LED Dimming Device Preserving Sine Wave Integrity
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Solution Overview
Problem
Existing LED dimming methods using silicon controlled rectifier dimmers disrupt sine waves, reduce power factor, increase harmonic coefficients, generate interference signals, and are inefficient for small loads, particularly in LED lighting applications.
Innovation Solution
A LED dimming device comprising a dimming action module, a dimming action detector, and a dimming state control module, which generates dimming signals and control currents without affecting input current sine waves, thereby improving power factor and reducing harmonic coefficients and interference, while maintaining compatibility with existing illumination systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If silicon controlled rectifier dimmer is used for LED dimming, then compatibility with existing illumination systems is achieved, but power factor is reduced and harmonic interference increases
Solution Approach 1:
The dimming control is segmented into multiple discrete levels (first dimming level, second dimming level, etc.) rather than continuous analog control. This segmentation allows the system to maintain clean sine wave input current while providing effective dimming control, avoiding the harmonic distortion associated with traditional phase-cut dimming methods.
Solution Approach 2:
The patent extracts the dimming control function from the power factor correction circuit by using a separate control path. The sampling module detects input voltage to determine dimming levels, while the power factor correction module independently controls LED current based on these levels, keeping the two functions separate to avoid interference.
2Ease of operation
If silicon controlled rectifier dimmer is used for LED dimming, then dimming control is achieved, but circuit complexity increases due to additional peripheral circuits
Solution Approach 1:
The patent merges the dimming control function with the existing power factor correction circuit by having the control module communicate with the power factor correction module through a standardized interface. This integration allows dimming control without adding significant peripheral circuitry, as the existing power management infrastructure is utilized.
Solution Approach 2:
The control module serves multiple functions: it receives dimming control signals, determines dimming levels based on input voltage sampling, generates appropriate control signals for the power factor correction module, and maintains power factor correction. This multi-functionality reduces the need for separate dedicated circuits for each function.
3Ease of operation
If silicon controlled rectifier dimmer is used for small load LED, then dimming is achieved, but efficiency is reduced due to power consumption by bleeder resistor
Solution Approach 1:
The control module uses the existing input voltage sampling for both power factor correction control and dimming level determination. By making the control system self-sufficient and utilizing existing voltage information, the patent eliminates the need for additional bleeder resistors that would consume power in small load conditions.
Data Source
AI summary
A LED dimming device, and a LED dimming and a driving circuit using such LED dimming device are discussed. In present embodiment, the LED dimming device multiplexes an inputting switch and/or a sampling module of the LED driving circuit for dimming. such LED dimming device will not affect the sine waves of input current, in such a way, power factor and work efficiency will be increased while the harmonic coefficient and interference signal will be reduced.