Dimmer Control Method for LED Overheating via Dynamic Mode Switching
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Solution Overview
Problem
Existing variator control methods for light loads, particularly LED lamps, face challenges in managing overheating, which can lead to damage and inefficiency, as they often rely on fixed operating modes that do not adapt effectively to temperature changes.
Innovation Solution
A method that dynamically adjusts the chopping mode of the input signal from angle conduction to angle cut-off based on temperature measurements, with intermediate steps of increasing switching slope and verifying load compatibility, to reduce heat emission and maintain light output, using a MOSFET transistor and temperature sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the variator operates in angle conduction mode with high duty cycle, then light output is maintained, but overheating risk increases
Solution Approach 1:
The patent implements dynamic switching between angle conduction mode and angle cut-off mode based on real-time temperature monitoring. When temperature exceeds the maximum operating threshold, the system transitions from angle conduction to angle cut-off mode, adjusting the transistor switching timing to reduce duty cycle and thereby reduce heat emission while maintaining adequate light output.
Solution Approach 2:
The patent changes the operating parameters of the transistor by switching between two distinct modes: angle conduction mode (with earlier transistor closure) and angle cut-off mode (with later transistor closure). This parameter change in switching timing directly controls the duty cycle, enabling the system to adjust power delivery to the LED load and manage thermal conditions.
2Temperature
If the duty cycle is reduced to prevent overheating, then temperature is controlled, but light output decreases
Solution Approach 1:
The system dynamically adjusts the duty cycle by switching modes based on temperature conditions. When temperature is within acceptable ranges, the system operates in angle conduction mode with higher duty cycle for optimal light output. When temperature exceeds thresholds, it transitions to angle cut-off mode with reduced duty cycle to control heating, thus dynamically balancing thermal management and illumination requirements.
3Temperature
If angle cut-off mode is used to reduce heat, then temperature is controlled, but load compatibility issues arise
Solution Approach 1:
The patent incorporates temperature sensing feedback to determine when to switch between operating modes. The temperature sensor continuously monitors the variator temperature, and when the maximum operating temperature is exceeded, the system activates angle cut-off mode. This feedback mechanism ensures that angle cut-off mode is only used when thermally necessary, maintaining compatibility with various LED loads under normal operating conditions.
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
This method effectively manages overheating by reducing heat emission and maintaining light output, ensuring compatibility with various loads and reducing the risk of damage, while allowing LED loads to operate in a reduced flicker mode.
Implementation Method 1
measure the temperature in the drive using the temperature sensor
Implementation Method 2
supply a light load using a power supply signal obtained by chopping a periodic input signal from the variator
Data Source
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AI summary
The present invention relates to a method for controlling a dimmer comprising a temperature sensor and a transistor, the dimmer powering a light load using an electrical supply signal obtained by chopping a periodic input signal from the dimmer. The method comprises, in a first mode (M1) in which the input signal is chopped according to an angle conduction mode with an initial switching slope and an initial duty cycle, the following successive steps: a) measuring the temperature in the dimmer using the temperature sensor; b) when the measured temperature is above a maximum operating temperature of the dimmer, switching (14) to a second operating mode (M2) in which the input signal is chopped according to an angle cutoff mode.