Trailing Edge Dimmer Conduction Angle Detection for LED Drivers
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Solution Overview
Problem
Traditional dimmers designed for incandescent lamps are not compatible with LED devices, particularly trailing edge dimmers, leading to inadequate dimming capabilities and interference issues.
Innovation Solution
A method and device to determine the conduction angle of trailing edge dimmers, allowing for compatibility with both leading and trailing edge dimmers, and generating a dimming signal to reduce interference and flickering in LEDs, using a conduction angle determining unit and a PWM DC/DC converter for effective isolation and dimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional phase control dimmers are used for LED devices, then brightness adjustment capability is improved, but compatibility with LED driving devices deteriorates
Solution Approach 1:
The patent introduces a dimming signal generating unit that acts as an intermediary between the traditional phase control dimmer and the LED driving device. This unit detects the conduction angle of the dimmer and generates appropriate PWM dimming signals, enabling communication and compatibility between incompatible systems without requiring changes to the traditional dimmer interface
Solution Approach 2:
The patent transforms the control parameter from direct voltage phase control to conduction angle detection and PWM signal generation. By detecting the conduction angle parameter of the dimmer and converting it to PWM duty cycle, the system maintains compatibility with traditional dimmers while enabling proper LED dimming control
2Measurement precision
If conduction angle detection is implemented for trailing edge dimmers, then dimming precision is improved, but device complexity increases
Solution Approach 1:
The dimming signal generating unit utilizes the existing output signal from the dimmer to detect the conduction angle by identifying when the output voltage transitions from zero to non-zero. The system serves itself by using the dimmer's own output characteristics for detection, eliminating the need for additional external detection circuits or complex measurement equipment
Solution Approach 2:
The patent replaces complex conduction angle detection circuitry with a simplified signal processing approach. Instead of using sophisticated measurement devices, the system uses basic voltage threshold detection and timing measurement to determine the conduction angle, significantly reducing device complexity while maintaining precision
3Adaptability or versatility
If PWM dimming signal is generated based on conduction angle, then compatibility with both leading and trailing edge dimmers is improved, but control system complexity increases
Solution Approach 1:
The dimming signal generating unit is designed with universal functionality to handle both leading edge and trailing edge dimmers through a single unified detection and control mechanism. The system detects the conduction angle regardless of dimmer type and generates appropriate PWM signals, eliminating the need for separate control circuits for different dimmer types
Solution Approach 2:
The control system dynamically adapts its operation based on the detected dimmer type. By automatically identifying whether a leading or trailing edge dimmer is connected and adjusting the PWM signal generation accordingly, the system achieves universal compatibility without requiring manual configuration or complex predetermined control logic for each dimmer type
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
Enables compatible dimming of LEDs with both leading and trailing edge dimmers, reduces random interference, and ensures effective isolation from high voltage power supplies, improving dimming precision and stability.
Implementation Method 1
a PWM DC/DC converter, configured to generate a driving voltage of LED according to the PWM control signal
Data Source
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AI summary
The present invention provides a method for obtaining a conduction angle of a trailing edge dimmer, an LED driving method, a conduction angle obtaining device for the trailing edge dimmer and an LED driving device. Wherein the method for obtaining the conduction angle of the trailing edge dimmer comprises: determining a time point t0 when the trailing edge dimmer starts to be conductive; determining an earliest time point t1 when a deviation from an ideal waveform appears; and determining the conduction angle t1-t0 of the trailing edge dimmer based on the earliest time point t1 when the deviation from the ideal waveform appears and the time point t0 when the trailing edge dimmer starts to be conductive.