Inductor with Reversed Track Sections for Parasitic Capacitance Reduction

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Solution Overview

Problem

Conventional inductors in integrated circuits face challenges in minimizing parasitic capacitance, which limits their resonant frequency and Q-factor, due to capacitance between conductive tracks and the substrate, as well as between inductor turns.

Innovation Solution

The inductor design features a conductive track with crossing points that reverse the order of track sections, reducing the potential difference between adjacent sections and thereby lowering parasitic capacitance, while maintaining self-inductance, resulting in increased resonant frequency and Q-factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional spiral inductor structure is used, then self-inductance is maintained, but parasitic capacitance between inductor turns is high

Engineering Contradiction:
Improveparasitic capacitanceVSAvoidresonant frequency and Q-factor
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies inversion by reversing the conventional ordering of track sections at crossing points. Instead of maintaining sequential ordering, the conductive track is configured so that adjacent track sections at crossing points have reversed ordering, which reduces the potential difference between them and thereby reduces parasitic capacitance between inductor turns.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies local quality by making specific track sections have different configurations based on their position. The crossing points are strategically placed at specific locations along the conductive track where track sections cross over, creating localized regions with reduced potential difference and reduced parasitic capacitance, while maintaining overall inductor performance.

Inventive Principle:
Principle #3Local quality

2Reliability

If inductor turns are increased to maintain self-inductance, then parasitic capacitance between turns increases

Engineering Contradiction:
Improveresonant frequencyVSAvoidparasitic capacitance between turns
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies inversion by reversing the conventional ordering of track sections at crossing points. Instead of maintaining sequential ordering, the conductive track is configured so that adjacent track sections at crossing points have reversed ordering, which reduces the potential difference between them and thereby reduces parasitic capacitance between inductor turns.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If conventional track configuration is used, then manufacturing is simple, but parasitic capacitance limits resonant frequency

Engineering Contradiction:
ImproveQ-factorVSAvoidtrack configuration complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies segmentation by dividing the conductive track into multiple track sections that are systematically configured. The track is segmented such that crossing points are placed at specific locations where track sections cross over, creating distinct regions with reduced parasitic capacitance. This segmented approach maintains manufacturability while improving performance.

Inventive Principle:
Principle #1Segmentation

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 effectively reduces parasitic capacitance, leading to higher resonant frequency and Q-factor without affecting self-inductance, and can be implemented in various inductor configurations, including three, four, and five turn inductors, with optimized inner diameters for enhanced performance.

Implementation Method 1

capacitance between the inductor turns themselves

Methodology Applied
Scientific EffectParasitic capacitance: Capacitance

Data Source

PatentEP2337038B1Inductor
Publication Date: 2014.03.12 NXP BV
  • EP2337038B1 patent drawingFigure 1A~2
  • EP2337038B1 patent drawingFigure 3~6
  • EP2337038B1 patent drawingFigure 7~8

AI summary

An inductor includes a conductive track forming at least three inductor turns. The conductive track has a plurality of track sections. The inductor also includes at least two groups of crossing points, each crossing point comprising a location at which the conductive track crosses over itself. The crossing points of each group collectively reverse the order of at least some of the track sections in the inductor, such that inner track sections of the conductive track cross over to become respective outer track sections, and such that outer track sections of the conductive track cross over to become respective inner track sections.