LED Dimming Module Two-Channel Planckian Curve Control
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Solution Overview
Problem
Existing LED dimming solutions require complex control units and multiple channels to achieve a dimming curve that mimics the planckian curve of incandescent light sources, which is not efficiently replicable with current RGB or multi-channel LED systems.
Innovation Solution
A two-channel LED dimming module with one string receiving a varying current and the other receiving a current proportional or dependent on the first string's current change, allowing for independent control and mimicking the planckian dimming curve on the CIE chromaticity diagram with reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RGB or multi-channel LED systems are used to achieve planckian dimming curve, then the dimming curve accuracy is improved, but the device complexity increases significantly
Solution Approach 1:
The LED system is segmented into two independent LED strings with distinct spectral characteristics. The first LED string emits light in a first wavelength region while the second LED string emits light in a second wavelength region. By independently controlling the intensity of each string through separate driving currents, the system achieves planckian dimming curve without requiring complex multi-channel RGB control units.
2Adaptability or versatility
If multiple LED strings with different wavelengths are used, then the color temperature range is improved, but the control system complexity increases
Solution Approach 1:
The system varies the correlated color temperature by changing the ratio of driving currents supplied to the two LED strings. By adjusting the intensity parameters of each LED string independently, the system can achieve a wide color temperature range from warm white to cool white without requiring sophisticated microcontrollers or complex control algorithms.
3Measurement precision
If pulse width modulation is used for LED dimming, then the dimming control precision is improved, but the control circuit complexity increases
Solution Approach 1:
The system employs pulse width modulation (PWM) to control the intensity of each LED string by varying the duty cycle of periodic square wave signals. This periodic action allows precise dimming control for both LED strings independently, achieving accurate planckian dimming curve while maintaining relatively simple control circuitry compared to multi-channel RGB systems.
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 achieves a dimming curve that closely follows the planckian curve of incandescent light sources with a simplified two-channel control system, providing a wide range of correlated color temperatures from 1500K to 7000K without the need for sophisticated microcontrollers.
Implementation Method 1
a first and a second LED string (1, 2) which are connected to a control unit (3)... at least one phosphor coated blue or UV LED (1a)... at least one amber light emitting LED (2a)
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
The present invention proposes an LED dimming module (10) comprising two LED strings (1,2), the first LED string (1) comprising at least one color converted blue or UV LED (1a) and the second LED string (2) comprising at least one amber light emitting LED (2a), the LED module further comprising control means (3) connected to the first and second LED string (1,2), said control means (3) being designed to selectively vary a current provided to the first LED string (1) such that a non-linear dimming curve (13b) of the resulting emitted light is obtained, said dimming curve (13b) approaching the planckian curve (9) on the CIE chromaticity diagram.