Non-volatile Memory Sector Erasure via Substitution Copying

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Solution Overview

Problem

Existing non-volatile memory technologies, such as FLASH-type memories, require sector-wide erasure before rewriting, leading to significant physical footprint and high write/erase cycles that accelerate memory aging, especially when dealing with mixed data containing both current and obsolete information.

Innovation Solution

A non-volatile memory system with a control circuit that selectively copies valid data from one sector to a substitution sector, erasing the original sector, allowing for efficient data management and reducing the number of write/erase cycles by identifying sectors with less valid data or higher erase counts for replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sector-wide erasure is performed before rewriting, then data integrity is ensured, but the number of write/erase cycles increases and memory aging accelerates

Engineering Contradiction:
Improvedata integrityVSAvoidmemory lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The memory is divided into current sectors and substitution sectors. When a current sector needs erasure, only the valid data is copied to a substitution sector, and then the entire current sector is erased. This segmentation allows selective data preservation while enabling full sector erasure when needed, reducing unnecessary write/erase cycles on sectors containing mixed valid and obsolete data.

Inventive Principle:
Principle #1Segmentation

2Loss of information

If sector-wide erasure is performed, then obsolete data is cleared, but the physical footprint and circuit complexity increase

Engineering Contradiction:
Improveobsolete data clearanceVSAvoidcircuit footprint
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The invention extracts only the valid data elements from a sector before erasure, copying them to a substitution sector. This extraction process allows the system to clear obsolete data while preserving current data, and the substitution sector mechanism enables full sector erasure without requiring complex in-place data migration circuits.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If multiple write operations are performed on the same sector, then data is updated, but the sector must be erased first increasing operation time

Engineering Contradiction:
Improvedata update capabilityVSAvoiderase time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by maintaining multiple current sectors and a substitution sector. When a sector needs to be updated, the system can switch to a different current sector or use the substitution sector, avoiding the need to erase the target sector first. This preliminary preparation of alternative sectors eliminates erase wait time for frequent updates.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4379723A1Non-volatile memory
Publication Date: 2024.06.05 STMICROELECTRONICS (ROUSSET) SAS
  • EP4379723A1 patent drawingFigure 1~2
  • EP4379723A1 patent drawingFigure 3
  • EP4379723A1 patent drawingFigure 4

AI summary

The present disclosure concerns a non-volatile memory comprising a plurality of current memory sectors (S1, S2), a substitution memory sector (S3), and a circuit for controlling the non-volatile memory configured to store data into the sectors and to erase data stored in one of the sectors by erasing all the data stored in said sector at once; a first current memory sector comprising at least one first valid data element (D1_0) and a second current sector comprising at least one second valid data element (D2_0); the memory control circuit being configured to determine that one of the current sectors is to be erased, and accordingly select one sector from among the current sectors; copy the valid data of the selected current sector into the substitution memory sector; and erase all the data of the selected current sector.