LED Driving Circuit Ghost Phenomenon Elimination
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Solution Overview
Problem
The ghost phenomenon occurs in light emitting diode (LED) driving circuits due to parasitic capacitance, especially during increased switch actions in multi-scanning structures, leading to reduced image quality.
Innovation Solution
A driving circuit with a ghost phenomenon elimination unit that adjusts the voltage level of current driving terminals to a high voltage level during black insertion periods, determined by a counter unit counting the gray scale clock signal, to reduce ghosting effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-scanning driving structure is used to drive multiple sets of light emitting diodes, then driving efficiency and coverage are improved, but ghost phenomenon worsens due to increased switch actions and parasitic capacitance
Solution Approach 1:
The patent applies preliminary action by actively pulling up the voltage level of the current driving terminal to a high voltage level during the black insertion period before the next scanning cycle begins. This preemptive voltage adjustment ensures that the LED fully turns off before the next driving cycle, preventing ghost phenomenon without reducing the multi-scanning driving efficiency
Solution Approach 2:
The patent implements periodic action by incorporating a black insertion period between scanning cycles and using a counter unit to periodically detect and identify these black insertion periods. The ghost phenomenon elimination unit is activated periodically during these identified intervals to pull up the voltage level, creating a rhythmic control pattern that effectively eliminates ghosting while maintaining high driving efficiency
2Adaptability or versatility
If scanning processes are switched frequently to drive multiple LED sets, then coverage and efficiency are improved, but ghost phenomenon increases due to parasitic capacitance effects
Solution Approach 1:
The patent applies preliminary action by actively pulling up the voltage level of the current driving terminal to a high voltage level during the black insertion period before the next scanning cycle begins. This preemptive voltage adjustment ensures that the LED fully turns off before the next driving cycle, preventing ghost phenomenon without reducing the multi-scanning driving efficiency
Solution Approach 2:
The patent implements feedback by using a counter unit to count clock signals and detect black insertion periods, then using this detection information to control the ghost phenomenon elimination unit. This closed-loop feedback mechanism ensures that voltage level adjustment occurs precisely when needed, maintaining adaptability while eliminating ghosting
3Device complexity
If voltage level of current driving terminal is not adjusted during black insertion period, then circuit complexity is reduced, but ghost phenomenon persists due to parasitic capacitance
Solution Approach 1:
The patent applies segmentation by dividing the driving circuit into functional modules: a counter unit for detecting black insertion periods, a ghost phenomenon elimination unit for voltage level adjustment, and a current driving unit for LED control. This modular segmentation allows each component to perform its specific function efficiently, managing complexity while effectively eliminating ghost phenomenon through coordinated operation
Solution Approach 2:
The patent introduces an intermediary approach by using the counter unit as a mediator that detects black insertion periods and generates control signals for the ghost phenomenon elimination unit. This intermediary mechanism coordinates the timing and activation of voltage level adjustment, enabling effective ghost elimination while keeping the overall circuit design organized and manageable
Data Source
AI summary
A driving circuit of a light emitting diode (LED) and a ghost phenomenon elimination circuit thereof are disclosed. The ghost phenomenon elimination circuit which includes a ghost phenomenon elimination unit and a counter unit may determine a black insertion period according to a gray scale clock signal, and output an enable signal to the ghost phenomenon elimination unit during the black insertion period. The ghost phenomenon elimination unit may pull up the voltage levels at current driving terminals of the driving circuit so as to prevent the ghost phenomenon from occurring.