Liquid Crystal Display Driving Circuit for Power Reduction
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Solution Overview
Problem
Liquid crystal displays face issues with heat generation and power consumption in data driving circuits, and picture quality degradation due to polarity inversion methods, leading to greenish tint and flicker phenomena.
Innovation Solution
A liquid crystal display system that includes a timing controller to determine gray levels and polarity inversion times, a data driving circuit to convert digital video data into data voltages with dynamic charge sharing and dot inversion control, and a gate driving circuit to supply scan pulses, which reduces heat and power consumption by selectively performing charge sharing and adjusting polarity inversion periods based on detected weakness patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarity inversion method is used to drive liquid crystal display, then liquid crystal degradation is reduced, but heat generation and power consumption of data driving circuit increase sharply
Solution Approach 1:
The patent applies dynamics by making the polarity inversion period adjustable rather than fixed. The data driving circuit dynamically changes the horizontal polarity inversion period based on display content and timing requirements, allowing optimization between power consumption and picture quality. This resolves the contradiction by enabling the system to adapt the inversion frequency to actual needs rather than using a constant high-frequency inversion that always maximizes power consumption.
Solution Approach 2:
The patent changes the parameter of polarity inversion period from a fixed value to a variable parameter that can be adjusted. By modifying the horizontal polarity inversion period according to different display scenarios and content types, the system can reduce power consumption when full-frequency inversion is not necessary, while still maintaining liquid crystal durability through periodic inversion when needed.
2Reliability
If polarity inversion method is used to drive liquid crystal display, then liquid crystal degradation is reduced, but picture quality deteriorates due to greenish tint and flicker
Solution Approach 1:
The patent dynamically adjusts the polarity inversion strategy based on detected weakness patterns in display content. When patterns prone to greenish tint or flicker are detected, the system modifies the inversion timing or skips inversion for specific regions or time periods, thereby maintaining picture quality while still providing protection against liquid crystal degradation through selective inversion.
Solution Approach 2:
The patent applies local quality by treating different regions or time periods differently regarding polarity inversion. Instead of uniform inversion across the entire display, the system identifies specific areas or time frames where inversion would cause picture quality issues and applies non-uniform inversion strategies, allowing picture quality to be maintained in problematic regions while still providing durability benefits in other regions.
3Use of energy by stationary object
If charge sharing circuit or precharge circuit is adopted to reduce data voltage swing width, then heat generation and power consumption are reduced, but the effect is not satisfactory
Solution Approach 1:
The patent applies preliminary action by proactively adjusting the polarity inversion period and applying compensation voltages before picture quality degradation or excessive heat generation occurs. The system detects weakness patterns in advance and pre-adjusts the driving parameters to prevent problematic situations, rather than reacting after heat or quality issues have already manifested.
Solution Approach 2:
The patent implements feedback by continuously monitoring the display content and detecting weakness patterns, then using this information to dynamically adjust the polarity inversion period and charge sharing strategy. This closed-loop control allows the system to respond to actual operating conditions and optimize power consumption and heat generation in real-time based on feedback from the display content analysis.
Data Source
AI summary
A liquid crystal display includes a timing controller to activate a dynamic charge share control signal to indicate a time at which the gray level of the data voltage is changed from a white gray level to a black gray level and a time at which the polarity of the data voltage is inverted, and to activate a dot inversion control signal for widening a horizontal polarity inversion period of data voltages to be supplied to the data lines when a weakness patterns are input, and a data driving circuit supplying one of a common voltage and a charge share voltage to data lines only when the gray level of data is changed from the white gray level to the black gray level and when the polarity of the data voltage in response to the dynamic charge share control signal.