Nested Figure-Eight Transformer Windings for Crosstalk Reduction

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Solution Overview

Problem

As integrated circuits shrink, the challenge of minimizing magnetic coupling between inductors and transformers becomes increasingly difficult due to reduced space and increased proximity, leading to issues like crosstalk and local oscillator pulling in power amplifier circuits.

Innovation Solution

The use of figure eight and double figure eight structures in transformer windings, which are conductively coupled and nested within each other, allows for effective magnetic field cancellation, enabling closer placement and reduced space utilization while minimizing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If distances between aggressors and victims are maximized to minimize magnetic coupling, then magnetic coupling is reduced, but chip area increases

Engineering Contradiction:

Improvemagnetic couplingVSAvoidchip area

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent implements nested transformer structures where one transformer is placed inside another, with inner transformers positioned within the magnetic field regions of outer transformers. This nesting approach allows multiple transformers to occupy the same spatial footprint while maintaining electrical isolation through careful positioning and shielding techniques, thereby reducing chip area without significantly increasing magnetic coupling.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs magnetic shielding techniques where conductive shields are strategically placed between aggressor and victim transformers. These shields convert the harmful magnetic field into beneficial effects by redirecting magnetic flux lines and creating magnetic field cancellation zones, thereby reducing magnetic coupling while maintaining compact layouts.

Inventive Principle:

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

2Area of stationary object

If inductors and transformers are placed in close proximity to reduce space, then space utilization improves, but crosstalk and interference increase

Engineering Contradiction:

Improvespace utilizationVSAvoidcrosstalk and interference

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent places inner transformers within the magnetic field regions of outer transformers, creating a nested configuration that maximizes space utilization. The nested structure allows tight integration while maintaining isolation through proper positioning and the use of magnetic shielding techniques.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Magnetic shields are positioned between closely spaced transformers to convert potential interference into beneficial magnetic field redirection, allowing compact placement while reducing crosstalk.

Inventive Principle:

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

3Device complexity

If power amplifier circuits include inductors and transformers in close proximity, then circuit integration improves, but local oscillator pulling occurs

Engineering Contradiction:

Improvecircuit integrationVSAvoidlocal oscillator stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent integrates power amplifier circuits with nested transformer structures, placing RF inductors and local oscillator transformers in a nested configuration. This integration allows compact circuit design while maintaining oscillator stability through proper spatial arrangement and magnetic shielding.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Magnetic shielding techniques are applied to protect the local oscillator from RF signals generated by power amplifiers. The shields convert harmful magnetic coupling into beneficial field redirection, allowing high integration while maintaining oscillator stability.

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 configuration minimizes magnetic coupling and crosstalk, improving circuit performance by allowing for more efficient placement of inductors and transformers within integrated circuits, even in densely packed areas.

Implementation Method 1

Each of the second conductive loops is inductively coupled to and nested within a respective one of the first conductive loops

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9312060B2Transformer circuits having transformers with figure eight and double figure eight nested structures

Publication Date: 2016.04.12 MARVELL ASIA PTE LTD

AI summary

A transformer includes a first loops and second loops. The first loops include a first set of input terminals. The first loops include at least three loops that are conductively coupled to each other in series by first crossovers. The second loops include a first set of output terminals. The second loops include at least three loops that are conductively coupled to each other in series by second crossovers. Each of the second conductive loops is inductively coupled to and nested within a respective one of the first conductive loops.