MRAM Toggle Write Error Correction Circuit
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Solution Overview
Problem
In magnetic random access memory (MRAM) employing the toggle write method, it is challenging to accurately correct data errors without determining whether they originate from the data cell or the reference cell, leading to potential erroneous corrections and increased error rates due to thermal disturbances and the limitations of existing error correction codes.
Innovation Solution
The proposed method involves a multi-step error detection and correction process, including initial data read, error detection, correction of the data cell, re-read operations, and subsequent correction of the reference cell, ensuring accurate data correction even when the error source is unknown, thereby reducing data error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-step error detection and correction process is implemented to correct data errors without determining the error source, then data reliability is improved, but device complexity and operation time increase
Solution Approach 1:
The error correction process is segmented into distinct steps: initial data read, error detection, data cell correction, re-read operations, and reference cell correction. Each segment handles a specific aspect of error correction, making the complex process more manageable and systematic while maintaining high data reliability
Solution Approach 2:
The method performs preliminary error detection and data cell correction before attempting to correct the reference cell. This preliminary action ensures that data errors are addressed first, and only then is the reference cell corrected if necessary, preventing erroneous corrections while maintaining reliability
2Reliability
If iterative correction operations are performed on both data cell and reference cell, then data integrity is improved, but operation time increases
Solution Approach 1:
The error correction employs periodic action through iterative re-read operations. After initial correction of the data cell, the system periodically re-reads the data to verify correction success before proceeding to reference cell correction. This periodic verification ensures data integrity while managing operation time through structured repetition
Solution Approach 2:
The method incorporates feedback mechanisms where re-read operations provide information about whether corrections were successful. This feedback determines whether further correction steps are needed, ensuring data integrity through verification while avoiding unnecessary operation time spent on already-corrected data
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 effectively corrects data errors at a high probability, ensuring reliable data integrity by iteratively correcting both the data cell and reference cell, even when the error source is indeterminate, thus minimizing the impact of thermal disturbances and improving data reliability.
Implementation Method 1
When the non-magnetic layer is formed from a very thin insulating film, the magneto-resistance element exhibits a TMR (Tunnel Magneto-Resistance) effect
Implementation Method 2
when the non-magnetic layer is formed of a non-magnetic conductor, the magneto-resistance element exhibits a GMR (Giant Magneto-Resistive) effect
Implementation Method 3
supplying write currents to a word line and a bit line, which are laid near a memory cell, to apply a magnetic field to the magnetization free layer
Implementation Method 4
The SAF is a structure in which the adjacent ferromagnetic layers composed of a plurality of ferromagnetic layers are magnetically coupled in anti-ferromagnetic manner
Data Source
AI summary
An operation method of an MRAM of the present invention is an operation method of the MRAM in which a data write operation is carried out in a toggle write. The operation method of the present invention includes: (A) reading a data from a data cell by using a reference signal which is generated by using a reference cell; (B) performing an error detection on the read data; (C) correcting the data stored in the data cell, when an error is detected in the read data; (D) reading the data from the data cell as a first re-read data after the (C), when the error is detected in the read data, (E) performing the error detection on the first re-read data; (F) correcting the data stored in the reference cell, when an error is detected in the first re-read data; (G) reading the data from the data cell as a second re-read data after the (F), when the error is detected in the first re-read data; (H) performing the error detection on the second re-read data; and (I) correcting the data stored in the data cell again, when the error is detected in the second re-read data.