LED Light Bar Foldback Circuit for Abnormal Current Protection

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Solution Overview

Problem

Large-size LED TVs lack an effective overcurrent protection circuit for LED light bars, leading to potential damage and high maintenance costs under abnormal conditions.

Innovation Solution

An LED light bar network current foldback circuit that includes a constant current source module, detection unit, and a comparison module to monitor and control the current, stopping the drive circuit when abnormal conditions are detected, thereby protecting the LED light bars.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If no overcurrent protection circuit is used, then the circuit structure is simple and maintenance cost is low, but the LED light bar may be damaged under abnormal conditions

Engineering Contradiction:
ImproveLED light bar protectionVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary protection by detecting abnormal currents before they cause damage to the LED light bar. The detection unit continuously monitors the current, and when an abnormal condition is detected (current exceeding threshold), the control unit immediately stops the drive circuit, preventing damage before it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediate components (detection unit, control unit) that mediate between the power source and LED light bar. These intermediaries monitor the electrical parameters and intervene when abnormalities are detected, providing protection without requiring complex circuit restructuring.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a protection circuit is added, then the LED light bar is protected from damage, but the maintenance cost increases

Engineering Contradiction:
ImproveLED light bar protectionVSAvoidmaintenance cost
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The protection circuit operates autonomously without requiring external intervention or complex maintenance. The detection unit automatically monitors current levels, and the control unit automatically responds to abnormal conditions, making the system self-protecting and reducing maintenance requirements.

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If constant current drive is used, then the LED light bar operates efficiently, but abnormal current increases can damage the LED light bar

Engineering Contradiction:
Improvepower supply efficiencyVSAvoidabnormal current damage
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback control by continuously detecting the current through the detection unit and using this information to control the drive circuit through the control unit. When abnormal current is detected, the feedback mechanism triggers the drive circuit to stop, preventing damage while maintaining efficient operation during normal conditions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3537851B1LED light bar network current foldback circuit, driving power supply and TV set
Publication Date: 2025.07.09 SHENZHEN SKYWORTH RGB ELECTRONICS CO LTD
  • EP3537851B1 patent drawingFigure 1
  • EP3537851B1 patent drawingFigure 2~3
  • EP3537851B1 patent drawingFigure 4

AI summary

LED light bar network current foldback circuit comprises: voltage reference module, voltage division and sampling module, comparison module. Power supply voltage passes through voltage reference module, generates voltage reference to voltage division and sampling module and comparison module; voltage division and sampling module performs voltage division on voltage reference, and outputs reference voltage to comparison module, which further receives detection voltage from converting detection current of LED light bars, before comparing with reference voltage; if detection voltage is greater than reference voltage, comparison module outputs driving stop command to control LED light bars to stop working. LED light bar network current foldback circuit controls driving circuit to stop working after current of LED light bars, or constant output current, increases abnormally, protecting LED light bars effectively, avoiding high screen body maintenance cost from LED light bars damaging.