Switchable Common Voltage Generator for Low-Area TFT-LCD Driving
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional common voltage generators for TFT-LCDs require a large area and high power consumption due to the presence of multiple amplifiers, external capacitors, and multiplexers, leading to increased costs and chip size.
Innovation Solution
A common voltage generator with an operational amplifier and switches that output different voltage levels based on control signals, using a voltage divider and multiplexer to select and transmit appropriate voltage levels, reducing the number of components and area required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional common voltage generator design with multiple amplifiers, external capacitors, and multiplexers is used, then voltage output functionality is achieved, but chip area increases and power consumption increases
Solution Approach 1:
The patent merges multiple amplifiers into a single operational amplifier by using switches to selectively connect different power supply voltage pairs (AVDD/AVSS or VC1/VC0) to the same operational amplifier. This consolidation reduces the component count from multiple amplifiers to one, thereby reducing chip area and power consumption while maintaining the ability to output multiple common voltage levels (VCOMH and VCOML).
Solution Approach 2:
The operational amplifier is designed to perform multiple functions by accepting different power supply voltage combinations. The same operational amplifier can output high common voltage (VCOMH) when powered by AVDD/AVSS and low common voltage (VCOML) when powered by VC1/VC0, making it a universal voltage output component that replaces multiple specialized amplifiers.
2Area of stationary object
If conventional common voltage generator with multiple amplifiers and external capacitors is used, then voltage output capability is maintained, but chip area increases
Solution Approach 1:
The patent consolidates multiple amplifier circuits into a single operational amplifier by using switch-controlled power supply selection. This merging reduces the total component count and the area required on the chip, as one operational amplifier occupies less space than multiple amplifiers plus their associated external capacitors and multiplexers.
Solution Approach 2:
The patent extracts and eliminates unnecessary components from the conventional design. By removing external capacitors and reducing multiplexer requirements, the design achieves the same voltage output functionality with fewer components, thereby reducing chip area and simplifying the overall circuit structure.
3Device complexity
If switches are used to dynamically select power supply voltages for operational amplifier, then power consumption is reduced and area is minimized, but circuit complexity increases
Solution Approach 1:
The patent introduces dynamic control through switches that can selectively connect different power supply voltage pairs to the operational amplifier based on the desired output voltage level. This dynamic switching mechanism allows the circuit to adapt its power consumption and output characteristics in real-time, optimizing performance while maintaining manageable control complexity through systematic switch control signals.
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 achieves a smaller area and higher efficiency, reducing power consumption and module costs while maintaining effective common voltage generation for improved liquid crystal display performance.
Implementation Method 1
an operational amplifier configured to amplify a difference between a first voltage and a second voltage and to output the amplified voltage as a common voltage
Implementation Method 2
a voltage divider connected between an output terminal and a first node and configured to divide a voltage between the output terminal and the first node and output the divided voltage
Data Source
AI summary
The common voltage generator includes an operational amplifier and a plurality of switches. The operational amplifier is configured to amplify a difference between a first voltage and a second voltage and to output the amplified voltage as a common voltage. The plurality of switches are configured to transmit a third voltage and a fourth voltage as a power supply to the operational amplifier in a first voltage output mode and to transmit a fifth voltage and a sixth voltage as a power supply to the operational amplifier in a second voltage output mode.