Gate Driving Circuit Qn Node Precharging for Leakage Prevention
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Solution Overview
Problem
Existing gate driving circuits for display devices face challenges in preventing electric leakage during All Gate On and All Gate Off functions, leading to increased power consumption and instability in display performance.
Innovation Solution
A multistage gate driving circuit with Qn node precharging, pull-up, and pull-down units, along with Pn node and Gn output units, utilizing transistors and capacitors to control signal transmission and voltage levels, effectively preventing electric leakage and reducing power consumption by using high-voltage signals for precharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing GOA circuit is used to realize All Gate On and All Gate Off functions, then the display device can achieve black frame insertion and TP scanning, but electric leakage occurs at Q nodes leading to increased power consumption
Solution Approach 1:
The patent applies preliminary action by precharging the Q node before the switching operation. The Q node precharging unit charges the Q node to a high level in advance using the VGH signal, so when the Q node switching operation occurs during All Gate On or All Gate Off functions, there is no electric leakage path formed, thereby preventing power consumption increase while maintaining display performance stability
Solution Approach 2:
The patent introduces an intermediary element - the Q node precharging unit with transistors Qn-1 and Qn+1 - that mediates the charging state of the Q node. This intermediary unit controls the voltage level of the Q node in advance, preventing direct electric leakage paths from forming during switching operations, thus resolving the contradiction between reliability and power consumption
2Reliability
If Q node is not precharged, then the circuit structure remains simple, but electric leakage occurs during All Gate On and All Gate Off functions
Solution Approach 1:
The patent applies segmentation by dividing the gate driving circuit into distinct functional units: the Q node precharging unit (with transistors Qn-1 and Qn+1), the Q node switching unit, and other supporting units. This segmentation allows the precharging function to be added independently without redesigning the entire circuit, preventing electric leakage while managing complexity through modular design
Solution Approach 2:
The patent makes the Q node precharging unit universal by designing it to work with both forward scanning and reverse scanning modes, and to support both All Gate On and All Gate Off functions. The same precharging unit structure serves multiple purposes across different operating conditions, preventing electric leakage universally without proportionally increasing circuit complexity
Data Source
AI summary
Disclosed are a gate driving circuit, a driving method thereof, and a display device which comprises the gate driving circuit. In the gate driving circuit, the Qn node in the nth stage circuit is precharged when an output signal of a Qn−1 node in a previous stage driving circuit and an output signal of a Qn+1 node in a next stage driving circuit are both in a high-level state. Both the Qn−1 node and the Qn+1 node are at low levels when the gate driving circuit is in an All Gate On display state, and thus a possibility of current leakage from the Qn node can be substantially reduced.