Flash Memory Page Buffer Data Restoration Logic

Solution Overview

Problem

Existing NAND-type flash memory devices require a backup RAM buffer to store data during programming, leading to increased costs and complex internal architecture, as they cannot retrieve and re-write data from the flash memory without a backup copy, especially in low-end systems.

Innovation Solution

A method to calculate and restore the original value of every bit in a page buffer based on the state of the corresponding bit in the flash memory, allowing data to be re-written without a backup RAM buffer by applying logic operations between the data buffer and memory cell bits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a backup RAM buffer is used to store data during programming, then data can be retrieved and re-written after programming failure, but the cost and internal architecture complexity increase

Engineering Contradiction:

Improvedata restoration capabilityVSAvoidinternal architecture

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flash memory device performs self-diagnosis and self-restoration by detecting programming failures through read operations and automatically restoring data using logic operations between the data buffer and memory cell bits, eliminating the need for external backup RAM buffer

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical/physical backup RAM buffer with a logical restoration mechanism using bit-wise logic operations (AND, OR, XOR) between the data buffer and memory cell contents, achieving data restoration through computational logic rather than physical backup storage

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a backup RAM buffer is used to store data during programming, then data can be retrieved and re-written after programming failure, but the cost increases

Engineering Contradiction:

Improvedata restoration capabilityVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The flash memory device performs self-diagnosis and self-restoration by detecting programming failures through read operations and automatically restoring data using logic operations between the data buffer and memory cell bits, eliminating the need for external backup RAM buffer

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent recovers original data by discarding the failed programming result and restoring the original bit values through logic operations, effectively recovering data without needing to preserve it in a backup buffer throughout the process

Inventive Principle:

Principle #34Discarding and recovering

3Ease of operation

If the flash memory uses standard programming operations, then the programming process is simple, but data cannot be restored after programming failure

Engineering Contradiction:

Improveprogramming processVSAvoiddata restoration capability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the programmed data is read back and compared with the original data buffer contents, and failure detection triggers an automatic restoration process using logic operations to recover original data

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary restoration actions by maintaining the original data in the data buffer and using logic operations to reconstruct original data from the combination of the data buffer and failed programming results, preparing the system for potential re-programming

Inventive Principle:

Principle #10Preliminary action

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

Enables data restoration in flash memory after a programming failure, reducing the need for a backup RAM buffer and simplifying the internal architecture, thereby lowering costs and improving performance in low-end systems.

Implementation Method 1

A method to calculate and restore the original value of every bit in a page buffer based on the state of the corresponding bit in the flash memory, allowing data to be re-written without a backup RAM buffer by applying logic operations between the data buffer and memory cell bits

Methodology Applied

Scientific EffectLogic operations:

Data Source

PatentUS7911836B2Data restoration in case of page-programming failure

Publication Date: 2011.03.22 SANDISK ISRAEL LTD

AI summary

The present invention discloses systems and methods for restoring data in flash memory after an operational failure. The method includes: setting bits of a data buffer in accordance with the data; programming a plurality of memory cells in accordance with the data buffer; and upon failure of the programming step, restoring the data buffer to be set in accordance with the data, wherein the restoring is based only on a present state of the data buffer and on a present state of the plurality of memory cells. A memory device includes: at least one cell; and a controller operative to store data in at least one cell by steps including those described in the method above. The system includes: a memory device that includes at least one cell; and a processor operative to store data in at least one cell by steps including those described in the method above.