SSD Bank Self-Refresh for Power Reduction
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Solution Overview
Problem
Semiconductor memory devices like DRAMs face power consumption issues due to charge leakage, necessitating frequent refresh operations, and in low power modes, existing solutions do not efficiently manage power distribution to maintain data retention without excessive consumption.
Innovation Solution
A solid state drive design incorporating a nonvolatile memory, volatile memory, and a memory controller that designates a specific bank for self-refresh operations in response to a power saving mode signal, cutting off power to nonessential components while maintaining data in designated banks, thereby reducing overall power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DRAM performs self refresh operation to retain data in sleep mode, then data retention is maintained, but power consumption increases
Solution Approach 1:
The patent divides the volatile memory into multiple banks and selects only one bank for self-refresh operations during sleep mode. This segmentation allows the system to maintain data retention in the active bank while leaving other banks in a lower-power state, thereby reducing overall power consumption while maintaining reliability for the active data.
Solution Approach 2:
The patent applies different operational states to different banks of volatile memory. The designated bank performs self-refresh to maintain data retention, while other banks remain in a non-refreshing state. This local differentiation optimizes power consumption by applying the energy-intensive refresh operation only where data retention is actually needed.
2Reliability
If all banks in volatile memory perform self refresh, then data retention is ensured across all banks, but power consumption increases significantly
Solution Approach 1:
Instead of performing self-refresh operations on all banks (excessive action), the patent applies partial action by selecting only one bank for self-refresh. This partial action is sufficient to maintain data retention for the active data while avoiding the unnecessary power consumption that would result from refreshing all banks.
3Use of energy by moving object
If power is cut off to nonvolatile memory and memory controller, then power consumption is reduced, but data accessibility may be affected
Solution Approach 1:
The patent performs preliminary actions by storing critical data in the designated volatile memory bank before cutting off power to nonvolatile memory and memory controller. This ensures that when power is restored, the data is already in a ready state in the volatile memory, minimizing disruption to data accessibility while still achieving significant power savings.
Data Source
AI summary
A solid state drive in accordance with embodiments of the present inventive concepts may include a nonvolatile memory, a volatile memory, a memory controller controlling the nonvolatile memory and the volatile memory, and a power generator providing power to the nonvolatile memory, the volatile memory, and the memory controller. A method of operating the solid state drive may include designating a bank that will perform a self refresh among a plurality of banks included in the volatile memory in response to a power saving mode signal. Information of the designated bank may be stored in a register in response to a command and an address signal; and a self refresh of the designated bank may be performed on the basis of the information stored in the register.