LCD Panel Driving Circuit With Interpolation DAC Area Reduction
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Solution Overview
Problem
The increasing resolution of liquid crystal display panels leads to a significant increase in the size of the driving circuit, resulting in higher manufacturing costs and reduced competitiveness due to the geometric progression of resistors and transistors required for the DAC, which in turn increases the circuit area.
Innovation Solution
A liquid crystal display panel driving circuit design that reduces the circuit area by utilizing a resistor string unit configured to output analog reference voltages across three areas, a digital-to-analog converter switching unit to select and output (Y+1) analog voltages based on upper X bits, and an interpolation amplifier to generate interpolated output voltages using multi-factors determined by the value of Y bits, thereby reducing the number of resistors and transistors needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution of the liquid crystal display panel is increased, then the display quality and natural color sense are improved, but the area of the driving circuit increases due to the geometric progression of resistors and transistors required in the resistor string unit and DAC switching units
Solution Approach 1:
The patent divides the N-bit digital data into upper X bits and lower Y bits, and divides the resistor string unit into multiple segments. Each segment handles a portion of the data bits, allowing the DAC switching units to be reduced in number while maintaining overall resolution. This segmentation breaks the geometric progression relationship between total bit depth and component count.
Solution Approach 2:
The patent introduces an interpolation amplifier as an intermediary component between the DAC switching units and the final output. This amplifier generates intermediate voltage levels by combining outputs from fewer DAC switching units, effectively acting as a mediator that reduces the need for a large number of discrete DAC switching units while maintaining high resolution output.
2Measurement precision
If the number of resistors and transistors in the resistor string unit and DAC switching units is increased to achieve higher DAC resolution, then the natural color sense is improved, but the manufacturing cost increases due to larger circuit area
Solution Approach 1:
The DAC switching units are divided into multiple groups, each handling a subset of the data bits. This segmentation allows the use of fewer switching units per group while maintaining overall DAC resolution through the combined output and interpolation amplification, thereby reducing total component count and manufacturing cost.
Solution Approach 2:
The interpolation amplifier serves as an intermediary that synthesizes high-resolution output from lower-resolution DAC switching unit outputs. This mediator component enables the system to achieve high DAC resolution without requiring a proportional increase in the number of expensive resistors and transistors, thus reducing manufacturing cost.
3Measurement precision
If a traditional DAC circuit is used for each output to maintain high resolution, then the natural color sense is achieved, but the circuit area occupies the bulk of the liquid crystal display panel driving circuit
Solution Approach 1:
The patent merges the functions of multiple DAC switching units and interpolation amplifiers into an integrated circuit architecture. By combining these components and sharing resources among color channels, the total DAC circuit area is significantly reduced while maintaining the resolution required for natural color sense in liquid crystal display panels.
Solution Approach 2:
The interpolation amplifier acts as an intermediary that reduces the burden on individual DAC switching units. By placing this mediator in the signal path, the system can use fewer DAC switching units per channel while achieving the same effective resolution, thereby reducing the overall DAC circuit area occupied in the driving circuit.
Data Source
AI summary
Disclosed is a liquid crystal display panel driving circuit for driving a liquid crystal display panel with a resolution of N bits. N-bit digital data including upper X bits and lower Y bits is inputted. The liquid crystal display panel driving circuit includes a resistor string unit according to areas, a DAC converter switching unit according to areas, and an interpolation amplifier. The resistor string unit outputs analog reference voltages at different ratios according to three areas. The DAC converter switching unit receives the N-bit digital data, selects (Y+1) analog voltages from the analog reference voltages based on the upper X bits, outputs the (Y+1) analog voltages, and outputs the (Y+1) analog voltages of different combinations based on the lower Y bits. The interpolation amplifier receives the (Y+1) analog voltages and generates an interpolated output voltage by setting weights for the (Y+1) analog voltages by using multi-factors.