Three-Terminal Multilayer Capacitor Reducing ESL
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Solution Overview
Problem
Current decoupling capacitors in power supply circuits face challenges with increased current consumption and miniaturization demands, requiring higher capacitance and lower equivalent series inductance (ESL) while also needing to withstand thermal and mechanical stress in harsh environments like in-vehicle systems.
Innovation Solution
A multilayer capacitor design featuring a body with layered dielectric and internal electrodes, and external electrodes made of metal and glass particles with a conductive resin, which are strategically positioned to reduce ESL and enhance durability and reliability by shortening current paths and providing excellent moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitance of the decoupling capacitor is increased to handle higher current consumption, then the ability to suppress voltage variation is improved, but the equivalent series inductance (ESL) tends to increase which reduces high-frequency performance
Solution Approach 1:
The patent transitions from a conventional two-terminal capacitor structure to a three-terminal structure with external electrodes disposed on the same surface. This dimensional change allows the current path to be shortened by connecting to multiple points on the same surface rather than traversing through the component body, thereby reducing ESL while maintaining high capacitance.
Solution Approach 2:
The capacitor is segmented into multiple electrode terminals (first, second, and third external electrodes) that can be independently connected to different circuit points. This segmentation allows the current to be distributed across multiple paths, reducing the overall equivalent series inductance while maintaining the required capacitance for voltage suppression.
2Volume of moving object
If the electronic component is miniaturized to meet portable device requirements, then the size is reduced, but the durability against thermal and mechanical stress deteriorates
Solution Approach 1:
The external electrodes are constructed as composite structures with multiple layers including metal layers, glass-containing layers, and conductive resin layers. This composite material approach provides both miniaturization capability and enhanced durability, as the different materials contribute different properties: metal for conductivity, glass for thermal stability and moisture resistance, and conductive resin for mechanical flexibility and stress distribution.
Solution Approach 2:
The patent modifies the material composition parameters of the external electrodes by incorporating glass particles and conductive resin in specific ratios. This parameter change allows the electrodes to maintain small dimensions while achieving improved thermal and mechanical stress resistance through the synergistic properties of the composite materials.
3Reliability
If external electrodes are made conductive to enable mounting connections, then the electrical connectivity is improved, but moisture infiltration through the electrodes increases which reduces reliability
Solution Approach 1:
The external electrodes use a composite structure where metal layers provide electrical conductivity while glass-containing layers and conductive resin layers provide moisture barrier properties. The glass particles form a dense matrix that resists moisture penetration, while the conductive resin provides both conductivity and sealing, thus achieving both electrical connectivity and moisture resistance simultaneously.
Solution Approach 2:
Different regions of the external electrode structure have different material compositions optimized for different functions: metal-rich regions provide conductivity for electrical connection, while glass-rich regions provide moisture barrier properties. This local quality differentiation allows the single electrode structure to simultaneously achieve both electrical connectivity and moisture infiltration prevention.
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 ESL, improved durability, and enhanced reliability by shortening current paths and preventing moisture infiltration, thus addressing the need for high-performance capacitors in demanding environments.
Implementation Method 1
the first and second electrode layers containing metal and glass particles
Implementation Method 2
the third electrode layer containing a conductive resin
Implementation Method 3
providing excellent moisture resistance
Data Source
AI summary
A multilayer capacitor includes a body including a capacitor body formed by layering a plurality of dielectric layers and a plurality of first and second internal electrodes in a width direction, the first and second internal electrodes including body portions overlapping each other and lead portions exposed to a mounting surface of the capacitor body and disposed to be spaced apart from each other, respectively; and first, second and third external electrodes disposed on the mounting surface of the capacitor body to be connected to the lead portions, respectively, wherein the first, second and third external electrodes each include first, second and third electrode layers which are sequentially stacked, the first and second electrode layers containing metal and glass particles, and the third electrode layer containing a conductive resin.