Motor vehicle seat belt safety system

Claim 2

An integrated circuit for providing a seat belt violation signal for controlling a load device on a motor vehicle said vehicle including a battery, a seat and seat switch means adapted to be actuated in response to seat occupancy, seat belts, and belt switch means adapted to be actuated in response to usage of said belts, said integrated circuit being characterized by relatively high immunity to voltage fluctuations and comprising: means for connecting said battery to a first junction in said circuit in response to actuation of said seat switch means, means for connecting said battery to a second junction in said circuit in response to actuation of said seat belt switch means, latch means comprising a PNP transistor and an NPN transistor, means cOnnecting the base of said PNP transistor with said first junction, means including a voltage dropping diode connecting the emitter of said PNP transistor to said second junction, means connecting the collector of said PNP transistor with the base of said NPN transistor, means connecting the emitter of said NPN transistor to ground and means connecting the collector of said NPN transistor to the base of said PNP transistor whereby said latch means is driven to a latched conductive state in response to actuation of said seat belt switch means prior to actuation of said seat switch means, and said latch means is maintained in an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said seat belt switch means, a second NPN transistor having its emitter connected to ground and its collector connected with the emitter of said PNP transistor, resistor means connecting said first junction to a third junction, first and second parallel diode networks respectively connecting the base of said second NPN transistor and the base of said PNP transistor to said third junction, said first diode network including at least one more diode than the number of diodes in said second diode network whereby the voltage at said third junction is sufficient to saturate said second NPN transistor and substantially ground the emitter of said PNP transistor when said belt switch means is actuated subsequent to actuation of said seat switch means and whereby the voltage at said third junction is insufficient to render said second NPN transistor conductive in response to actuation of said seat switch means subsequent to actuation of said belt switch means due to conduction of said latch means, output transistor switch means for producing said violation signal in response to conduction of said latch means.

Claim 3

An integrated circuit for providing a seat belt violation signal for controlling a load device on a motor vehicle, said vehicle including a battery, a seat and seat switch means adapted to be actuated in response to seat occupancy, seat belts and belt switch means adapted to be actuated in response to usage of said belts, said integrated circuit comprising: means for connecting said battery to a first junction in said circuit in response to actuation of said seat switch means, means for connecting said battery to a second junction in said circuit in response to actuation of said seat belt switch means, latch means comprising a PNP transistor and an NPN transistor, means connecting the base of said PNP transistor with said first junction, means connecting the collector of said PNP transistor with the base of said NPN transistor, means connecting the emitter of said NPN transistor to ground and means connecting the collector of said NPN transistor to the base of said PNP transistor, means connecting the emitter of said PNP transistor to said second junction, whereby said latch means is driven to a latched conductive state in response to actuation of said seat belt switch means prior to actuation of said seat switch means and said latch means is maintained in an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said seat belt switch means, circuit means for rendering said latch means relatively immune to voltage fluctuations at said first and second junctions and including a voltage dropping diode connected in series with the emitter of said PNP transistor, a second NPN transistor having its emitter connected to ground and its collector connected with the emitter of said PNP transistor, means including a resistor and a first series diode network connecting the base of said second NPN transistor to said first junction, a second diode network connected between the base of said PNP transistor and a third junction between said resistor means and said first diode network, said first diode network including at least one more diode then the number of diodes in said second diode network whereby the voltage at said third junction is sufficient to saturate said second NPN transistor and substantially ground the emitter of said PNP transistor when said belt switch means is actuated subsequent to actuation of said seat switch means and whereby the voltage at said third junction is insufficient to render said second NPN transistor conductive in response to actuation of said seat switch means subsequent to actuation of said belt switch means due to conduction of said latch means, a third NPN transistor having its emitter collector path in parallel with said seat switch means and its base connected with said third junction through said first diode network whereby said third NPN transistor is rendered conductive in response to actuation of said seat belt switch means subsequent to actuation of said seat switch means to maintain the voltage at said first junction despite momentary deactuation of said seat switch means, means including a timing capacitor responsive to deactuation of said seat switch means for a predetermined time for lowering the voltage at said third junction and rendering said third NPN transistor nonconductive.

Claim 4

An integrated circuit for providing a seat belt violation signal for controlling a load device on a motor vehicle, said vehicle including a battery, a seat and seat switch means adapted to be actuated in response to seat occupancy, seat belts and belt switch means adapted to be actuated in response to usage of said belts, said integrated circuit comprising: means for connecting said battery to a first junction in said circuit in response to actuation of said seat switch means, means for connecting said battery to a second junction in said circuit in response to actuation of said seat belt switch means, latch means comprising a PNP transistor and an NPN transistor, means connecting the base of said PNP transistor with said first junction, means connecting the collector of said PNP transistor with the base of said NPN transistor, means connecting the emitter of said NPN transistor to ground and means connecting the collector of said NPN transistor to the base of said PNP transistor, means connecting the emitter of said PNP transistor to said second junction, whereby said latch means is driven to a latched conductive state in response to actuation of said seat belt switch means prior to actuation of said seat switch means and said latch means is maintained in an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said seat belt switch means, circuit means for rendering said latch means relatively immune to voltage fluctuations at said first and second junctions and including a voltage dropping diode connected in series with the emitter of said PNP transistor, a second NPN transistor having its emitter connected to ground and its collector connected with the emitter of said PNP transistor, means including a resistor and a first series diode network connecting the base of said second NPN transistor to said first junction, a second diode network connected between the base of said PNP transistor and a third junction between said resistor means and said first diode network, said first diode network including at least one more diode then the number of diodes in said second diode network whereby the voltage at said third junction is sufficient to saturate said second NPN transistor and substantially ground the emitter of said PNP transistor when said belt switch means is actuated subsequent to actuation of said seat switch means and whereby the voltage at said third junction is insufficient to render said second NPN transistor conductive in response to actuation of said seat switch means subsequent to actuation of said belt switch means due to conduction of said latch means, a third NPN transistor having its emitter collector path in parallel with said seat switch means and its base connected with said third junction through said first diode network whereby said third NPN transistor is rendered conductive in response to actuation of said seat belt switch means subsequent to actuation of said seat switch means to maintain the voltage at said first junction despite momentary deactuation of said seat switch means, means including a timing capacitor responsive to deactuation of said seat switch means for a predetermined time for lowering the voltage at said third junction and rendering said third NPN transistor nonconductive.

Claim 5

An integrated circuit for providing a seat belt violation signal for controlling a starter circuit interrupt relay on a motor vehicle, said vehicle including a battery, a seat and seat switch means responsive to seat occupancy, seat belts and switch means responsive to usage of said belts, said integrated circuit being characterized by relatively high immunity to voltage fluctuation and comprising: a first control transistor, means for connecting said battery to said first control transistor to drive said first control transistor to saturation upon actuation of said seat switch means, output transistor switch means for producing said violation signal in response to saturation of said first control transistor, a second control transistor, means for connecting said battery to said second control transistor to drive said second control transistor to saturation and divert drive current from said first control transistor in response to actuation of said belt switch means, latch means comprising a PNP transistor and an NPN transistor, means regeneratively coupling said PNP and said NPN transistors, means connecting the base of said PNP transistor to said battery in response to actuation of said seat switch means, means including a voltage dropping diode connecting the emitter of said PNP transistor to said battery in response to actuation of said belt switch means whereby said latch means is driven to a conductive latched state in response to actuation of said belt switch means prior to actuation of said seat switch means and said latch means is maintained in a nonconductive unlatched state in response to actuation of said seat switch means prior to actuation of said belt switch means, means connecting said latch means in parallel with said first control transistor whereby said output transistor switch means produces said violation signal in response to conduction of either said first control transistor or said latch means, a second NPN transistor, means connecting the emitter of said PNP transistor to ground through the emitter collector path of said second NPN transistor means responsive to the state of said latch means for driving said second NPN transistor to saturation if said latch means is in a nonconductive state after actuation of both said seat switch means and said belt switch means.

Claim 6

An integrated circuit for providing a seat belt violation signal for controlling a starter circuit interrupt relay on a motor vehicle, said vehicle including a battery, a seat and seat switch means responsive to seat occupancy, seat belts and switch means responsive to usage of said belts, said integrated circuit being characterized by relatively high immunity to voltage fluctuation and comprising: a first control transistor, means for connecting said battery to said first control transistor to drive said first control transistor to saturation upon actuation of said seat switch means, output transistor switch means for producing said violation signal in response to saturation of said first control transistor, a second control transistor, means for connecting said battery to said second control transistor to drive said second control transistor to saturation and divert drive current from said first control transistor in response to actuation of said belt switch means, latch means comprising a PNP transistor and an NPN transistor, means regeneratively coupling said PNP and said NPN transistors, means connecting the base of said PNP transistor to said battery in response to actuation of said seat switch means, means including a voltage dropping diode connecting the emitter of said PNP transistor to said battery in response to actuation of said belt switch means whereby said latch means is driven to a conductive latched state in response to actuation of said belt switch means prior to actuation of said seat switch means and said latch means is maintained in a nonconductive unlatched state in response to actuation of said seat switch means prior to actuation of said belt switch means, means connecting said latch means in parallel with said first control transistor whereby said output transistor switch means produces said violation signal in response to conduction of either said first control transistor or said latch means, a second NPN transistor, means connecting the emitter of said PNP transistor to ground through the emitter collector path of said second NPN transistor means responsive to the state of said latch means for driving said second NPN transistor to saturation if said latch means is in a nonconductive state after actuation of both said seat switch means and said belt switch means.

Claim 7

An integrated circuit for providing a seat belt violation signal for controlling a starter circuit interrupt relay on a motor vehicle, said vehicle including a battery, a seat and seat switch means responsive to seat occupancy, seat belts and switch means responsive to usage of said belts, said integrated circuit comprising: a first control transistor, means for connecting said battery to said first control transiStor to drive said first control transistor to saturation upon actuation of said seat switch means, output transistor switch means for producing said violation signal in response to saturation of said first control transistor, a second control transistor, means for connecting said battery to said second control transistor to drive said second control transistor to saturation and divert drive current from said first control transistor in response to actuation of said belt switch means, first latch means comprising a PNP transistor and an NPN transistor, means regeneratively coupling said PNP and said NPN transistors, means connecting the base of said PNP transistor to said battery in response to actuation of said seat switch means, means connecting the emitter of said PNP transistor to said battery in response to actuation of said belt switch means whereby said first latch means is driven to a conductive latched state in response to actuation of said seat belt switch means prior to actuation of said seat switch means and said latch is maintained in a nonconductive unlatched state in response to actuation of said seat switch means prior to actuation of said belt switch means, means connecting said first latch means in parallel with said first control transistor whereby said output transistor switch means produces a violation signal in response to conduction of either said first control transistor or said first latch means, circuit means for stabilizing the operation of said first latch means in the presence of voltage fluctuations in said circuit comprising a voltage dropping diode connected in series with the emitter of said PNP transistor, a second NPN transistor, means connecting the emitter of said PNP transistor to ground through the emitter collector path of said second NPN transistor, means responsive to the state of said latch for driving said second NPN transistor to saturation if said latch means is in a nonconductive state after actuation of both of said seat switch means and said belt switch means, second latch means adapted to be driven to a conductive latched state in response to movement of the vehicle ignition switch to a Start position in the absence of said violation signal, and means responsive to conduction of said second latch means for disconnecting said first latch means from said output transistor switch means.

Claim 8

An integrated circuit for providing a seat belt violation signal for controlling a starter circuit interrupt relay on a motor vehicle, said vehicle including a battery, a seat and seat switch means responsive to seat occupancy, seat belts and switch means responsive to usage of said belts, said integrated circuit comprising: a first control transistor, means for connecting said battery to said first control transiStor to drive said first control transistor to saturation upon actuation of said seat switch means, output transistor switch means for producing said violation signal in response to saturation of said first control transistor, a second control transistor, means for connecting said battery to said second control transistor to drive said second control transistor to saturation and divert drive current from said first control transistor in response to actuation of said belt switch means, first latch means comprising a PNP transistor and an NPN transistor, means regeneratively coupling said PNP and said NPN transistors, means connecting the base of said PNP transistor to said battery in response to actuation of said seat switch means, means connecting the emitter of said PNP transistor to said battery in response to actuation of said belt switch means whereby said first latch means is driven to a conductive latched state in response to actuation of said seat belt switch means prior to actuation of said seat switch means and said latch is maintained in a nonconductive unlatched state in response to actuation of said seat switch means prior to actuation of said belt switch means, means connecting said first latch means in parallel with said first control transistor whereby said output transistor switch means produces a violation signal in response to conduction of either said first control transistor or said first latch means, circuit means for stabilizing the operation of said first latch means in the presence of voltage fluctuations in said circuit comprising a voltage dropping diode connected in series with the emitter of said PNP transistor, a second NPN transistor, means connecting the emitter of said PNP transistor to ground through the emitter collector path of said second NPN transistor, means responsive to the state of said latch for driving said second NPN transistor to saturation if said latch means is in a nonconductive state after actuation of both of said seat switch means and said belt switch means, second latch means adapted to be driven to a conductive latched state in response to movement of the vehicle ignition switch to a Start position in the absence of said violation signal, and means responsive to conduction of said second latch means for disconnecting said first latch means from said output transistor switch means.

Claim 9

An integrated circuit for providing a seat belt violation signal for controlling an indicator on a motor vehicle, said vehicle including a battery, a seat and switch means responsive to seat occupancy, seat belts and switch means responsive to usage of said belts, said integrated circuit comprising: first input transistor switch means for connecting said battery to a first junction in said circuit in response to actuation of said seat switch means, second input transistor switch means for connecting said battery to a second junction in said circuit in response to actuation of said seat belt switch means, output transistor switch means, a first control transistor, means connecting said first control transistor to said first junction to provide drive current to said first control transistor, means interconnecting said first control transistor with an output transistor switch means to provide said violation signal upon conduction of said first control transistor, a second control transistor, means connecting said second control transistor to said second junction to provide drive current to said second control transistor, means interconnecting said first and second control transistor to divert drive current from said first control transistor upon conduction of said second control transistor to thereby render said first control transistor nonconductive, latch means comprising a PNP transistor and an NPN transistor, means connecting the base of said PNP transistor with said first junction, means connecting the emitter of said PNP transistor to said second junctIon whereby said PNP transistor is rendered conductive in response to actuation of said seat belt switch means prior to actuation of said seat switch means and said PNP transistor is reverse biased in response to actuation of said seat switch means prior to actuation of said seat belt switch means, said NPN transistor being coupled to said PNP transistor to be rendered conductive in response to conduction of said PNP transistor and to maintain said PNP transistor in conduction once rendered conductive, means connecting said latch means with said output transistor means to produce said violation signal in response to conduction of said latch means, means for insuring maintenance of the reverse biased condition of said PNP transistor in the presence of voltage fluctuations at said first and second junctions comprising at least one diode connected in series between said second input switch means and the emitter of said PNP transistor, a second NPN transistor, means connecting said second NPN transistor with said latch means and said first junction whereby application of voltage to said first junction prior to application of voltage to said second junction drives said second NPN transistor to saturation to apply substantially ground potential to the emitter of said PNP transistor.

Claim 10

An integrated circuit for providing a seat belt violation signal for controlling an indicator on a motor vehicle, said vehicle including a battery, a seat and switch means responsive to seat occupancy, seat belts and switch means responsive to usage of said belts, said integrated circuit comprising: first input transistor switch means for connecting said battery to a first junction in said circuit in response to actuation of said seat switch means, second input transistor switch means for connecting said battery to a second junction in said circuit in response to actuation of said seat belt switch means, output transistor switch means, a first control transistor, means connecting said first control transistor to said first junction to provide drive current to said first control transistor, means interconnecting said first control transistor with an output transistor switch means to provide said violation signal upon conduction of said first control transistor, a second control transistor, means connecting said second control transistor to said second junction to provide drive current to said second control transistor, means interconnecting said first and second control transistor to divert drive current from said first control transistor upon conduction of said second control transistor to thereby render said first control transistor nonconductive, latch means comprising a PNP transistor and an NPN transistor, means connecting the base of said PNP transistor with said first junction, means connecting the emitter of said PNP transistor to said second junctIon whereby said PNP transistor is rendered conductive in response to actuation of said seat belt switch means prior to actuation of said seat switch means and said PNP transistor is reverse biased in response to actuation of said seat switch means prior to actuation of said seat belt switch means, said NPN transistor being coupled to said PNP transistor to be rendered conductive in response to conduction of said PNP transistor and to maintain said PNP transistor in conduction once rendered conductive, means connecting said latch means with said output transistor means to produce said violation signal in response to conduction of said latch means, means for insuring maintenance of the reverse biased condition of said PNP transistor in the presence of voltage fluctuations at said first and second junctions comprising at least one diode connected in series between said second input switch means and the emitter of said PNP transistor, a second NPN transistor, means connecting said second NPN transistor with said latch means and said first junction whereby application of voltage to said first junction prior to application of voltage to said second junction drives said second NPN transistor to saturation to apply substantially ground potential to the emitter of said PNP transistor.

Claim 11

In a motor vehicle provided with a battery, a starter solenoid, an ignition switch movable from an Off position to a Start position to energize said solenoid, and relay means responsive to a seat belt violation signal for disconnecting said solenoid from said ignition switch, said vehicle further including seat occupancy responsive switch means and switch means responsive to usage of seat belts provided in said vehicle, an integrated circuit having input terminals for connection with said battery, said seat switch means, said belt switch means, and said ignition switch and an output terminal for connection with said relay means, said circuit comprising: first latch means including a first NPN transistor and a first PNP transistor, means connecting the base of said PNP transistor to said battery in response to actuation of said seat occupancy responsive switch means, means connecting the collector of said NPN transistor to said battery through the emitter-base junction of said PNP transistor in response to actuation of said seat belt switch means, means connecting the collector of said PNP transistor to ground through the emitter-base junction of said NPN transistor whereby said first NPN and PNP transistors are driven to a latched conductive state to provide said violation signal at said output terminal in response to actuation of said belt switch means prior to actuation of said seat switch means and are reverse biased to an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said belt switch means, second latch means including a second NPN transistor and a second PNP transistor, means connecting the collector of said second NPN transistor to said battery through the base-emitter junction of said second PNP transistor in response to actuation of said seat occupancy responsive switch, means connecting the collector of said second PNP transistor to ground through the base-emitter junction of said second NPN transistor, means for connecting the base of said second NPN transistor to said battery in response to movement of said ignition switch to said Start position, first transistor switch means responsive to said violation signal for substantially grounding the base of said second NPN transistor whereby said second NPN and second PNP transistors are driven to a latched conductive state upon movement of said ignition switch to said Start position only in the absence of said violation signal.

Claim 12

In a motor vehicle provided with a battery, a starter solenoid, an ignition switch movable from an Off position to a Start position to energize said solenoid, and relay means responsive to a seat belt violation signal for disconnecting said solenoid from said ignition switch, said vehicle further including seat occupancy responsive switch means and switch means responsive to usage of seat belts provided in said vehicle, an integrated circuit having input terminals for connection with said battery, said seat switch means, said belt switch means, and said ignition switch and an output terminal for connection with said relay means, said circuit comprising: first latch means including a first NPN transistor and a first PNP transistor, means connecting the base of said PNP transistor to said battery in response to actuation of said seat occupancy responsive switch means, means connecting the collector of said NPN transistor to said battery through the emitter-base junction of said PNP transistor in response to actuation of said seat belt switch means, means connecting the collector of said PNP transistor to ground through the emitter-base junction of said NPN transistor whereby said first NPN and PNP transistors are driven to a latched conductive state to provide said violation signal at said output terminal in response to actuation of said belt switch means prior to actuation of said seat switch means and are reverse biased to an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said belt switch means, second latch means including a second NPN transistor and a second PNP transistor, means connecting the collector of said second NPN transistor to said battery through the base-emitter junction of said second PNP transistor in response to actuation of said seat occupancy responsive switch, means connecting the collector of said second PNP transistor to ground through the base-emitter junction of said second NPN transistor, means for connecting the base of said second NPN transistor to said battery in response to movement of said ignition switch to said Start position, first transistor switch means responsive to said violation signal for substantially grounding the base of said second NPN transistor whereby said second NPN and second PNP transistors are driven to a latched conductive state upon movement of said ignition switch to said Start position only in the absence of said violation signal.

Claim 13

In a motor vehicle provided with a battery, a starter solenoid, an ignition switch movable from an Off position to a Start position to energize said sTarter solenoid, and relay means responsive to a seat belt violation signal for disconnecting said solenoid from said ignition switch, said vehicle further including seat occupancy responsive switch means and switch means responsive to usage of seat belts provided in said vehicle, an integrated circuit having input terminals for connection with said battery, said seat switch means, said belt switch means, and said ignition switch and an output terminal for connection with said relay means, said circuit comprising: first latch means including a first NPN transistor and a first PNP transistor, means connecting the base of said PNP transistor to said battery in response to actuation of said seat occupancy responsive switch means, means connecting the collector of said NPN transistor to said battery through the emitter-base junction of said PNP transistor in response to actuation of said seat belt switch means, means connecting the collector of said PNP transistor to ground through the emitter-base junction of said NPN transistor whereby said first NPN and PNP transistors are driven to a latched conductive state to provide said violation signal at said output terminal in response to actuation of said belt switch means prior to actuation of said seat switch means and are reverse biased to an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said belt switch means, second latch means including a second NPN transistor and a second PNP transistor, means connecting the collector of said second NPN transistor to said battery through the base-emitter junction of said second PNP transistor in response to actuation of said seat occupancy responsive switch, means connecting the collector of said second PNP transistor to ground through the base-emitter junction of said second NPN transistor, means for connecting the base of said second NPN transistor to said battery in response to movement of said ignition switch to said Start position, control transistor switch means responsive to seat occupancy and the absence of seat belt usage for providing said violation signal, means including a first switching transistor responsive to the violation signal produced by either said first latch means or said control transistor switch means for diverting drive current from the base of said second NPN transistor upon movement of said ignition switch to said Start position in the presence of said violation signal, a blocking diode connected between said first switching transistor and the collector of said second PNP transistor, means for applying said violation signal to said output terminal, and third transistor switch means responsive to conduction of said second latch means for inhibiting the application of said violation signal to said output terminal.

Claim 14

In a motor vehicle provided with a battery, a starter solenoid, an ignition switch movable from an Off position to a Start position to energize said sTarter solenoid, and relay means responsive to a seat belt violation signal for disconnecting said solenoid from said ignition switch, said vehicle further including seat occupancy responsive switch means and switch means responsive to usage of seat belts provided in said vehicle, an integrated circuit having input terminals for connection with said battery, said seat switch means, said belt switch means, and said ignition switch and an output terminal for connection with said relay means, said circuit comprising: first latch means including a first NPN transistor and a first PNP transistor, means connecting the base of said PNP transistor to said battery in response to actuation of said seat occupancy responsive switch means, means connecting the collector of said NPN transistor to said battery through the emitter-base junction of said PNP transistor in response to actuation of said seat belt switch means, means connecting the collector of said PNP transistor to ground through the emitter-base junction of said NPN transistor whereby said first NPN and PNP transistors are driven to a latched conductive state to provide said violation signal at said output terminal in response to actuation of said belt switch means prior to actuation of said seat switch means and are reverse biased to an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said belt switch means, second latch means including a second NPN transistor and a second PNP transistor, means connecting the collector of said second NPN transistor to said battery through the base-emitter junction of said second PNP transistor in response to actuation of said seat occupancy responsive switch, means connecting the collector of said second PNP transistor to ground through the base-emitter junction of said second NPN transistor, means for connecting the base of said second NPN transistor to said battery in response to movement of said ignition switch to said Start position, control transistor switch means responsive to seat occupancy and the absence of seat belt usage for providing said violation signal, means including a first switching transistor responsive to the violation signal produced by either said first latch means or said control transistor switch means for diverting drive current from the base of said second NPN transistor upon movement of said ignition switch to said Start position in the presence of said violation signal, a blocking diode connected between said first switching transistor and the collector of said second PNP transistor, means for applying said violation signal to said output terminal, and third transistor switch means responsive to conduction of said second latch means for inhibiting the application of said violation signal to said output terminal.

Claim 15

In a motor vehicle provided with a battery, a starter solenoid, an ignition movable from an Off position to a Start position to energize said solenoid, and relay means responsive to a seat belt violation signal or disconnecting said solenoid from said ignition switch, said vehicle further including seat occupancy responsive switch means and switch means responsive to usage of seat belts provided in said vehicle, an integrated circuit having input terminals for connection with said battery, said seat switch means, said belt switch means, and said ignition switch and an output terminal for connection with said relay means, said circuit comprising: first input transistor switch means for applying said battery potential to a first junction in said circuit in response to actuation of said seat switch means, second input transistor switch means for applying said battery potential to a second junction in said circuit in response to actuation of said seat belt switch means, a first control transistor, means connecting said first control transistor to said first junction whereby said first control transistor is driven to saturation upon actuation of said seat switch means, a second control transistor, means connecting said second control transistor to said second junction whereby said second control transistor is driven to saturation to divert drive current from said first control transistor in response to actuation of said seat belt switch means, latch means comprising a PNP transistor and an NPN transistor, means connecting the base of said PNP transistor with said first junction, means connecting the emitter of the PNP transistor to said second junction, means connecting the collector of said PNP transistor with the base of said NPN transistor, means connecting the emitter of said NPN transistor to ground and means connecting the collector of said NPN transistor to the base of said PNP transistor whereby said latch means is driven to a latched conductive state in response to actuation of said seat belt switch means prior to actuation of said seat switch means, and said latch means is maintained in an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said seat belt switch means, circuit means for rendering said first latch means relatively immune to voltage fluctuations and comprising a voltage dropping diode connected in series with the emitter of said PNP transistor, a second NPN transistor having its emitter connected to ground and its collector connected with the emitter of said PNP transistor, resistor means connecting said first junction to a third junction, first and second parallel diode networks respectively connecting the base of said second NPN transistor and the base of said PNP transistor to said third junction, said first diode network including at least one more diode than the number of diodes in said second diode network whereby the voltage at said third junction is sufficient to saturate said second NPN transistor and substantially ground the emitter of said PNP transistor when said seat belt switch means is actuated subsequent to actuation of said seat switch means and whereby the voltage at said third junction is insufficient to render said second NPN transistor conductive in response to actuation of said seat switch means subsequent to actuation of said belt switch means due to conduction of said latch means, controlled output transistor switch means for producing said violation signal in response to saturation of said first control transistor or said first latch means, second latch means including a third NPN transistor and a second PNP transistor, means connecting the collector of said third NPN transistor to the said first junction through the base-emitter junction of said second PNP transistor, and means connecting the collector of said second PNP transistor to ground through the base-emitter junction of said third NPN transistor, circuit means for rendering said second latch means relatively immune to voltage fluctuations and comprising clamping diode means connecting the emitter of said second PNP transistor with the emitter of said third NPN transistor to prevent conduction of said second PNP transistor until said third NPN transistor is driven to saturation, a substrate zener diode connected across said clamping diode means to prevent negative transients from driving said second latch means to conductance, a blocking diode having its cathode connected with the collector of said second PNP transistor and its anode connected to ground through the collector emitter path of a first switching transistor, means connecting the base of said first switching transistor to the output of said controlled transistor switch means, means connecting the anode of said blocking diode to said battery in response to movement of said ignition switch to said Start position, a second switching transistor, means connecting said second switching transistor with said battery in response to closure of said ignition switch to drive said sEcond switching transistor to saturation and substantially ground the anode of said blocking diode, first transistor switch means responsive to seat occupancy and nonconductance of said first latch means for rendering said second switching transistor nonconductive, means connecting the output of said controlled transistor switch means to said output terminal, third transistor switch means responsive to conduction of said second latch means for inhibiting application of said violation signal to said output terminal, fourth transistor switch means responsive to conduction of said second latch means for substantially grounding the emitter of said first PNP transistor, a fourth NPN transistor having its emitter collector path in parallel with said seat switch means and its base connected with said third junction through said first diode network whereby said fourth NPN transistor is rendered conductive in response to actuation of said seat belt switch means subsequent to actuation of said seat switch means to maintain the voltage at said first junction despite momentary deactuation of said seat switch means, means including a timing capacitor responsive to deactuation of said seat switch means for a predetermined time for lowering the voltage at said third junction and rendering said fourth NPN transistor nonconductive.

Claim 16

In a motor vehicle provided with a battery, a starter solenoid, an ignition movable from an Off position to a Start position to energize said solenoid, and relay means responsive to a seat belt violation signal or disconnecting said solenoid from said ignition switch, said vehicle further including seat occupancy responsive switch means and switch means responsive to usage of seat belts provided in said vehicle, an integrated circuit having input terminals for connection with said battery, said seat switch means, said belt switch means, and said ignition switch and an output terminal for connection with said relay means, said circuit comprising: first input transistor switch means for applying said battery potential to a first junction in said circuit in response to actuation of said seat switch means, second input transistor switch means for applying said battery potential to a second junction in said circuit in response to actuation of said seat belt switch means, a first control transistor, means connecting said first control transistor to said first junction whereby said first control transistor is driven to saturation upon actuation of said seat switch means, a second control transistor, means connecting said second control transistor to said second junction whereby said second control transistor is driven to saturation to divert drive current from said first control transistor in response to actuation of said seat belt switch means, latch means comprising a PNP transistor and an NPN transistor, means connecting the base of said PNP transistor with said first junction, means connecting the emitter of the PNP transistor to said second junction, means connecting the collector of said PNP transistor with the base of said NPN transistor, means connecting the emitter of said NPN transistor to ground and means connecting the collector of said NPN transistor to the base of said PNP transistor whereby said latch means is driven to a latched conductive state in response to actuation of said seat belt switch means prior to actuation of said seat switch means, and said latch means is maintained in an unlatched nonconductive state in response to actuation of said seat switch means prior to actuation of said seat belt switch means, circuit means for rendering said first latch means relatively immune to voltage fluctuations and comprising a voltage dropping diode connected in series with the emitter of said PNP transistor, a second NPN transistor having its emitter connected to ground and its collector connected with the emitter of said PNP transistor, resistor means connecting said first junction to a third junction, first and second parallel diode networks respectively connecting the base of said second NPN transistor and the base of said PNP transistor to said third junction, said first diode network including at least one more diode than the number of diodes in said second diode network whereby the voltage at said third junction is sufficient to saturate said second NPN transistor and substantially ground the emitter of said PNP transistor when said seat belt switch means is actuated subsequent to actuation of said seat switch means and whereby the voltage at said third junction is insufficient to render said second NPN transistor conductive in response to actuation of said seat switch means subsequent to actuation of said belt switch means due to conduction of said latch means, controlled output transistor switch means for producing said violation signal in response to saturation of said first control transistor or said first latch means, second latch means including a third NPN transistor and a second PNP transistor, means connecting the collector of said third NPN transistor to the said first junction through the base-emitter junction of said second PNP transistor, and means connecting the collector of said second PNP transistor to ground through the base-emitter junction of said third NPN transistor, circuit means for rendering said second latch means relatively immune to voltage fluctuations and comprising clamping diode means connecting the emitter of said second PNP transistor with the emitter of said third NPN transistor to prevent conduction of said second PNP transistor until said third NPN transistor is driven to saturation, a substrate zener diode connected across said clamping diode means to prevent negative transients from driving said second latch means to conductance, a blocking diode having its cathode connected with the collector of said second PNP transistor and its anode connected to ground through the collector emitter path of a first switching transistor, means connecting the base of said first switching transistor to the output of said controlled transistor switch means, means connecting the anode of said blocking diode to said battery in response to movement of said ignition switch to said Start position, a second switching transistor, means connecting said second switching transistor with said battery in response to closure of said ignition switch to drive said sEcond switching transistor to saturation and substantially ground the anode of said blocking diode, first transistor switch means responsive to seat occupancy and nonconductance of said first latch means for rendering said second switching transistor nonconductive, means connecting the output of said controlled transistor switch means to said output terminal, third transistor switch means responsive to conduction of said second latch means for inhibiting application of said violation signal to said output terminal, fourth transistor switch means responsive to conduction of said second latch means for substantially grounding the emitter of said first PNP transistor, a fourth NPN transistor having its emitter collector path in parallel with said seat switch means and its base connected with said third junction through said first diode network whereby said fourth NPN transistor is rendered conductive in response to actuation of said seat belt switch means subsequent to actuation of said seat switch means to maintain the voltage at said first junction despite momentary deactuation of said seat switch means, means including a timing capacitor responsive to deactuation of said seat switch means for a predetermined time for lowering the voltage at said third junction and rendering said fourth NPN transistor nonconductive.