Resin-Sealed Semiconductor Fuse for Overcurrent Protection
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Solution Overview
Problem
Resin-sealed semiconductor devices face issues with overcurrents causing smoking and ignition due to carbonization of silicone gel covering copper wires, which fails to effectively cut off short-circuit currents.
Innovation Solution
A resin-sealed semiconductor device with a fuse portion in the power lead, covered by a first resin sealing portion and blocked from atmospheric air by a second resin sealing portion, preventing combustion reactions and ensuring reliable overcurrent cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thin metal wire is used as a fuse in the power lead, then the device structure is simple, but the fuse cannot effectively cut off overcurrent because the melted metal has no space to migrate to, causing continuous overcurrent flow
Solution Approach 1:
The patent introduces resin as an intermediary substance surrounding the power lead. This resin serves as a mediator that receives and contains the melted metal from the fuse wire, enabling the fuse to effectively cut off overcurrent while maintaining structural simplicity. The resin acts as the intermediate medium that resolves the contradiction between simple structure and reliable overcurrent cutoff.
Solution Approach 2:
The patent creates an inert environment by surrounding the power lead with resin that has lower melting points than the metal wire. This resin environment prevents the melted metal from migrating to surrounding spaces (as would happen in air), confining it within the resin matrix and ensuring reliable fuse operation.
2Object-affected harmful factors
If silicone gel is used to cover the copper wire for fuse function, then the wire is protected, but the silicone gel carbonizes under overcurrent heat and causes combustion reactions leading to smoking and ignition
Solution Approach 1:
The patent changes the material parameter from silicone gel to resin with specific properties (lower melting point than the metal wire, non-combustible). This parameter change transforms the protective covering from a combustible material to a non-combustible one, eliminating the carbonization and combustion problem while maintaining wire protection and fuse functionality.
3Reliability
If a chip-type overcurrent cutting fuse is inserted between the power semiconductor device and the battery, then overcurrent cutoff is reliable, but the device cost becomes very expensive
Solution Approach 1:
The patent replaces the expensive chip-type fuse with a simple metal wire fuse that is integrated into the power lead structure. This wire fuse is a low-cost, simple component that achieves the same overcurrent cutoff reliability through the resin-embedded design, dramatically reducing device cost while maintaining reliable protection.
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
The solution effectively cuts off overcurrents without fail, preventing smoking and ignition, while maintaining high resistance against combustion reactions and water infiltration.
Implementation Method 1
a first resin sealing portion configured to cover the fuse portion, and a second resin sealing portion configured to block the first resin sealing portion from atmospheric air
Implementation Method 2
having high resistance against combustion reactions and water infiltration
Data Source
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AI summary
Provided is a resin-sealed semiconductor device, which includes a power semiconductor element and a power lead connected to a main electrode of the power semiconductor element. The power semiconductor element is molded with resin, and the power lead is protruded from a molded resin portion. The resin-sealed semiconductor device includes a fuse portion formed in the power lead, a first resin sealing portion configured to cover the fuse portion, and a second resin sealing portion configured to block the first resin sealing portion from atmospheric air and to form the molded resin portion.