Magnetic Tunnel Junction Amplifier for High-Speed Power Gain

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Solution Overview

Problem

Conventional power amplifiers based on bipolar transistors and MOSFETs face limitations in switching speed and bandwidth due to significant coupling capacitance and power added efficiency, and are costly and large due to complex CMOS fabrication processes.

Innovation Solution

Magnetic logic units (MLUs) configured as amplifiers, utilizing magnetic tunnel junctions without silicon transistors, with arrays of MLUs to achieve high gain and extended cutoff frequencies while minimizing coupling capacitance, using ferromagnetic materials and thermally assisted switching technology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional bipolar transistors or MOSFETs are used in power amplifiers, then the amplifier can handle high output power levels, but the coupling capacitance increases which limits switching speed and bandwidth

Engineering Contradiction:
Improveoutput power levelVSAvoidswitching speed
Core Design Contradiction:
PowerVSSpeed

Solution Approach 1:

The patent replaces the conventional transistor-based electronic amplification mechanism with a magnetic logic unit-based mechanism. The MLU uses magnetic field coupling between input and output magnetic circuits, eliminating the need for transistor switching and associated coupling capacitance, thereby achieving high switching speed and bandwidth while maintaining power amplification capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic coupling as an intermediary mechanism between input and output circuits. The input magnetic circuit generates a magnetic field that couples to the output magnetic circuit through magnetic flux, serving as an intermediate energy transfer mechanism that avoids direct electrical coupling and its associated capacitance limitations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If conventional bipolar transistors or MOSFETs are used in power amplifiers, then the amplifier can handle high output power levels, but the power added efficiency is limited by transistor characteristics

Engineering Contradiction:
Improveoutput power levelVSAvoidpower added efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent replaces transistor-based electronic amplification with magnetic logic unit-based amplification. The MLU operates by detecting magnetic field states and switching output accordingly, eliminating transistor junction capacitances and resistances that cause power loss, thereby achieving superior power added efficiency while maintaining high output power capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If CMOS processes with twelve layers are used to fabricate amplifiers, then the amplifier can be manufactured with high precision, but the cost and size increase

Engineering Contradiction:
Improvefabrication precisionVSAvoidnumber of fabrication layers
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex multi-layer CMOS semiconductor fabrication with magnetic logic unit fabrication that can be implemented using fewer process layers. The MLU structure with its magnetic circuits and logic elements requires simplified manufacturing processes, reducing both the number of fabrication layers and overall device complexity while maintaining manufacturing precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs magnetic materials and magnetic logic unit structures that can be fabricated using alternative processes requiring fewer layers compared to conventional CMOS. The use of magnetic circuits, magnetic field coupling structures, and MLU-specific materials enables simplified fabrication while achieving the required precision

Inventive Principle:
Principle #40Composite materials

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 MLU-based amplifiers demonstrate increased gain, reduced coupling capacitance, and improved power added efficiency, with scalable output power and extended frequency range, and are more compact and cost-effective compared to traditional semiconductor-based solutions.

Implementation Method 1

a magnetic logic unit (MLU) amplification module including a array of magnetic tunnel junctions (MTJs)

Methodology Applied
Scientific EffectMagnetic tunnel junction: Magnetoresistance

Implementation Method 2

An input signal 130 may be applied to the MLU-based amplifier 200 through a field line 112 that controls a resistance of the MLU's 102

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnet

Data Source

PatentEP2815401B1Magnetic logic units configured as an amplifier
Publication Date: 2018.04.04 CROCUS TECHNOLOGY
  • EP2815401B1 patent drawingFigure 1
  • EP2815401B1 patent drawingFigure 2
  • EP2815401B1 patent drawingFigure 3

AI summary

An apparatus includes a circuit and a field line. The circuit includes a magnetic tunnel junction including a storage layer and a sense layer. The field line is configured to generate a magnetic field based on an input signal, where the magnetic tunnel junction is configured such that a magnetization direction of the sense layer and a resistance of the magnetic tunnel junction vary based on the magnetic field. The circuit is configured to amplify the input signal to generate an output signal that varies in response to the resistance of the magnetic tunnel junction.