Chip-Type Filter Integrating Inductor to Reduce ESL
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Solution Overview
Problem
Conventional chip-type solid electrolytic capacitors used in π-type filters experience increased impedance due to extra resistance and inductance components in the connection path, which limits their performance in high-frequency applications.
Innovation Solution
A chip-type filter design that integrates a laminated body with stacked capacitor elements, a pair of positive and negative electrode terminals, and an inductor section, where the capacitor elements are alternately oriented and the inductor is insulated from the negative electrode sections, reducing equivalent series inductance and resistance by integrating the inductor within the package and forming a four-terminal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chip-type solid electrolytic capacitors are used in π-type filters with external connection, then the filter can be assembled, but extra resistance and inductance components occur in the connection path causing increased impedance
Solution Approach 1:
The patent combines the capacitor and inductor into a single integrated chip-type filter component. The capacitor elements and inductor are manufactured together in one device, eliminating the need for external connection paths between separate components. This merging removes the extra resistance and inductance that would otherwise occur in external connections, directly improving impedance characteristics.
Solution Approach 2:
The chip-type filter serves multiple functions within a single component: it provides both capacitance (through the capacitor elements) and inductance (through the integrated inductor), while also functioning as a complete filter unit. This multi-functionality eliminates the need for separate discrete components and their interconnections, reducing parasitic effects.
2Reliability
If the capacitor elements are stacked through negative electrode sections with alternating positive electrode sections, then the equivalent series inductance is reduced, but the manufacturing precision requirement increases
Solution Approach 1:
The filter is segmented into distinct functional groups: capacitor elements (with positive and negative electrode sections) and inductor sections. This segmentation allows for standardized manufacturing of each component type that can then be precisely assembled. The alternating arrangement of positive electrode sections creates symmetric current paths that cancel magnetic flux, reducing ESL while the modular segmentation facilitates controlled manufacturing.
Solution Approach 2:
The patent employs asymmetric stacking where capacitor elements are arranged with alternating orientations of positive electrode sections. This asymmetric arrangement creates specific current flow patterns that generate opposing magnetic fluxes, which cancel each other to reduce equivalent series inductance. The asymmetric design is optimized for electrical performance while maintaining manufacturability.
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 design significantly reduces equivalent series inductance and resistance, enhancing impedance characteristics and responsiveness to high-frequency demands, while also improving soldering reliability and simplifying the manufacturing process.
Implementation Method 1
an inductor section insulated from the negative electrode sections and coupling the positive electrode terminals
Implementation Method 2
a capacitor as one of electronic components has been also demanded to have an impedance characteristic in a region of a frequency higher than that in a conventional capacitor. In order to reply such a demand, various solid electrolytic capacitors containing conductive polymer of high electric conductivity as solid electrolyte have been studied.
Data Source
AI summary
A chip-type filter has a laminated body formed by stacking a plurality of capacitor elements, a pair of positive electrode terminals, a pair of negative electrode terminals, insulating outer resin, and an inductor section. The laminated body includes capacitor elements in a first group and capacitor elements in a second group, the positive electrode sections in both groups are disposed on the opposite sides with respect to the negative electrode sections. Positive electrode terminals are electrically connected to the positive electrode sections of capacitor elements in the first group and those of capacitor elements in the second group, respectively. Negative electrode terminals are electrically connected to the negative electrode sections in the laminated body, and are disposed at both ends of the direction crossing the connecting direction between the positive electrode terminals. The inductor section is insulated from the negative electrode sections and couples the positive electrode terminals.