US 5,331,211 A · Releasing circuit for actuating vehicular safety device

Abstract

A circuit for controlling the actuation of a vehicle air bag system includes a two terminal electrically actuated ignition element connectable to a drive voltage line through a first transistor and to a circuit ground through another transistor. The voltage source includes the vehicle battery and a capacitor that is charged by the vehicle battery and which supplies operating power in the event the vehicle battery is removed from the circuit, for example, as a consequence of a collision. The transistors are normally biased to a non-conducting state sufficient to isolate the ignition element from the drive voltage source and circuit ground. Vehicle acceleration is sensed by an acceleration sensor which, in the event of a collision, biases both transistors into conduction to effectively connect the two terminals of the ignition element to the drive voltage line and to ground to actuate the vehicle air bag. During normal operation, a bias circuit controls one of the transistors to provide a minute current flow that is used to sense fault conditions and illuminate an alarm lamp. During a collision, the acceleration sensing circuit re-configures the bias circuit to drive both transistors into conduction. A low-voltage circuit senses the drive voltage and controls the bias to the one transistor to inhibit the minute current flow to conserve power during low-voltage conditions.

Claims41

Dependent claims

A release circuit for a vehicle passenger-safety device having a current-actuated release element connectable to an electrical power source for actuation thereof, comprising:

a controllable semiconductive device in a circuit path between the release element and the electrical power source and biasable from and between a non-conducting state and a current-conducting state sufficient to actuate the release element;
means connected to the electrical power source and the controllable semiconductor device for detecting the voltage of the electrical power source and for controlling the controllable semiconductor device to its non-conducting state to prohibit conduction when the voltage of the electrical power source is below a selected value;
and
means for sensing the acceleration of the vehicle and providing an electrical signal thereof indicative of abnormal acceleration to the controllable semiconductor device to control the controllable semiconductor device to the current-conducting state sufficient to actuate the release element, the abnormal acceleration signal controlling the controllable semiconductor device to the current-conducting state sufficient to actuate the release element irrespective to the means for detecting controlling the controllable semiconductor device to its non-conducting state to prohibit conduction.

1 more element

A releasing circuit for a safety device having a release element (10) actuable in response to a current sufficient for activation thereof provided through a current path from at least one of a battery (Ba) and a capacitor (20) charged by said battery (Ba) through said current path, the safety device actuable in response to activation of the release element (10) to protect passengers of a vehicle, comprising:

an acceleration sensor (71) for providing an acceleration signal responsive to accelerations of the vehicle,
evaluating circuit means (70,70A) for evaluating the acceleration signal from said acceleration sensor (71) in relation to a predetermined evaluating condition for supplying said sufficient current to the release element (10) from at least one of said battery (Ba) and said capacitor (20) and for generating an evaluating signal when the predetermined evaluating condition is satisfied,
first means (50,10a,60) controllable in at least a low conducting state and a high conducting state provided within said current path and for supplying a minute current continuously to the release element (10) from at least one of said battery (Ba) and said capacitor (20) through said current path when controlled in a low conducting state thereof and for supplying said sufficient current to the release element (10) from at least one of said battery (Ba) and said capacitor (20) through said current path when controlled in a high conducting state thereof,
second means (79,79c,10b,80,80a-80f) including control means maintainable in a first condition to control said first means (50,10a,60) in the low conducting state and maintainable in a second condition to control said first means (5,10a,60) in the high conducting state, said second means arranged for effecting the first condition of said control means when said evaluating circuit means (70,70A) does not generate any evaluating signal and for effecting the second condition of said control means in response to the evaluating signal from said evaluating circuit means (70,70A), and
third means (30,40,40A) including means for detecting a decrease of an electric voltage from at least one of said battery (Ba) and said capacitor (20) relative to a reference value to generate a detecting signal therefrom, said third means prohibiting operation of said first means (50,10a,60) in response to said detected voltage decrease.

2 more elements

an acceleration sensor (71) arranged to provide an acceleration signal responsive to accelerations of the vehicle,
evaluating circuit means (70,70A) for evaluating the acceleration signal from said acceleration sensor (71) in relation to a predetermined evaluating condition for supplying the sufficient current to the release element (10) from at least one of said battery (Ba) and said capacitor (20) and for generating an evaluating signal when the predetermined evaluation condition is satisfied,
transistor circuit means (50,10a,60) provided within said current path for supplying a minute current continuously to the release element (10) from at least one of said battery (Ba) and said capacitor (20) through said current path when controlled in a low conducting state thereof and for supplying said sufficient current to the release element (10) from at least one of said battery (Ba) and said capacitor (20) through said current path when controlled in a high conducting state thereof,
first means (79,10b,79c,80,80a-80f) including control means maintainable in a first condition to control said transistor circuit means (50,10a,60) in the low conducting state and maintainable in a second condition to control said transistor circuit means (50,10a,60) in the high conducting state, said first means arranged for effecting the first condition of said control means when said evaluating circuit means (70,70A) does not generate any evaluating signal and for effecting the second condition of said control means in response to the evaluation signal from said evaluating circuit means (70,70A), and
second means (30,40,40A) including means for detecting a decrease of an electric voltage from at least one said battery (Ba) and said capacitor (20) to generate a detecting signal therefrom, said second means (30,40,40A) prohibiting operation of said transistor circuit means (50,10a,60) in response to the detecting signal.

2 more elements

A releasing circuit for a safety device having a release element (10) actuable in response to a current sufficient for activation thereof provided from an electric power source (Ba,20) through a current path, the safety device actuable in response to activation of the release element (10) to protect passengers of a vehicle, comprising:

an acceleration sensor (71) arranged to provide an acceleration signal responsive to acceleration of the vehicle,
evaluating circuit means (70,70A) for evaluating the acceleration signal from said acceleration sensor (71) in relation to a predetermined evaluating condition for supplying the sufficient current to the release element (10) from said electric power source (Ba,20) and for generating an evaluating signal when the predetermined evaluating condition is satisfied,
first means (50,10a,60) arranged within said current path for controlling the supply of a current from said electric power source (Ba,20) to the release element (10),
second means (80a,80e,79c,10b) for supplying a driving current for driving said first means to said first means from said electric power source (Ba,20),
third means (79) responsive to the evaluating signal from said evaluating circuit means (70,70A) for cooperating with said first means (50,10a,60) so as to supply the sufficient current through said current path to the release element (10) from said electric power source (Ba,20), and
fourth means (30,40,40A) for controlling said first means (50,10a,60) so as to prohibit supply of the sufficient current to the release element (10) when a predetermined prohibitive condition for prohibiting activation of the release element (10) is detected,
wherein said second means includes limiting means (80a-80f) for limiting the driving current in a first current value before generation of the evaluating signal from said evaluating circuit means (70,70A), and
said second means including means (80,79c,60) for switching over a value of the driving current from the first current value into a second current value larger than the first current value at the start of control by said third means (79), said means for switching over (80,79c,60) conditioning said first means (50,10a,60) in a mode enabling supply of the sufficient current to the release element (10) under control of said third means (79).

5 more elements

A releasing circuit for a safety device having a release element (10) actuable in response to a current sufficient for activation thereof from an electric power source (Ba,20) provided through a current path, the safety device actuable in response to activation of the release element (10) to protect passengers of a vehicle, comprising:

an acceleration sensor (71) arranged to provide an acceleration signal responsive to the accelerations of the vehicle,
evaluating circuit means (70,70A) for evaluating the acceleration signal from said acceleration sensor (71) in relation to a predetermined evaluating condition for supplying the sufficient current to the release element (10) from said electric power source (Ba,20) and for generating an evaluating signal when the predetermined evaluating condition is satisfied,
first means (50,10a,60) arranged within said current path for controlling the supply of a current from said electric power source (Ba,20) to the release element (10),
second means (80a-80e,79c,10b) for supplying a driving current for driving said first means (50,10a,60) to said first means from said electric power source (Ba,20),
third means (79) responsive to the evaluating signal from said evaluating circuit means (70,70A) for cooperating with said first means (50,10a,60) so as to supply the sufficient current through said current path to the release element (10) from said electric power source (Ba,20), and
fourth means (30,40,40a) for controlling said first means so as to prohibit supply of the sufficient current to the release element (10) when a predetermined prohibitive condition for prohibiting activation of the release element (10) is detected,
wherein said second means includes limiting means (80a-80d,80f) for limiting the driving current to a first current value until operation of said third means (79),
said second means including means (80,79c,60) responsive to operation of said third means (79) for switching over a value of the driving current from the first current value into a second current value larger than the first current value, said means for switching over (80,79c,60) conditioning said first means in a mode enabling supply of the sufficient current to the release element (10) under control of said third means (79).

5 more elements

an acceleration sensor (71) arranged to provide an acceleration signal responsive to the accelerations of the vehicle,
evaluating circuit means (70,70A) for evaluating the acceleration signal from said acceleration sensor (71) in relation to a predetermined evaluating condition for supplying the sufficient current to the release element (10) and for generating an evaluating signal when the predetermined evaluating condition is satisfied,
a transistor (50) arranged within said current path for controlling the supply of a current from said electric power source (Ba,20) to the release element (10),
first means (80a,80b) for supplying a driving current to a base of said transistor (50) from said electric power source (Ba,20),
second means (79) responsive to the evaluating signal from said evaluating circuit means (70,70A) for cooperating with said transistor (50) so as to supply the sufficient current through said current path to the release element (10) from said electric power source (Ba,20), and
third means (30,40) for controlling said transistor (50) so as to prohibit supply of the sufficient current to the release element (10) when a predetermined prohibitive condition for prohibiting activation of the release element (10) is detected,
wherein said first means (80a,80ba) includes limiting means (80a,80b) for limiting the driving current to a first current value before generation of the evaluating signal from said evaluating circuit means (70,70A), and
said second means including means (80) for switching over a value of the driving current from the first current value upon control by said second means (79), said means for switching over conditioning said transistor (50) in a mode enabling supply of the sufficient current into the release element (10) under control of said second means (79).

5 more elements

Dependencies are inferred from the claim text.

Releasing circuit for actuating vehicular safety device

Life of this patent

Releasing circuit for actuating vehicular safety device

Life of this patent

Abstract

Claims41