Nonvolatile Memory Read Voltage Adjustment Per ECC Unit
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Solution Overview
Problem
Conventional nonvolatile memory devices face challenges with reduced lifespan and increased error likelihood due to miniaturization, and existing error correction codes have limited capacity to correct errors, necessitating new approaches to enhance reliability and error correction.
Innovation Solution
A nonvolatile memory device with a memory cell array comprising multiple ECC units, where read voltage levels are individually set based on data detection results for each ECC unit, allowing for re-reading of data using specifically adjusted voltages during a read retry operation to minimize errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If device miniaturization is implemented to reduce size, then device size is reduced, but lifespan decreases and error likelihood increases
Solution Approach 1:
The memory device is divided into multiple banks, with each bank containing multiple planes and blocks. This segmentation allows independent management and operation of different memory sections, enabling targeted error correction and voltage adjustment for specific affected areas without impacting the entire device, thereby maintaining reliability despite miniaturization.
Solution Approach 2:
Different read voltages are applied to different banks based on their specific error characteristics. The system detects errors in individual banks and adjusts the read voltage locally for each bank, rather than applying a uniform voltage across the entire device. This localized approach optimizes reading accuracy for each miniaturized section while accounting for variations in error rates.
2Reliability
If conventional ECC circuits are used for error correction, then some error bits can be corrected, but the correction capacity is limited
Solution Approach 1:
The ECC functionality is distributed across multiple banks, with each bank having its own error detection and correction capabilities. This segmentation allows the system to handle errors independently in each bank, effectively increasing the overall error correction capacity without requiring a single complex centralized ECC circuit.
Solution Approach 2:
The system dynamically adjusts read voltages based on detected error patterns in different banks. By changing the voltage parameter adaptively, the system enhances error correction effectiveness without adding complex hardware, utilizing voltage modulation to improve signal integrity and reduce read errors.
3Ease of operation
If uniform read voltage is applied to all ECC units, then device operation is simple, but read errors occur due to variations in data detection requirements
Solution Approach 1:
The read voltage is made dynamic and adaptive rather than static and uniform. The system continuously monitors error rates in different banks and adjusts the read voltage for each bank accordingly. This dynamic adjustment maintains simplicity in the basic read operation while significantly improving data detection accuracy through automated voltage optimization.
Solution Approach 2:
Different read voltage levels are applied to different banks based on their specific detection requirements. The system identifies which banks require higher or lower voltages for optimal reading and implements these parameter changes automatically, maintaining ease of operation while enhancing reliability through customized voltage profiles for each bank.
Data Source
AI summary
A nonvolatile memory device includes a memory cell array including a selected page including multiple error correction code (ECC) units, and a voltage generation unit configured to generate a read voltage to read data from the selected page. Read voltage levels are set individually for the respective ECC units according to data detection results for each of the ECC units. During a read retry section performed with respect to selected ECC units of the selected page for which read errors have been detected, a re-read operation of the selected ECC units is performed according to the respective read voltage levels set for the selected ECC units.