Scan Driving Circuit Area Reduction via Control Signal Sequencing
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Solution Overview
Problem
The existing scan driving circuits for liquid crystal displays require a large circuit area and high cost due to the need for multiple high-voltage transistors and resistors in level-shift drivers, which increases the overall size and expense of the circuit.
Innovation Solution
A novel scan driving circuit is introduced, which includes a control circuit that reduces the circuit area of each level-shift driving circuit by using a decoding circuit and a control circuit to produce control signals that enable and disable level-shift driving circuits sequentially, thereby reducing the number of required high-voltage transistors and resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three levels of level-shift drivers are used to shift the scan signal level, then the scan signal can be properly level-shifted to VGH and VGL, but the circuit area increases due to requiring at least ten high-voltage transistors and two resistors
Solution Approach 1:
The patent combines the level-shifting function with the scan driving function into a single integrated circuit. The level-shifting circuit is merged with the scan driving circuit, allowing the same circuit to perform both level shifting and scan signal generation, thereby eliminating the need for separate level-shift drivers and reducing the total number of high-voltage transistors from at least ten to a fewer number.
Solution Approach 2:
The scan driving circuit is designed to perform multiple functions: it generates scan signals and simultaneously performs level shifting to VGH and VGL. This multi-functional design eliminates the need for dedicated level-shift drivers, reducing circuit area while maintaining the required level-shifting capability.
2Reliability
If multiple high-voltage transistors and resistors are used in level-shift drivers, then the scan signal can be raised to high voltage levels, but the cost increases
Solution Approach 1:
The patent merges the level-shifting function with the scan driving function into a single integrated circuit. This consolidation reduces the total number of high-voltage transistors and resistors required, thereby lowering manufacturing costs while maintaining the ability to generate high-voltage scan signals.
Solution Approach 2:
The patent changes the operating parameters of the transistors by utilizing them in different operating regions and configurations within the integrated circuit. By carefully controlling the gate voltages and current paths, the same transistors can perform both level shifting and scan driving functions, reducing the total component count and manufacturing cost.
Data Source
AI summary
The present invention relates to a scan driving circuit, which comprises a decoding circuit, a plurality of level-shift driving circuits, and a control circuit. The decoding circuit produces a decoding signal according to a decoding control signal. The plurality of level-shift driving circuits are coupled to the decoding circuit and produce scan signal sequentially according to the decoding signal. The control circuit is coupled to the plurality of level-shift driving circuit. The control circuit produces a first control signal and a second control signal according to the decoding control signal and transmits the first and second control signals to the plurality of level-shift driving circuits for controlling their turning on and off. Accordingly, by means of the control circuit according to the present invention, the circuit area of each level-shift driving circuit can be reduced, and thus the cost can be reduced as well.