Storage Device Power Control for Idle State Transitions

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Solution Overview

Problem

In storage devices using nonvolatile memory, the power consumption during transitions from an idle state to sleep states is higher than maintaining the idle state, leading to undesirable power consumption increases.

Innovation Solution

A storage device with a power control method that includes a controller and a power circuit, which manages power supply to nonvolatile memory and controller components, allowing transitions to shallow and deep sleep states while minimizing power consumption by optimizing save and return processes, and notifying a host for scheduling access requests to reduce power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If the storage device transitions to a sleep state to reduce power consumption, then power consumption during idle periods is reduced, but power consumption during the transition from idle state to sleep state increases

Engineering Contradiction:

Improvepower consumption during idle periodsVSAvoidpower consumption during state transition

Core Design Contradiction:

Use of energy by stationary objectVSUse of energy by moving object

Solution Approach 1:

The controller performs a save process of data before transitioning to the sleep state, and the host schedules access requests based on notification from the storage device. This preliminary action ensures that data is preserved and future access needs are anticipated, allowing the device to enter sleep state without compromising performance while avoiding unnecessary wake-up transitions that would consume excessive power.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The storage device dynamically adjusts its operational state based on the scheduled access requests and current idle duration. The controller monitors whether the idle state has persisted for a predetermined period and transitions to sleep state only when appropriate, creating a dynamic power management system that adapts to actual usage patterns rather than following fixed schedules.

Inventive Principle:

Principle #15Dynamics

2Use of energy by stationary object

If the storage device transitions to a deep sleep state to maximize power savings, then power consumption is minimized, but the time required to return to active state increases

Engineering Contradiction:

Improvepower consumption in sleep stateVSAvoidtime for state transition and data recovery

Core Design Contradiction:

Use of energy by stationary objectVSLoss of time

Solution Approach 1:

The host receives notification from the storage device about scheduled access requests and performs access operations before the storage device transitions to sleep state. This preliminary action ensures that data is retrieved while the device is still accessible, eliminating the need for time-consuming wake-up and data recovery processes that would occur if access were attempted after sleep transition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The host acts as an intermediary that coordinates between the storage device's power management decisions and data access requirements. By scheduling access requests based on notifications from the storage device, the host ensures that all necessary data operations are completed before the storage device enters sleep state, effectively mediating between power savings and data accessibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by stationary object

If the storage device frequently transitions between idle and sleep states to manage power, then power consumption is reduced, but the frequency of transitions increases power expenditure

Engineering Contradiction:

Improvepower consumption during idle periodsVSAvoidenergy lost during repeated transitions

Core Design Contradiction:

Use of energy by stationary objectVSLoss of energy

Solution Approach 1:

The host schedules access requests based on notification from the storage device before the device transitions to sleep state. This preliminary scheduling action prevents unnecessary wake-up transitions by ensuring that all access requests are accounted for and scheduled before the power-saving transition occurs, thereby eliminating energy-wasting frequent transitions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The storage device notifies the host about scheduled access requests and power state transitions, creating a feedback loop that allows the host to adjust its access pattern accordingly. This feedback mechanism enables the system to optimize power consumption by aligning access requests with the storage device's power state, preventing unnecessary transitions and reducing energy loss from frequent state changes.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11073896B2Storage device and a power control method for storage device

Publication Date: 2021.07.27 KIOXIA CORP

AI summary

A storage device comprises a nonvolatile memory, a controller that controls access to the nonvolatile memory, and a power circuit that supplies power to the nonvolatile memory and the controller. The power circuit can control the supply of power to at least parts of the nonvolatile memory and at least parts of the controller. The controller executes a data save process when a sleep transition request is received from the host requesting at least one of a plurality of sleep states according to a requested sleep state of the sleep transition request. The controller provides the host with state transition determination information that includes at one of a power consumption amount for a transition to a sleep state from an idle state and power consumption amount for a transition from the sleep state to the idle state.