Memory Controller Transfer Phase Suspension for Read Latency
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Solution Overview
Problem
In memory systems, there is a challenge to minimize latency for read requests from hosts while efficiently managing data transfer and storage in non-volatile memory, particularly in NAND-type flash memory systems, where existing methods may lead to increased latency due to the need to suspend and resume data transfer phases.
Innovation Solution
The memory controller suspends the data transfer phase in the memory system and executes a read sequence, saving data from the transfer buffer to a backup buffer before resuming the transfer phase, allowing for efficient data handling and reducing latency by avoiding the need to retransfer data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the data transfer phase is suspended to execute a read sequence, then read latency is reduced, but the total program time increases due to phase suspension and resumption overhead
Solution Approach 1:
The patent applies preliminary action by saving transfer buffer data to a backup buffer before suspending the data transfer phase. This preparation ensures that when the read sequence is executed, the original data can be restored without retransmission, thereby reducing read latency while minimizing the impact on total program time.
Solution Approach 2:
The patent implements discarding and recovering by temporarily moving data from the transfer buffer to a backup buffer during phase suspension, then restoring it after the read sequence completes. This allows the system to prioritize read operations while preserving the original data for continued program operations, effectively managing the trade-off between read latency and program time.
2Loss of time
If data is saved and restored frequently to handle read requests during transfer phase, then read latency is reduced, but power consumption increases
Solution Approach 1:
The patent applies partial action by selectively saving only the necessary portion of transfer buffer data to the backup buffer when a read request is received during the data transfer phase. This selective approach reduces the overhead of frequent save/restore operations compared to saving entire buffers, thereby lowering power consumption while still achieving low read latency for the specific requested data.
Data Source
AI summary
According to one embodiment, a memory system includes a non-volatile memory and a controller. The memory includes a memory cell array. The controller is configured to control a transfer phase in which a command, an address, and first data are transferred to the memory, and a program phase in which the first data is programmed into the memory cell array by the memory after the transfer phase. The controller is configured to suspend the transfer phase after initiating the transfer phase before completion of the transfer phase, then read second data from the memory, and resume the transfer phase after reading of the second data is completed.