LCD Data Driver Voltage Switching for Lower Line-Charging Power
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Solution Overview
Problem
As LCD TV screens increase in size, the capacitance of data lines also increases, leading to higher charging and discharging power consumption, which results in increased heat generation and power consumption in the driver LSI, posing challenges for reducing power consumption and heat management.
Innovation Solution
A data driver configuration that includes positive-polarity and negative-polarity amplifiers with optimized voltage supply arrangements, using an intermediate-potential voltage supply close to the opposing substrate electrode voltage, and an output switch circuit for efficient voltage switching, reducing power consumption and area requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If LCD TV screen size increases, then display area is improved, but power consumption and heat generation increase due to higher data line capacitance
Solution Approach 1:
The patent divides the voltage supply system into multiple segments: a first voltage supply for the differential input stage and a second voltage supply for the output stage. This segmentation allows independent optimization of each stage's power consumption, enabling the output stage to use lower voltage when full swing is not required, thus reducing overall power consumption while maintaining the ability to drive larger displays.
Solution Approach 2:
The patent changes the voltage parameter dynamically by using different voltage supplies for different operating conditions. The differential input stage uses a first voltage supply optimized for signal processing, while the output stage uses a second voltage supply that can be adjusted based on the required output swing, thereby adapting power consumption to the actual display size and capacitance requirements.
2Area of stationary object
If data line capacitance increases with screen size, then charging and discharging power consumption increases, but display area is improved
Solution Approach 1:
The patent segments the amplifier into a differential input stage and an output stage with separate voltage supplies. The output stage uses a second voltage supply that provides sufficient voltage swing only when needed for driving large-capacitance data lines in larger displays, while the input stage continues to operate efficiently with the first voltage supply, thereby reducing unnecessary charging and discharging power consumption.
Solution Approach 2:
The patent applies partial action by providing the second voltage supply only to the output stage where it is needed for driving the data line capacitance, rather than applying full voltage swing throughout the entire amplifier. This allows the system to handle large capacitance loads when required while avoiding excessive power consumption during normal operation with smaller displays.
3Area of stationary object
If voltage supply configuration is optimized to reduce power consumption, then area and cost are reduced, but voltage switching efficiency must be maintained
Solution Approach 1:
The patent merges the two voltage supply systems into a single integrated amplifier structure where the first and second voltage supplies operate cooperatively. The differential input stage and output stage are combined in a unified configuration that allows seamless voltage transition without requiring complex external switching circuitry, thereby reducing area while maintaining voltage switching efficiency.
Data Source
AI summary
A data driver includes a positive-polarity reference voltage generation circuit that outputs positive-polarity reference voltages, a positive-polarity decoder that receives the positive-polarity reference voltages from the positive-polarity reference voltage generation circuit, end selects and outputs at least one positive-polarity reference voltage in accordance with first digital data, a positive-polarity amplifier which includes a first differential units that receives the selected reference voltage selected by the positive-polarity decoder, performs amplification, and outputs a voltage to a first amplifier output terminal, δ negative-polarity reference voltage generation circuit that outputs negative-polarity reference voltages, and a negative-polarity decoder that receives the negative-polarity reference voltages from the negative-polarity reference voltage generation circuit, and selects and outputs at least one negative-polarity reference voltage in accordance with second digital data.