3-Terminal Capacitor Noise Filter via Via Interconnect
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Solution Overview
Problem
Conventional noise filters lack a failsafe function and suffer from increased equivalent series inductance when multiple capacitors are connected in series, leading to degraded noise reduction performance in high-frequency bands.
Innovation Solution
A noise filter design featuring 3-terminal capacitors mounted on both surfaces of a circuit substrate, connected in series via vias, which reduces equivalent series inductance and ensures a failsafe function by maintaining insulation between hot and ground sides even if one capacitor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple capacitors are connected in series between the hot line and the ground line to achieve failsafe function, then reliability is improved, but equivalent series inductance increases and noise reduction performance in high-frequency band deteriorates
Solution Approach 1:
The patent transitions from a planar arrangement (all capacitors on one surface) to a three-dimensional arrangement by placing capacitors on both the front and rear surfaces of the circuit substrate. This spatial reconfiguration allows the connecting lines to pass through the substrate thickness via vias, significantly reducing the loop area and thus the equivalent series inductance while maintaining the series connection configuration for failsafe functionality.
Solution Approach 2:
The patent embeds the connecting lines within the circuit substrate itself by forming vias through the substrate. The capacitors on the front and rear surfaces are interconnected through these embedded vias, effectively nesting the connection path within the substrate structure. This reduces the external connecting line length and minimizes the inductance of the overall noise filter structure.
2Device complexity
If a single capacitor is connected between the hot line and the ground line to simplify the structure, then device complexity is reduced, but reliability deteriorates due to lack of failsafe function
Solution Approach 1:
The patent divides the noise filtering function across multiple capacitor units (at least two capacitors) connected in series between the hot line and ground line. Each capacitor unit can be independently mounted on the front or rear surface of the circuit substrate, providing modular segmentation that enhances reliability through redundancy while maintaining manageable structural complexity.
Solution Approach 2:
The patent combines the capacitors and connecting lines into an integrated structure where the capacitors are mounted on both surfaces of the circuit substrate and interconnected through vias formed in the substrate. This merging of components into a compact three-dimensional arrangement achieves failsafe functionality without proportionally increasing overall device complexity.
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 effectively reduces noise across high-frequency bands while providing a failsafe function by minimizing inductance and ensuring reliable insulation, enhancing noise reduction performance compared to traditional 2-terminal capacitor configurations.
Implementation Method 1
a first capacitor unit and a second capacitor unit which are connected in series between the hot line and the ground line
Data Source
AI summary
A front-surface-side 3-terminal capacitor and a rear-surface-side 3-terminal capacitor are disposed respectively on a front surface and a rear surface of a circuit substrate at opposing positions. A first outer terminal and a second outer terminal of the front-surface-side 3-terminal capacitor are electrically connected to hot-side conductor patterns and, respectively. Third outer terminals and of the rear-surface-side 3-terminal capacitor are electrically connected to ground-side conductor patterns and, respectively. Third outer terminals and of the front-surface-side 3-terminal capacitor are electrically connected to a first outer terminal and a second outer terminal of the rear-surface-side 3-terminal capacitor by employing vias and, respectively. The front-surface-side 3-terminal capacitor and the rear-surface-side 3-terminal capacitor are thereby electrically connected in series.