TLC Flash Memory Controller Dynamic SLC Mode Switching
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Solution Overview
Problem
Triple-Level Cell (TLC) flash memory is prone to data loss due to environmental factors, particularly high temperatures, which affects data retention and is more susceptible than Single-Level Cell (SLC) or Multi-Level Cell (MLC) flash memory.
Innovation Solution
A data storage device with a controller that distributes TLC-data blocks into three regions, writes prewrite data sectors into TLC-data blocks using a Single-Level Cell (SLC) storage mode before exposure to high temperatures, and then converts them back to TLC mode after the temperature event, utilizing SLC-spare blocks for temporary storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If TLC storage mode is used to maximize memory capacity, then storage density is improved, but data retention under high temperature is worsened
Solution Approach 1:
The patent dynamically switches the storage mode of TLC data blocks between TLC and SLC based on temperature conditions. During high-temperature periods (temperature > threshold), the system switches to SLC mode for enhanced data retention, and during normal conditions, it operates in TLC mode for maximum storage density. This dynamic adaptation resolves the contradiction between storage capacity and data reliability under thermal stress.
Solution Approach 2:
The patent changes the operational parameters of the flash memory by adjusting the storage mode (TLC vs. SLC) in response to temperature parameter changes. When temperature exceeds a predetermined threshold, the system changes the storage parameter from TLC to SLC mode, which has better thermal stability, thereby maintaining data retention while adapting to environmental conditions.
2Quantity of substance
If TLC blocks are used for storage, then storage capacity is improved, but susceptibility to temperature-induced data loss is worsened
Solution Approach 1:
The patent introduces SLC mode as an intermediary state between TLC blocks during high-temperature conditions. Instead of directly exposing TLC blocks to harmful temperatures, the system mediates by temporarily converting them to SLC mode, which is more resistant to thermal effects. This intermediary approach protects data from temperature-induced loss while maintaining the ability to return to high-capacity TLC mode when conditions normalize.
3Reliability
If SLC mode is used during high temperature, then data retention is improved, but memory space is worsened
Solution Approach 1:
The patent implements periodic monitoring of temperature conditions and switches between TLC and SLC modes accordingly. During high-temperature periods, the system periodically switches to SLC mode for enhanced retention, then returns to TLC mode when temperatures normalize. This periodic switching ensures data protection during critical thermal events while maximizing storage capacity during normal operation, resolving the space-retention trade-off.
Data Source
AI summary
The present invention provides a data storage device including a flash memory and a controller. The controller distributes TLC-data blocks of the flash memory into three regions, obtains three sub-prewrite data sectors according to a prewrite data sector and a logic address, determines a first TLC-data block according to the logic address, selects a new first TLC-data block with the lowest erase count from the first region when the first TLC-data block has valid data, selects two TLC-data blocks according to the new first TLC-data block, writes the three sub-prewrite data sectors into the new first TLC-data block and the two selected TLC-data blocks, and maps the first new TLC-data block and the two selected TLC-data blocks to the logic address.