Nested Inductor Topology for Low-Coupling Multi-Band Chips

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Solution Overview

Problem

Integrated circuits face challenges in reducing the layout area occupied by inductors, leading to increased chip size and costs, particularly in circuits like power dividers, combiners, and switches, where multiple inductors are required for different frequency bands.

Innovation Solution

The design incorporates a first inductor with a loop having an opening and a second inductor with coils connected in series, where the magnetic field directions of the coils are opposite, allowing them to be nested within the first inductor, reducing the overall layout area by approximately 50% without direct contact and maintaining operational efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiple inductors are separately disposed in the integrated circuit, then each inductor can be independently designed and manufactured, but the total layout area occupied by the inductors increases significantly

Engineering Contradiction:

ImproveIndependent design and manufacturing of inductorsVSAvoidTotal layout area occupied by inductors

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent implements nesting by placing the second coil and third coil inside the first coil structure. The second coil is positioned within the first coil, and the third coil is positioned within the second coil, creating a nested configuration where multiple inductor windings occupy the same physical footprint area, thereby significantly reducing the total layout area while maintaining independent manufacturability

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges multiple inductor structures into a single integrated inductor assembly where the first inductor, second inductor, and third inductor share common physical space. The coils are combined in a nested arrangement with shared magnetic core or support structure, achieving area reduction while preserving the electrical independence of each inductor through proper winding configurations

Inventive Principle:

Principle #5Merging (Combining)

2Area of stationary object

If the second coil and third coil are nested in the first coil to reduce layout area, then the total area is reduced by about 50%, but magnetic coupling between inductors may be affected

Engineering Contradiction:

ImproveTotal layout area of first inductor and second inductorVSAvoidMagnetic coupling between inductors

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by assigning different magnetic field directions to different coils. The second coil is wound to produce a magnetic field in one direction, while the third coil is wound to produce a magnetic field in the opposite direction. This local differentiation of magnetic field orientation allows the nested coils to cancel each other's magnetic coupling effects, ensuring that the first inductor remains magnetically isolated from the second and third inductors despite their close physical proximity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the potentially harmful magnetic coupling effect into a beneficial cancellation mechanism. By nesting the second and third coils with opposite magnetic field directions, the magnetic flux generated by one coil is counteracted by the other, transforming what would normally be unwanted mutual inductance into a useful isolation mechanism that prevents interference between inductors while enabling compact nesting

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively reduces the layout area and costs of the chip by minimizing the space required for inductors while ensuring normal operation of circuits like single-frequency and dual-frequency power dividers and switches, supporting multiple frequency bands without the need for active circuits.

Implementation Method 1

The second coil and the third coil are nested in the first coil, wherein a magnetic field direction of the second coil is opposite to a magnetic field direction of the third coil

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250006418A1Integrated circuit, chip, and terminal

Publication Date: 2025.01.02 HUAWEI TECH CO LTD

AI summary

Embodiments of this application relate to an integrated circuit, a chip, and a terminal, and relate to the field of circuit technologies. An example integrated circuit includes a first inductor and a second inductor. The first inductor includes a first coil, and the first coil is a loop having a first opening. The second inductor includes a second coil and a third coil that are connected in series, and the second coil has a second opening. A magnetic field direction of the second coil is opposite to a magnetic field direction of the third coil. The second coil and the third coil are nested in the first coil, and the first inductor is not in direct contact with the second inductor.