WO1999005005A1 - Circuit for igniting two ignition units, especially airbag ignition units - Google Patents
Circuit for igniting two ignition units, especially airbag ignition units Download PDFInfo
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- WO1999005005A1 WO1999005005A1 PCT/DE1998/001562 DE9801562W WO9905005A1 WO 1999005005 A1 WO1999005005 A1 WO 1999005005A1 DE 9801562 W DE9801562 W DE 9801562W WO 9905005 A1 WO9905005 A1 WO 9905005A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
- B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
- B60R21/017—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
- B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
- B60R2021/01034—Controlling a plurality of restraint devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
- B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
- B60R21/017—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including arrangements for providing electric power to safety arrangements or their actuating means, e.g. to pyrotechnic fuses or electro-mechanic valves
- B60R21/0173—Diagnostic or recording means therefor
Definitions
- the invention relates to a circuit for igniting two ignition units, in particular airbag ignition units, according to the preamble of the main claim.
- Airbag units are used, for example, in the steering wheel, in the
- the individual airbag units should not always be triggered or ignited at all times, but individually depending on sensor signals, the evaluation of which reveals the need to trigger the individual airbag units.
- the triggering of the airbag units or of their ignition units is controlled by means of a control unit which has a microprocessor with associated memories and converts input signals coming from the sensors into output signals for triggering the ignition units.
- the squib resistance is determined by means of a test current provided by an integrated circuit that is relatively imprecise and smaller than a squib current.
- the ignition pill resistance can be determined.
- the squib is connected to an energy source for triggering via a controllable field effect transistor.
- the invention has for its object to reduce the wiring associated with the use of several airbag units in a vehicle.
- the circuit according to the invention which is not only suitable for airbag ignition units, but for any type of electrically triggered ignition units, enables two ignition units to be controlled or triggered independently of one another via a two-pole line.
- the subclaims 2 to 5 are directed to advantageous embodiments of the circuit according to the invention, it being achieved with the features of claims 4 and 5, respectively, that the ignition units, which can be ignited independently of one another according to the polarity of the ignition pulses, by measuring resistance when subjected to a low diagnostic voltage, or preferably with a low one Diagenosis current, can be checked with regard to their function.
- the invention is explained below with reference to a block diagram shown in FIGS. 1 to 3, for example and with further details.
- a control device 2 which in a manner known per se contains a microprocessor with associated memory device (ROM memory and RAM memory), has inputs 4, outputs 6 and 8 and a connection to a power supply U B , m which is, for example, an operating or ignition switch 10.
- the control unit 2 controls two ignition units 12 and 14, each of which is connected in series with a self-conducting DMOS-FET (depletion metal oxide semiconductor field effect transistor) 16 and 18 at the outputs 6 and 8.
- DMOS-FET depletion metal oxide semiconductor field effect transistor
- Substrate or bulk electrode B of the DMOS-FET 16 connected.
- the output 8 of the control device 2 is connected to the gate electrode G of the DMOS-FET 18 and the drain electrode D of the DMOS-FET 16 and via the ignition unit 14 to the source electrode S and the bulk electrode B of the DMOS-FET 18 connected.
- the DMOS-FETs act at higher voltages to a certain extent like opposing diodes which are shown with dots.
- the circuit works as follows: There is a high voltage (ignition voltage) at outputs 6 and 8 Current flow direction from 6 to 8, this leads to a high current flow through the ignition unit 12 and the DMOS-FET 16, so that the ignition unit 12 ignites.
- the drop voltage across the ignition unit 12 additionally controls the DMOS-FET 16 so that it becomes more mediohm.
- the DMOS-FET 18, on the other hand, has a high impedance at this polarity, so that the ignition unit 14 has only a small current flowing through it, which is not sufficient for ignition.
- the ignition unit 14 If the ignition pulse lying between the outputs 6 and 8 has reversed polarity, then the ignition unit 14, as a result of the DMOS-FET 18 then polarized in the direction of current flow, has a current flowing through it which is sufficient to trigger or ignite the ignition unit 14.
- the ignition unit 12 because of the high impedance of the DMOS-FET 16 at this polarity, only a very small current flows through it, which is not sufficient for ignition.
- the voltage drop across the ignition unit 14 also switches through the DMOS-FET 18 so that it becomes even more mediohm.
- FIG. 2 shows the circuit according to FIG. 1 m of the test phase, in particular when measuring the resistance of the increase 12.
- a diagnostic current I meSs is impressed, which flows from output 6 to output 8.
- the DMOS-FET 16 becomes more medium-resistance, while the resistance value of the DMOS-FET 18 increases somewhat.
- the resistance of the ignition unit 12 can thus be measured with certain tolerance limits despite the additional current flow through the DMOS-FET 18 and the ignition unit 14.
- the voltage drops occurring here on the ignition units 12 and 14 are shown with DUX or DU ⁇ 4 , indicating the respective polarities.
- both DMOS-FETs 16 and 18 are current-permeable due to their self-conduction, so that both igniters 12 and 14 are traversed by low diagnostic currents, can alternatively be used from the effective to the Outputs 6 and 8 occurring resistance can also be summarized to the state of both ignition units.
- the resistance has a predetermined value in the case of functional ignition units 12 and 14. If the control device 2 determines that the effective resistance at the outputs 6 and 8 has the predetermined value, then this is assessed as a perfect functional humidity of the two ignition units 12 and 14. In the event of a short circuit or a line interruption in or on a ignition unit 12 or 14, the diagnostic resistance changes, which, just as in the case of an individual evaluation, leads to an error display of the control unit 2.
- the invention creates the possibility of igniting two ignition units 12 and 14 independently of one another via only one two-pole line (outputs 6 and 8) by means of the polarity of an ignition pulse, and to monitor their functionality with the aid of small diagnostic currents.
- small diagnostic currents are preferably impressed for measuring the resistance of the ignition units 12 and 14, since this improves controllability and can even better suppress undesired effects on the ignition units 12 and 14.
- self-conducting DMOS-FETs are used, which are each inverted with the ignition units 12 and 14 in series are.
- self-blocking DMOS transistors instead of the self-conducting DMOS transistors 16 and 18.
- a small but tolerable falsification of the measured values by the diode voltages occurs during the resistance measurement.
- normal MOSFETs or other components with rectifier characteristics in the simplest case diodes, each with the opposite direction to the
- Ignition units 12 and 14 are connected. However, due to the very low-resistance characteristic of normally-on DMOS-FETs, these are generally preferred, whereby their inverse diode characteristics are used.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Air Bags (AREA)
Abstract
The invention relates to a circuit for igniting two ignition units (12, 14), especially airbag ignition units, comprising a control device (2) that generates an ignition pulse to ignite at least one ignition unit between two outputs (6, 8) which are connected to the ignition unit. The control device is configured in such a way that the trigger pulse can have different polarity depending on the signals fed through their inputs. Both ignition units (12, 14) are each parallel connected to the outputs of the control device (2) by means of a DMOS-FET (16, 18). Both DMOS-FETs (16, 18) are connected in opposition so that either ignition unit is ignited depending on the polarity of the ignition pulse.
Description
Beschreibungdescription
Schaltung zum Zünden von zwei Zündeinheiten, insbesondere Airbag-ZündeinheitenCircuit for igniting two ignition units, in particular airbag ignition units
Die Erfindung betrifft eine Schaltung zum Zünden von zwei Zündeinheiten, insbesondere Airbag-Zündeinheiten, gemäß dem Oberbegriff des Hauptanspruchs.The invention relates to a circuit for igniting two ignition units, in particular airbag ignition units, according to the preamble of the main claim.
Moderne Kraftfahrzeuge werden in zunehmendem Maße mit Airbag- Einheiten ausgerüstet, wobei jede Airbag-Einheit eine Zündeinheit mit dem zugehörigen, aufblasbarem Sack enthält. Air- bag-Einheiten werden beispielsweise im Lenkrad, in derModern motor vehicles are increasingly equipped with airbag units, each airbag unit containing an ignition unit with the associated inflatable bag. Airbag units are used, for example, in the steering wheel, in the
Schalttafel vor dem Beifahrer, in den Verkleidungen der Türen, im Holmbereich seitlich des Kopfes usw. vorgesehen. Dabei sollen die einzelnen Airbag-Einheiten durchaus nicht immer alle gleichzeitig ausgelöst bzw. gezündet werden, sondern individuell in Abhängigkeit von Sensorsignalen, deren Auswertung die Notwendigkeit der Auslösung der einzelnen Airbag- Einheiten ergibt. Die Auslösung der Airbag-Einheiten bzw. von deren Zündeinheiten wird mittels eines Steuergerätes gesteuert, das einen Mikroprozessor mit zugehörigen Speichern aufweist und von den Sensoren kommende Eingangssignale in Ausgangssignale zur Auslösung der Zündeinheiten umrechnet.Control panel in front of the passenger, in the door panels, in the spar area on the side of the head, etc. The individual airbag units should not always be triggered or ignited at all times, but individually depending on sensor signals, the evaluation of which reveals the need to trigger the individual airbag units. The triggering of the airbag units or of their ignition units is controlled by means of a control unit which has a microprocessor with associated memories and converts input signals coming from the sensors into output signals for triggering the ignition units.
Bekannt ist (DE 33 26 277 C2 ) , für die Ansteuerung jeder Zündeinheit eine eigene zweipolige Leitung zu verwenden. Über diese zweipolige Leitung erfolgt auch eine individuelle Funktionsüberwachung der jeweiligen Zündeinheit, indem deren Widerstand durch Beaufschlagung mit einer geringen Diagnosespannung, die erheblich unter der Spannung eines Auslöseim-
pulses liegt, und Messung des zugehörigen Diagnosestroms bestimmt wird.It is known (DE 33 26 277 C2) to use a separate two-pole line for controlling each ignition unit. Individual function monitoring of the respective ignition unit is also carried out via this two-pole line, by reducing its resistance by applying a low diagnostic voltage which is considerably lower than the voltage of a tripping unit. pulses, and measurement of the associated diagnostic current is determined.
Aus der DE 195 30 238 AI ist ein Insassenschutzsystem bekannt, daß den Zundpillenwiderstand mittels eines von einer integrierten Schaltung gelieferten, relativ unprazisen und kleiner als ein zundimpulsstrom ausgebildeten Prufstroms ermittelt wird. Mit Hilfe einer Spannungsmessung eines mit dem Prufstrom beaufschlagten prazisionswiderstandes und einer Spannungsmessung an der mit dem Prufstrom beaufschlagten Zundpille kann der Zundpillenwiderstand ermittelt werden. Die Zundpille wird zum Auslosen über einen steuerbaren Feldeffekttransistor mit einer Energiequelle verbunden.From DE 195 30 238 AI an occupant protection system is known that the squib resistance is determined by means of a test current provided by an integrated circuit that is relatively imprecise and smaller than a squib current. With the help of a voltage measurement of a precision resistor to which the test current is applied and a voltage measurement to the test pill to which the test current is applied, the ignition pill resistance can be determined. The squib is connected to an energy source for triggering via a controllable field effect transistor.
Der Erfindung liegt die Aufgabe zugrunde, den mit dem Einsatz mehrerer Airbag-Einheiten m einem Fahrzeug verbundenen Verkabelungsaufwand zu vermindern.The invention has for its object to reduce the wiring associated with the use of several airbag units in a vehicle.
Diese Aufgabe wird mit den Merkmalen des Hauptanspruchs gelost. Die erfmdungsgemaße Schaltung, die nicht nur für Air- bag-Zundemheiten geeignet ist, sondern für jedwelche Art von elektrisch ausgelosten Zundemheiten, ermöglicht, über eine zweipolige Leitung zwei Zundemheiten unabhängig voneinander anzusteuern bzw. auszulosen.This task is solved with the features of the main claim. The circuit according to the invention, which is not only suitable for airbag ignition units, but for any type of electrically triggered ignition units, enables two ignition units to be controlled or triggered independently of one another via a two-pole line.
Die Unteranspruche 2 bis 5 sind auf vorteilhafte Ausfuhrungsformen der erfmdungsgemaßen Schaltung gerichtet, wobei mit den Merkmalen der Ansprüche 4 bzw. 5 erreicht wird, daß die e nach Polarität der Zundimpulse unabhängig voneinander zundbaren Zundemheiten durch Widerstandsmessung bei Beaufschlagung mit niedriger Diagnosespannung, oder bevorzugt mit niedrigem Diagenosestrom, hinsichtlich ihrer Funktion überprüft werden können.
Die Erfindung wird im folgenden anhand eines in den Fig. 1 bis 3 gezeigten Blockschaltbildes beispielsweise und mit wei- teren Einzelheiten erläutert.The subclaims 2 to 5 are directed to advantageous embodiments of the circuit according to the invention, it being achieved with the features of claims 4 and 5, respectively, that the ignition units, which can be ignited independently of one another according to the polarity of the ignition pulses, by measuring resistance when subjected to a low diagnostic voltage, or preferably with a low one Diagenosis current, can be checked with regard to their function. The invention is explained below with reference to a block diagram shown in FIGS. 1 to 3, for example and with further details.
Gemäß Figur 1 weist ein Steuergerat 2, das in an sich bekannter Weise einen Mikroprozessor mit zugehöriger Speicherein- richtung (ROM-Speicher und RAM-Speicher) enthalt, Eingänge 4, Ausgange 6 und 8 sowie einen Anschluß an eine Stromversorgung UB auf, m der beispielsweise ein Betriebs- bzw. Zundschalter 10 liegt. Von dem Steuergerat 2 aus werden zwei Zundemheiten 12 und 14 gesteuert, die jeweils in Reihe mit einem selbst- leitenden DMOS-FET (depletion metal oxid semiconductor field effect transistor) 16 und 18 parallel an den Ausgangen 6 und 8 liegen.According to FIG. 1, a control device 2, which in a manner known per se contains a microprocessor with associated memory device (ROM memory and RAM memory), has inputs 4, outputs 6 and 8 and a connection to a power supply U B , m which is, for example, an operating or ignition switch 10. The control unit 2 controls two ignition units 12 and 14, each of which is connected in series with a self-conducting DMOS-FET (depletion metal oxide semiconductor field effect transistor) 16 and 18 at the outputs 6 and 8.
Genauer ist der Ausgang 6 mit der Drain-Elektrode D des DMOS- FETs 18, mit der Gate-Elektrode G des DMOS-FETs 16 und über die Zunde heit 12 mit der Source-Elektrode S und derMore precisely, the output 6 with the drain electrode D of the DMOS-FET 18, with the gate electrode G of the DMOS-FET 16 and via the igniter 12 with the source electrode S and
Substrat- bzw. Bulk-Elektrode B des DMOS-FETs 16 verbunden.Substrate or bulk electrode B of the DMOS-FET 16 connected.
Der Ausgang 8 des Steuergeräts 2 ist mit der Gate-Elektrode G des DMOS-FETs 18 und der Drain-Elektrode D des DMOS-FETs 16 sowie über die Zundemheit 14 mit der Source-Elektrode S und der Bulk-Elektrode B des DMOS-FETs 18 verbunden.The output 8 of the control device 2 is connected to the gate electrode G of the DMOS-FET 18 and the drain electrode D of the DMOS-FET 16 and via the ignition unit 14 to the source electrode S and the bulk electrode B of the DMOS-FET 18 connected.
In der beschriebenen Schaltung wirken die DMOS-FETs bei höheren Spannungen in gewisser Weise wie gegensinnige Dioden, die gepunktet eingezeichnet sind.In the circuit described, the DMOS-FETs act at higher voltages to a certain extent like opposing diodes which are shown with dots.
Die Wirkungsweise der Schaltung ist folgende: Liegt an den Ausgangen 6 und 8 eine hohe Spannung (Zündspannung) mit
Stromflußrichtung von 6 nach 8, so fuhrt dies zu einem hohen Stromfluß durch die Zundemheit 12 und den DMOS-FET 16, so daß die Zundemheit 12 zündet. Die Abfallspannung über die Zundemheit 12 steuert den DMOS-FET 16 zusätzlich, so daß dieser mederohmiger wird. Der DMOS-FET 18 dagegen ist: bei dieser Polarität hochohmig, so daß die Zundemheit 14 nur von einem geringen Strom durchflössen ist, der zum Zünden nicht ausreicht.The circuit works as follows: There is a high voltage (ignition voltage) at outputs 6 and 8 Current flow direction from 6 to 8, this leads to a high current flow through the ignition unit 12 and the DMOS-FET 16, so that the ignition unit 12 ignites. The drop voltage across the ignition unit 12 additionally controls the DMOS-FET 16 so that it becomes more mediohm. The DMOS-FET 18, on the other hand, has a high impedance at this polarity, so that the ignition unit 14 has only a small current flowing through it, which is not sufficient for ignition.
Weist der zwischen den Ausgangen 6 und 8 liegende Zundimpuls umgekehrte Polarität auf, so wird die Zundemheit 14 infolge des dann in Stromflußrichtung gepolten DMOS-FET 18 von einem Strom durchflössen, der zur Auslosung bzw. Zündung der Zundemheit 14 ausreicht. Die Zundemheit 12 dagegen ist wegen der Hochohmigkeit des DMOS-FETs 16 bei dieser Polarität nur von einem sehr geringen Strom durchflössen, der zum Zünden nicht ausreicht. Auch hier gilt, wie bereits vorstehend be- zuglich der Zündung der Zundemheit 12 angegeben, daß die an der Zundemheit 14 abfallende Spannung den DMOS-FET 18 zusatzlich durchschaltet, so daß dieser noch mederohmiger wird.If the ignition pulse lying between the outputs 6 and 8 has reversed polarity, then the ignition unit 14, as a result of the DMOS-FET 18 then polarized in the direction of current flow, has a current flowing through it which is sufficient to trigger or ignite the ignition unit 14. The ignition unit 12, on the other hand, because of the high impedance of the DMOS-FET 16 at this polarity, only a very small current flows through it, which is not sufficient for ignition. Here too, as already stated above with regard to the ignition of the ignition unit 12, the voltage drop across the ignition unit 14 also switches through the DMOS-FET 18 so that it becomes even more mediohm.
Das Vorhandensein eines Zundimpulses an den Ausgangen 6 und 8 sowie dessen Polarität hangt von den Signalen ab, die den Eingängen des Steuergerätes 4 von unterschiedlichen, im Fahrzeug vorhandenen Beschleunigungssensoren oder weiteren Sensoren zugeführt werden.The presence of an ignition pulse at the outputs 6 and 8 and its polarity depend on the signals which are fed to the inputs of the control device 4 by different acceleration sensors or other sensors present in the vehicle.
Im Folgenden wird die Diagnose der Zundemheiten 12 und 14 erläutert :
In Figur 2 ist die Schaltung gemäß Fig. 1 m der Testphase, insbesondere bei der Widerstandsmessung der Zunαemheit 12 dargestellt. Hierzu wird ein Diagnosestrom ImeSs eingeprägt, der vom Ausgang 6 zum Ausgang 8 fließt. Bei dieser Polarität wird der DMOS-FET 16 mederohmiger, wahrend der Widerstandswert des DMOS-FETs 18 etwas ansteigt. Damit laßt sich der Widerstand der Zundemheit 12 trotz des zusätzlichen Stromflus- ses durch den DMOS-FET 18 und die Zundemheit 14 m gewissen Toleranzgrenzen messen. Die hierbei an den Zundemheiten 12 und 14 auftretenden Spannungsabfalle sind mit DUX bzw. DUι4 unter Angabe der jeweiligen Polaritäten dargestellt.The diagnosis of ignition units 12 and 14 is explained below: FIG. 2 shows the circuit according to FIG. 1 m of the test phase, in particular when measuring the resistance of the increase 12. For this purpose, a diagnostic current I meSs is impressed, which flows from output 6 to output 8. With this polarity, the DMOS-FET 16 becomes more medium-resistance, while the resistance value of the DMOS-FET 18 increases somewhat. The resistance of the ignition unit 12 can thus be measured with certain tolerance limits despite the additional current flow through the DMOS-FET 18 and the ignition unit 14. The voltage drops occurring here on the ignition units 12 and 14 are shown with DUX or DUι 4 , indicating the respective polarities.
In Figur 3 ist die Schaltung bei umgekehrter Stromrichtung des Diagnosestroms Imess vom Ausgang 8 zum Ausgang 6 dargestellt. Bei dieser Stromflußrichtung laßt sich insbesondere der Widerstand der Zundemheit 14 m gewissen Toleranzberei- chen bestimmen.In Figure 3, the circuit is shown with reverse current direction of the diagnostic current I me ss from output 8 to output 6. With this current flow direction, the resistance of the ignition unit 14 can be determined in particular within certain tolerance ranges.
Da, wie vorstehend anhand der Fig. 2 und 3 erläutert, die Stromrichtung des Diagnosestroms von gewisser Bedeutung ist unα die Widerstandsmessung der einen oder der anderen Zundemheit 12 bzw. 14 betont, kann aus bei diesen Zyklen mit Diagnosestromumkehrung jeweils gemessenen Widerstandswerten zwischen den Ausgangen 6 und 8 selektiv auf den Zustand der Zundemheiten 12 und 14 geschlossen werden.Since, as explained above with reference to FIGS. 2 and 3, the current direction of the diagnostic current is of some importance and the resistance measurement of one or the other ignition unit 12 or 14 is emphasized, resistance values measured in each case between the outputs 6 can be measured in these cycles with diagnostic current reversal and 8 selectively infer the condition of the ignition units 12 and 14.
Da bei kleinen zwischen den Ausgangen 6 und 8 fließenden Strömen (Diagnosestromen) beide DMOS-FETs 16 und 18 infolge ihrer Selbstleitung stromdurchlassig sind, so daß beide Zundemheiten 12 und 14 von geringen Diagnosestromen durchflössen werden, kann alternativ aus dem effektiven, an den
Ausgangen 6 und 8 auftretenden Widerstand auch summarisch auf den Zustand beider Zundemheiten geschlossen werden. Der Wi- derstand hat bei funktionstüchtigen Zundemheiten 12 und 14 einen vorbestimmten Wert. Wenn das Steuergerat 2 feststellt, daß der effektive, an den Ausgangen 6 und 8 liegende Widerstand den vorbestimmten Wert hat, so wird dies als einwandfreie Funktionstuchtigkeit der beiden Zundemheiten 12 und 14 gewertet. Bei einem Kurzschluß oder einer Leitungsunterbre chung in oder an einer Zundemheit 12 oder 14 ändert sich der Diagnosewiderstand, was ebenso wie bei einer Einzelauswertung zu einer Fehleranzeige des Steuergeräts 2 fuhrt.Since with small currents flowing between the outputs 6 and 8 (diagnostic currents) both DMOS-FETs 16 and 18 are current-permeable due to their self-conduction, so that both igniters 12 and 14 are traversed by low diagnostic currents, can alternatively be used from the effective to the Outputs 6 and 8 occurring resistance can also be summarized to the state of both ignition units. The resistance has a predetermined value in the case of functional ignition units 12 and 14. If the control device 2 determines that the effective resistance at the outputs 6 and 8 has the predetermined value, then this is assessed as a perfect functional humidity of the two ignition units 12 and 14. In the event of a short circuit or a line interruption in or on a ignition unit 12 or 14, the diagnostic resistance changes, which, just as in the case of an individual evaluation, leads to an error display of the control unit 2.
Insgesamt wird mit der Erfindung die Möglichkeit geschaffen, zwei Zundemheiten 12 und 14 über lediglich eine zweipolige Leitung (Ausgange 6 und 8) durch die Polarität eines Zundimpulses unabhängig voneinander zu zünden sowie mit Hilfe kleiner Diagnosestrome hinsichtlich ihrer Funktionstuchtigkeit zu überwachen.Overall, the invention creates the possibility of igniting two ignition units 12 and 14 independently of one another via only one two-pole line (outputs 6 and 8) by means of the polarity of an ignition pulse, and to monitor their functionality with the aid of small diagnostic currents.
Bei der Erfindung werden vorzugsweise kleine Diagnosestrome zur Widerstandsmessung der Zundemheiten 12 und 14 eingeprägt, da hierdurch die Steuerbarkeit verbessert ist und un- erwünschte Auswirkungen auf die Zundemheiten 12 und 14 noch besser unterdruckt werden können. Es ist aber auch möglich, zum Testen der Zundemheiten 12 und 14 kleine Diagnosespannungen anzulegen, deren Wert deutlich unterhalb der zum Zünden angelegten Zundi pulse liegt.In the invention, small diagnostic currents are preferably impressed for measuring the resistance of the ignition units 12 and 14, since this improves controllability and can even better suppress undesired effects on the ignition units 12 and 14. However, it is also possible to apply small diagnostic voltages for testing the ignition units 12 and 14, the value of which is significantly below the ignition pulse applied for ignition.
Bei dem vorstehend erläuterten Ausfuhrungsbeispiel werden selbstleitende DMOS-FETs eingesetzt, die jeweils invertiert zueinander mit den Zundemheiten 12 bzw. 14 in Reihe geschal
tet sind. Es ist aber auch möglich, DMOS-Transistoren mit Selbstsperrung anstelle der selbstleitenden DMOS-Transistoren 16 und 18 zu verwenden. Bei der Widerstandsmessung tritt hierbei zwar eine geringe, jedoch verkraftbare Verfälschung der Meßwerte durch die Diodenspannungen auf. Es ist auch möglich, normale MOSFETS oder sonstige Bauelemente mit Gleichrichtercharakteristik, im einfachsten Fall Dioden, zu verwen- den, die jeweils mit umgekehrter Leitrichtung mit denIn the exemplary embodiment explained above, self-conducting DMOS-FETs are used, which are each inverted with the ignition units 12 and 14 in series are. However, it is also possible to use self-blocking DMOS transistors instead of the self-conducting DMOS transistors 16 and 18. A small but tolerable falsification of the measured values by the diode voltages occurs during the resistance measurement. It is also possible to use normal MOSFETs or other components with rectifier characteristics, in the simplest case diodes, each with the opposite direction to the
Zündeinheiten 12 bzw. 14 verbunden sind. Aufgrund der sehr niederohmigen Charakteristik von selbstleitenden DMOS-FETs sind diese jedoch in der Regel bevorzugt, wobei ihre Invers- diodencharakteritik ausgenutzt wird.
Ignition units 12 and 14 are connected. However, due to the very low-resistance characteristic of normally-on DMOS-FETs, these are generally preferred, whereby their inverse diode characteristics are used.
Claims
1. Schaltung zum Zünden von zwei Zundemheiten (12, 14), insbesondere Airbag-Zunde heiten, enthaltend ein Steuergerat (2) , das zur Zündung wenigstens einer1. Circuit for igniting two ignition units (12, 14), in particular airbag igniters, containing a control device (2) which is used to ignite at least one
Zundemheit zwischen zwei mit der Zundemheit verbundenenTiedness between two associated with tiedness
Ausgangen (6, 8) einen Zundimpuls erzeugt, dadurch gekennzeichnet, daß das Steuergerat (2) derart aufgebaut ist, daß m Abhan- gigkeit von seinen Eingängen (4) zugefuhrten Signalen dieOutputs (6, 8) generate an ignition pulse, characterized in that the control device (2) is constructed in such a way that, depending on its inputs (4), the signals supplied to it
Zundimpulse mit unterschiedlichen Polaritäten erzeugbar sind, und daß die beiden Zundemheiten (12, 14) über je ein BauelementIgnition pulses with different polarities can be generated, and that the two ignition units (12, 14) each have a component
(16, 18), das bei einem Zundimpuls Gleichπchtercharakteri- stik zeigt, parallel mit den Ausgangen (6, 8) des Steuergerätes verbunden sind, wobei die beiden Bauelemente (16, 18), die bei einem Zundimpuls Gleichrichtercharakteristik zeigen, gegensinnig geschaltet sind, so daß je nach Polarität des Zundimpulses die eine oder die andere Zundemheit z ndet.(16, 18), which shows rectifier characteristics in the case of an ignition pulse, are connected in parallel to the outputs (6, 8) of the control device, the two components (16, 18), which show rectifier characteristics in the case of an ignition pulse, being connected in opposite directions, so that one or the other ignites depending on the polarity of the ignition pulse.
2. Schaltung nach Anspruch 1, dadurch gekennzeichnet, daß die Bauelemente (16, 18) MOSFETs, insbesondere DMOS-FETs, sind.2. Circuit according to claim 1, characterized in that the components (16, 18) are MOSFETs, in particular DMOS-FETs.
3. Schaltung nach Anspruch 2, dadurcn gekennzeichnet, daß der eine Ausgang (6) des Steuergerätes (2) mit der Drain- Elektrode des zweiten DMOS-FETs (18), mit der Gate-Elektrode des ersten DMOS-FETs (16) und über die erste Zundemheit (12) mit der Source-Elektrode und der Bulk-Elektrode des ersten DMOS-FETs (16) verbunden ist, und der andere Ausgang (8) des Steuergeräts mit der Gate-Elektrode des zweiten DMOS-FETs (18), mit der Dram-Elektrode des ersten DMOS-FETs (16) sowie
über die zweite Zündeinheit (14) mit der Source-Elektrode und der Bulk-Elektrode des zweiten DMOS-FETs (18) verbunden ist.3. A circuit according to claim 2, characterized in that the one output (6) of the control device (2) with the drain electrode of the second DMOS-FET (18), with the gate electrode of the first DMOS-FET (16) and is connected via the first ignition unit (12) to the source electrode and the bulk electrode of the first DMOS-FET (16), and the other output (8) of the control device to the gate electrode of the second DMOS-FET (18) , with the dram electrode of the first DMOS-FET (16) and is connected to the source electrode and the bulk electrode of the second DMOS-FET (18) via the second ignition unit (14).
4. Schaltung nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß zum Testen der Zündeinheiten (12, 14) ein im Vergleich zum Zündimpulsstrom kleiner Diagnosestrom eingeprägt wird.4. Circuit according to one of the preceding claims, characterized in that a small compared to the ignition pulse current diagnostic current is impressed for testing the ignition units (12, 14).
5. Schaltung nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Bauelemente (16, 18), die bei einem Zündimpuls Gleichrichtercharakteristik zeigen, derart selbstleitend sind, daß eine Diagnosespannung oder ein Diagnosestrom mit im Vergleich zu den Zündimpulsen geringerer Spannung an den Aus- gangen des Steuergerätes (2) unabhängig von der Polarität zu einem Diagnosestromfluß durch beide Zündeinheiten (12, 14) und die zugehörigen DMOS-FETs (16, 18) führt.
5. Circuit according to one of claims 1 to 4, characterized in that the components (16, 18), which show rectifier characteristics in the case of an ignition pulse, are self-conducting in such a way that a diagnostic voltage or a diagnostic current with a lower voltage in comparison to the ignition pulses Outputs of the control unit (2), regardless of the polarity, leads to a diagnostic current flow through both ignition units (12, 14) and the associated DMOS-FETs (16, 18).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19731717.0 | 1997-07-23 | ||
| DE1997131717 DE19731717C5 (en) | 1997-07-23 | 1997-07-23 | Circuit for igniting two ignition units, in particular airbag ignition units |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1999005005A1 true WO1999005005A1 (en) | 1999-02-04 |
Family
ID=7836683
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/DE1998/001562 WO1999005005A1 (en) | 1997-07-23 | 1998-06-08 | Circuit for igniting two ignition units, especially airbag ignition units |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE19731717C5 (en) |
| WO (1) | WO1999005005A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999059843A1 (en) * | 1998-05-20 | 1999-11-25 | Siemens Aktiengesellschaft | Method and device for checking an electric circuit, especially an ignition circuit of a motor vehicle occupant protection system |
| EP1032514B1 (en) * | 1997-11-27 | 2002-03-13 | Siemens Aktiengesellschaft | Motor vehicle passenger protection system with several squibs, and process for driving the ignition circuit of such a passenger protection system |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6131947A (en) * | 1998-01-23 | 2000-10-17 | Trw Inc. | Electrical connector for air bag inflator |
| DE19932250A1 (en) * | 1999-07-10 | 2001-01-25 | Daimler Chrysler Ag | Method for measuring the ohmic resistance of an electrical connection and an igniter of an occupant protection device connected via this electrical connection and a connection of a metallic housing part to a ground potential |
| DE10005785C1 (en) * | 2000-02-10 | 2001-09-06 | Siemens Ag | Arrangement for triggering a restraint in a motor vehicle |
| DE10349888B4 (en) * | 2003-10-25 | 2006-10-05 | Adam Opel Ag | Coded ignition unit for an airbag module and thus equipped airbag module for a motor vehicle airbag system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3326277C2 (en) | 1983-07-21 | 1989-10-05 | Robert Bosch Gmbh | |
| US5446442A (en) * | 1992-03-31 | 1995-08-29 | Siemens Aktiengesellschaft | Circuit arrangement for triggering a vehicle passenger protection system |
| EP0705740A1 (en) * | 1993-06-28 | 1996-04-10 | Sensor Technology Co., Ltd. | Starting device for crew protecting system |
| DE29609556U1 (en) * | 1996-05-29 | 1996-08-14 | Siemens AG, 80333 München | Release device for at least one restraint device in a motor vehicle |
| US5596497A (en) * | 1994-02-17 | 1997-01-21 | Mitsubishi Denki Kabushiki Kaisha | Control circuit for vehicle safety device |
| DE19530238A1 (en) | 1995-08-17 | 1997-02-20 | Bosch Gmbh Robert | Method for checking a safety device and device for carrying out the method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2740545B1 (en) * | 1995-10-30 | 1997-12-05 | Livbag Snc | PYROTECHNIC GAS GENERATOR, VARIABLE FLOW RATE, FOR PROTECTIVE CUSHIONS |
-
1997
- 1997-07-23 DE DE1997131717 patent/DE19731717C5/en not_active Expired - Fee Related
-
1998
- 1998-06-08 WO PCT/DE1998/001562 patent/WO1999005005A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3326277C2 (en) | 1983-07-21 | 1989-10-05 | Robert Bosch Gmbh | |
| US5446442A (en) * | 1992-03-31 | 1995-08-29 | Siemens Aktiengesellschaft | Circuit arrangement for triggering a vehicle passenger protection system |
| EP0705740A1 (en) * | 1993-06-28 | 1996-04-10 | Sensor Technology Co., Ltd. | Starting device for crew protecting system |
| US5596497A (en) * | 1994-02-17 | 1997-01-21 | Mitsubishi Denki Kabushiki Kaisha | Control circuit for vehicle safety device |
| DE19530238A1 (en) | 1995-08-17 | 1997-02-20 | Bosch Gmbh Robert | Method for checking a safety device and device for carrying out the method |
| DE29609556U1 (en) * | 1996-05-29 | 1996-08-14 | Siemens AG, 80333 München | Release device for at least one restraint device in a motor vehicle |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1032514B1 (en) * | 1997-11-27 | 2002-03-13 | Siemens Aktiengesellschaft | Motor vehicle passenger protection system with several squibs, and process for driving the ignition circuit of such a passenger protection system |
| WO1999059843A1 (en) * | 1998-05-20 | 1999-11-25 | Siemens Aktiengesellschaft | Method and device for checking an electric circuit, especially an ignition circuit of a motor vehicle occupant protection system |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19731717C5 (en) | 2004-06-24 |
| DE19731717C1 (en) | 1998-12-10 |
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