Inductively Coupled Multi-Stage Amplifier for High-Frequency Gain

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Solution Overview

Problem

Conventional amplifiers face limitations in bandwidth extension due to parasitic capacitance, making it difficult to achieve the required 56 GHz bandwidth for high-speed data transmission standards like IEEE 802.3, even with conventional bandwidth extension techniques.

Innovation Solution

The implementation of an amplification circuit with inductively coupled first and second inductor units, where the change in output voltage is positively fed back, enhancing the bandwidth through mutual inductance between the inductors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional bandwidth extension techniques are applied, then amplifier bandwidth is extended to around 10 GHz, but it remains difficult to achieve the required 56 GHz bandwidth for high-speed data transmission

Engineering Contradiction:
ImprovebandwidthVSAvoidgain maintenance at high frequency
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent implements positive feedback by inductively coupling the first inductor (connected to input terminal) and second inductor (connected to output terminal). The changing output voltage induces a voltage in the first inductor through mutual inductance, which feeds back to the input terminal. This feedback mechanism compensates for signal attenuation at high frequencies, enabling the amplifier to maintain gain across an extended bandwidth up to 56 GHz and beyond.

Inventive Principle:
Principle #23Feedback

2Speed

If parasitic capacitance of transistors is present, then amplifier operates at lower frequencies, but bandwidth is inherently limited to around 10 GHz

Engineering Contradiction:
ImprovebandwidthVSAvoidparasitic capacitance effect
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent introduces inductors as intermediary elements between the input and output terminals. These inductors, when inductively coupled, act as mediators that transfer energy and provide positive feedback to counteract the limiting effects of parasitic capacitance. This intermediary mechanism enables the amplifier to operate at frequencies much higher than what would be possible with conventional transistor-based bandwidth extension alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If conventional amplifiers are used, then device structure is simple, but bandwidth is limited and cannot comply with 224 Gbps transmission standard requiring 56 GHz bandwidth

Engineering Contradiction:
ImprovebandwidthVSAvoidinductor coupling structure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent changes the electrical parameters of the amplifier system by introducing inductive coupling with specific mutual inductance values. By adjusting the inductance values and coupling coefficient between the first and second inductors, the system achieves extended bandwidth while maintaining controlled impedance and stability. This parameter optimization allows compliance with 224 Gbps transmission standards despite the added structural complexity.

Inventive Principle:
Principle #35Parameter changes

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 significantly increases the bandwidth of the amplification circuit, enabling high-speed operation and compliance with advanced data transmission standards by maintaining gain for high-frequency input signals, unlike conventional techniques which reduce gain and hinder normal operation.

Implementation Method 1

the first inductor unit and the second inductor unit are inductively coupled to each other so that a change in output voltage of the amplification circuit is positively fed back

Methodology Applied
Scientific EffectMutual inductance: Electromagnetic Induction

Data Source

PatentEP4492682A1Amplification circuit, multi-stage amplifier and amplifier
Publication Date: 2025.01.15 SAMSUNG ELECTRONICS CO LTD
  • EP4492682A1 patent drawingFigure 1
  • EP4492682A1 patent drawingFigure 2A~2B
  • EP4492682A1 patent drawingFigure 3

AI summary

An amplification circuit (100) includes an amplifier (120) comprising an input terminal and an output terminal, a first inductor unit (110) connected to the input terminal, and a second inductor unit (130) connected to the output terminal. The first inductor unit (110) and the second inductor unit (130) may be inductively coupled to each other so that a change in output voltage of the amplification circuit (100) is positively fed back.