LED Signal Light Circuit Topology for Safe Cut-Off Detection

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Solution Overview

Problem

Existing railway LED signal lights face issues with unsafe and uncontrollable cut-off, high possibility of mistaken lighting due to failures or cable interference, reduced reliability due to power resistors as dummy loads, and lack of communication between indoor and outdoor units leading to incorrect detection of turn-off status.

Innovation Solution

A signal light system with a lighting circuit and light-emitting mechanism, incorporating a control unit with CPUs, sensors, and safety modules to ensure safe cut-off, eliminate dummy loads, and enable communication between indoor and outdoor units for accurate status detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If power resistors are connected in parallel to the light end as dummy loads, then the power supply current can meet the minimum triggering value of filament relays, but the power resistors generate heat that reduces reliability and may cause failure

Engineering Contradiction:
Improvepower supply currentVSAvoidequipment reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent extracts and eliminates the power resistor component from the circuit by transitioning to LED light sources that inherently provide sufficient current without requiring external dummy loads, thereby removing the heat generation and reliability issues associated with power resistors while maintaining adequate current for relay triggering

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fundamental parameter of light source technology from incandescent bulbs to LED, which fundamentally alters the electrical characteristics and current output, eliminating the need for power resistors while providing sufficient current for control circuits

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional relay circuit control technology is used, then the system structure is simple and easy to manufacture, but the system cannot achieve intelligent, informationalized, and maintenance-free operation

Engineering Contradiction:
Improvesystem manufacturing simplicityVSAvoidintelligent control capability
Core Design Contradiction:
Ease of manufactureVSExtent of automation

Solution Approach 1:

The patent replaces the mechanical relay-based control system with an electronic control system utilizing microprocessors, sensors, and digital communication protocols, thereby eliminating mechanical components while achieving intelligent, automated, and maintenance-free operation

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

Solution Approach 2:

The patent introduces communication modules and control units as intermediaries between the power supply and lighting components, enabling intelligent monitoring, diagnostics, and automated control while maintaining system functionality

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If indoor detection units detect LED light end current index alone, then the detection circuit is simple, but the detection accuracy is insufficient due to partial LED breakdown, low lighting current, and large distributed capacitance

Engineering Contradiction:
Improvedetection circuit complexityVSAvoidturn-off status detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where outdoor detection units monitor LED light end status and communicate with indoor control units, enabling accurate detection of turn-off status by comparing actual current readings with expected values and providing corrective feedback to eliminate detection errors

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces communication modules as intermediaries between indoor and outdoor detection units, enabling the transmission of detection data and control commands, thereby allowing comprehensive status monitoring that overcomes the limitations of simple current detection

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4253187B1Signal light, system and control method
Publication Date: 2026.01.21 CRSC RESEARCH & DESIGN INSTITUTE GROUP CO LTD
  • EP4253187B1 patent drawingFigure 1
  • EP4253187B1 patent drawingFigure 2
  • EP4253187B1 patent drawingFigure 3

AI summary

The present invention discloses a signal light, including a lighting circuit and a light-emitting mechanism. The light-emitting mechanism includes a plurality of groups of light-emitting diode (LED) light panels connected in parallel. The lighting circuit includes an alternating-current side main circuit, a direct-current side main circuit, and a control unit. In addition, the present invention provides a signal light system, including the signal light, a lighting control circuit, and a power supply. The present invention may implement, by improving a circuit topology, safety cut-off of a light-end main circuit to turn off the light. The present invention detects, by improvement, a voltage and a current of each string of light beads on the LED light panels, so that an operation status of each string of light beads can be reflected. When the light beads are damaged by 30% and 50%, communication is performed by a main power supply circuit through a carrier wave (without adding a new connecting wire), and status information of the LED light panels is sent to the lighting control circuit.