Linear LED Lamp Electric Shock Prevention via Current Control

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Solution Overview

Problem

Linear LED tube lamps face safety issues due to electric shock hazards and internal arcing when used with electronic ballasts, particularly during maintenance or relamping, as conventional shock prevention switches are ineffective against high-voltage, high-frequency arcing, leading to potential fires and injuries.

Innovation Solution

A linear LED-based solid-state lamp with an electric current flow control module that detects electric shocks and shuts off the current flow using a control loop compensation device, rectifier, and switch control mechanism, ensuring safe operation with both AC mains and electronic ballasts by preventing through-lamp electric shock current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional shock prevention switches are used in linear LED lamps, then electric shock protection is provided during normal operation, but they fail to prevent internal arcing and fires when used with electronic ballasts due to high-voltage, high-frequency conditions

Engineering Contradiction:

Improveelectric shock protectionVSAvoidinternal arcing and fire risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the shock prevention function from conventional mechanical switches and implements it through a semiconductor-based detection and control system. The system separates the detection function (monitoring current characteristics) from the protection function (controlling the triac to interrupt current flow), eliminating the limitations of mechanical switches in high-frequency ballast environments.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical shock prevention switches with an electronic control system using a microprocessor, current sensing circuitry, and triac-based switching. This substitution enables the system to respond to high-frequency conditions from electronic ballasts that mechanical switches cannot handle, while maintaining shock protection functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of energy

If AC mains-operable LED lamps are designed without ballasts, then energy efficiency is improved and maintenance is simplified, but electric shock hazards increase during installation and maintenance due to exposed conductors

Engineering Contradiction:

Improveballast power consumptionVSAvoidelectric shock hazard during maintenance

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary detection of shock conditions before they become hazardous. The system continuously monitors current characteristics and detects potential shock conditions in advance, allowing it to preemptively interrupt current flow through the triac before a person can be exposed to dangerous voltage levels during maintenance activities.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs feedback through current sensing circuitry that continuously monitors the electrical conditions in the lamp. When abnormal conditions indicating potential electric shock are detected, the feedback loop triggers the microprocessor to activate the triac, which interrupts current flow and eliminates the shock hazard.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If dual-ended linear LED lamps are used with electronic ballasts, then compatibility is improved, but the risk of internal fire increases due to high-voltage arcing at the lamp ends

Engineering Contradiction:

Improveballast compatibilityVSAvoidinternal arcing and fire

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a triac as an intermediary device between the ballast and the LED lamp elements. The triac acts as a controlled switch that mediates the high-voltage connection, allowing the lamp to remain compatible with electronic ballasts while the control system monitors and manages the connection to prevent dangerous arcing conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9986619B2Linear solid-state lighting with electric shock prevention

Publication Date: 2018.05.29 ALEDDRA INC

AI summary

A linear light-emitting diode (LED)-based solid-state lamp comprises an LED driving circuit, LED arrays, at least one rectifier, and an electric current flow control module. The LED driving circuit comprises a control loop compensation device with a control loop correction signal to precisely control an electric current to flow into the LED arrays. The electric current flow control module uses the control loop correction signal in a way that it detects and determines if the linear LED-based solid-state lamp is operated in a normal mode or in an electric shock hazard mode. When an electric shock hazard is identified, the electric current flow control module shuts off a return current flow from the LED arrays to reach the at least one rectifier, thus eliminating an overall through-lamp electric shock current. The scheme can effectively prevent a through-lamp electric shock from occurring during relamping or maintenance.