Series Lighting Circuit With PWM Control of Mixed Light Sources
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Solution Overview
Problem
Existing lighting systems combining different types of light sources, such as LEDs and laser diodes, require separate current control for each source, making it difficult to control the overall light output flux and color effectively with a single driver configuration.
Innovation Solution
A lighting circuit with a driver that delivers a controllable current comprising a DC component and a modulated component, such as a pulse width modulated component, to a series connection of different light source types, allowing independent control of their contributions to the overall light output flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate current drivers are used for each light source type, then independent control of each light source is achieved, but device complexity increases
Solution Approach 1:
The patent combines multiple current drivers into a single integrated driver that controls both LED and laser diode light sources. The driver includes a LED driver circuit and a laser diode driver circuit merged into one device, with a single controller coordinating both outputs. This reduces component count and system complexity while maintaining independent control capability through separate control signals from the unified controller.
Solution Approach 2:
The single driver is designed with multi-functionality to control different types of light sources (LED and laser diode) with different electrical characteristics. The driver incorporates multiple output channels with independent current regulation capabilities, allowing each light source type to be controlled according to its specific flux versus drive current characteristics while using a unified control architecture.
2Device complexity
If a series connection of different light source types is used, then device complexity is reduced, but control precision over individual light source contributions deteriorates
Solution Approach 1:
The single driver is segmented into functionally independent control channels, each tailored to specific light source types. The driver includes separate current regulation circuits for LEDs and laser diodes, with independent control signals that can be adjusted to achieve precise control of each light source's contribution to the overall light output, despite the series connection architecture.
3Manufacturing precision
If different flux versus drive current characteristics of light sources are accommodated, then light output control accuracy is improved, but device complexity increases
Solution Approach 1:
The driver accommodates different flux versus drive current characteristics by implementing parameter-changing control strategies. The controller adjusts current magnitude, pulse width modulation duty cycles, and switching frequencies independently for each light source type based on their specific characteristics. This allows accurate control of light output flux without requiring completely separate control circuits, as the same driver hardware adapts its control parameters for different light sources.
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 efficient control of light output flux and color by exploiting the threshold and flux-current characteristics of different light sources, providing a wide range of adjustable combinations with a single driver using a series connection.
Implementation Method 1
superluminescent diodes (SLED) combine the features of laser diodes and light emitting diodes
Implementation Method 2
SLEDs exhibit threshold-like behavior of light-current-voltage (LIV) characteristics
Implementation Method 3
the driver is configurable to set a modulation by setting a duty cycle of a superposed pulse width modulated component of the controllable current
Data Source
AI summary
A lighting circuit comprises a first light source arrangement and a second light source arrangement, of different types, in series. A driver delivers a controllable current to the light source circuit, with an adjustable DC component and an adjustable modulated component, for example an adjustable duty cycle of a superposed pulse width modulated component. This enables control of the contributions to the overall light output flux from the different types of light source.