Switched-mode CCT Control Circuit for LED Lighting

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Solution Overview

Problem

Existing linear drive LED lighting systems are unable to simultaneously adjust illuminance and correlated color temperature (CCT) effectively, and lack a memory function, which limits their functionality and user experience.

Innovation Solution

A switched-mode control circuit that integrates a switched-mode CCT control module and a linear drive control module, allowing for the adjustment of both CCT and illuminance, with optional memory function, using parallel LED groups and a CCT adjustment module comprising resistors and diodes to control the emission of different CCTs and varying illuminance levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a linear drive circuit is used for LED lighting, then the circuit structure is simple and it works at power frequency without high frequency interference, but the drive circuit is unable to achieve the adjustment of both illuminance and CCT

Engineering Contradiction:
Improvecircuit structureVSAvoidadjustment capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent combines the linear drive circuit and CCT adjustment circuit into a single integrated control circuit. The control circuit includes a control module that can simultaneously regulate both the illuminance (via PWM dimming) and the correlated color temperature (via switching between different LED groups), thereby achieving multiple functions while maintaining circuit simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control circuit is designed with multi-functionality to perform both illuminance adjustment and CCT adjustment. The control module can switch between different operating modes (e.g., single-group LED operation for illuminance control, dual-group LED operation for CCT control) based on user input, making the circuit adaptable to various lighting requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple LED groups with different CCTs are used to enable CCT adjustment, then the adjustment of both illuminance and CCT becomes possible, but the number of LEDs and energy consumption increases

Engineering Contradiction:
ImproveCCT and illuminance adjustmentVSAvoidnumber of LEDs
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The LED lighting system is segmented into multiple groups of LEDs, where each group has a different correlated color temperature (CCT). By switching between these segmented groups or combining them in different proportions, the circuit can achieve variable CCT output without requiring a completely different LED configuration for each temperature level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control circuit dynamically switches between different LED groups based on the desired CCT and illuminance levels. The switching is controlled by a microcontroller or control module that adjusts the duty cycle of each LED group independently, allowing for dynamic adaptation to user preferences while optimizing power consumption.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If existing CCT adjustment circuits are used, then CCT adjustment is possible, but the circuits lack a memory function and cannot retain personalized lighting settings

Engineering Contradiction:
ImproveCCT adjustmentVSAvoidpersonalized settings retention
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The control circuit incorporates a memory function that stores pre-configured lighting scenarios and user preferences. When the system is powered on or when a scene is selected, the circuit automatically retrieves the stored settings and applies them, eliminating the need for users to manually reconfigure parameters each time and providing personalized lighting experiences.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system includes feedback mechanisms through user input interfaces (e.g., buttons, sensors) that allow users to select preferred lighting scenarios. The control module processes these inputs, adjusts the LED groups accordingly, and the memory function retains these selections for future use, creating a closed-loop system that adapts to user preferences.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3691413B1Switched-mode control circuit for correlated color temperature based on linear drive LED lighting
Publication Date: 2021.07.28 WUXI AOLIJIE TECH
  • EP3691413B1 patent drawingFigure 1
  • EP3691413B1 patent drawingFigure 2
  • EP3691413B1 patent drawingFigure 3

AI summary

A switched-mode control circuit for correlated color temperature (CCT) based on linear drive LED lighting, including a switched-mode CCT control module, a linear drive control module, and an LED lighting module which is connected with the switched-mode CCT control module and the linear drive module. The switched-mode CCT control module is used to control and adjust the CCT of the LED lighting module, so that the LED lighting module emits light with different CCTs, and it may or may not have a memory function. The linear drive control module is capable of controlling and adjusting illuminance of the LED lighting module. The control circuit has a simple design and enables the adjustment of both the CCT and the illuminance, promoting the user experience.