Solid State Lighting Dimmer Phase Angle Detection Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional dimmers cause inconsistencies in light output for solid state lighting systems due to varying dimming ranges and phase angles, leading to issues like low end dropout, triac misfiring, and high end flicker, especially when used with LED loads.
Innovation Solution
A dimmer phase angle detection circuit dynamically adjusts the power output of a power converter based on detected maximum and minimum dimmer phase angles to maintain uniform light levels across different dimmer types, using look-up tables and power control signals to ensure consistent high and low end light outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional phase-cutting dimmers are used with solid state lighting loads, then dimming control is achieved, but light output consistency varies across different dimmer types and settings
Solution Approach 1:
The system dynamically adjusts the power converter operating parameters based on detected dimmer phase angles. By measuring the actual phase angle at which the dimmer chops the waveform and modifying the power converter's switching parameters accordingly, the system compensates for dimmer-specific variations and maintains consistent light output across different dimmer types and settings.
Solution Approach 2:
The system implements a feedback mechanism by detecting the dimmer's phase angle through measurement of the chopped waveform characteristics. This detected information is fed back to the power converter controller, which then adjusts its operation to compensate for the detected phase angle, ensuring consistent light output despite variations in dimmer behavior.
2Adaptability or versatility
If different dimmer types with varying phase angles are used, then dimming range flexibility is improved, but light output levels become inconsistent at maximum and minimum settings
Solution Approach 1:
The system detects the specific phase angles at which different dimmer types operate at their maximum and minimum settings, then dynamically changes the power converter's operating parameters to compensate. This allows the system to maintain uniform light output across maximum and minimum settings regardless of which dimmer type is used, while still preserving the flexibility to work with various dimmer ranges.
3Ease of operation
If phase chopping dimming method is used, then dimming control is achieved, but solid state lighting loads experience dropout and flicker issues
Solution Approach 1:
The system takes preliminary action by detecting the dimmer's phase angle before the lighting issues occur, and pre-adjusts the power converter parameters to prevent dropout and flicker. By anticipating and compensating for the problematic effects of phase chopping in advance, the system eliminates these harmful effects while maintaining dimming control.
Solution Approach 2:
The system uses feedback from phase angle detection to continuously monitor the dimming operation and adjust power converter parameters in real-time. This feedback mechanism allows the system to respond to changing dimmer settings and prevent dropout and flicker conditions before they manifest as visible lighting problems.
Data Source
Figure 1A~2
Figure 3
Figure 4
AI summary
A method is provided for controlling a power converter (220) to provide a uniform dimming range to a solid state lighting load (240) independent of a type of dimmer. The method includes detecting maximum and minimum phase angles of a dimmer (204) connected to the power converter (220) during operation of the solid state lighting load (240), and dynamically adjusting an output power of the power converter based on the detected maximum and minimum phase angles of the dimmer. The adjusted output power of the power converter adjusts a high end level of light output by the solid state lighting load at the maximum phase angle to match a predetermined high end value and adjusts a low end level of light output by the solid state lighting load at the minimum phase angle to match a predetermined low end value.