Gate Driver Dummy Stages for Q Node Stress Relief in Touch Displays
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Solution Overview
Problem
Touch sensing display devices experience Q node holding stress during time-divisional display and touch periods, particularly when using oxide transistors, which can lead to adverse operational effects.
Innovation Solution
A gate driving circuit with odd and even main stages, odd and even reset dummy stages, and odd and even set dummy stages is implemented to maintain Q nodes at a reset level during touch periods, minimizing stress by alternately resetting and setting voltages in specific stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time-divisional display and touch periods are implemented, then display and touch sensing functions can be performed alternately, but Q node holding stress is applied to gate driving circuit stages during touch periods
Solution Approach 1:
The gate driving circuit is segmented into multiple stages (first plurality of first odd main stages, second plurality of first odd main stages, first plurality of second odd main stages, second plurality of second odd main stages) that operate at different times. By dividing the circuit into these segments, Q nodes in different stages can be reset at different times, allowing the circuit to maintain reliability during touch periods while preserving display and touch sensing functionality.
Solution Approach 2:
The odd reset dummy stage performs preliminary reset actions on Q nodes of the second plurality of first odd main stages during the first display period before the touch period begins. This preliminary action ensures that Q nodes are in a known state (reset level) when the touch period starts, preventing Q node holding stress during touch sensing operations.
Solution Approach 3:
The odd set dummy stage performs preliminary set actions on Q nodes of the first plurality of second odd main stages during the second display period before the next touch period. This ensures Q nodes are properly initialized before the subsequent touch period, maintaining circuit reliability.
2Productivity
If Q nodes are not discharged during touch period, then display driving can continue uninterrupted, but pull-up element stress increases due to long-time charging state
Solution Approach 1:
The gate driving circuit is divided into multiple operational stages with different Q nodes. By segmenting the circuit, the patent can selectively reset Q nodes in specific stages (second plurality of first odd main stages) during the first display period without interrupting display driving in other stages. This segmentation allows continuous display operation while reducing stress on individual pull-up elements.
Solution Approach 2:
The patent implements periodic reset actions on Q nodes during display periods (first display period and second display period) rather than continuously maintaining charging states. This periodic action prevents prolonged stress on pull-up elements while maintaining display continuity, as Q nodes are reset at scheduled intervals rather than being held in charging state throughout the entire touch period.
Data Source
AI summary
A gate driving circuit includes a plurality of first odd main stages configured to drive first odd gate lines of a first display block in a first display period, a plurality of second odd main stages configured to drive second odd gate lines of a second display block adjacent to the first display block in a second display period, an odd reset dummy stage configured to reset a Q node included in a first lower-priority operation stage that is relatively late in operation order among the plurality of first odd main stages in the first display period; and an odd set dummy stage configured to set a Q node included in a first higher-priority operation stage that is relatively advanced in operation order among the plurality of second odd main stages in the second display period.