Flash Memory Retention Checking and Writing

The patent applies preliminary action by performing retention checking and retention writing procedures during stand-by mode before data loss occurs. The system proactively identifies memory cells with threshold voltage degradation and reinforces their charge storage capability through additional writing operations, preventing data retention deterioration rather than reacting after failure occurs.

The patent implements feedback mechanisms through retention checking procedures that measure threshold voltage of memory cells and compare against reference values. Based on the check results, the system dynamically adjusts retention writing procedures to target specific memory cells that require reinforcement, creating a closed-loop system that adapts to individual cell degradation patterns.

The patent applies universality by designing the retention checking and retention writing procedures to serve multiple functions: they not only maintain data retention but also characterize memory cell performance, identify degraded cells, and provide a basis for targeted maintenance operations. This multi-functionality reduces the need for separate dedicated systems for each purpose.

The system performs self-service by autonomously executing retention checking and retention writing procedures without external intervention. The memory device monitors its own health, identifies cells requiring maintenance, and performs self-repair operations during stand-by mode, eliminating the need for complex external monitoring and maintenance systems.