NVDIMM Rank Segmentation for Emergency Power Backup

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Solution Overview

Problem

Current Non-Volatile Dial In Line Memory Modules (NVDIMM) require high-capacity capacitors for emergency power, leading to increased production costs due to high power consumption.

Innovation Solution

A memory module design that includes an emergency power supplier, multiple ranks of volatile and non-volatile memories, and a controller that sequentially backs up data from volatile memories to non-volatile memories using emergency power, with ranks being controlled in self-refresh or maximal power-saving modes to minimize power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-capacity capacitors are used as emergency power supply for NVDIMM, then data protection capability is improved, but production cost increases

Engineering Contradiction:

Improvedata protection capabilityVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The memory ranks are divided into multiple groups that can be independently controlled. During power failure, the controller selectively backs up data from active ranks to non-volatile memory while placing other ranks in self-refresh mode, segmenting the power consumption across time and memory banks rather than requiring all memory to remain fully powered.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses periodic self-refresh operations to maintain data in volatile memory during power failure. Ranks not currently being backed up enter self-refresh mode, performing periodic refresh cycles to maintain data integrity while consuming minimal power, rather than requiring continuous high power supply.

Inventive Principle:

Principle #19Periodic action

2Reliability

If all memory ranks remain fully powered during power failure, then data integrity is maintained, but power consumption increases

Engineering Contradiction:

Improvedata integrityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The memory system is segmented into actively backed-up ranks and ranks in self-refresh mode. This segmentation allows different parts of the memory system to operate at different power levels simultaneously, maintaining data integrity where needed while reducing overall power consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the operational parameters of memory ranks during power failure by transitioning from full operation mode to self-refresh mode. This parameter change reduces the power consumption state of ranks not currently being backed up while maintaining their ability to preserve data through periodic refresh operations.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10127982B2Volatile memory, memory module including the same, and method for operating the memory module

Publication Date: 2018.11.13 SK HYNIX INC

AI summary

A memory module includes an emergency power supplier, a plurality of ranks each including one or more volatile memories, a non-volatile memory, and a controller suitable for backing up data of the ranks into the non-volatile memory by using the emergency power supplier during a power failure, wherein the ranks are sequentially backed up, and while one rank is backed up among the ranks, the other ranks are controlled in a self-refresh mode.