LED Driver Circuit with Automatic Ballast Detection

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Solution Overview

Problem

Conventional fluorescent tube circuits are not compatible with LED lamp tubes, requiring removal of starter and electronic ballast for installation, leading to increased installation complexity and production costs due to the inability of traditional ballasts to adjust voltage for LED lamps, resulting in potential damage and inefficient assembly processes.

Innovation Solution

A circuit structure with a substrate and light-source control-loop device, including constant current circuits, high voltage protection, bridge rectifier circuits, and limited current protection, which can detect input waveforms and adjust voltage to safely power LED lamps directly from mains or electronic ballasts without additional identification or implementation, ensuring compatibility with various lamp holders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional fluorescent tube circuit is used with LED lamp tube, then LED lamp tube can be installed in conventional luminaire, but starter and electronic ballast must be removed which increases installation complexity and production cost

Engineering Contradiction:
Improvecompatibility with conventional lamp holdersVSAvoidinstallation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LED lamp tube integrates multiple functions including constant current driving circuit, startup circuit, and protection circuits within a single module that can directly replace conventional fluorescent tubes in existing lamp holders without removing ballasts or starters, achieving universal compatibility across different lamp holder types

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

Solution Approach 2:

The patent combines the ballast, starter, and LED driving circuit into a single integrated control module that handles both conventional ballast-powered and direct mains-powered operations, eliminating the need for separate components and reducing installation complexity

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If conventional ballast is used with LED lamp tube, then LED lamp tube can operate in conventional circuit, but voltage cannot be adjusted which may damage LED lamp tube

Engineering Contradiction:
Improvecompatibility with conventional circuitsVSAvoidprotection against voltage damage
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The circuit employs dynamic voltage detection and switching mechanisms that automatically adjust operating mode based on detected input conditions, enabling the LED lamp tube to safely operate whether powered by conventional ballasts or direct mains voltage by activating appropriate protection circuits

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The circuit performs preliminary detection of input voltage characteristics before powering the LED lamp tube, and pre-activates appropriate protection circuits based on detected conditions, preventing voltage damage before it can occur

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If starter and electronic ballast are removed for LED installation, then LED lamp tube can be installed, but assembly process becomes manual which increases production cost

Engineering Contradiction:
Improvecompatibility with LED lamp holdersVSAvoidassembly automation capability
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The LED lamp tube is designed as a segmented modular structure where the control module can be pre-assembled and tested separately, then automatically installed into lamp holders using standardized interfaces, enabling partial automation of the assembly process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circuit uses parameter detection (voltage, current characteristics) to automatically configure operating mode, eliminating the need for manual identification or configuration during assembly, thereby enabling automated production lines

Inventive Principle:
Principle #35Parameter changes

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 proposed circuit structure allows for seamless integration with both mains and electronic ballasts, preventing damage to LED lamps by dynamically controlling current and voltage, facilitating easy installation and reducing production costs through automatic compatibility with any lamp holder type.

Implementation Method 1

The bridge rectifier circuits (26) can convert an AC (Alternating Current) current outputted from the ballast into a DC (Direct Current) current provided to the light source modules (22)

Methodology Applied
Scientific EffectRectification:

Data Source

PatentEP3297405B1Compatible inductor-type circuit structure with direct input from commercial power
Publication Date: 2020.03.04 HOU CHIH YUNG
  • EP3297405B1 patent drawingFigure 1
  • EP3297405B1 patent drawingFigure 2
  • EP3297405B1 patent drawingFigure 3

AI summary

A compatible inductor-type circuit structure with direct input from commercial power includes a substrate and a light-source control-loop device. The light-source control-loop device is disposed on the substrate and includes a constant current circuit, plural light source modules, a switch, a commercial power simulation circuit, a high voltage protection circuit, plural bridge rectifier circuits and a limited current protection circuit. The constant current circuit, the light source modules, the switch, the commercial power simulation circuit, the high voltage protection circuit, the bridge rectifier circuits and the limited current protection circuit are connected together electrically. By the abovementioned structures, a luminaire can be installed directly on any lamp holder, without considering whether to remove the ballast. The circuit structure can be compatible with a dedicated LED lamp holder or a lamp holder activated by a ballast, thereby facilitating the usage.