Gate Driver Output Current Control for LCD Crosstalk Suppression
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Solution Overview
Problem
Crosstalk in liquid crystal display devices occurs due to variations in the low-potential gate voltage, which existing technologies fail to completely prevent despite efforts to suppress common voltage variations.
Innovation Solution
A gate driver system that includes a gate shift register, AND operation unit, level shifter, and buffer unit, where each output buffer outputs different current levels for high-potential and low-potential gate voltages, allowing for controlled variation of the low-potential gate voltage to prevent crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the common voltage variation is suppressed using existing technologies, then the crosstalk is partially reduced, but the low-potential gate voltage variation remains uncontrolled causing residual crosstalk
Solution Approach 1:
The invention changes the output current parameter of the gate driver to suppress low-potential gate voltage variation. Specifically, when transitioning from high-potential gate voltage to low-potential gate voltage, the gate driver outputs a first current during the transition period and then outputs a second current (different from the first) afterward, thereby controlling the gate line voltage to prevent crosstalk while maintaining display quality
2Device complexity
If the gate driver outputs fixed current for both high-potential and low-potential gate voltages, then the circuit is simple, but the low-potential gate voltage varies causing crosstalk
Solution Approach 1:
The invention makes the gate driver dynamic by adjusting the output current based on the gate voltage state. The gate driver selectively outputs different current levels depending on whether it is driving high-potential or low-potential gate voltage, and whether it is in the transition period or steady state, thereby actively suppressing crosstalk while maintaining circuit feasibility
3Speed
If the gate driver transitions quickly from high-potential to low-potential gate voltage, then the scanning speed is high, but the stray capacitance causes voltage distortion and crosstalk
Solution Approach 1:
The invention applies preliminary action by controlling the current output during the transition period before the low-potential gate voltage is fully established. By outputting a specific current (first current) during the transition period and then switching to a different current (second current) afterward, the gate driver proactively compensates for voltage distortion caused by stray capacitance, preventing crosstalk before it occurs
Data Source
AI summary
A liquid crystal display device includes: a liquid crystal panel having gate lines and data lines, the gate lines and the data lines defining pixels; a gate driver for providing scan signals to the gate lines of the liquid crystal panel; and a data driver for providing video data to the data lines of the liquid crystal panel. The gate driver outputs a high-potential gate voltage to one gate line and outputs a low-potential gate voltage to the remaining gate lines. An output current of the low-potential gate voltage is different from that of the high-potential gate voltage.