Dynamic Pass Voltage Adjustment for Memory Cell Protection

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Solution Overview

Problem

Repetitive read operations in non-volatile memory devices lead to deterioration of memory cells, resulting in delays and errors during the reading process.

Innovation Solution

A memory device that adjusts the pass voltage based on changes in the read voltage, recorded and transmitted to the host, to prevent deterioration of memory cells and maintain data read operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a high pass voltage is applied during read operations, then data reading speed is improved, but memory cell deterioration occurs

Engineering Contradiction:

Improvedata reading speedVSAvoidmemory cell durability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of the pass voltage based on the number of read operations performed on each memory block. The pass voltage is initially set to a first value for fast reading, then automatically changed to a second value after a predetermined number of reads, and restored after a refresh operation. This dynamic voltage adjustment resolves the contradiction by adapting the voltage level to the operational state of the memory block.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the pass voltage parameter from a fixed high value to a variable value that switches between at least two different levels. This parameter change allows the system to optimize between reading speed and memory cell protection by selecting appropriate voltage levels based on read operation counts and refresh timing.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If read operations are performed repeatedly, then data access frequency is improved, but read delays and errors occur

Engineering Contradiction:

Improvedata access frequencyVSAvoidread operation accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary refresh operations on memory blocks after a predetermined number of read operations to prevent deterioration before it causes read errors. By proactively refreshing the memory cells based on read count monitoring, the system maintains data integrity and prevents read delays and errors from occurring.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism that monitors the number of read operations performed on each memory block and uses this information to automatically adjust the pass voltage and trigger refresh operations. This closed-loop control ensures that memory blocks are refreshed at appropriate intervals to maintain read accuracy while maximizing data access frequency.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250037777A1Memory device capable of changing pass voltage, memory system, and operating method of the memory device

Publication Date: 2025.01.30 SAMSUNG ELECTRONICS CO LTD

AI summary

According to the inventive concept, a memory device may receive a pass voltage signal set in advance from a host and perform a verification operation with respect to a memory cell array based on the received pass voltage signal. The memory device includes an aggressor word line on which a read operation is performed, and a memory block including a victim word line adjacent to the aggressor word line, and a change in a read voltage with respect to the memory block is recorded and the recorded change in the read voltage is sent to the host.