Gate Driver Stage Circuit for Low-Speed Display Node Stability
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Solution Overview
Problem
In display devices, driving pixels at low speeds can lead to increased node voltage due to current leakage and noise during skip periods, reducing the driving force of the gate driver and causing poor image quality.
Innovation Solution
A gate driver design that includes a Q node controller and QB node controller to minimize leakage current and filter noise, using transistors and capacitors to maintain stable node voltages and output levels, with a reset unit to stabilize the Q1 node voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the display panel is driven at low speed for a long time, then power consumption is reduced, but node voltage increases due to current leakage and noise during skip periods
Solution Approach 1:
The reset unit proactively resets the Q1 node to the second level voltage before noise or voltage drift can affect the Q node, preventing voltage increase during skip periods. This preliminary action maintains node voltage stability while enabling low-speed driving mode for reduced power consumption.
Solution Approach 2:
The Q1 node acts as an intermediary between the reset unit and the Q node. By controlling the voltage at the Q1 node through the first transistor, the system can stabilize the Q node voltage without directly intervening in the main signal path, thus preventing voltage drift during low-speed operation.
2Use of energy by moving object
If the display panel is driven at low speed, then power consumption is reduced, but driving force of the gate driver decreases due to increased node voltage
Solution Approach 1:
The reset unit performs a preliminary reset action to ensure the Q1 node is at the correct voltage level before the gate driver operates during skip periods. This prevents voltage accumulation that would otherwise reduce the gate driver's driving force, allowing sustained low-power operation.
Solution Approach 2:
The Q node controller monitors the voltage at the Q node and uses this feedback to control the first transistor, which in turn controls the voltage at the Q1 node. This feedback mechanism ensures the node voltage remains stable and does not increase during low-speed driving, maintaining gate driver performance.
3Use of energy by moving object
If the display panel is driven at low speed for a long time, then power consumption is reduced, but image quality deteriorates due to node voltage increase
Solution Approach 1:
The reset unit performs a preliminary reset of the Q1 node before each skip period, preventing voltage drift that would otherwise degrade image quality. This allows the system to maintain stable node voltages during extended low-speed operation, preserving image quality while reducing power consumption.
Solution Approach 2:
The Q1 node serves as an intermediary that isolates the Q node from direct exposure to noise and voltage drift during skip periods. By controlling the voltage at the Q1 node through the first transistor, the system protects the Q node and maintains stable gate driver operation, thus preserving image quality during low-power mode.
Data Source
AI summary
In one aspect, a display device includes a plurality of stage circuits configured to output gate signals to gate lines in response to a gate clock signal. Each stage circuit includes an output unit configured to output a first level voltage or a second level voltage to one of the gate lines according to a corresponding voltage at a Q node and a QB node; an input unit configured to control a voltage at a Q1 node according to a gate start signal or a carry signal output from a previous stage circuit in response to the gate clock signal; a Q node controller configured to control the voltage at the Q node according to the voltage at the Q1 node; and a QB node controller configured to control the voltage at the QB node according to the voltage at the Q1 node and the voltage at the Q node.