Dimming Mixed Light Sources Using PWM Control
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Solution Overview
Problem
Existing systems for dimming light sources, particularly combining incandescent lights and LEDs, face challenges in achieving simultaneous and uniform dimming without flicker or irregularities, due to differences in their operational characteristics.
Innovation Solution
The implementation of a circuit with logic/driver circuitry, including low pass filters and microprocessors, that uses pulse-width modulation (PWM) to control the power supply, ensuring that both incandescent light sources and LEDs dim in concert by matching their brightness and extinguishing rates, utilizing components like resistors, capacitors, inductors, and transistors to smooth current transitions and adjust current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PWM dimming is applied to both incandescent lights and LEDs, then energy efficiency and longevity are improved, but uniform and simultaneous dimming without flicker becomes difficult to achieve
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the PWM duty cycle for each light source type based on its specific characteristics. Incandescent lights and LEDs are assigned different duty cycle profiles that account for their respective response times, thermal inertia, and brightness curves, enabling uniform dimming despite different operational parameters
Solution Approach 2:
The system implements dynamics by using feedback mechanisms that continuously monitor the actual brightness output of each light source and dynamically adjust the PWM control parameters in real-time. This dynamic adaptation allows the system to compensate for differences in thermal response and light emission characteristics between incandescent and LED sources
2Duration of action of moving object
If different PWM duty cycles are used for incandescent lights and LEDs, then simultaneous dimming is achieved, but flicker and irregularities occur
Solution Approach 1:
The patent employs periodic action by using synchronized PWM signal generation with carefully selected frequencies that are above the human perceptible range. The system applies periodic dimming cycles with different duty ratios for incandescent and LED sources, coordinated to achieve simultaneous brightness levels while maintaining frequencies that prevent visible flicker
Solution Approach 2:
The patent introduces an intermediary control system that acts as a mediator between the PWM signal generation and the actual light sources. This intermediary layer processes and coordinates the control signals, adding smoothing functions and transition management that eliminate irregularities while maintaining synchronized dimming behavior across different light source types
3Device complexity
If simple PWM control is used, then device complexity is reduced, but inability to match brightness and extinguishing rates of different light sources occurs
Solution Approach 1:
The patent implements feedback mechanisms that monitor the actual brightness output of each light source and use this information to adjust the PWM control parameters. The feedback loop enables the system to automatically compensate for differences in light emission characteristics, ensuring precise brightness matching between incandescent and LED sources without requiring overly complex manual calibration
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 approach ensures that both incandescent light sources and LEDs dim uniformly and simultaneously, eliminating flicker and irregularities, thereby providing a consistent and aesthetically pleasing dimming effect.
Implementation Method 1
The implementation of a circuit with logic/driver circuitry, including low pass filters and microprocessors, that uses pulse-width modulation (PWM) to control the power supply
Implementation Method 2
uses pulse-width modulation (PWM) to control the power supply, ensuring that both incandescent light sources and LEDs dim in concert by matching their brightness and extinguishing rates
Data Source
AI summary
A system for dimming one or more light sources includes a first light source that emits a light of a first brightness according to an operating condition of the first light source, a second light source that emits a light of a second brightness according to an operating current of the second light source, wherein the light of the first brightness is different than that of the light of the second brightness, and one or more components that references the operating condition of the first light source, wherein, in response to the referenced operating condition of the first light source, the one or more components modifies the operating current of the second light source to substantially match the light of the second brightness to the light of the first brightness. A method for dimming one or more light sources is also disclosed.