STT-MRAM Programmable Logic Arrays for Low-Power Reconfigurability

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Solution Overview

Problem

Current field-programmable gate arrays (FPGAs) and programmable logic arrays (PLAs) face limitations in programmability, scalability, and power efficiency due to reliance on conventional memory technologies, which restrict their ability to perform complex logic functions efficiently and quickly.

Innovation Solution

The integration of Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) technology, utilizing spin-polarized electrons to switch the polarity of magnetic tunnel junction devices, allows for the creation of software programmable logic arrays with low power consumption, high speed, and reconfigurability, enabling efficient logic function implementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional memory technologies are used in FPGAs and PLAs, then device complexity and manufacturing are simplified, but programmability, scalability, and power efficiency are limited

Engineering Contradiction:

ImproveprogrammabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameter of memory technology from conventional volatile memory to STT-MRAM, which enables reconfigurability and enhanced programmability. The magnetic tunnel junction devices can be programmed to different resistance states, allowing the logic array to perform various logic functions dynamically, thus improving adaptability without proportionally increasing device complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining magnetic tunnel junction devices with logic array architecture. The MTJ devices consist of multiple magnetic layers with different properties (fixed layer, free layer, reference layer) that work together to achieve both memory storage and logic functionality, enabling versatile programmability within a unified device structure.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If conventional memory technologies are used in FPGAs and PLAs, then device structure remains simple, but power efficiency and ability to perform complex logic functions are restricted

Engineering Contradiction:

Improvepower consumptionVSAvoidlogic function performance

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The STT-MRAM devices perform dual functions as both memory storage and logic operation elements. The same magnetic tunnel junction devices that store configuration data also execute logic functions, eliminating the need for separate memory and logic circuits. This self-service capability reduces overall power consumption while enhancing logic function performance.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent utilizes the resistance state parameter of MTJ devices to encode logic values and perform logic operations. By changing the resistance state through spin transfer torque, the system achieves low-power memory writes and maintains data without continuous power, improving power efficiency while enabling complex logic operations through programmed resistance patterns.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If conventional memory technologies are used, then manufacturing processes are straightforward, but scalability and reconfigurability are limited

Engineering Contradiction:

ImprovereconfigurabilityVSAvoidease of manufacture

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal logic array architecture where STT-MRAM devices serve multiple functions: configuration storage, logic operation, and interconnect routing. The same hardware infrastructure supports various logic functions through software programming, achieving high reconfigurability without requiring multiple specialized manufacturing processes for different function types.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables the realization of complex logic functions with low power consumption, scalability, and reconfigurability, overcoming the limitations of conventional memory technologies by using STT-MRAM to program magnetic tunnel junction devices in arrays, facilitating efficient and high-speed logic operations.

Implementation Method 1

Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) technology, utilizing spin-polarized electrons to switch the polarity of magnetic tunnel junction devices

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 2

Magnetoresistive Random Access Memory (MRAM) uses magnetic elements... a change in the polarity 32 of the free layer 30 will change the resistance of the MTJ storage element 105

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentUS7728622B2Software programmable logic using spin transfer torque magnetoresistive random access memory

Publication Date: 2010.06.01 QUALCOMM INC

AI summary

Systems, circuits and methods for software programmable logic using Spin Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) technology are disclosed. Magnetic tunnel junction (MTJ) storage elements can be formed into input planes and output planes. The input planes and output planes can be coupled together to form complex arrays that allow for the realization of logic functions.