Timing Controller Noise Detection for LCD Signal Integrity
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Solution Overview
Problem
Conventional timing controllers for liquid-crystal display devices fail to effectively inhibit the influence of exogenous noise synchronized with synchronizing signals or transmission clock periods without increasing the circuit size, leading to display malfunctions such as noise recognition, black screens, and image degradation.
Innovation Solution
Incorporating a noise detecting circuit and a line memory system to detect and suppress noise synchronized with synchronizing signals or transmission clock periods, allowing the output enable signal of the scanning line driving gate driver IC to remain active, and using image data from previous lines to supplement and average noise-affected data, thereby preventing noise from appearing on the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a noise filter is added to each synchronizing signal to prevent noise influence, then noise immunity is improved, but the circuit size increases
Solution Approach 1:
A noise detecting circuit is introduced as an intermediary component that monitors synchronizing signals for noise conditions. When noise is detected, the circuit generates a control signal to suppress the output enable of the scanning line driving gate driver, preventing noise from affecting the display without requiring noise filters on each signal line
Solution Approach 2:
The noise detecting circuit continuously monitors the synchronizing signals and provides feedback control by generating a suppression signal when noise is detected. This feedback mechanism dynamically adjusts the output enable state based on noise conditions, achieving noise immunity through active control rather than passive filtering
2Reliability
If the output enable of scanning line driving gate driver is suppressed when noise is detected, then noise influence is reduced, but display continuity is interrupted causing black screens
Solution Approach 1:
The output enable is suppressed only during the specific period when noise is detected in the synchronizing signal, rather than being continuously suppressed. This periodic suppression approach limits the impact to brief intervals synchronized with the noise occurrence, allowing display continuity to be maintained during normal operation periods
Solution Approach 2:
The noise detecting circuit detects noise conditions in advance during the synchronizing signal period before the scanning line driving occurs. By detecting noise preliminarily and suppressing the output enable proactively, the system prevents noise influence before it can affect the display, while maintaining continuity by only suppressing during necessary intervals
3Reliability
If frame memory is used to save previous frame data for noise suppression, then noise immunity is improved, but the circuit size and cost increase significantly
Solution Approach 1:
Instead of using a single large frame memory to store entire frame data, the invention segments the data storage function by utilizing the existing line memory structure that is already present in the display system. The line memory, which stores data for individual scanning lines, is repurposed to provide previous line data for noise suppression, achieving noise immunity without requiring additional large-scale memory resources
Solution Approach 2:
The existing line memory, originally designed for storing scanning line data during normal operation, is given a dual function by also serving as a source for noise suppression. The same memory structure is used both for its original purpose and for providing backup data when noise is detected, eliminating the need for separate dedicated noise suppression memory
4Reliability
If noise filter is added to synchronizing signals, then synchronizing noise immunity is improved, but the device complexity and cost increase
Solution Approach 1:
The noise detection and suppression functions are merged into a single integrated noise detecting circuit that processes synchronizing signals. Instead of adding separate noise filters to each signal line and each processing stage, the invention combines the noise detection capability with the existing signal processing architecture, achieving synchronizing noise immunity through a unified approach that minimizes additional circuit complexity
Data Source
AI summary
When applying exogenous noise with a synchronizing signal or a transmission clock period, influence by the applied noise is inhibited from appearing on a liquid crystal display, without increasing circuit size. There are included: a timing controller generating a control signal of a scanning line driving gate driver and a control signal of a signal line driving source driver based on an input signal to be a reference inputted from the outside; an enable signal generation unit including a noise detecting circuit for detecting various items of noise entering the input signal and outputs an enable signal for turning OFF or ON the output of a gate driver control signal for a predetermined period based on output from the noise detecting circuit; and an image data output control circuit when detecting noise synchronized in a vertical period. The gate driver control signal is controlled to have an idle period.