Fault tolerant power supply and bus topology for a distributed architecture supplemental restraint system
First Claim
1. A vehicular supplemental restraint system including a plurality of sensing modules and deployment modules in distributed locations of the vehicle, comprising:
- a power and communications bus coupled to each of said sensing and deployment modules for supplying power to said modules and for enabling communication among said modules, said bus including a ground wire and a power wire;
a power supply circuit coupled to a vehicle storage battery and to said bus for developing a regulated voltage across the ground and power wires of said bus, said power supply including a transformer having primary and secondary windings, a power device switched on and off to periodically connect said primary winding to said vehicle battery, an energy storage circuit referenced to the ground wire of said bus and connected between said secondary winding and the power wire of said bus for transferring energy coupled between said primary and secondary windings to the power wire of said bus; and
a control circuit for controlling the switching of said power device based on a measured voltage across said primary winding while said power device is switched off.
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Accused Products
Abstract
An improved distributed architecture SIR system wherein the idle voltage of the power and communications bus is regulated by a fault tolerant power supply circuit, and portions of the bus coupled to devices located in a crush zone of the vehicle may be de-coupled from other portions of the bus in the event of a short circuit across the wires of that portion of the bus. The power and communications bus comprises two wires (signal and ground) and the bus ground wire is weakly biased to a reference voltage. A boost power supply referenced to the bus ground establishes the nominal voltage of the signal wire, and supplies charging current over the signal wire to the energy reserve circuits of various devices coupled to the bus. The power supply is transformer-isolated from the bus, and the feedback circuitry for controlling the operation of the power supply senses the bus voltage as coupled through the transformer. Consequently, the power supply retains the ability to regulate the bus voltage in fault conditions where the ground or signal wires of the bus are shorted to vehicle ground or battery voltage. In such conditions, the bus ground shifts from its normal value, and is detected to provide a warning indication to the operator of the vehicle. Open circuit failures of the bus wires are addressed by configuring the bus in a closed ring topology, and short circuits across the bus wires are addressed by configuring the bus so that portions of the bus disposed in one or more crush zones of the vehicle can be de-coupled from the rest of the bus.
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Citations
7 Claims
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1. A vehicular supplemental restraint system including a plurality of sensing modules and deployment modules in distributed locations of the vehicle, comprising:
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a power and communications bus coupled to each of said sensing and deployment modules for supplying power to said modules and for enabling communication among said modules, said bus including a ground wire and a power wire; a power supply circuit coupled to a vehicle storage battery and to said bus for developing a regulated voltage across the ground and power wires of said bus, said power supply including a transformer having primary and secondary windings, a power device switched on and off to periodically connect said primary winding to said vehicle battery, an energy storage circuit referenced to the ground wire of said bus and connected between said secondary winding and the power wire of said bus for transferring energy coupled between said primary and secondary windings to the power wire of said bus; and a control circuit for controlling the switching of said power device based on a measured voltage across said primary winding while said power device is switched off. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification