Series-Connected LED Driver with Parallel Switch Duty Cycle Control
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Solution Overview
Problem
Existing LED driver and controller systems with parallel connected LEDs suffer from low efficiency due to high current levels and voltage drops, leading to inefficiencies and increased costs.
Innovation Solution
A system with LEDs connected in series, utilizing a constant current source and duty cycle modulated control signals to control the conductivity of switches, allowing for efficient intensity and color variation by varying the duty cycle of switches connected in parallel to LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If LEDs are connected in parallel with individual current control, then each LED can be individually controlled for intensity and color, but the system suffers from high current levels and voltage drops resulting in low efficiency
Solution Approach 1:
The patent inverts the conventional parallel connection approach by using series connection of LEDs. Instead of controlling each LED independently through separate current paths, the invention controls LEDs in series by modulating the duty cycle of switches connected in parallel across individual LEDs or groups of LEDs, thereby reducing overall current levels and improving efficiency while maintaining control capability
Solution Approach 2:
The patent introduces dynamic control through duty cycle modulation of switches. By varying the duty cycle of switches connected in parallel across LEDs, the system dynamically controls the effective current through each LED during the switching period, enabling intensity and color control without requiring high continuous current levels
2Illumination intensity
If high current levels are used to control LED intensity in parallel configurations, then LED brightness can be adjusted, but power drops increase and system efficiency decreases
Solution Approach 1:
The patent employs periodic switching action where switches are turned on and off at high frequency with varying duty cycles. This periodic action allows LED intensity control through average current modulation rather than continuous high current, significantly reducing power drops and improving efficiency while maintaining brightness control
Solution Approach 2:
The patent changes the control parameter from continuous current level adjustment to duty cycle modulation. By varying the duty cycle parameter of switches in the series configuration, the system achieves LED intensity control with much lower power losses compared to traditional parallel high-current approaches
3Adaptability or versatility
If parallel LED connections are used with individual switch control, then color mixing and intensity variation are achievable, but the system requires larger components and has increased complexity
Solution Approach 1:
The patent merges multiple control functions into a unified series connection architecture. By controlling switches in parallel across LEDs that are series-connected, the system achieves color mixing and intensity variation through coordinated duty cycle modulation of multiple switches, reducing overall system complexity and component size compared to fully parallel configurations
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 configuration increases system efficiency, reduces power loss, and enables the use of smaller components, resulting in lower system costs and improved performance by allowing for a wide spectrum of colors and intensity control.
Implementation Method 1
Light emitting diodes (LEDs) are becoming particularly attractive as main stream light sources
Implementation Method 2
LEDs are semiconductor devices and are driven by direct current. The intensity of the LED varies in direct proportion to the current flowing through the LED.
Data Source
AI summary
A LED driver and controller system utilizes switches to parallel connect to respective sets of one or more LEDs and a current source to provide efficient control of the LEDs. In at least one embodiment, the LEDs are connected in series. An LED controller of the LED driver and controller system 200 controls conductivity of the switches. In at least one embodiment, the LED controller provides control signals to one or more LED drivers. The LED drivers receive the control signals and, in response to the control signals, control the conductivity of each switch. In at least one embodiment, the conductivity of the each switch is controlled using a duty cycle modulated control signal. In at least one embodiment, the duty cycle modulated control signal is a pulse width modulated control signal. In another embodiment, the duty cycle modulated control signal is a pulse density modulated control signal.