Bidirectional Gate Drive Circuit for Flexible LCD PCB Mounting
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Solution Overview
Problem
Conventional liquid crystal display (LCD) gate drive circuits face issues with directional signal output, leading to abnormal image display when gate signals are output from the lower portion to the upper portion of the display panel.
Innovation Solution
A bi-directionally driven gate drive circuit is designed with a signal circuit comprising sequentially coupled driving stages, including pull-up, carry, and pull-down parts, which can operate in both forward and reverse direction modes by adjusting power signals to ensure reliable gate signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gate drive circuit outputs gate signals from the lower portion to the upper portion of the display panel, then the PCB can be disposed on the upper long side, but the display panel does not display a normal image
Solution Approach 1:
The patent implements bidirectional gate signal output capability by inverting the signal transmission direction control. The gate drive circuit can switch between outputting signals from upper to lower portions (forward direction) and from lower to upper portions (reverse direction), allowing the PCB to be mounted on either the upper or lower long side of the display panel while maintaining normal image display through directional signal inversion
Solution Approach 2:
The gate drive circuit employs dynamic direction control through a direction control signal that switches the signal transmission direction based on PCB mounting position. This dynamic adaptability allows the circuit to adjust its operation mode (forward or reverse direction) to match the physical configuration, ensuring reliable image display regardless of PCB placement
2Productivity
If the gate drive circuit is integrated on the display panel to decrease size and enhance productivity, then manufacturing efficiency improves, but the circuit must handle bidirectional signal output which increases complexity
Solution Approach 1:
The gate drive circuit is designed with universal bidirectional operation capability, allowing the same circuit structure to function in both forward and reverse signal transmission modes. This multi-functionality eliminates the need for separate circuit designs for different PCB mounting positions, maintaining manufacturing efficiency while handling directional flexibility through a single integrated circuit implementation
Solution Approach 2:
The gate drive circuit is divided into multiple driving stages (first through fourth stages) that can operate independently in series. Each stage contains transistors configured to handle signal transmission in both directions, allowing the circuit to process bidirectional signals through segmented functional units while maintaining overall integration on the display panel
Data Source
AI summary
A gate drive circuit includes a plurality of driving stages. An n-th (‘n’ is a natural number) driving stage includes a pull-up part, a carry part, a first pull-down part, a first pull-up/down control part and a second pull-up/down control part. The first pull-up/down control part applies a first power signal of an ON voltage to a control terminal of the pull-up part in a forward direction mode, and applies the first power signal of a second OFF voltage to a control terminal of the pull-up part in a reverse direction mode. The second pull-up/down control part applies a second power signal of the second OFF voltage to the control terminal of the pull-up part in the forward direction mode, and applies the second power signal of the ON voltage to the control terminal of the pull-up part in the reverse direction mode.