Scan Driver Node Control Circuit for Variable Frequency Display Driving
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Solution Overview
Problem
Conventional display devices with low frequency driving technology do not effectively reduce power consumption when still images are displayed only on partial areas of the display panel, as the entire panel is often driven at normal frequency.
Innovation Solution
A scan driver that provides scan signals with different frequencies to variable areas of a display panel, allowing for selective output of scan signals based on an enable signal to reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the entire display panel is driven at normal frequency, then the display quality and responsiveness are maintained, but power consumption increases
Solution Approach 1:
The display panel is divided into multiple scan line groups, each group being driven at different frequencies. The scan driver includes multiple output circuits that can independently control the driving frequency for different scan line groups, allowing partial area low-frequency driving while maintaining normal frequency for other areas.
Solution Approach 2:
The scan driver dynamically adjusts the driving frequency for different scan line groups based on the display content requirements. When still images are displayed in partial areas, those areas are driven at low frequency while other areas continue at normal frequency, optimizing power consumption based on real-time display needs.
2Use of energy by moving object
If low frequency driving is applied to the entire panel, then power consumption is reduced, but display quality deteriorates when full refresh is needed
Solution Approach 1:
Different driving frequencies are applied to different regions of the display panel according to their specific requirements. Areas displaying still images use low frequency driving to save power, while areas requiring dynamic content updates use normal frequency to maintain display quality and responsiveness.
3Productivity
If the scan driver outputs scan signals continuously at normal frequency, then display responsiveness is maintained, but energy waste occurs in partial still image areas
Solution Approach 1:
The scan driver implements periodic scanning with variable frequencies for different scan line groups. Instead of continuous uniform scanning, each scan line group is scanned periodically at an optimized frequency based on its content requirements, reducing unnecessary energy consumption in static areas.
Data Source
AI summary
A scan driver includes: stages. Each stage includes: a first node control circuit for controlling a voltage of a first node; an inverted carry node control circuit for controlling a voltage of an inverted carry node; a carry output circuit for outputting a carry signal; a fourth node control circuit for controlling a voltage of a fourth node in response to the carry signal; a second node control circuit for controlling a voltage of a second node in response to the carry signal, an enable signal, and the voltage of the inverted carry node; a third node control circuit for controlling a voltage of a third node in response to the voltage of the second node and the voltage of the fourth node; and a scan output circuit for outputting a scan signal in response to the voltage of the third node and the voltage of the fourth node.