TLC Flash Memory Access Method Using Dummy Data for Error Reduction

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Solution Overview

Problem

TLC flash memory with quality issues, such as incomplete write voltage levels, leads to data writing and reading errors, resulting in waste and reduced storage capability, as manufacturers often discard such memory due to these problems.

Innovation Solution

A method to convert TLC flash memory to a MLC-like accessing type by generating dummy data and writing it into the flash memory, allowing only certain write voltage levels to be used, effectively utilizing flash memory that would otherwise be discarded.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If TLC flash memory is used to increase storage density, then storage capacity is improved, but data writing and reading errors occur due to quality problems in manufacturing

Engineering Contradiction:

Improvestorage densityVSAvoiddata writing and reading accuracy

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the accessing type parameter of the flash memory from TLC to MLC-like mode. By modifying the access parameters and using dummy data writing, the system adapts the memory operation mode to match the actual quality capabilities of the memory cells, thereby maintaining reliable data storage while utilizing the available voltage levels correctly

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a controller as an intermediary between the host and the flash memory. The controller generates dummy data according to specific algorithms and writes it into designated pages, acting as a mediator that compensates for the quality issues in the memory cells and ensures accurate data storage and retrieval

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If TLC flash memory with quality problems is discarded, then data reliability is maintained, but manufacturing costs increase due to waste

Engineering Contradiction:

Improvedata reading accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent converts the harmful effect of quality problems in TLC flash memory into a beneficial outcome by transforming the unusable memory into functional MLC-like storage. Instead of discarding the defective memory, the system uses dummy data writing and parameter changes to make the memory reliable, thereby reducing waste and manufacturing costs while maintaining data accuracy

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If dummy data is generated and written into flash memory pages, then data writing errors are reduced, but writing time and complexity increase

Engineering Contradiction:

Improvedata writing accuracyVSAvoiddata writing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by generating and writing dummy data into specific pages before actual data storage operations. This preparatory step ensures that the memory is in the correct state for subsequent data writing, preventing errors and ensuring reliability from the outset of data storage operations

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9489143B2Method for accessing flash memory and associated controller and memory device

Publication Date: 2016.11.08 SILICON MOTION INC

AI summary

The present invention provides a method for accessing a flash memory, wherein the flash memory is a Triple-Level Cell flash memory and each word line of the flash memory constitutes a least significant bit (LSB) page, a central significant bit (CSB) page and a most significant bit (MSB) page, each storage unit of each word line of the flash memory is implemented by a floating-gate transistor, and each storage unit supports at least eight write voltage levels, the method includes: generating dummy data according to data of a first page and a second page corresponding to a specific word line of the flash memory, wherein the dummy data is going to be written in a third page corresponding to the specific word line; and writing the data and the dummy data into the flash memory.