On-Chip Capacitor Eddy Current Reduction in Magnetic Sensors
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Solution Overview
Problem
Existing magnetic sensors require external decoupling capacitors to enhance EMC and reduce long-wire noise, which increase costs and package size due to the need for additional components and circuitry.
Innovation Solution
Integration of on-chip capacitors formed by conductive layers and a dielectric layer on a substrate within the sensor, eliminating the need for external decoupling capacitors and reducing package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external decoupling capacitors are used, then EMC protection is enhanced, but package size and cost increase
Solution Approach 1:
The patent integrates the decoupling capacitor function directly into the sensor package by forming a capacitor structure using conductive layers and dielectric material within the same semiconductor substrate. This merging of functions eliminates the need for separate external capacitor components, thereby maintaining EMC protection while reducing overall package size.
Solution Approach 2:
The sensor structure is designed to perform multiple functions: the conductive layers serve both as interconnect elements for the sensor circuitry and as electrodes for the decoupling capacitor. The dielectric layers provide both electrical insulation and capacitor dielectric function. This multi-functionality allows the same structural elements to provide both sensing and decoupling capabilities.
2Reliability
If external decoupling capacitors are used, then EMC protection is enhanced, but manufacturing cost increases
Solution Approach 1:
The decoupling capacitor is manufactured as an integrated part of the sensor using the same semiconductor fabrication processes. The conductive layers and dielectric materials are deposited and patterned in the same manufacturing sequence as the sensor elements, eliminating the need for separate capacitor component assembly steps and reducing overall manufacturing complexity and cost.
Solution Approach 2:
The sensor structure itself provides the decoupling function through its own conductive and dielectric layers. The same manufacturing infrastructure that produces the sensor automatically creates the capacitor structure, making the system self-sufficient and eliminating the need for additional external components and their associated assembly processes.
3Object-generated harmful factors
If slots are added to conductive layers, then eddy currents are reduced, but device complexity increases
Solution Approach 1:
The conductive layers are segmented by introducing slots that divide the continuous conductive path into separate regions. This segmentation interrupts the formation of large eddy current loops while maintaining the electrical connectivity needed for sensor operation. The slots create smaller current paths that reduce overall eddy current magnitude.
Solution Approach 2:
Slots are strategically positioned in specific locations within the conductive layers where eddy currents would otherwise form large loops. The slot placement is optimized to target regions of high eddy current density while preserving conductive pathways in areas critical for sensor function. This localized modification reduces eddy currents without unnecessarily complicating the overall device structure.
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 solution provides effective EMC protection and reduces costs by integrating capacitive impedance directly on the sensor, while maintaining or improving sensitivity and reducing eddy currents through strategic slot placement in the conductive layers.
Implementation Method 1
a dielectric layer disposed between the first and second conductive layers such that the first and second conductive layers and the dielectric layer form a capacitor
Implementation Method 2
a slot is formed in at least one of the first and second conductive layers proximate the magnetic field sensor for reducing eddy currents in the first and second conductive layers
Data Source
AI summary
Methods and apparatus for providing an integrated circuit including a substrate having a magnetic field sensor, first and second conductive layers generally parallel to the substrate, and a dielectric layer disposed between the first and second conductive layers such that the first and second conductive layers and the dielectric layer form a capacitor, wherein a slot is formed in at least one of the first and second conductive layers proximate the magnetic field sensor for reducing eddy currents in the first and second conductive layers.