Active Power Blocking Circuit for Duplex Squib Control
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Solution Overview
Problem
The Integrated Duplex Firing concept for vehicle restraints restricts simultaneous deployment of squibs due to the absence of bidirectional firing capability, necessitating a solution for independent control and safety diagnostics.
Innovation Solution
An active power blocking circuit with a logic circuit, multiple switches, and amplifiers is integrated into the restraint control module, enabling duplex firing and providing safety diagnostics through a silicon on insulator (SOI) process for voltage isolation and multiple switch functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a single wire pair is used to connect two squibs to the Restraints ECU (Integrated Duplex Firing), then the number of wires and connectors is reduced, but simultaneous deployment of squibs is restricted
Solution Approach 1:
The firing path is segmented into two independent paths with separate blocking circuits for each squib. Each squib has its own blocking circuit that can independently control current flow, allowing one squib to be deployed while the other remains blocked or is deployed simultaneously through bidirectional current control.
Solution Approach 2:
The patent uses bidirectional firing current that can flow in opposite directions through the single wire pair. By inverting the current direction, the blocking circuits can be selectively activated to control which squib fires, enabling simultaneous deployment despite using a single wire pair connection.
2Adaptability or versatility
If blocking circuits are integrated into the firing path for independent squib control, then bidirectional firing capability is achieved, but circuit complexity increases
Solution Approach 1:
Multiple functions are merged into the Restraints ECU: the blocking circuits, diagnostic circuits, control logic, and power management are all integrated into a single control module. This consolidation reduces overall system complexity despite adding functionality, as shared components and unified control architecture eliminate the need for separate discrete circuits.
Solution Approach 2:
The Restraints ECU is designed as a universal control unit that handles multiple functions: firing control for multiple squibs, diagnostic monitoring, blocking circuit control, and bidirectional current management. This multi-functional design reduces the need for separate specialized circuits for each function.
3Loss of substance
If duplex firing configuration is implemented, then wire count is reduced, but safety diagnostic capability is limited
Solution Approach 1:
Diagnostic circuits are integrated into the Restraints ECU that continuously monitor the firing path and provide feedback on system status. These circuits detect faults, resistance changes, and abnormal conditions in real-time, enabling comprehensive safety diagnostics despite the reduced wiring configuration of duplex firing.
Solution Approach 2:
The Restraints ECU acts as an intermediary that provides diagnostic monitoring between the squibs and the vehicle's control systems. The ECU includes dedicated diagnostic circuits that interface with the firing path, enabling fault detection and safety monitoring without requiring additional external monitoring equipment.
Data Source
AI summary
An active power blocking circuit in series with a squib. The active power blocking circuit may include a logic circuit, a first switch, a second switch, and an amplifier. The first switch may have a first side connected to a positive connection and a second side connected to a negative connection. The second switch may have a first side connected to the positive connection and a second side connected to the negative connection through a diode. The amplifier may be connected the second side of the second switch and the output of the amplifier may be connected to the logic circuit.