LED Driver Circuit for Uniform Dimming and Color Temperature Control
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Solution Overview
Problem
Conventional luminaires face challenges in adjusting the relationship between dimming level and color temperature, leading to inconsistent color temperatures when multiple luminaires are dimmed using a single dimmer, due to individual differences in current supply characteristics.
Innovation Solution
A light-emitting apparatus with a constant current supply, including a first and second light-emitting element column connected in parallel, a detector circuit to monitor current flow, and an adjuster circuit to adjust the current distribution based on detected values, allowing for precise control of the dimming level and color temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional luminaires adjust current flowing through light-emitting element columns following dimming, then color temperature of the luminaire as a whole can be changed, but it is not possible to adjust the relationship between the dimming level and the color temperature
Solution Approach 1:
The patent applies parameter changes by introducing adjustable parameters in the current adjuster circuits and relationship adjuster circuits. The current adjuster circuits have adjustable coefficients (α1, α2) that can be modified to change the relationship between dimming level and color temperature. The relationship adjuster circuits further adjust the dimming level at changing points, enabling flexible control over how color temperature varies with dimming level without requiring hardware changes.
2Ease of operation
If multiple luminaires are dimmed using a single dimmer, then operation is simplified, but individual differences in current supply characteristics lead to inconsistent color temperatures
Solution Approach 1:
The patent implements feedback mechanisms through detector circuits that monitor the actual current flowing through each light-emitting element column. The detected current values are fed back to the current adjuster circuits, which use this information to compensate for individual differences in current supply characteristics. This closed-loop feedback ensures that each luminaire achieves its target color temperature despite variations in the dimming system or individual component characteristics.
Solution Approach 2:
The relationship adjuster circuits adjust the dimming level at changing points where the relationship between magnitude of current flowing through the first light-emitting element column and the dimming level changes. This parameter adjustment compensates for individual differences between luminaires, ensuring consistent color temperature characteristics across all units when controlled by a single dimmer.
3Manufacturing precision
If current adjuster circuits adjust the magnitude of current flowing through light-emitting element columns, then color temperature control is improved, but device complexity increases
Solution Approach 1:
The patent divides the current control function into separate modular components: detector circuits for monitoring, current adjuster circuits for coefficient-based adjustment, and relationship adjuster circuits for dimming level adjustment. Each module performs a specific function independently, making the overall system more manageable despite the increased complexity. This segmentation allows for easier debugging, maintenance, and potential optimization of individual components.
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
The solution enables uniform dimming and color temperature adjustment across multiple luminaires, reducing deviations and improving light distribution characteristics, while maintaining a simplified and cost-effective configuration.
Implementation Method 1
a first light-emitting element column including one of a single first light-emitting element or a plurality of first light-emitting elements connected in series, and a second light-emitting element column connected in parallel with the first light-emitting element column
Data Source
AI summary
A light-emitting apparatus includes: a light source unit to which constant current corresponding to a dimming level is supplied from a constant current supply (dimming LED driver), and which includes a first light-emitting element column and a second light-emitting element column connected in parallel with the first light-emitting element column; a first detector circuit (resistor) which is connected in series to the first light-emitting element column, and detects a magnitude of a current flowing through the first light-emitting element column; a current adjuster circuit which adjusts a relationship of the magnitude of the current flowing through the first light-emitting element column to the constant current, based on the magnitude of the detected current; and a relationship adjuster circuit (variable resistor) which adjusts the dimming level at a changing point where a relationship of the magnitude of the current flowing through the first light-emitting element column to the dimming level changes.