Memory Controller Bad Block Replacement via Pseudo-Blocks

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Solution Overview

Problem

Memory devices with bad blocks experience reduced program operation performance due to the inability to efficiently utilize all planes for parallel operations, leading to lower efficiency compared to systems without defective blocks.

Innovation Solution

A controller that replaces bad blocks with replacement blocks to form reproduced superblocks, allowing for program operations using an interleaving scheme, and subsequently moves data to pseudo-replacement blocks, releasing the original replacement blocks for reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bad blocks are replaced with replacement blocks to maintain superblock functionality, then reliability is improved, but device complexity increases due to additional block management overhead

Engineering Contradiction:

Improvesuperblock functionalityVSAvoidblock management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a pseudo-replacement block as an intermediary component that mediates between the replacement block and the bad block. The pseudo-replacement block serves as a temporary placeholder during program operations, allowing the replacement block to be released and reused while maintaining superblock functionality. This intermediary mechanism reduces the number of permanent replacement blocks needed, thereby reducing device complexity while preserving reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If replacement blocks are permanently allocated to replace bad blocks, then reliability is improved, but productivity decreases due to reduced available blocks for data storage

Engineering Contradiction:

Improvesuperblock operationVSAvoiddata storage capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements a mechanism where replacement blocks are temporarily used (discarded to pseudo-replacement blocks) during program operations and then recovered (released back to the available block pool) after operations complete. This allows the same replacement blocks to be reused multiple times, maintaining superblock reliability while preserving productivity by keeping blocks available for data storage when not actively replacing bad blocks.

Inventive Principle:

Principle #34Discarding and recovering

3Productivity

If all planes are utilized for parallel program operations, then productivity is improved, but measurement precision worsens due to difficulty in tracking bad block locations across planes

Engineering Contradiction:

Improveprogram operation speedVSAvoidbad block tracking

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the superblock management into plane-specific components, with each plane having its own pseudo-replacement block. This segmentation allows independent tracking and management of bad blocks in each plane, maintaining measurement precision while enabling all planes to operate in parallel for improved productivity.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11537483B2Controller for managing superblocks and operation method thereof

Publication Date: 2022.12.27 MIMIRIP LLC

AI summary

A method for operating a controller that controls a memory device includes: replacing a bad block of a superblock with a replacement block to form a reproduced superblock; controlling the memory device to perform a program operation on the reproduced superblock according to an interleaving scheme; moving data stored in the replacement block to a pseudo-replacement block when the program operation on the reproduced superblock is completed; and releasing the replacement block from the reproduced superblock.