Memory Controller Read Voltage Adaptation for SLC and MLC Interleaving
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Solution Overview
Problem
Current memory systems face challenges in simultaneously performing read operations on single-level cell and multi-level cell storage regions due to differences in read voltages required for each, making it difficult to achieve efficient interleaving performance.
Innovation Solution
A controller is designed to control a nonvolatile memory device by changing read voltages for multi-level cell modes to match those of single-level cell modes, allowing for simultaneous read operations across both types of storage regions through an error correction engine that decodes data accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate read operations are performed for single-level cell and multi-level cell storage regions, then read accuracy is maintained, but interleaving performance deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the read voltage based on the storage region being accessed. When reading from the first storage region (single-level cell), the controller uses a first read voltage, while when accessing the second storage region (multi-level cell), it switches to a second read voltage. This voltage parameter adaptation enables the system to maintain optimal read accuracy for each region while achieving efficient interleaving operations, resolving the contradiction between productivity and device complexity.
2Measurement precision
If multiple read voltages are used for different storage regions, then read accuracy is improved, but operation simplicity deteriorates
Solution Approach 1:
The patent implements self-service by having the controller automatically select and switch between different read voltages based on the current storage region without requiring manual intervention. The controller monitors whether the read operation targets the first or second storage region and autonomously adjusts the read voltage accordingly, maintaining high read accuracy while simplifying the operation interface for the user or host system.
3Adaptability or versatility
If read voltage is changed during operation, then interleaving capability is enabled, but system stability may be affected
Solution Approach 1:
The patent applies preliminary action by having the controller pre-establish and store multiple read voltage values corresponding to different storage regions before actual read operations occur. When a read operation is initiated, the controller retrieves the appropriate pre-configured read voltage based on the target region, enabling smooth voltage switching without disrupting system stability. This advance preparation allows the system to adapt to different storage regions while maintaining operational stability.
Data Source
AI summary
A memory system includes a nonvolatile memory device and a controller configured to control the nonvolatile memory device. The nonvolatile memory device includes a first data storage region in which a memory cell stores one-bit data in a first mode and a second data storage region in which a memory cell stores two-bit or more data in a second mode. The controller controls the nonvolatile memory device to perform a read operation on the first data storage region and the second data storage region in the second mode. The controller decodes first data read from the first data storage region, and decodes second data read from the second data storage region. The controller controls the nonvolatile memory device to perform the read operation on the first data storage region in the second mode.