Interrupt Wire Segmentation for Overcurrent Protection in Electronic Control Devices
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Solution Overview
Problem
In electronic control devices with densely arranged small components, conventional fuses take a long time to interrupt short-circuit currents, leading to increased component temperatures and voltage drops, especially in vehicles with many mounted devices, where a large fuse is used for cost reduction and the interrupting current is insufficient for effective overcurrent protection.
Innovation Solution
The electronic control device incorporates two interrupt wires coupled with the common wire and branch wires, allowing one interrupt wire to melt and interrupt a corresponding circuit block while others continue operating, ensuring overcurrent protection without affecting other circuit blocks, with the interrupting current of the smaller wire melting earlier than the larger wire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a large fuse is used to protect multiple circuit blocks to reduce cost and fuse count, then manufacturing cost is reduced, but the interrupting current is insufficient and interrupt time is prolonged
Solution Approach 1:
The patent divides the single fuse protection system into multiple interrupt wire segments, each protecting a specific circuit block. This segmentation allows each interrupt wire to be optimized for its specific circuit's current requirements, enabling faster and more appropriate interrupting action for each block while maintaining cost-effectiveness through integration on the same substrate.
2Reliability
If a fuse is used for overcurrent protection in densely arranged small components, then protection is provided, but the interrupt time is long causing temperature increase and voltage drop
Solution Approach 1:
The patent replaces the traditional mechanical fuse system with an interrupt wire system that can be integrated directly into the circuit board substrate. This substitution enables much faster response times because the interrupt wires are positioned closer to the fault location and have lower thermal mass, allowing them to melt and interrupt current almost immediately upon detecting overcurrent conditions, thereby preventing temperature rise and voltage drops.
3Reliability
If an interrupt wire is disposed for overcurrent protection, then interrupt speed is improved, but entire circuit blocks stop operation when the interrupt wire melts
Solution Approach 1:
The patent implements segmentation by providing separate interrupt wires for different circuit blocks, allowing localized protection. When an overcurrent fault occurs in one circuit block, only the interrupt wire associated with that specific block melts and interrupts, while other interrupt wires and their corresponding circuit blocks continue to operate normally. This selective isolation maintains system productivity by limiting the impact to only the affected circuit block.
4Device complexity
If a single interrupt wire protects multiple circuit blocks, then device complexity is reduced, but voltage drop in one block affects other blocks
Solution Approach 1:
The patent applies segmentation by assigning dedicated interrupt wires to specific circuit blocks, creating electrical isolation between blocks through the substrate layout. This configuration prevents voltage drops caused by overcurrent in one block from propagating to other blocks, as each block has its own protected power supply path. The segmentation approach balances complexity by using multiple interrupt wires only where needed for isolation, rather than providing redundant protection for all blocks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration provides timely overcurrent protection, preventing voltage drops and ensuring the operation of multiple circuit blocks by allowing the interrupt wire to melt earlier than the fuse, thus reducing the risk of damage to other circuit blocks and improving processing speed.
Implementation Method 1
when one of the interrupt wires is coupled with one of the branch wires and melts by heat generated by overcurrent
Implementation Method 2
the interrupt wire melts and the power supply wire is interrupted
Data Source
AI summary
An electronic control device includes one or more substrates, a casing, a plurality of circuit blocks, a common wire, a plurality of branch wires and two interrupt wires. The circuit blocks are disposed on the substrates and the substrates are disposed in the casing. The common wire is shared by the circuit blocks. The branch wires are respectively coupled between the circuit blocks and the common wire. The two interrupt wires are respectively coupled with two of the common wire and the branch wires for overcurrent protection of the circuit blocks.