Current Sensor Rigid Substrate Stabilizes Magnetoelectric Element
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Solution Overview
Problem
Existing current sensors with magnetoelectric conversion elements suffer from variations in measurement sensitivity due to deformation of the insulating member during resin encapsulation, and require dedicated apparatuses for manufacturing, leading to increased costs and complexity.
Innovation Solution
A current sensor design that incorporates a magnetoelectric conversion element, a signal processing IC, and a conductor encapsulated in a semiconductor package, where the element supporting portion is made of a stiff semiconductor substrate or metal plate to prevent deformation and stabilize the position of the magnetoelectric conversion element, and the manufacturing process uses standard back-end process apparatuses to reduce costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an insulating member is used to support the magnetoelectric conversion element, then the element can be positioned and electrically insulated, but the insulating member deforms during resin encapsulation causing variations in measurement sensitivity
Solution Approach 1:
The patent replaces the deformable insulating member with a rigid semiconductor substrate that serves as both the supporting structure and the element carrier. The semiconductor substrate maintains dimensional stability during resin encapsulation, preventing position variations of the magnetoelectric conversion element and ensuring consistent measurement sensitivity.
Solution Approach 2:
The patent uses a composite structure where the semiconductor substrate integrates multiple functions: mechanical support, electrical insulation, and precise positioning. This composite approach eliminates the need for separate insulating members and reduces deformation issues during encapsulation.
2Manufacturing precision
If dedicated apparatuses are used for manufacturing the current sensor, then manufacturing precision can be achieved, but device complexity and cost increase
Solution Approach 1:
The patent designs the semiconductor substrate and lead frame structure to be compatible with standard back-end process apparatuses. The unified structure allows existing multi-functional equipment to perform multiple manufacturing steps, eliminating the need for dedicated specialized apparatuses while maintaining manufacturing precision.
Solution Approach 2:
The patent combines the magnetoelectric conversion element, signal processing IC, and supporting structures into a single integrated semiconductor package. This merging allows standard packaging equipment to handle the entire assembly, reducing the need for separate dedicated apparatuses for each component.
3Measurement precision
If the magnetoelectric conversion element is positioned close to the conductor for high sensitivity, then measurement sensitivity improves, but electrical insulation becomes more difficult to maintain
Solution Approach 1:
The semiconductor substrate acts as an intermediary between the magnetoelectric conversion element and the conductor. It provides adequate electrical insulation while allowing the element to be positioned close to the conductor for high magnetic field sensitivity, thus resolving the conflict between insulation requirements and sensitivity optimization.
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 achieves reduced variations in measurement sensitivity, improved quality of the current sensor, and cost reduction through efficient production and the use of standard manufacturing apparatuses.
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 such that at least one magnetoelectric conversion element, a conductor, and a signal processing IC are encapsulated with an encapsulating portion. The current sensor is comprised of a pair of first lead terminals that is partially exposed on a side surface of the encapsulating portion, is electrically connected to the conductor, inputs a measurement current to the conductor, and outputs the measurement current from the conductor; a metal member that is partially exposed on a side surface of the encapsulating portion and is spaced apart from the conductor; and an element supporting portion that is comprised of a metal plate or a semiconductor substrate, supports the at least one magnetoelectric conversion element and a metal member on a surface on a same side as the first surface, and is spaced apart from the conductor.