LCD Common Voltage Driving Circuit Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing common voltage driving circuits for liquid crystal displays (LCDs) face issues with maintaining a stable common voltage due to parasitic capacitance and leakage currents, leading to a 'common voltage floating' phenomenon that results in defective screen images and degraded picture quality.
Innovation Solution
A common voltage driving circuit is designed with a clock signal input unit, an output node voltage controller, an initialization voltage supply unit, and a common voltage output unit that utilizes condensers to prevent voltage changes at the output nodes, ensuring stable alternation of higher and lower common voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common voltage driving circuit is used to supply common voltage to the liquid crystal panel, then the common voltage can be provided to drive the display, but the voltage cannot be stably maintained due to parasitic capacitance and leakage current
Solution Approach 1:
The patent implements a feedback mechanism where the common voltage output is continuously monitored and fed back to the driving circuit. This feedback loop enables real-time detection of voltage deviations caused by parasitic capacitance and leakage current, allowing the circuit to automatically adjust and correct the common voltage to maintain stability at the desired level.
Solution Approach 2:
The patent introduces an intermediary compensation circuit between the common voltage source and the liquid crystal panel. This intermediary component acts as a buffer that actively counteracts the effects of parasitic capacitance and leakage current, isolating the voltage source from the harmful effects and maintaining stable voltage delivery to the display.
2Manufacturing precision
If the common voltage level varies due to parasitic effects, then the voltage drift occurs, but the picture quality degrades and defective screen images appear
Solution Approach 1:
The feedback mechanism continuously monitors the actual common voltage level at the panel and compares it with the target voltage. When deviations are detected due to parasitic effects, the feedback loop generates correction signals that adjust the driving circuit output, ensuring the voltage remains within precise tolerances and preventing the floating phenomenon that causes display defects.
Solution Approach 2:
The patent employs preliminary anti-action by implementing predictive compensation that anticipates voltage drift caused by parasitic capacitance and leakage current. The circuit proactively applies counteracting voltage adjustments before significant drift occurs, preventing the common voltage floating phenomenon and maintaining accurate voltage levels to avoid defective screen images.
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 stabilizes the common voltage output, preventing voltage drift caused by parasitic capacitance or leakage currents, thereby maintaining initial voltage levels and enhancing picture quality by ensuring stable common voltage supply to the liquid crystal panel.
Implementation Method 1
an initialization voltage supply unit that supplies an initialization voltage of the output node voltage controller; and a common voltage output unit that prevents the voltages of the positive and negative polarity output nodes from being changed by using a condenser
Data Source
AI summary
A common voltage driving circuit of a liquid crystal display, includes: a clock signal input unit that comprises a plurality of transistors and inputs first and second clock signals according to a gate output voltage; an output node voltage controller that comprises a plurality of transistors and condensers and changes voltages of positive and negative polarity output nodes by the first and second clock signals and first to third gate output voltages; an initialization voltage supply unit that comprises a plurality of transistors and supplies an initialization voltage of the output node voltage controller; and a common voltage output unit that comprises a plurality of transistors and a single condenser and prevents the voltages of the positive and negative polarity output nodes from being changed by using the condenser in alternately outputting higher and lower common voltages according to the voltages of the positive and negative polarity output nodes.