Dual LED Driver Control Loops for Multi-Step Color Temperature

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Solution Overview

Problem

Existing color-temperature adjustable light emitting arrangements face challenges in achieving precise, efficient, and cost-effective control over multiple LED driver circuits, particularly when adjusting beyond 3-steps, due to increased complexity, cost, and power inefficiency in existing control mechanisms.

Innovation Solution

A driver arrangement utilizing a single manual switch device to control two driver circuits through a control loop, allowing simultaneous adjustment of power output by connecting or disconnecting setting components such as resistors to each control loop, facilitating intuitive and resource-efficient color-temperature adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a DIP switch with multiple LED arrangements is used for color-temperature adjustment, then the number of color-temperature steps can be increased, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvecolor-temperature adjustment stepsVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the control of multiple LED arrangements into a single integrated driver circuit with a unified control interface. Instead of using separate DIP switches and control circuits for each LED string, the invention combines all control functions into one driver that can selectively activate different LED arrangements based on a single control signal, thereby reducing overall system complexity while maintaining multi-step color-temperature adjustment capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single driver circuit is designed to perform multiple functions: it can drive different types of LED arrangements (high color temperature, low color temperature, mixed color temperature), provide multiple output current levels, and interface with a simple control mechanism. This universal driver replaces what would traditionally require multiple specialized drivers and control circuits, achieving versatility without proportionally increasing complexity.

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

2Measurement precision

If additional resistors are connected in series with LED arrangements to adjust current, then color-temperature can be tuned, but power efficiency decreases due to power loss

Engineering Contradiction:
Improvecolor-temperature precisionVSAvoidpower loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent replaces the passive mechanical approach of using resistors to limit and adjust current with an active electronic control approach. The driver circuit uses electronic switching and current regulation techniques to control the current flowing through LED arrangements, eliminating the need for power-dissipating series resistors while maintaining precise current control and color-temperature adjustment capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The driver circuit dynamically changes operating parameters (current magnitude, switching duty cycle) to control LED output and color-temperature. Instead of using fixed resistive values that dissipate power, the system adjusts electrical parameters through electronic control, achieving the same current regulation effect without the associated power losses.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If small forward voltage differences in LEDs are present, then manufacturing variation occurs, but this leads to significant current difference and big color-temperature variation

Engineering Contradiction:
ImproveLED manufacturing toleranceVSAvoidcolor-temperature accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The driver circuit incorporates feedback mechanisms that monitor the actual current flowing through LED arrangements and adjust the control signal accordingly. This feedback loop compensates for forward voltage variations between individual LEDs or LED strings, ensuring that each arrangement receives the intended current level despite manufacturing tolerances, thereby maintaining accurate and consistent color-temperature control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The driver circuit performs preliminary current regulation and matching before the LEDs are activated. By pre-adjusting the current distribution to different LED arrangements based on their characteristics, the system compensates for expected variations due to manufacturing tolerances, ensuring uniform performance and accurate color-temperature output without requiring post-assembly calibration.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If a microcontroller unit with digital control and mapping table is used, then precise control over each driver output is achieved, but the cost and resource requirements increase

Engineering Contradiction:
Improveoutput control precisionVSAvoidcontrol system resources
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the complex digital control functions (microcontroller, ADC, mapping tables, computational algorithms) from the system and replaces them with dedicated analog control circuitry implemented directly in the driver. This extraction of computational complexity and its replacement with purpose-built electronic control logic achieves the same precision in controlling driver outputs without requiring expensive digital components, thereby reducing overall system cost and resource requirements while maintaining control accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4449819B1Driver arrangement for a light emitting arrangement
Publication Date: 2026.02.11 SIGNIFY HOLDING BV
  • EP4449819B1 patent drawingFigure 1~2
  • EP4449819B1 patent drawingFigure 3~4
  • EP4449819B1 patent drawingFigure 5~6

AI summary

:A driver arrangement for a light emitting arrangement. The driver arrangement comprises two driver circuits. The power output by each driver circuit is controlled by a respective control loop. A control system comprises a single manual switch device that is switchable between multiple switch positions. Switching between different positions simultaneously changes which, if any, of one or more setting components form part of each control loop. Changing which setting component(s) forms part of a control loop changes or controls the power output by a respective driver circuit.