Digital Phase Angle Detection for Universal Dimmer Control
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Solution Overview
Problem
Existing methods for digitally processing dimmer signals in lighting control systems are limited in their ability to accurately generate a normalized digital representation of lighting brightness across different dimmer types and edge control scenarios, leading to inconsistent and unreliable light intensity control.
Innovation Solution
The method involves digitally time-sampling rectified AC waveforms to generate a DIM code, which is normalized with respect to an allowable edge control window, allowing for the generation of a digital value that corresponds to a full-scale DAC output for maximum brightness and minimum brightness, applicable to both leading-edge and trailing-edge dimmers without identifying the dimmer type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If digital time sampling is used to capture phase angle, then the ability to control lighting brightness is improved, but the accuracy varies depending on dimmer type (leading edge vs. trailing edge)
Solution Approach 1:
The system implements a universal phase angle detection method that works with both leading-edge and trailing-edge dimmers. The controller automatically adapts to the dimmer type by detecting edge characteristics and applying the appropriate measurement logic, making the system multi-functional without requiring separate detection circuits for different dimmer types.
Solution Approach 2:
The system dynamically changes measurement parameters based on detected dimmer type. For leading-edge dimmers, it measures the time from waveform start to rising edge; for trailing-edge dimmers, it measures from waveform start to falling edge. This parameter adaptation ensures consistent accuracy across different dimmer technologies.
2Measurement precision
If separate processing methods are used for leading-edge and trailing-edge dimmers, then measurement accuracy for each type is improved, but system complexity increases
Solution Approach 1:
The system employs dynamic processing logic that automatically adapts to the input waveform characteristics. The controller continuously monitors edge transitions and dynamically switches between leading-edge and trailing-edge measurement modes, providing type-specific accuracy without requiring manual configuration or complex hardwired logic for each dimmer type.
Solution Approach 2:
The system performs self-identification of dimmer type by analyzing the waveform characteristics automatically. The controller detects whether incoming signals are leading-edge or trailing-edge type and autonomously selects the appropriate measurement methodology, eliminating the need for external identification or manual setup.
3Reliability
If normalization is applied to generate DIM codes, then consistency across different dimmer types is improved, but the processing time increases
Solution Approach 1:
The system pre-calculates normalization parameters and establishes reference waveforms before actual dimming operation. By preparing lookup tables and normalization constants in advance, the system reduces real-time processing requirements while maintaining consistent light intensity output across different dimmer types.
Data Source
AI summary
Apparatus and methods operate to perform digital time sampling of a waveform associated with a rectified alternating current, edge-controlled power signal, whether leading or trailing edge-controlled. A dimming code (DIM code) is generated based upon rising and falling edge zero crossing timing. The DIM code is normalized with respect to an allowable edge control window synchronized with the waveform. A minimally-dimmed waveform results in a maximum DIM code corresponding to a full-scale DAC maximum brightness analog output signal. The DIM code is loaded into a DAC to be converted to an analog brightness signal. The analog brightness signal may be used by a lighting power controller to control the brightness of one or more lighting elements. Accurate and repeatable light intensities independent of dimmer type may result.