LED Power Supply Mode Switching for Flicker and Noise Control
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Solution Overview
Problem
Existing dimming control methods for LED power supplies, such as DC voltage and PWM, have limitations in compatibility and effectiveness for different types of lamps, leading to issues like flicker, dimming noise, and inadequate brightness adjustment.
Innovation Solution
A method for an LED power supply that allows users to freely switch between DC voltage dimming, PWM dimming, and PWM frequency conversion dimming by integrating a power supply main drive module, power MOS tube, DC dimming control module, dimming signal collection module, main control module, and mode switching module to detect and adjust dimming control methods based on lamp load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM dimming control method is used, then dimming control accuracy is improved, but flicker and dimming noise occur when PWM frequency is low
Solution Approach 1:
The system dynamically adjusts the PWM frequency based on the required dimming level. When high dimming accuracy is needed at higher brightness levels, a higher PWM frequency is used. When lower brightness levels are required, the system switches to DC voltage dimming to avoid flicker and noise, thus adaptively optimizing the dimming control
Solution Approach 2:
The invention changes the dimming control parameter from fixed PWM frequency to variable frequency PWM or DC voltage control. By adjusting the PWM frequency parameter or switching to DC voltage dimming, the system resolves the contradiction between maintaining high dimming control accuracy and avoiding flicker/noise at low frequencies
2Object-affected harmful factors
If PWM frequency is increased to eliminate flicker, then flicker and noise are reduced, but brightness cannot be adjusted to very low levels
Solution Approach 1:
The dimming control range is segmented into different zones: higher brightness levels use high-frequency PWM control to eliminate flicker, while lower brightness levels use DC voltage dimming to achieve smooth dimming. This segmentation allows each method to operate in its optimal range, resolving the contradiction between eliminating flicker and maintaining low brightness capability
Solution Approach 2:
The power supply system is designed with multi-functionality, supporting both PWM dimming and DC voltage dimming methods. This universal design enables the system to switch between different dimming strategies based on the required brightness level, achieving both flicker elimination and wide brightness adjustment range
3Measurement precision
If DC voltage dimming control method is used, then dimming control accuracy and smoothness are improved, but it cannot control lamps with high voltage drop
Solution Approach 1:
The power supply system is designed with multi-functionality, supporting both PWM dimming and DC voltage dimming methods. This universal design enables the system to adapt to different lamp types: PWM mode for lamps requiring frequency-based control and DC voltage mode for lamps needing precise voltage adjustment, thus resolving the contradiction between dimming accuracy and lamp compatibility
Solution Approach 2:
The system dynamically selects the appropriate dimming control method based on the lamp characteristics and operating conditions. For lamps with high voltage drop, the system can switch between PWM and DC voltage dimming to maintain both high dimming control accuracy and broad adaptability across different lamp types
4Adaptability or versatility
If single dimming control method is used, then device complexity is reduced, but adaptability to different lamp loads is limited
Solution Approach 1:
The control system uses an intermediary switching mechanism that selects between PWM and DC voltage dimming modes based on lamp load characteristics. This intermediary layer manages the complexity by providing a unified interface while handling different dimming methods internally, thus improving lamp compatibility without significantly increasing user-facing system complexity
Data Source
AI summary
The present invention provides a method for realizing a multiple dimming control mode of an LED power supply, which enables users to switch the dimming control method of the power supply to a DC voltage dimming, a PWM dimming, a PWM combined with PWM frequency conversion dimming, etc. according to a load of the lamp condition. The LED dimming power supply using this method combines the advantages of the above dimming control methods, significantly improves the compatibility with existing various types of lamps, and enables users to select a more appropriate dimming control method according to the load of the lamp of a practical application and its dimming characteristic, so as to achieve the optimal usage status and dimming effect of the lamp.