LED Driver Phase-Cut Demodulation for Flicker-Free Dimming
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Solution Overview
Problem
Current dimming techniques for LED lighting systems, such as phase cutting, often lead to reduced lighting efficiency and light flickering due to interference with the waveform of the input voltage, making it difficult to achieve effective dimming control while maintaining power conversion efficiency.
Innovation Solution
An LED lighting system that adjusts the phase-cut angle of the input power within a dimming phase range, using a dimmer to generate a dimmer-adjusted input power, which is then processed by an LED lighting apparatus to maintain power conversion efficiency and control luminance without significant interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phase cutting is used to adjust the effective value of input voltage for dimming control, then dimming effect is achieved, but lighting efficiency is lowered and light flickering occurs
Solution Approach 1:
The patent changes the parameter of phase-cut angle from conventional large angles (causing waveform distortion) to a small range (0-45 degrees), maintaining waveform completeness while achieving dimming through demodulation of the phase information by the LED driver circuit
Solution Approach 2:
The patent introduces a demodulating circuit as an intermediary that extracts dimming information from the phase-cut waveform without requiring large phase cuts, allowing the waveform to remain complete and avoid efficiency loss while still achieving luminance control
2Illumination intensity
If phase cutting is used to adjust the effective value of input voltage for dimming control, then dimming effect is achieved, but light flickering occurs
Solution Approach 1:
The patent changes the phase-cut angle parameter to a small range (0-45 degrees) that does not significantly distort the waveform, and uses demodulation to translate this small phase variation into luminance control, eliminating the flickering caused by large phase cuts
Solution Approach 2:
The demodulating circuit detects the phase-cut angle information from the input waveform and generates appropriate dimming control signals, creating a feedback mechanism that maintains stable light output while achieving dimming control
3Adaptability or versatility
If large phase-cut angle is used for dimming, then dimming range is increased, but waveform completeness is compromised and power conversion efficiency is reduced
Solution Approach 1:
The demodulating circuit acts as an intermediary that extracts dimming information from the phase-cut waveform, allowing the use of small phase-cut angles that maintain waveform completeness and high power conversion efficiency while still providing effective dimming control
Solution Approach 2:
The patent replaces the conventional mechanical approach of using large phase cuts to directly control luminance with an electronic demodulation system that extracts dimming information from the waveform, substituting a more efficient electronic control mechanism
Data Source
AI summary
An LED lighting apparatus is configured to light in response to an input power signal. The LED lighting apparatus includes a power supply module, configured to receive the input power signal in order to generate a driving power signal, and an LED module configured to light in response to the driving power signal. The power supply module comprises a demodulating circuit configured to receive the input power signal and demodulate the received input power signal, in order to generate a dimming control signal for controlling luminance of the LED module, wherein the demodulating circuit demodulates the input power signal based on a phase-cut angle of the input power signal.