Insulated Current Sensor Package to Reduce IC Thermal Stress
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Solution Overview
Problem
Current sensors with magnetoelectric conversion elements face issues with thermal stress and insulation due to the use of metal members for IC supporting portions, leading to potential cracking of signal processing ICs and poor embeddability of mold resin, which compromises insulation between the primary conductor and signal processing IC.
Innovation Solution
A current sensor design featuring a semiconductor package with a supporting portion made of an insulating material, such as polymeric or semiconductor materials, that is separate from the conductor and lead terminals, reducing thermal stress and ensuring reliable insulation by spacing the signal processing IC away from the conductor and using a thin package configuration to facilitate resin embeddability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal member is used for the IC supporting portion, then the structural strength is improved, but thermal stress increases causing potential cracking of the signal processing IC
Solution Approach 1:
An insulating member is introduced as an intermediary between the metal IC supporting portion and the signal processing IC. This mediator reduces thermal stress transmission to the IC while maintaining structural support, thereby preventing cracking without sacrificing strength.
Solution Approach 2:
The supporting structure uses a composite configuration combining metal (for strength) and insulating materials (for thermal stress reduction). This composite approach allows simultaneous achievement of structural integrity and thermal management for IC protection.
2Device complexity
If the IC supporting portion is in contact with the primary conductor, then the device complexity is reduced, but insulation reliability deteriorates due to poor resin embeddability
Solution Approach 1:
The insulating member serves as a mediator that enables spatial separation between the metal IC supporting portion and the primary conductor. This intermediary structure maintains electrical insulation and improves resin embeddability without significantly increasing device complexity.
3Productivity
If the package thickness is reduced, then the productivity is improved, but the insulation between conductor and IC becomes compromised
Solution Approach 1:
The insulating member extends in the thickness direction (Z-axis) to provide adequate insulation distance between the conductor and IC, enabling thin package design while maintaining insulation reliability through optimized dimensional arrangement.
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 design enhances insulation reliability and reduces thermal stress on the signal processing IC, allowing for a thinner package with improved resin embeddability and reduced risk of electrical contact issues during the molding process.
Implementation Method 1
a magnetoelectric conversion element that detects a magnetic field generated by the measurement current
Data Source
AI summary
A current sensor is configured by at least one magnetoelectric conversion element, a conductor, and a signal processing IC being encapsulated by an encapsulating portion. The current sensor includes a pair of first lead terminals that is partially exposed outside of the encapsulating portion, is electrically connected to the conductor, inputs the measurement current to the conductor, and outputs the measurement current from the conductor; a metal member that is partially exposed outside the encapsulating portion and is spaced apart from the conductor; and a supporting portion that supports the at least one magnetoelectric conversion element, the signal processing IC, and the metal member on a first surface, is separated from the conductor, and is separate from the metal member.