Intelligent LED Driver with Spread Spectrum Modulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LED lighting systems face issues with luminous flux and color distortion due to temperature variations and aging, causing electromagnetic interference and spectral content problems in control signals, which affect the accuracy of color mixing and overall lighting performance.
Innovation Solution
An intelligent light source device with sensors and processing capabilities that monitor junction temperatures, output intensities, and accumulated operating time, using stochastic signal density modulation and pseudorandom sequence controllers to generate control signals that adjust LED currents to maintain desired color points and luminous flux values, reducing electromagnetic interference and compensating for temperature and aging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pulse width modulation (PWM) with uniform frequency is used to control LED luminous flux, then the LED switching control is achieved, but electromagnetic interference (EMI) is generated to sensitive devices nearby
Solution Approach 1:
The patent applies periodic action by using spread spectrum modulation that distributes the periodic LED switching control across multiple frequency components rather than a single uniform frequency. This achieves the required periodic control function while distributing electromagnetic energy across a broader spectrum, reducing peak EMI at any single frequency.
Solution Approach 2:
The patent changes the frequency parameter of the control signal from a uniform single frequency to a spread spectrum signal with varying frequency components. This parameter change transforms the EMI profile from concentrated high-amplitude peaks to distributed lower-amplitude components across a broader frequency range, reducing harmful EMI effects.
2Illumination intensity
If conventional PWM control is used to adjust LED luminous flux, then the desired average current is achieved, but color distortion occurs due to temperature variations and aging
Solution Approach 1:
The patent implements feedback by continuously monitoring LED junction temperature and aging characteristics, then using this information to dynamically adjust the spread spectrum modulation parameters and LED drive currents. This closed-loop feedback compensates for temperature-induced luminous flux variations and aging effects, maintaining accurate color rendering despite environmental changes.
Solution Approach 2:
The patent applies dynamics by making the control system adaptive rather than static. The spread spectrum modulation parameters and LED drive signals are dynamically adjusted based on real-time temperature and aging data, allowing the system to maintain optimal color accuracy under varying operating conditions rather than relying on fixed PWM parameters.
3Ease of operation
If individually addressed microcontrollers are used in DMX512 network, then precise control of each light source is achieved, but system complexity increases
Solution Approach 1:
The patent merges multiple individually addressed microcontrollers into a single networked LED driver unit that receives spread spectrum modulation signals. This consolidation maintains precise control capability while reducing the number of separate control devices and simplifying the network architecture, as the single driver internally manages multiple LED channels with temperature and aging compensation.
Data Source
AI summary
An intelligent light source converts color and luminous flux data to luminous flux levels of individual color sources and automatically compensates for variations in operating conditions.