SoC Display Controller Panel Self-Refresh Power Optimization

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Solution Overview

Problem

The increasing image resolution in mobile devices leads to higher data traffic between application processors and display driver ICs, resulting in increased power consumption and reduced battery duration due to frequent screen refresh operations.

Innovation Solution

A System on Chip (SoC) with a display controller that uses an error check algorithm to determine if the current frame data has been updated, triggering either a panel self-refresh active or inactive command to minimize data transmission and conserve power, including a transmitter to output these commands and an interrupt module to manage user events.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If frequent screen refresh operations are performed to maintain image quality, then display refresh rate is improved, but power consumption increases

Engineering Contradiction:

Improvedisplay refresh rateVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The display controller implements panel self-refresh (PSR) operation that periodically refreshes the display panel using stored frame data instead of continuously receiving new data from the application processor. The controller determines whether to activate PSR based on whether the current frame data differs from the previous frame data, creating a periodic refresh pattern that reduces power consumption while maintaining display quality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The display controller enables the display panel to refresh itself using internally stored frame data through PSR operation. When the current frame data is identical to the previous frame data, the controller activates PSR, allowing the display panel to maintain its display without requiring continuous data input from the application processor, thereby reducing power consumption.

Inventive Principle:

Principle #25Self-service

2Reliability

If full frame data transmission is performed for every refresh operation, then display update completeness is improved, but data traffic increases

Engineering Contradiction:

Improvedisplay update completenessVSAvoiddata traffic

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of transmitting complete frame data for every refresh operation, the display controller performs partial data transmission by comparing current frame data with previous frame data using an error check algorithm. When the data is identical, only a partial update or no transmission is needed, as the display panel can refresh using stored data, thereby reducing data traffic while maintaining display update completeness.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The display controller implements a feedback mechanism by comparing current frame data with previous frame data using an error check algorithm. Based on the comparison result, the controller dynamically determines whether to activate PSR operation or transmit full frame data, creating a feedback-controlled data transmission system that reduces data traffic while ensuring display update completeness.

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If panel self-refresh operation is continuously activated to reduce power consumption, then energy efficiency is improved, but display update responsiveness deteriorates

Engineering Contradiction:

Improveenergy efficiencyVSAvoiddisplay update responsiveness

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The display controller dynamically adjusts the PSR operation state based on real-time comparison of frame data. When frame data changes are detected through the error check algorithm, the controller deactivates PSR and activates full data transmission mode. When no changes are detected, the controller activates PSR to reduce power consumption. This dynamic switching mechanism maintains energy efficiency while ensuring display update responsiveness.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The error check algorithm provides continuous feedback about frame data changes, enabling the display controller to dynamically switch between PSR operation and full data transmission mode. This feedback mechanism ensures that PSR is activated only when appropriate (no data changes), maintaining energy efficiency, while immediately deactivating PSR when data changes occur, preserving display update responsiveness.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9916814B2System on chip, operation method of the same, and mobile device including the same

Publication Date: 2018.03.13 SAMSUNG ELECTRONICS CO LTD

AI summary

A system on chip (SoC) includes a display controller configured to receive data of a current frame and to determine whether the data of the current frame has been updated from data of a previous frame, and a transmitter configured to output a panel self-refresh (PSR) inactive command and the data of the current frame when the display controller determines that the data of the current frame has been updated and to transmit a panel self-refresh (PSR) active command when the display controller determines that the data of the current frame has not been updated.