Multi-Function Light Assembly With PWM Power Switching
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Solution Overview
Problem
Existing light assemblies struggle to efficiently manage multiple lighting functions with varying power requirements using a single driver, as all LEDs typically participate in the same function, making it difficult to control power requirements effectively for different lighting functions.
Innovation Solution
A light assembly comprising multiple lighting modules with dedicated switching units and a controller using Pulse Width Modulation (PWM) to manage power distribution, allowing for independent control of each lighting function, including high beam, low beam, daytime running light, and position lighting, with optional absorber and attenuation circuits to prevent surge currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all LEDs are connected in series and participate in the same lighting function, then the power control is simplified, but the ability to perform multiple lighting functions with different power requirements is lost
Solution Approach 1:
The lighting module is segmented into multiple independent LED strings (first LED string, second LED string, third LED string), each capable of being controlled independently through dedicated switching units. This segmentation allows different combinations of LED strings to be activated for different lighting functions (high beam, low beam, daytime running light), enabling multiple functions while maintaining manageable control complexity through modular architecture.
2Ease of operation
If a single driver with fixed output power is used, then the device simplicity is maintained, but the ability to provide different power levels for different lighting functions is limited
Solution Approach 1:
The system employs dynamic control through switching units that can selectively connect or disconnect different LED strings based on the required lighting function. The controller dynamically adjusts which LED strings are active and for how long (through PWM dimming control), enabling a single driver with fixed output power to effectively provide different power levels for different functions without requiring multiple drivers or complex power management circuits.
Solution Approach 2:
PWM (Pulse Width Modulation) dimming control is implemented to periodically switch the LED strings on and off at high frequency, creating the effect of continuous dimming. This periodic action allows precise control of the average power delivered to each LED string while maintaining the driver's fixed output power, enabling flexible power distribution across multiple lighting functions.
3Reliability
If multiple LED strings are connected in series, then the voltage utilization is improved, but the surge current risk when switching functions increases
Solution Approach 1:
The controller is designed to predict and prepare for potential surge current conditions by implementing a controlled switching sequence. Before activating a lighting function that requires higher power, the controller can pre-charge capacitors or gradually increase the duty cycle to prevent sudden surge currents. This preliminary action protects the LED strings and switching units from damage while maintaining efficient switching performance for different lighting functions.
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 flexible performance of multiple lighting functions with different power requirements using a single driver, optimizing power usage and preventing excessive surge currents, thus enhancing the assembly's adaptability and safety.
Implementation Method 1
The controller is configured to vary the power provided to the first lighting module or to the second lighting module by controlling the first switching unit or the second switching unit using Pulse Width Modulation, PWM
Data Source
AI summary
A light assembly includes a first lighting module configured to perform a first lighting function, a second lighting module configured to perform a second lighting function, a driver connected in series with the lighting modules. Each lighting module is controlled via a switching unit by a controller. The driver is configured to generate a constant output power and the controller is configured to vary the power provided to the first lighting module or to the second lighting module by controlling the first switching unit or the second switching unit using Pulse Width Modulation (PWM).