Dual-Loop Shielding Circuit for LC Tank Radiation Containment

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Solution Overview

Problem

Inductor and capacitor circuits in integrated circuits generate undesirable radiation, causing signal interference due to magnetic fields, which existing technologies fail to effectively mitigate.

Innovation Solution

A shielding circuit with two independent closed-loop structures, one surrounding the inductor and the other surrounding coupled electronic components, formed from metal materials to reduce or eliminate radiation by creating a closed loop for electronic signals, preventing electrical contact and implemented on the same or different layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an LC tank circuit is used to operate at higher frequency with better phase noise performance, then the circuit performance is improved, but radiation is generated causing signal interference

Engineering Contradiction:
Improvephase noise performanceVSAvoidradiation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies the principle of converting harm into benefit by using the magnetic field generated by the inductor (which causes radiation interference) and redirecting it through a shielding circuit. The shielding circuit includes a first closed loop adjacent to the inductor and a second closed loop adjacent to the capacitor, which guide the magnetic field lines to circulate within the loops rather than radiating outward. This converts the harmful radiated energy into contained magnetic field circulation, thereby reducing electromagnetic interference while preserving the LC tank circuit's high frequency operation and phase noise performance.

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

2Object-affected harmful factors

If shielding structures are added to reduce radiation, then radiation interference is reduced, but device complexity increases

Engineering Contradiction:
Improveradiation interferenceVSAvoidcircuit structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the shielding function with the existing LC tank circuit by integrating the shielding structures directly adjacent to the inductor and capacitor components. The first closed loop is positioned adjacent to the inductor and the second closed loop is positioned adjacent to the capacitor, forming a unified shielding system that works in conjunction with the resonant circuit rather than as a separate addition. This merging approach reduces overall device complexity while effectively containing radiation interference.

Inventive Principle:
Principle #5Merging (Combining)

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 shielding circuit significantly reduces radiation interference, enhancing signal integrity and phase noise performance in resonant circuits by effectively containing magnetic fields and signal currents within closed loops.

Implementation Method 1

The shielding circuit significantly reduces radiation interference, enhancing signal integrity and phase noise performance in resonant circuits by effectively containing magnetic fields within closed loops

Methodology Applied
Scientific EffectMagnetic field containment: Magnetic Field

Implementation Method 2

an inductor is a passive electronic component that stores energy in a magnetic field created by an electric current passing through it

Methodology Applied
Scientific EffectMagnetic field energy storage: Magnetic Field

Implementation Method 3

an inductor-capacitor resonant cavity (LC tank) circuit, which is used as an electronic resonator to store oscillation energy when the circuit resonates

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4287254A1Shielding circuits and semiconductor devices
Publication Date: 2023.12.06 REALTEK SEMICON CORP
  • EP4287254A1 patent drawingFigure 1
  • EP4287254A1 patent drawingFigure 2
  • EP4287254A1 patent drawingFigure 3

AI summary

A shielding circuit (130) applied to a semiconductor device (100) includes a first shielding structure (231, 331, 431, 531) and a second shielding structure (232, 332, 432, 532). The first shielding structure (231, 331, 431, 531) forms a first closed loop and is disposed adjacent to an inductor (110, 210, 310, 410, 510) comprised in the semiconductor device (100). The second shielding structure (232, 332, 432, 532) forms a second closed loop and is disposed adjacent to an electronic component (120) coupled to the inductor (110, 210, 310, 410, 510).