Ignition circuit for a squib in an air bag in a vehicle
First Claim
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1. An ignition circuit for a squib in an air bag in a vehicle, comprisinga battery;
- a first capacitor which is charged by said battery;
a second capacitor which is connected in parallel with said first capacitor, and charged by said battery;
a sensor that detects a collision of the vehicle; and
an igniting means which connects said first capacitor and said second capacitor in series, and supplies electric energy charged in said first capacitor and said second capacitor to said squib when the collision of said vehicle is detected by the sensor.
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Abstract
An object of the present invention is provide an ignition circuit for a squib in an air bag in a vehicle able to supply sufficient energy to ignite the squib which does not use converter or a high capacity capacitor.
The first capacitor 12 and the second capacitor 13 are charged by the battery 11. The sensor 17 is closed and the control circuit 10 makes the NPN type transistor 19 active when a collision is detected. The squib 16 is connected to the junction of the first capacitor 12 and the second capacitor 13 so that sufficient energy can be supplied to the squib even when a converter is not used.
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Citations
7 Claims
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1. An ignition circuit for a squib in an air bag in a vehicle, comprising
a battery; -
a first capacitor which is charged by said battery; a second capacitor which is connected in parallel with said first capacitor, and charged by said battery; a sensor that detects a collision of the vehicle; and an igniting means which connects said first capacitor and said second capacitor in series, and supplies electric energy charged in said first capacitor and said second capacitor to said squib when the collision of said vehicle is detected by the sensor.
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2. An ignition circuit for a squib in an air bag in a vehicle, comprising:
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a battery, a negative electrode thereof being grounded; a first capacitor, a positive electrode thereof being applied to a positive electrode of the battery, and a negative electrode thereof being grounded; a second capacitor, a positive electrode therefore being applied to the positive electrode of the battery via a positive side current limiting resistor, and a negative electrode thereof being grounded via a negative side current limiting resistor; a squib, a first terminal thereof being applied to the positive electrode of the battery via a sensor which mechanically closes when the sensor detects a collision, and a second terminal thereof being applied to the negative electrode of the second capacitor; a diode, an anode thereof being applied to the second terminal of the squib and a cathode thereof being applied to the positive electrode of the second capacitor; a main switch which causes the positive electrode of the second capacitor to be grounded when the main switch closes; and a control circuit which causes the main switch to close when the control circuit detects a collision.
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3. An ignition circuit for a squib in an air bag in a vehicle, comprising:
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a DC-DC converter for increasing a voltage of a battery, a negative electrode thereof being grounded; a first capacitor, a positive electrode thereof being applied to a positive electrode of the DC-DC converter, and a negative electrode thereof being grounded; a second capacitor, a positive electrode thereof being applied to the positive electrode of the DC-DC converter via a positive side current limiting resistor, and a negative electrode thereof being grounded via a negative side current limiting resistor; a squib, a first terminal thereof being connected to the positive electrode of the DC-DC converter via a sensor which mechanically closes when the sensor detects a collision, and a second terminal thereof being applied to the negative electrode of the second capacitor; a sub-switch which causes the second terminal of the squib to be connected to ground via a negative voltage protecting diode when the sub-switch closes; a main switch which causes the positive electrode of the second capacitor to be connected to ground when the main switch closes; and a control circuit which causes the sub-switch to close when the control circuit detects a collision, and the main switch to close when a predetermined period of time has elapsed after the sub-switch has closed. - View Dependent Claims (4)
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5. A method for igniting a squib for an air bag of a vehicle, comprising the steps of:
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(1) storing electric power in a first capacitor, a positive electrode thereof being applied to a positive electrode of a battery, and a negative electrode thereof being grounded; (2) storing electric power in a second capacitor, a positive electrode thereof being applied to the positive electrode of the battery via a positive side current limiting resistor, and a negative electrode thereof being grounded via a negative side current limiting resistor; (3) supplying electric power to a squib, a first terminal thereof being applied to the positive electrode of the battery via a sensor which mechanically closes when the sensor detects a collision, and a second terminal thereof being applied to the negative electrode of the second capacitor; (4) blocking an electric current which flows from the squib to a positive electrode of the second capacitor by a diode, an anode thereof being applied to the second terminal of the squib and a cathode thereof being applied to the positive electrode of the second capacitor; (5) causing the positive electrode of the second capacitor to ground when a main switch closes; and (6) causing the main switch to close when a control circuit detects a collision.
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6. A method for igniting a squib for an air bag of a vehicle, comprising the steps of:
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(1) increasing a voltage of a battery by a DC-DC converter, a negative electrode of the DC-DC converter being grounded; (2) storing electric power supplied from the DC-DC converter in a first capacitor, a positive electrode of the first capacitor being applied to a positive electrode of the DC-DC converter, and a negative electrode of the first capacitor being grounded; (3) storing electric power supplied from the DC-DC converter in a second capacitor, a positive electrode of the second capacitor being applied to a positive electrode of the DC-DC converter via a positive side current limiting resistor, and a negative a electrode of the second capacitor being grounded via a negative side current limiting resistor; (4) supplying electric power to a squib, a first terminal thereof being applied to the positive electrode of the DC-DC converter via a sensor which mechanically closes when the sensor detects a collision, and a second terminal thereof being applied to the negative electrode of the second capacitor; (5) causing the second terminal of the squib to be connected to ground via a negative voltage protecting diode when a sub-switch closes; (6) causing the positive electrode of the second capacitor to ground when a main switch closes; (7) causing the sub-switch to close when a control circuit detects a collision; and (8) causing the main switch to close when a predetermined period of time has elapsed after the sub-switch has closed. - View Dependent Claims (7)
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Specification