Display Refresh Rate Control for Semi-Active Workloads

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Solution Overview

Problem

Current systems lack a low latency solution to reduce display refresh rate during semi-active workloads, such as browsing and productivity, which results in high power consumption and reduced battery life, as they require the display engine to maintain a high refresh rate even when the image is static.

Innovation Solution

An autonomous low refresh rate mode is implemented, where the display engine sends an indication to the Timing Controller (TCON) to skip self-refresh and lower the display refresh rate without changing the frame rate, allowing the TCON to autonomously reduce the refresh rate to a lower setting, such as from 60Hz to 20Hz, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the display engine maintains a high refresh rate during semi-active workloads, then the image quality and responsiveness are preserved, but the power consumption increases and battery life is reduced

Engineering Contradiction:

Improveimage responsivenessVSAvoiddisplay power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the display refresh rate based on workload activity. During semi-active workloads, the TCON autonomously lowers the refresh rate from the default rate (e.g., 60Hz) to a reduced rate (e.g., 20Hz) when no frame updates are detected, and restores the default rate when updates occur, optimizing the balance between power consumption and image responsiveness

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the refresh rate parameter of the display based on detected workload conditions. The TCON monitors for frame updates and adjusts the refresh rate parameter accordingly - maintaining high refresh rate when updates are detected and lowering it when the display is static, thereby reducing power consumption during semi-active workloads while preserving responsiveness when needed

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the display refresh rate is reduced during semi-active workloads, then power consumption is lowered, but latency increases and image responsiveness deteriorates

Engineering Contradiction:

Improvedisplay power consumptionVSAvoidrefresh latency

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The TCON implements a feedback mechanism by monitoring for frame updates from the display engine. When a frame update is detected, the system immediately restores the default refresh rate, ensuring that latency is minimized when content changes occur. This feedback loop allows the system to maintain low latency on-demand while enjoying power savings during static periods

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system uses periodic monitoring of frame updates to determine when to switch between refresh rates. The TCON continuously checks for new frames and adjusts the refresh rate periodically based on this monitoring, creating a responsive system that can quickly transition between power-saving mode and full-performance mode when content changes occur

Inventive Principle:

Principle #19Periodic action

3Use of energy by moving object

If the display engine enters power saving mode, then power consumption is reduced, but the frame rate must be changed which causes latency overhead

Engineering Contradiction:

Improvedisplay power consumptionVSAvoidcontrol complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent separates the refresh rate control function from the frame rate control function. The TCON handles refresh rate adjustments independently from the display engine's frame rate, allowing the refresh rate to be modified without changing the frame rate or requiring the display engine to enter power saving mode. This segmentation eliminates the need for complex coordinated control between multiple components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The TCON acts as an intermediary between the display engine and the display panel. It receives frames from the display engine at the original frame rate and autonomously adjusts the refresh rate to the display panel, decoupling the frame rate from the refresh rate. This intermediary role allows power saving without requiring changes to the display engine's operation or introducing latency overhead

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11538437B2Low power refresh during semi-active workloads

Publication Date: 2022.12.27 INTEL CORP

AI summary

Particular embodiments described herein provide for an electronic device that includes a display and is configured enabling a low power refresh during a semi-active workload. The electronic device includes a display engine, where the display engine generates a video stream with a frame rate, a display, where the display includes an image viewable by a user and the image is refreshed at a first refresh rate, and a timing controller located in the display, where the timing control receives an indicator from the display engine and uses the indicator to determine that the first refresh rate can be lowered to a second refresh rate without the frame rate of the video stream from the display engine being changed. In an example, the indicator is frame with no image data at the start of the frame. In another example, the indicator is an implicit indictor sent by the display engine.