Dimmer Compatibility Controller for LED Loads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Triac-based leading edge dimmers in lighting systems often prematurely reset due to low current levels, leading to inefficient power conversion and malfunction, especially when dealing with small current loads, resulting in unstable phase cutting and increased resistor-based power losses.
Innovation Solution
A controller system that coordinates a low impedance path, switch mode power conversion, and an inactive state to maintain a stable phase angle and prevent premature resetting, ensuring consistent dimming levels by enabling a low impedance path during zero volt crossings and controlling switch mode power conversion to maintain dimmer current above a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If triac-based leading edge dimmers are used to control small current loads, then dimming functionality is provided, but premature resetting occurs due to low current levels falling below holding current threshold
Solution Approach 1:
A controller is introduced as an intermediary device between the dimmer and the load. The controller receives the dimmer output signal and generates appropriate drive signals for the load, while also providing feedback to the dimmer to prevent premature resetting. This mediator resolves the conflict by decoupling the dimmer's holding current requirement from the actual load current.
Solution Approach 2:
The system dynamically adjusts operating parameters based on load conditions. When small current loads are detected, the controller modifies the dimmer operation parameters to maintain current above the holding threshold, preventing premature resetting while preserving dimming control functionality.
2Ease of manufacture
If resistor-based networks are used for voltage conversion, then simplicity of implementation is achieved, but resistor-based power losses increase reducing efficiency
Solution Approach 1:
The patent replaces resistor-based analog voltage conversion with a digital control system that uses pulse-width modulation (PWM) and digital signal processing. This substitution eliminates the need for power-dissipating resistors while maintaining implementation simplicity through programmable control logic.
Solution Approach 2:
The system uses periodic switching action in a switch-mode power converter rather than continuous resistive voltage division. This periodic action transfers energy efficiently during switching intervals, dramatically reducing resistive power losses while keeping the implementation relatively simple through periodic control cycles.
3Power
If reactive load networks are used with dimmers, then voltage conversion is achieved, but triac malfunction occurs due to interference with phase cutting operation
Solution Approach 1:
The controller serves as an intermediary that buffers the triac from the reactive load. It measures the actual voltage and current conditions after the triac and uses this feedback to generate appropriate drive signals, preventing the reactive load from interfering with triac phase cutting operation while maintaining voltage conversion functionality.
Solution Approach 2:
The system implements feedback control where the controller continuously monitors the electrical conditions and adjusts its output to compensate for reactive load effects. This feedback mechanism prevents triac malfunction by ensuring that control signals account for the actual load conditions rather than being disrupted by reactive effects.
4Loss of energy
If dimmers operate at low current levels, then energy efficiency is improved, but phase angle stability deteriorates causing inconsistent dimming
Solution Approach 1:
The controller dynamically adjusts operating parameters based on the detected dimming level and load conditions. At low current levels, it modifies timing parameters and control signal characteristics to maintain phase angle stability, ensuring consistent dimming while preserving energy efficiency benefits of low-current operation.
Solution Approach 2:
The system uses feedback from current sensing to detect phase angle variations and adjusts control signals accordingly. This feedback loop maintains phase angle stability even at low current levels where stability would naturally deteriorate, ensuring consistent dimming performance across the full operating range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution stabilizes the phase angle cutting in dimmers, prevents premature resetting, reduces resistor-based power losses, and ensures a constant current output to loads, enhancing the compatibility and efficiency of triac-based dimmers with various lighting systems.
Implementation Method 1
for state A, enable a low impedance path for a dimmer current of the dimmer, wherein the impedance of the low impedance path is sufficiently low to maintain a stable phase angle of the dimmer
Implementation Method 2
for state B, enable control of switch mode power conversion of the dimmer voltage; and control the switch mode power conversion to maintain the dimmer current above a current threshold
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electronic system (300) comprising a load (308) including one or more light emitting diodes, a power converter system (304) for providing compatibility between a dimmer (306) and the load (308), wherein the dimmer provides a dimmer voltage (VΦ_DIM) to the power converter system (304), the dimmer voltage comprising three states: A. an approximately zero volt crossing of the dimmer voltage (VΦ_DIM) of the dimmer (306) until a phase cut, leading edge of the dimmer voltage (VΦ_DIM); B. an end of state A until energy transferred to the load (308) is sufficient to meet at least one energy transfer parameter; and C. an end of state B until a beginning of a next state A, the electronic system (300) further comprising a controller (302, 402) for controlling the power converter system (304), characterized in that the controller (302, 402) comprises a low impedance path state controller (310, 404) configured to, for state A, enable a low impedance path (316) for a dimmer current of the dimmer (306), wherein the impedance of the low impedance path is sufficiently low to maintain a stable phase angle of the dimmer (306), a switch mode power conversion controller (312, 406) configured to, for state B, control power conversion by the power converter system (304) of the dimmer voltage; and control the power converter system to maintain the dimmer current above a current threshold and an inactive state controller (314, 408) configured to, for state C, enter an inactive state, wherein during the inactive state the low impedance path and the power conversion are disabled.