Sparse Refresh Control via Auxiliary Channel for Display Power Savings

Solution Overview

Problem

Updating a self-refreshing display device introduces significant delays and energy consumption due to the time required to 'wake-up' the graphics controller and associated communication channels, especially when frequently entering and exiting self-refresh mode.

Innovation Solution

A method that involves executing a fast resume routine, using a low-speed auxiliary communications channel to update pixel data, and returning to a power-saving state, minimizing the initialization of the GPU and high-speed communication channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the graphics controller and high-speed communication channels are fully initialized to update image data, then the display device can be updated, but the initialization time and energy consumption increase significantly

Engineering Contradiction:

Improveimage update capabilityVSAvoidinitialization time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The display device maintains a local frame buffer that continuously stores image data even when the graphics controller is in a low-power state. This preliminary preparation allows the display to quickly refresh images without requiring full initialization of the graphics controller, thus reducing initialization time while maintaining update capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The communication interface is divided into two separate channels: a high-speed channel for transferring complete frame buffers and a low-speed auxiliary channel for sending control commands and small data updates. This segmentation allows the system to use only the necessary channel for each operation, reducing unnecessary initialization overhead

Inventive Principle:

Principle #1Segmentation

2Reliability

If the graphics controller and high-speed communication channels are fully initialized to update image data, then the display device can be updated, but the energy consumption increases significantly

Engineering Contradiction:

Improveimage update capabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The display device maintains a local frame buffer that continuously stores image data even when the graphics controller is in a low-power state. This preliminary preparation allows the display to quickly refresh images without requiring full initialization of the graphics controller, thus reducing initialization time while maintaining update capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The communication interface is divided into two separate channels: a high-speed channel for transferring complete frame buffers and a low-speed auxiliary channel for sending control commands and small data updates. This segmentation allows the system to use only the necessary channel for each operation, reducing unnecessary initialization overhead

Inventive Principle:

Principle #1Segmentation

3Speed

If the graphics controller is kept active to enable quick image updates, then update speed improves, but power consumption increases

Engineering Contradiction:

Improveupdate speedVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The display device maintains a local frame buffer that continuously stores image data even when the graphics controller is in a low-power state. This preliminary preparation allows the display to quickly refresh images without requiring full initialization of the graphics controller, thus reducing initialization time while maintaining update capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically switches between two operational modes: using the low-speed auxiliary channel for small updates when the graphics controller is in low-power state, and using the high-speed channel for complete frame buffer transfers when rapid updates are needed. This dynamic adaptation optimizes both speed and power consumption based on actual requirements

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9047085B2Method and apparatus for controlling sparse refresh of a self-refreshing display device using a communications path with an auxiliary communications channel for delivering data to the display

Publication Date: 2015.06.02 NVIDIA CORP

AI summary

A method and apparatus for controlling sparse refresh of a self-refreshing display device coupled to a graphics controller are disclosed. The display device includes capabilities to drive the display based on video signals generated from a local frame buffer. The graphics controller may optimally be placed in one or more power-saving states when the display device is operating in a panel self-refresh mode. When exiting the power-saving state to update the image displayed by the display device, a fast-resume initialization routine may be run to reconfigure the GPU when operating in a sparse refresh mode, i.e., where the image being displayed on the display device is updated infrequently. In such cases, the graphics controller may be configured to receive instructions and data from a central processing unit via an alternative low-bandwidth communications path instead of the high-bandwidth communications path used in normal operation.