Dual-Amplifier Circuit for Wide-Range LED Current Measurement

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Solution Overview

Problem

Current lighting technologies face challenges in precisely controlling the electrical current of light-emitting diodes (LEDs) over a wide dynamic range to maintain accurate color temperature and illuminance, especially during dimming, which is essential for user well-being and productivity, but existing solutions are inefficient and costly due to the need for numerous converters.

Innovation Solution

A circuit arrangement that uses two amplifier circuits with different amplification factors to generate a weighted combination of the measured current, allowing for precise determination and control of the electrical current through LEDs, enabling accurate regulation of light output and color temperature across a wide dimming range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple converters are used to achieve precise current measurement over a wide dynamic range, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecurrent measurement precisionVSAvoidconverter quantity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the current measurement range into multiple segments, each handled by a dedicated amplifier circuit with optimized gain. The first amplifier circuit handles lower current ranges with higher gain, while the second amplifier circuit handles higher current ranges with lower gain. This segmentation allows each amplifier to be optimized for its specific range, achieving high measurement precision across the entire dynamic range without requiring multiple complete converter systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal current measurement system that can handle the entire dynamic range by having amplifier circuits that can be selectively activated based on the current magnitude. The system universally covers all current ranges from very low to very high by switching between or combining the output signals of the different amplifier circuits, eliminating the need for multiple separate converter systems.

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

2Manufacturing precision

If multiple converters are used to maintain accurate color temperature and illuminance control, then lighting quality is improved, but cost increases

Engineering Contradiction:
Improvecolor temperature control accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent segments the control function by dedicating specific amplifier circuits to control specific lighting parameters. The first amplifier circuit's output is used for controlling color temperature, while the second amplifier circuit's output is used for controlling illuminance. This segmentation allows independent optimization of each control function while reducing the total number of converters needed compared to previous multi-converter approaches.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters of the amplifier circuits to optimize performance for different lighting control functions. By adjusting the gain and bandwidth parameters of each amplifier circuit according to the specific requirements of color temperature and illuminance control, the system achieves high manufacturing precision for lighting quality while minimizing the number of components required.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3646674B1Circuit arrangement and method for determining a signal representing an actual current value
Publication Date: 2024.10.23 TRIDONIC GMBH & CO KG
  • EP3646674B1 patent drawingFigure 1
  • EP3646674B1 patent drawingFigure 2
  • EP3646674B1 patent drawingFigure 3

AI summary

The invention relates to a circuit arrangement for determining a signal representing a current actual value enabling the LED current in a large dynamic range, in particular with a continuous transition between the current measuring areas, to be accurately measured. The circuit arrangement comprises detection means (2) for detecting a measurement variable representing a current, a first current measurement path (4) with a first amplification circuit (6) for amplifying the detected measurement variable with a first amplification factor, a second current measuring path (5) with a second amplification circuit (7) for amplifying the detected measurement variable with a second amplification factor, combination means (21) for generating a combined signal as a weighted combination of the first amplified measurement variable with the second amplified measurement variable, and output means for outputting the combined signal as a basis for determining the current actual value.