an electronic device 1 of the species. This device comprises a sensor 2, which detects the vehicle's acceleration values and whose output terminal is linked to the input terminal of a control device 3, which analyzes the output signals from sensor 2. Control unit 3, in turn, is linked to restraining devices 4a, 4b for protecting vehicle occupants, such as, in particular, airbags, belt tighteners, and/or the like. Control unit 3 responds to a critical accident situation, by activating restraining devices 4a, 4b, which then offer protection to the occupants.
FIG. 2 shows a detailed block diagram of an electronic device of the species, squib 5 itself also being depicted. Device 1 includes, a sensor 2, which is linked to a control unit 3. Output terminals of control unit 3 are co
REFERENCES:
patent: 5365114 (1994-11-01), Tsurushima et al.
patent: 5587906 (1996-12-01), Mciver et al.
patent: 5596497 (1997-01-01), Honda
patent: 5809439 (1998-09-01), Damisch
Drobny Wolfgang
Karl Otto
Kohler Dietmar
Nitschke Werner
Seibold Jochen
Mai Lanna
McKinley Kevin
Robert & Bosch GmbH
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