Display Panel Driving Circuit EMI Reduction via Variable Pulse Widths
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Solution Overview
Problem
Display devices using LEDs face high electromagnetic interference (EMI) due to existing driving methods, which affects displaying quality.
Innovation Solution
A driving circuit that varies the frequency of the driving signal within a frame time, incorporating multiple turn-on and turn-off pulse widths with different durations and frequencies to reduce EMI and enhance display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional driving signal with fixed pulse width is used to drive LED display elements, then the display can operate stably, but high electromagnetic interference (EMI) is generated affecting display quality
Solution Approach 1:
The patent applies dynamics by making the driving signal parameters variable rather than fixed. Specifically, the pulse width modulation (PWM) duty cycle is dynamically adjusted within a frame time, and the driving frequency is modulated according to a predetermined pattern. This dynamic variation in signal characteristics reduces electromagnetic interference while maintaining display stability through controlled modulation rather than random changes.
Solution Approach 2:
The patent implements parameter changes by modifying key characteristics of the driving signal: (1) varying the pulse width duty cycle among multiple different values within each frame time, (2) changing the driving frequency according to a predetermined modulation pattern, and (3) adjusting the brightness level through PWM control. These parameter variations effectively reduce EMI while preserving display reliability.
2Object-affected harmful factors
If the driving signal frequency is varied within a frame time to reduce EMI, then display quality improves, but the circuit complexity increases
Solution Approach 1:
The patent applies periodic action by implementing frequency modulation and pulse width variation at regular intervals synchronized with the display frame rate. The driving signal parameters are adjusted periodically within each frame time according to predetermined patterns, which reduces EMI while maintaining manageable circuit complexity through systematic rather than arbitrary modifications.
Solution Approach 2:
The driving circuit incorporates self-service mechanisms by using the existing frame timing signal to trigger the frequency modulation and pulse width variation. The system utilizes its own operational rhythm (frame rate) to control the EMI reduction technique, eliminating the need for separate complex control circuits and reducing overall system complexity.
Data Source
AI summary
The present application provides a driving circuit for display panel, which comprises a driving-signal generating circuit generating a driving signal in a frame time for driving a display element of a display panel. The driving signal includes at least one first turn-on pulse width, at least one first turn-off pulse width, at least one second turn-on pulse width, and at least one second turn-off pulse width. The first turn-on pulse width is greater than the second turn-on pulse width. The first turn-off pulse width is smaller than the second turn-off pulse width. By adopting the driving circuit according to the present application, EMI may be reduced and the displaying quality may be improved.