Reserved Pilot Cells for Defective Memory Cell Position Marking

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Solution Overview

Problem

Non-volatile memory systems face inefficiencies in identifying and correcting defective data storage cells, which can lead to distorted information and reduced storage reliability due to limitations in existing error correction codes and defect management schemes.

Innovation Solution

The use of reserved 'pilot' cells to identify and mark defective data storage cells, allowing for improved error correction by differentiating their voltage levels and storing information about defective cell locations, thereby enhancing the system's ability to avoid reading or writing to defective positions and correct errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional error correction codes and defect management schemes are used, then defective cells can be corrected to some extent, but error correction power is limited and storage reliability is reduced

Engineering Contradiction:

Improvestorage reliabilityVSAvoiderror correction power

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by pre-marking defective cell positions during manufacturing or initial operation using reserved pilot cells. This advance identification and marking of defective positions enables the error correction system to proactively avoid these positions during data read/write operations, rather than attempting to correct errors after they occur. The pilot cells store position information about defective cells in advance, which significantly enhances error correction capability by allowing the system to bypass problematic areas before data corruption can occur.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If additional resources are allocated to improve error correction capability, then storage reliability improves, but device complexity and resource overhead increase

Engineering Contradiction:

Improveerror correction capabilityVSAvoidresource overhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by making the reserved pilot cells serve multiple functions: they continue to provide their traditional role as reference cells for voltage leveling and threshold determination, while simultaneously storing position information about defective cells. This multi-functionality allows the system to gain enhanced error correction capability without adding separate dedicated storage resources or increasing overall device complexity. The same hardware resources (pilot cells) are utilized dually, eliminating the need for additional overhead.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If more reserved cells are used to mark defective positions, then error correction power increases, but storage density and effective capacity decrease

Engineering Contradiction:

Improveerror correction powerVSAvoidstorage density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent resolves this contradiction by enabling reserved pilot cells to perform dual functions: maintaining their traditional role as reference cells for voltage determination while simultaneously encoding defective position information. This eliminates the need to allocate additional dedicated storage resources for defect mapping, as the existing pilot cells are repurposed to carry both their original function and the new defect position marking function, thereby preserving storage density.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies parameter changes by utilizing the voltage level parameters of pilot cells to encode defective position information. Instead of requiring separate storage resources, the system modifies the parameter space of existing pilot cells to carry additional information about defective positions. By changing how the pilot cell states are interpreted and utilized, the system gains enhanced error correction capability without consuming additional storage capacity.

Inventive Principle:

Principle #35Parameter changes

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

This approach improves error correction capabilities and storage efficiency by utilizing existing reserved cells to identify defective cells, reducing the need for additional resources and doubling the error correction power of the system.

Implementation Method 1

Methodology Applied

Scientific EffectVoltage level differentiation: Electric Field

Data Source

PatentUS8266484B1Circuits, architectures, apparatuses, systems, methods, algorithms, software and firmware for using reserved cells to indicate defect positions

Publication Date: 2012.09.11 MARVELL ASIA PTE LTD

AI summary

A system including a plurality of data storage cells, where each of the plurality of data storage cells is configured to store a plurality of data bits, and a plurality of reserved cells configured to store status information of one or more of the plurality of data storage cells. Each of the plurality of reserved cells includes a multi-bit cell configured to store the status information at a lower density than each of the data storage cells.