Dual Controller Memory System Architecture for NAND Reliability
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Solution Overview
Problem
In nonvolatile memory systems, such as NAND type flash memory, the miniaturization of chip layout leads to changes in error correction symbols, requiring adaptations in controller functions to maintain page size and command sequence reliability, especially in memory systems with different erasure block sizes and command sequences.
Innovation Solution
A memory system architecture with dual controllers, where a first controller manages the entire system and interacts with a host equipment, and a second controller specifically controls access to nonvolatile memory, receiving commands and performing access processes, including error correction, to adapt to varying memory configurations and ensure reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If miniaturization of line width is implemented to reduce chip size, then chip area is reduced, but error correction requirements increase and controller function complexity increases
Solution Approach 1:
The controller is divided into two separate controllers: a first controller that manages the entire memory system and interacts with host equipment, and a second controller that specifically controls access to the nonvolatile memory. This segmentation allows each controller to be optimized for its specific function, reducing the complexity burden on any single controller while maintaining overall system functionality.
Solution Approach 2:
The second controller acts as an intermediary between the first controller and the nonvolatile memory. It receives commands via the first controller and carries out access processes to the nonvolatile memory, handling error correction and adapting to varying memory configurations. This intermediary structure isolates the complexity of error correction and adaptation logic from the main system controller.
2Reliability
If error correction symbols are changed to maintain reliability with miniaturization, then reliability is maintained, but controller function changes are required
Solution Approach 1:
The error correction functionality is extracted from the first controller and implemented in the second controller that directly interfaces with the nonvolatile memory. The second controller handles error correction symbols and adaptation to varying memory configurations, isolating this complex functionality from the main system controller.
Solution Approach 2:
The second controller is designed to dynamically adapt to varying memory configurations and change error correction symbols as needed. This dynamic capability allows the system to maintain reliability across different memory generations and configurations without requiring changes to the first controller.
3Adaptability or versatility
If dual controller architecture is implemented to manage complexity, then controller function adaptability improves, but device complexity increases
Solution Approach 1:
The control functions are segmented between two specialized controllers rather than one general-purpose controller. The first controller handles high-level system management and host interface, while the second controller handles low-level memory access and error correction. This segmentation improves adaptability to different memory configurations while keeping each controller's complexity manageable.
Solution Approach 2:
The first controller is designed as a universal controller that can manage different types of nonvolatile memory through the second controller. The second controller is designed to be memory-specific, handling the particulars of error correction and access protocols. This multi-functionality approach allows the system to adapt to various memory configurations without redesigning the entire controller.
Data Source
AI summary
A memory system including a nonvolatile memory, a first controller connected to a host equipment, the first controller controlling the entire memory system, a second controller connected to the first controller and also connected to the nonvolatile memory, the second controller controlling an access process to said nonvolatile memory, the second controller receives a command via the first controller and carries out the access process to the nonvolatile memory according to the command, the command being input from the host equipment.