LED Driver Merging Power Supplies for Spectral Control
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Solution Overview
Problem
Existing systems require multiple main power supplies to drive differently colored LED strings, making them bulky, expensive, and inefficient, while also struggling to control the spectral composition of mixed light effectively.
Innovation Solution
A driver system that uses a single main power supply and secondary power supplies to manage delta currents between LED junctions, allowing for efficient control of spectral composition and overall light level, with the secondary power supplies being smaller, cheaper, and more efficient to mitigate the drawbacks of the main SMPS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple main power supplies are used to drive differently colored LED strings, then the spectral composition can be controlled, but the device becomes bulky, expensive, and inefficient
Solution Approach 1:
The patent merges the power supply functions by using a single main power supply to provide base current to all LED strings and secondary power supplies to provide differential current adjustments. This consolidation reduces the number of power supplies from multiple main supplies to one main supply plus smaller secondary supplies, thereby reducing device complexity while maintaining spectral composition control capability
Solution Approach 2:
The patent segments the current control into two parts: a main power supply that handles the bulk current (delta current) and secondary power supplies that handle the differential current adjustments. This segmentation allows the main power supply to be larger and more efficient while the secondary supplies remain smaller and less complex, resolving the contradiction between control precision and device simplicity
2Ease of operation
If multiple main power supplies are used for each colored LED string, then independent control is achieved, but the system becomes more expensive and less efficient
Solution Approach 1:
The patent combines the power supply functions into a hierarchical structure where one main power supply serves multiple LED strings, reducing the total number of power conversion stages. This merging reduces energy losses associated with multiple separate power supplies while maintaining independent control through the secondary power supplies that provide precise differential adjustments
3Device complexity
If a single main power supply is used for all LED strings, then device complexity is reduced, but the spectral composition control becomes difficult
Solution Approach 1:
The patent introduces secondary power supplies as intermediary components between the single main power supply and the LED strings. These secondary power supplies receive the base current from the main supply and provide the necessary differential current adjustments to achieve precise spectral composition control, thereby enabling fine-grained control without requiring multiple main power supplies
4Power
If main power supplies are used for each LED string, then sufficient current is provided, but the system becomes bulkier and more expensive
Solution Approach 1:
The patent segments the power delivery into two hierarchical levels: a main power supply that provides the bulk current (approximately 90-95% of total current) and secondary power supplies that provide the differential current (approximately 5-10%). This segmentation allows the main power supply to be optimized for high current delivery while the secondary supplies are smaller and less complex, reducing overall system bulk and cost
Data Source
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AI summary
The present invention relates to a driver for a string (STi) of series arranged light emitting diodes (D1i, D2i, D3i) of which at least two emit light having different spectra. The driver comprises a main power supply (PAi) which has outputs coupled across the string (STi) to supply a main current (IAi) to the string (STi). A secondary power supply (PBi) is coupled to at least one of junctions (J1i) between successive light emitting diodes (D1i, D2i) in the string (STi) to supply or withdraw a delta current (IBi) from the junction (J1i). The delta current (IBi) is at least a factor 5 smaller than the main current (IAi). A controller (CO) controls the secondary power supply (PBi) to generate the delta current (IBi) to obtain a desired spectral composition of the mixed light emitted by the string (STi).