Redundant Memory Cell Voting for Radiation-Tolerant Arrays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits with volatile memory elements are susceptible to soft error upset events caused by cosmic rays and radioactive impurities, leading to data corruption and increased complexity and power consumption in error correction mechanisms.
Innovation Solution
Incorporating an array of memory elements with redundant cells and a voting circuit that uses majority voting schemes to correct single and double cell errors, with thyristor-based cells being less prone to errors than SRAM-based cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic error checking with redundant information is implemented, then soft error tolerance is improved, but power consumption and circuit complexity increase
Solution Approach 1:
The patent divides each memory element into multiple redundant memory cells (typically three or five cells) that store identical data. This segmentation allows the system to tolerate errors in individual cells through majority voting, achieving soft error tolerance without requiring complex external error correction codes and checkers.
Solution Approach 2:
The patent creates redundant copies of the same data in multiple memory cells within each memory element. By storing identical information in multiple cells and using majority voting to determine the correct value, the system achieves error tolerance without the complexity of traditional error correction coding schemes.
2Reliability
If periodic reading out of data is performed for error checking, then soft error detection is improved, but power consumption increases
Solution Approach 1:
The patent maintains continuous error protection capability by keeping redundant memory cells actively powered and ready to vote. Unlike periodic checking methods that consume power only during check operations, this approach provides continuous error tolerance with minimal additional power consumption since the redundant cells are already powered for normal operation.
Solution Approach 2:
The memory element performs its own error detection and correction internally through majority voting among its redundant cells. This self-service mechanism eliminates the need for external error correction circuitry and periodic reading operations, reducing both power consumption and circuit complexity.
3Reliability
If traditional error correction codes are used, then data integrity is improved, but circuit cost and complexity increase
Solution Approach 1:
The patent segments each memory element into multiple identical redundant cells, eliminating the need for complex error correction codes. The segmentation approach uses simple majority voting logic instead of sophisticated coding schemes, reducing circuit cost and complexity while maintaining data integrity.
Solution Approach 2:
The patent changes the fundamental parameter of error protection from using complex error correction codes to using redundant cell copies with majority voting. This parameter change simplifies the circuit implementation and reduces cost while achieving the same goal of data integrity protection.
Data Source
AI summary
An integrated circuit may have an array of memory elements. Each memory element may have multiple memory cells. Each memory element may have a voting circuit that receives signals from the memory cells in that memory element. The voting circuit can produce an output based on the signals. The signals stored by the memory cells of each memory element may be redundant so that the voting circuit can produce an accurate output even in the event that a radiation strike causes some of the memory cells to flip their states to erroneous values. The memory elements may be based on memory cells such as static random-access memory cells and thyristor-based cells.