Display Power Supply Voltage Control for Overcurrent Protection
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Solution Overview
Problem
Display panels can be damaged by overcurrents due to unadjusted luminance levels based on input image data loads, leading to potential damage during frame transitions when luminance adjustment functions are delayed.
Innovation Solution
A display device and method that senses power supply current and adjusts the power supply voltage based on current levels, using a power supply voltage generator with current sensing and voltage control blocks to prevent overcurrents by determining a scale factor for gray scale adjustment and generating appropriate power supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If luminance adjustment is delayed by one frame to determine load of input image data, then the luminance adjustment function can operate based on accurate load measurement, but overcurrent may flow during the delay period causing damage to the display panel or data driver
Solution Approach 1:
The patent applies preliminary action by performing luminance adjustment based on the load of the previous frame (N-1) rather than waiting for the current frame (N) load determination. This allows the system to proactively adjust luminance before overcurrent conditions occur, preventing damage while maintaining measurement accuracy. The power supply voltage is adjusted in advance based on previously determined load characteristics.
Solution Approach 2:
The patent introduces a current sensing block as an intermediary component that continuously monitors power supply current and provides real-time feedback to the power supply voltage generator. This intermediary mechanism enables the system to detect overcurrent conditions immediately and adjust the power supply voltage accordingly, bridging the gap between load determination and luminance adjustment.
2Reliability
If luminance adjustment function is activated immediately when load exceeds threshold, then overcurrent prevention is achieved, but delay in frame processing occurs affecting display timing
Solution Approach 1:
The patent implements periodic action by performing luminance adjustment at regular frame intervals rather than continuously. The system determines the load of each frame, adjusts the power supply voltage for the next frame, and repeats this cycle. This periodic approach prevents overcurrent conditions while maintaining synchronized frame processing timing.
Solution Approach 2:
The system performs preliminary luminance adjustment based on the previous frame's load determination before the current frame is fully processed. This allows the power supply voltage to be adjusted in advance for the upcoming frame, preventing overcurrent while avoiding disruption to the current frame's display timing.
3Reliability
If power supply voltage is continuously adjusted to prevent overcurrent, then display panel protection is improved, but system complexity increases due to additional sensing and control circuits
Solution Approach 1:
The patent applies self-service by enabling the power supply voltage generator to automatically adjust the power supply voltage based on feedback from the current sensing block. The system monitors its own current consumption and autonomously regulates the power supply voltage without requiring external intervention or complex control algorithms, simplifying the overall control architecture.
Solution Approach 2:
The patent implements a feedback mechanism where the current sensing block continuously monitors the power supply current and provides real-time information to the power supply voltage generator. This feedback loop enables automatic power supply voltage adjustment to maintain current within safe limits, providing robust protection with a relatively simple control structure.
Data Source
AI summary
A display device may include a display panel which displays an image based on a data voltage, a driving controller including a net power control setter which determines a scale factor for adjusting a gray scale of (N+1)th frame data based on a load of Nth frame data and a net power control reference value, where the driving controller generates a data signal based on input image data, and N is a natural number greater than or equal to 2, a data driver which converts the data signal into the data voltage and outputs the data voltage to the display panel, and a power supply voltage generator which senses a power supply current applied to the display panel in an Nth frame and generates a power supply voltage based on a current level of the power supply current.