Symmetrical Inductor with Half-Loop Pairs for IC Area Reduction

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Solution Overview

Problem

Inductors in integrated circuits occupy significant area and it is challenging to implement inductors with high quality factor (Q) effectively due to their size constraints.

Innovation Solution

A symmetrical inductor design is implemented using half-loop pairs in conductive layers of an integrated circuit, where each half-loop pair includes a first and second half-loop, with terminal electrodes and a center-tap electrode, allowing for series combinations across conductive layers to reduce size and increase inductance while maintaining high quality factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If traditional inductor designs are used in integrated circuits, then inductance can be achieved, but the inductor occupies significant area

Engineering Contradiction:
Improveinductor areaVSAvoidquality factor
Core Design Contradiction:
Area of moving objectVSReliability

Solution Approach 1:

The inductor is divided into multiple discrete loops arranged in a symmetrical pattern, with each loop contributing to the total inductance. The segmentation into half-loop pairs in different conductive layers allows for compact arrangement while maintaining high quality factor through reduced parasitic effects

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inductor design transitions from planar winding to a three-dimensional structure utilizing multiple conductive layers stacked vertically. This dimensional change allows loops to be arranged in space rather than confined to a single plane, significantly reducing the footprint area while preserving inductance and quality factor

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of moving object

If inductor size is reduced for integration, then area is saved, but implementing high quality factor becomes difficult

Engineering Contradiction:
Improveinductor areaVSAvoidquality factor
Core Design Contradiction:
Area of moving objectVSReliability

Solution Approach 1:

Multiple half-loop pairs are nested across different conductive layers, with inner loops positioned within the footprint of outer loops in adjacent layers. This nesting arrangement maximizes the use of three-dimensional space, achieving high inductance in a compact footprint while maintaining quality factor through proper layer stacking

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The inductor utilizes composite construction with multiple conductive layers separated by dielectric materials. This composite structure allows optimization of each layer's contribution to inductance and quality factor, achieving high performance in reduced area through the synergistic combination of multiple materials and layers

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2628164B1A multiple-loop symmetrical inductor
Publication Date: 2016.06.08 XILINX INC
  • EP2628164B1 patent drawingFigure 1
  • EP2628164B1 patent drawingFigure 2
  • EP2628164B1 patent drawingFigure 3~4

AI summary

A symmetrical inductor includes pairs of half-loops (e.g., 312, 314, 316, 318), first and second terminal electrodes (e.g., 302, 304), and a center-tap electrode (e.g., 310). The half-loop pairs are in respective conductive layers (e.g., 101, 201 ) of an integrated circuit. Each half-loop pair includes a first (e.g., 312, 316) and second half-loop (e.g., 314, 318) in the respective conductive layer. The first and second terminal electrodes are in a first conductive layer, and the center-tap electrode is in a second conductive layer. The first terminal electrode and the center-tap electrode are coupled through a first series combination that includes the first half-loop of each half-loop pair. The second terminal electrode and the center-tap electrode are coupled through a second series combination that includes the second half-loop of each half-loop pair.