Display Power Supply Voltage Transition for Luminance Stability
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Solution Overview
Problem
Display devices experience luminance deviations and increased power consumption when switching between normal and power saving modes due to rapid voltage changes, which affect user perception and energy efficiency.
Innovation Solution
A display device design that includes a power supply and data driver system, utilizing converters and transistors to gradually decrease voltage levels during vertical blank periods, maintaining a preset reference difference between source and gate driving voltages, and adjusting auxiliary power voltages to minimize power consumption and prevent luminance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pixels are driven at a low frequency in power saving mode, then power consumption is decreased, but luminance deviation occurs due to rapid voltage change
Solution Approach 1:
The power supply decreases the voltage level of the first power voltage to a first power saving voltage level before the mode switching is completed. This preliminary voltage reduction during the vertical blank period ensures that when the display switches from normal mode to power saving mode, the voltage change is already prepared and minimized, preventing luminance deviation while maintaining low power consumption
Solution Approach 2:
The power supply acts as an intermediary between the external input voltage and the display panel, specifically managing the first power voltage. By controlling the voltage level transition through the power supply during the vertical blank period, the harmful luminance deviation is mediated and prevented, allowing smooth mode switching without affecting display quality
2Loss of energy
If the voltage level is rapidly decreased to reduce power consumption, then energy efficiency is improved, but luminance deviation is recognized by the user
Solution Approach 1:
The voltage level reduction is performed preliminarily during the vertical blank period before the actual display content changes. This timing ensures that the voltage transition is completed before the user would perceive any luminance change, thereby maintaining energy efficiency while preventing noticeable luminance deviation
Solution Approach 2:
The voltage level is decreased rapidly during the vertical blank period when no image is displayed, effectively skipping the visible display period. This allows the voltage transition to occur during an invisible time window, achieving fast voltage change for energy efficiency without user-perceivable luminance deviation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively minimizes power consumption and prevents luminance deviations by smoothly transitioning voltage levels, ensuring stable image display and reduced energy usage during mode changes.
Implementation Method 1
a first converter which generates the first power voltage, the first converter may include a switch unit including a first inductor and first and second transistors and connected between a first input terminal to which an external input voltage is applied and a first output terminal from which the first power voltage is output
Data Source
AI summary
A display device includes a display panel including a plurality of pixels and a power line, and displaying an image in a normal mode or a power saving mode, a data driver which provides a data signal to the pixels, and a power supply which supplies a source driving voltage to the data driver and supplies a first power voltage to the power line in the normal mode. The data driver supplies a first auxiliary power voltage to the power line in the power saving mode, and the power supply outputs the first power voltage by decreasing a voltage level of the first power voltage to a first power saving voltage level in a vertical blank period in which the pixels do not display an image during a first switching period changing from the normal mode to the power saving mode.