Semiconductor Memory Device Garbage Collection Based on Programmed Page Ratio

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Solution Overview

Problem

Existing semiconductor memory devices face inefficiencies in garbage collection operations, which are often based on the number of free blocks, leading to unnecessary background operations and reduced performance.

Innovation Solution

A semiconductor memory device and controller system that checks the ratio of programmed pages and uses this information to determine a garbage collection policy, optimizing the frequency and timing of garbage collection operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If garbage collection is performed based on the number of free blocks, then the memory management is simplified, but unnecessary background operations occur and performance deteriorates

Engineering Contradiction:

Improvegarbage collection managementVSAvoidsystem performance

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent changes the parameter basis for garbage collection from 'number of free blocks' to 'programmed page ratio'. By monitoring the ratio of programmed pages to total pages in each block, the system can more accurately determine when garbage collection is needed, avoiding unnecessary operations while maintaining simple management logic.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If frequent garbage collection operations are performed, then free blocks are maintained, but system response time decreases and energy is wasted

Engineering Contradiction:

Improvenumber of free blocksVSAvoidresponse time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where the programmed page ratio is continuously monitored and used to dynamically adjust garbage collection timing. When the ratio exceeds a threshold, garbage collection is triggered; otherwise, operations are deferred. This feedback loop ensures free blocks are maintained only when necessary, reducing unnecessary interruptions to system operations.

Inventive Principle:

Principle #23Feedback

3Device complexity

If garbage collection is performed based on free block count, then the control logic is simple, but the timing of operations is suboptimal

Engineering Contradiction:

Improvecontrol logicVSAvoidoperation timing efficiency

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent changes the monitoring parameter from free block count to programmed page ratio, which provides more accurate timing information for garbage collection. This parameter change improves operational timing efficiency without significantly increasing control logic complexity, as the same basic monitoring and threshold-comparison mechanisms are used.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250157554A1Semiconductor memory device, controller, and method of operating the semiconductor memory device and controller

Publication Date: 2025.05.15 SK HYNIX INC

AI summary

A semiconductor memory device includes a plurality of memory blocks, a peripheral circuit, control logic, and a status checker. Each of the plurality of memory blocks includes a plurality of physical pages. The peripheral circuit is configured to perform a program operation, an erase operation, or a read operation on a selected memory block among the plurality of memory blocks. The control logic controls the program operation, the erase operation, or the read operation of the peripheral circuit. The status checker checks a ratio of a programmed page among the physical pages included in the plurality of memory blocks.