Multi-Level Gate Select Waveform for Lower Display EMI
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Solution Overview
Problem
Existing display devices face challenges in generating effective gate select signals for selecting subpixels during display updating, which can lead to electromagnetic interference and inefficiencies in selecting and deselecting gate lines for updating.
Innovation Solution
A processing system for a display device generates a gate select signal with multiple voltage transitions, transitioning from a first voltage to a second, then to a third voltage, and back to the first, where the second voltage is greater than the first and maintained for a period, and the third voltage is greater than the second and also maintained for a period, to drive the gate select signal on gate lines for display updating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional gate select signal with simple voltage transitions is used, then the device complexity is low, but electromagnetic interference peaks occur and may violate regulation requirements
Solution Approach 1:
The gate select signal waveform is segmented into multiple distinct voltage levels (first voltage level, second voltage level, third voltage level) instead of using a simple single-transition waveform. This segmentation of the voltage profile distributes the electromagnetic energy across different time intervals, reducing peak interference while maintaining the necessary gate line selection functionality.
Solution Approach 2:
The signal parameters are changed by introducing multiple voltage levels with specific duration relationships (second duration ≥ first duration, third duration ≥ first duration). This parameter modification transforms the electromagnetic spectrum distribution, reducing peak power while maintaining effective gate control.
2Object-affected harmful factors
If a multi-voltage level gate select signal is used, then electromagnetic interference is reduced, but the signal generation complexity increases
Solution Approach 1:
The gate select signal employs periodic voltage transitions between multiple levels during the gate line selection period. The signal cycles through first, second, and third voltage levels in a structured periodic manner, which distributes electromagnetic energy over time and reduces spectral peaks without requiring complex external interference suppression circuitry.
3Speed
If the gate select signal transitions quickly between voltage levels, then the gate line selection speed is high, but electromagnetic interference peaks increase
Solution Approach 1:
The voltage transition is segmented into multiple steps (first voltage to second voltage to third voltage) rather than a single abrupt transition. This segmentation extends the transition time while maintaining selection speed, thereby reducing the power peaks in the electromagnetic interference spectrum.
Solution Approach 2:
The signal uses periodic dwelling at intermediate voltage levels (second voltage level maintained for second duration, third voltage level maintained for third duration), which distributes the energy transfer over time. This periodic action reduces instantaneous power peaks while maintaining overall selection efficiency.
Data Source
AI summary
A processing system for a display device comprises a display driver configured to generate a gate select signal and output the gate select signal to gate select control circuitry to be driven on gate lines for display updating. The gate select signal comprises a transition from a first voltage to a second voltage, a transition from the second voltage to a third voltage, and a transition from the third voltage to the first voltage. The second voltage is greater than the first voltage and the second voltage is maintained for a first period. The third voltage is greater than the second voltage and the third voltage is maintained for a second period. The gate select signal is driven by the gate select control circuitry on gate lines of the display device to select one or more subpixels of the display device for display updating.