Vehicle LED Module Current Control for Bin-Class Brightness Matching

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Solution Overview

Problem

Current LED lighting systems for vehicles require separate boards and drivers for each lighting function, leading to a lack of interchangeability and inefficiencies due to varying LED brightness bins, which complicates standardization and dimming control.

Innovation Solution

An LED light module with an analog controller that branches off a partial current, using a signal proportional to the total current and bin classification, allowing for intelligent bin classification and efficient power management, including the use of a resistor in the LED branch to regulate current and minimize power loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a parallel resistor is used to compensate for brightness deviations in LEDs with different bin classes, then brightness uniformity is improved, but energy efficiency deteriorates due to unnecessary energy conversion into heat

Engineering Contradiction:
Improvebrightness uniformityVSAvoidenergy efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent implements a feedback mechanism where the control unit receives information about the LED's bin class (through direct indication or indirect measurement of forward voltage) and adjusts the drive current accordingly. This closed-loop control compensates for brightness deviations without dissipating energy through parallel resistors, as the current is optimized for each LED's specific characteristics.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the electrical parameter (drive current) based on the LED's bin class characteristics. By adjusting the current magnitude according to the specific LED's forward voltage and brightness properties, the system achieves uniform brightness across different bin classes without requiring energy-dissipating parallel resistors.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If separate LED circuit boards with drivers are developed for each lighting function, then lighting function control is improved, but device complexity and interchangeability deteriorate

Engineering Contradiction:
Improvelighting function controlVSAvoidcircuit board complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal LED module design with standardized electrical and mechanical interfaces that can be used across different lighting functions. The single integrated circuit board incorporates multiple LED branches with different bin class combinations, allowing the same module type to serve various lighting purposes (headlights, fog lights, turn signals) while maintaining interchangeability through standardized connectors and mounting.

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

3Device complexity

If LEDs with different brightness bins are operated with the same current, then circuit simplicity is improved, but brightness uniformity deteriorates

Engineering Contradiction:
Improvecircuit simplicityVSAvoidbrightness uniformity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The patent introduces dynamic current adjustment based on the LED's bin class characteristics. Rather than using a fixed current for all LEDs, the system dynamically adapts the drive current to match each LED's specific forward voltage and brightness properties, achieving uniform brightness while keeping the circuit design relatively simple through automated control.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If the upstream control device regulates to a standardized current, then interchangeability is improved, but brightness consistency across different bin classes deteriorates

Engineering Contradiction:
ImproveinterchangeabilityVSAvoidbrightness consistency
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent implements a two-stage control approach: the upstream control device provides standardized current regulation for interchangeability, while the module's integrated control unit receives feedback about the specific LED's bin class and adjusts the current accordingly to maintain brightness consistency. This layered feedback system preserves both interchangeability and brightness uniformity.

Inventive Principle:
Principle #23Feedback

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

Enables easy connection to a regulated power source, ensures standardized LED operation across different bin classes, and reduces power loss by only dissipating necessary heat, facilitating interchangeable and dimmable LED solutions.

Implementation Method 1

The invention relates to an LED light module for a lighting device for vehicles, which has at least one LED branch with at least one LED

Methodology Applied
Scientific EffectLight Emitting Diode effect: Light Emitting Diode

Implementation Method 2

a parallel resistor can be provided in parallel with the series connection of two or more LEDs, the value of which is selected depending on the brightness class

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3305026B1LED light module for a lighting device for vehicles
Publication Date: 2024.01.10 ZKW GRP GMBH
  • EP3305026B1 patent drawingFigure 1
  • EP3305026B1 patent drawingFigure 2

AI summary

The invention relates to a LED light module (M) for a lighting device for vehicles, which LED light module has at least one LED branch having at least one LED (LED1....LEDn), wherein at least one component (RR) for identifying a bin class is arranged on the module, and the module is designed for operation with a total current (IG), and an analog controller (3, T2) for branching off a partial current (IB) is connected in parallel with the LED branch (Z) carrying a partial current (ID) of the total current (IG), wherein a signal (US) corresponding to the total current (IG) is fed to the analog controller as a reference variable and a signal (UR) proportional to one of the partial currents (IB, ID) and provided by the component (RR) for identifying the bin class is fed to the analog controller as a controlled variable.