Distributed airbag firing system and interface circuit therefor
First Claim
1. An interface circuit having first and second inputs and first and second outputs, comprising:
- a first switching circuit (70) having a first conduction terminal coupled to the first input, a second conduction terminal coupled to the first output;
a control input coupled to the second input through a current limiting circuit, and an over-voltage protection circuit coupled between the control input and the second conduction terminal; and
a second switching circuit (90) having a first conduction terminal coupled to the second input, a second conduction terminal coupled to the second output, a control input coupled to the first input through a current limiting circuit, and an over-voltage protection circuit coupled between the control input and the second conduction terminal,wherein the second conduction terminal of the first switching circuit couples with a power supply terminal for receiving a positive potential, andwherein when the first input receives a positive signal with respect to the second input, the first output is coupled with the power supply terminal, andwherein when the second input receives a positive signal with respect to the first input, the first output is coupled with the power supply terminal.
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Accused Products
Abstract
A distributed airbag firing system (10) includes a controller (12) receiving sensor signals from a sensor (20) over a two-wire bus (18). The controller provides a firing command over to the two-wire bus to a squib driver circuit (26), which provides the firing current necessary to detonate a squib device (32) and inflate the airbag. The squib driver circuit includes a rectifier (42) with its first and second inputs interchangeably connected to the two-wire bus. The rectifier circuit converts the voltage orientation on the first and second conductors to a positive potential on a first output conductor and a negative or ground potential on a second output conductor. The interchangeability of the first and second inputs of the rectifier to the two-wire bus makes the connection arbitrary and fail-safe.
55 Citations
20 Claims
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1. An interface circuit having first and second inputs and first and second outputs, comprising:
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a first switching circuit (70) having a first conduction terminal coupled to the first input, a second conduction terminal coupled to the first output;
a control input coupled to the second input through a current limiting circuit, and an over-voltage protection circuit coupled between the control input and the second conduction terminal; anda second switching circuit (90) having a first conduction terminal coupled to the second input, a second conduction terminal coupled to the second output, a control input coupled to the first input through a current limiting circuit, and an over-voltage protection circuit coupled between the control input and the second conduction terminal, wherein the second conduction terminal of the first switching circuit couples with a power supply terminal for receiving a positive potential, and wherein when the first input receives a positive signal with respect to the second input, the first output is coupled with the power supply terminal, and wherein when the second input receives a positive signal with respect to the first input, the first output is coupled with the power supply terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A distributed airbag firing system, comprising:
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first and second conductors coupled for receiving first and second control signals; and a squib driver circuit having first and second inputs interchangeably connected to the first and second conductors, the squib driver circuit having first and second outputs wherein when the first input of the squib driver receives a positive signal with respect to the second input, the first output is coupled with a positive power supply terminal, and wherein when the second input of the squib driver receives a positive signal with respect to the first input, the first output is coupled with the positive power supply terminal. - View Dependent Claims (11, 12)
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13. An integrated circuit for supplying a firing signal to a squib detonation device, the integrated circuit comprising:
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an interface circuit having first and second inputs interchangeably coupled to first and second conductors; and a control and driver circuit having first and second inputs coupled to first and second outputs of the interface circuit, respectively, and further having first and second outputs for providing the firing signal, wherein when the first input of the interface circuit receives a positive signal with respect to the second input, the first output is coupled with a positive power supply terminal providing a positive power supply signal on the first input of the control and driver circuit, and wherein when the second input of the interface circuit receives a positive signal with respect to the first input, the first output is coupled with the positive power supply terminal providing a positive power supply signal on the first input of the control and driver circuit. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method of interchangeably connecting first and second inputs of a squib driver circuit to first and second control conductors in an airbag deployment system, comprising the steps of:
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arbitrarily connecting the first input of the squib driver circuit to the first control conductor; and connecting the second input of the squib driver circuit to the second control conductor, wherein when the first input receives a positive signal with respect to the second input, the first output is provided with a positive voltage from a power supply terminal to provide an airbag firing signal, and wherein when the second input receives a positive signal with respect to the first input, the first output is provided with a positive voltage from a power supply terminal to provide the airbag firing signal.
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Specification