Fuse Element Auxiliary Heating Circuit for Overcurrent Protection

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Solution Overview

Problem

Existing overcurrent protection devices using fuses can cause component or circuit failure due to the sputtering of blown fuses, which is not adequately addressed by separate semiconductor devices for grounding.

Innovation Solution

An overcurrent protection device that includes a fuse element connected to a high-voltage unit and an auxiliary circuit with components that heat the fuse element, controlling the current flow by heat generation, thereby reducing the current required to melt the fuse and preventing circuit failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fuse is blown by overcurrent to protect the circuit, then the circuit is protected from damage, but the blown fuse causes sputtering that can induce component or circuit failure

Engineering Contradiction:

Improvecircuit protectionVSAvoidfuse sputtering

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful sputtering effect by introducing a dedicated reception space that captures and isolates the sputtered particles, preventing them from contaminating other circuit components. The fuse is separated from sensitive components through spatial arrangement, with the reception space positioned to intercept sputtering trajectories.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a reception space as an intermediary structure between the fuse and other circuit components. This intermediate zone serves as a containment area that absorbs the harmful sputtering effect, acting as a buffer that protects the broader circuit from fuse-related contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a separate semiconductor device is provided for grounding the fuse to enable fuse blowing, then the fuse can be blown by overcurrent, but the device complexity increases

Engineering Contradiction:

Improveovercurrent protection capabilityVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the fuse grounding function with existing circuit structures rather than adding completely separate semiconductor devices. The fuse is integrated into the circuit board layout with grounding paths that utilize available circuit elements, reducing the need for additional discrete components while maintaining overcurrent protection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent designs the fuse integration system to serve multiple functions: the same structural elements that provide mechanical support and electrical connectivity also serve as grounding paths and sputtering containment structures. This multi-functionality reduces the overall component count and system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If high current is applied to melt the fuse element for protection, then the fuse blows to protect the circuit, but the rapid melting causes fuse scattering and potential damage

Engineering Contradiction:

Improvecircuit protectionVSAvoidfuse scattering

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent provides beforehand cushioning by creating a dedicated reception space that is positioned to intercept sputtered particles before they can reach other circuit components. This pre-positioned containment structure absorbs the kinetic energy of sputtered particles, preventing them from causing damage to sensitive areas.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent converts the harmful sputtering effect into a contained phenomenon by designing the reception space to channel and concentrate sputtered particles in a specific area. The harm of sputtering is redirected and localized, transforming a potentially damaging scattered effect into a controlled, contained process that protects the broader circuit.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 device effectively protects circuits by reducing the current needed to melt the fuse, preventing fuse scattering and ensuring reliable protection without causing additional failures, and allows for gradual heating to prevent rapid melting and scattering.

Implementation Method 1

an auxiliary circuit including a component which heats the fuse element. An amount of electric current flowing in the fuse element when the fuse element melts is controlled by heat generated by the component

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a heat transfer plate provided in the control substrate and thermally connecting the surfaces of the first component, the second component, and the fuse element that face the surface of the control substrate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9515477B2Overcurrent protection device, overcurrent protection method, and non-transitory medium

Publication Date: 2016.12.06 TOYOTA JIDOSHA KK

AI summary

An overcurrent protection device includes a fuse element and an auxiliary circuit. Power is applied from a high-voltage unit of a main circuit to the fuse element. The auxiliary circuit includes a component which heats the fuse element. An amount of electric current flowing in the fuse element when the fuse element melts is controlled by heat generated by the component.