Display Device Power Voltage Adjustment for Variable Refresh Rate
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Solution Overview
Problem
Display devices using technologies like G-sync and Free-sync often experience fluctuations in display frequency, leading to issues such as tearing, stuttering, and flicker when rendering speed and display frequency do not match.
Innovation Solution
A display device and method that include a processor supplying grayscale data during active frame periods and stopping its supply during blank periods, with a timing controller generating a change signal based on the difference between blank periods of consecutive frame periods, and a power supply adjusting voltage levels on power lines to match the change signal, ensuring pixels receive appropriate power voltages to synchronize rendering speed with display frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If G-sync or Free-sync technology is applied to match rendering speed and display frequency, then tearing and stuttering are reduced, but display frequency fluctuates frequently causing flicker
Solution Approach 1:
The power supply voltage is dynamically adjusted based on the display frequency. When display frequency increases, the power supply voltage is increased to compensate for the reduced pixel on-time, maintaining consistent luminance output despite frequency fluctuations. This dynamic compensation resolves the contradiction by allowing frequency variation while maintaining visual stability.
Solution Approach 2:
The patent changes the power supply voltage parameter in response to display frequency changes. By monitoring display frequency and adjusting the power voltage accordingly, the system compensates for luminance variations caused by frequency fluctuation, thereby preventing flicker while maintaining the benefits of variable refresh rate technology.
2Manufacturing precision
If blank period is extended to allow complete rendering, then rendering completeness is improved, but display frequency decreases
Solution Approach 1:
The patent adjusts the power supply voltage parameter based on blank period duration. When the blank period is extended, the power voltage is increased to maintain consistent pixel response characteristics, ensuring that rendering completeness is achieved without excessive penalty to display frequency and overall performance.
3Reliability
If power voltage is increased to compensate for short blank period, then pixel response is improved, but power consumption increases
Solution Approach 1:
The power supply voltage is dynamically adjusted based on the actual blank period duration and display frequency conditions. The voltage is increased only when necessary to maintain pixel response reliability, and reduced when conditions allow, thereby optimizing the balance between response reliability and power consumption rather than using a fixed high voltage.
Solution Approach 2:
The patent changes the power voltage parameter adaptively based on operating conditions. By monitoring blank period duration and adjusting voltage accordingly, the system maintains pixel response reliability while minimizing power consumption, avoiding the need for continuously high voltage operation.
Data Source
AI summary
A display device includes a processor which supplies grayscale data in active periods of frame periods and stops supply of the grayscale data in blank periods of the frame periods, a timing controller which generates a change signal when a difference between a first blank period of a first frame period and a second blank period of a second frame period is greater than a threshold value, a power supply which supplies a first power voltage having a voltage level changed based on the change signal to a first power line, and pixels commonly connected to the first power line.