Igniter Circuit Current Threshold Detection and Shutdown Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in protecting semiconductor devices from damage due to high current flows during ignition coil operations, leading to increased costs and reliability issues, as existing fuses may trigger false open circuits or fail to detect short circuits promptly.
Innovation Solution
An igniter circuit with a detect circuit and shutdown control mechanism that monitors current thresholds and control states to selectively disable the load switch and decouple the DC voltage source, preventing damage by quickly responding to short circuits and abnormal current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fuse is used to protect the semiconductor device from high current, then the semiconductor device is protected from damage, but the fuse may trigger false open circuits during normal operation or fail to detect short circuits promptly
Solution Approach 1:
The patent replaces the mechanical/chemical fuse system with an electronic protection circuit that uses active components (transistors, resistors, capacitors) to detect and respond to abnormal current conditions. The protection mechanism transitions from a passive fuse that opens under excessive current to an active electronic circuit that can distinguish between normal high current operation and actual fault conditions, eliminating false positives and improving detection accuracy.
Solution Approach 2:
The patent introduces intermediate sensing components (sense resistors, comparator circuits) between the current path and the protection decision. These intermediaries allow the system to monitor current levels without directly interrupting the circuit, enabling precise threshold detection and differentiation between normal operating conditions and actual faults before triggering protection actions.
2Speed
If the fuse sensitivity is increased to detect short circuits faster, then the semiconductor device is protected more quickly, but the fuse may form an open circuit during normal operating conditions
Solution Approach 1:
The patent implements dynamic threshold adjustment where the protection circuit adapts its current threshold based on operating conditions. The circuit can differentiate between transient high current during normal operation and sustained high current indicating a fault, adjusting its response accordingly. This dynamic behavior allows fast response to actual faults while maintaining stability during normal high-current operation.
Solution Approach 2:
The protection circuit incorporates feedback mechanisms that continuously monitor circuit conditions and adjust the protection response. The system uses feedback from voltage and current sensors to determine whether to activate protection, allowing it to respond quickly to genuine faults while ignoring normal operating variations that would trigger a false positive in a simpler system.
3Reliability
If the fuse sensitivity is decreased to avoid false open circuits, then the semiconductor device operates more reliably, but the semiconductor device may be damaged before the fuse forms the open circuit
Solution Approach 1:
The patent replaces the slow-acting mechanical fuse with an electronic protection system that can respond in microseconds to abnormal conditions. The electronic circuit uses fast-switching transistors and comparators to detect and interrupt fault currents before they can cause damage, providing both the reliability of high operational thresholds and the speed of immediate protection when needed.
Data Source
AI summary
In one embodiment, an igniter circuit may include a circuit to determine if the current through a load switch exceeds a threshold value, and to responsively disable a second switch that couples DC power to the igniter circuit.