LED Backlight Unit Dynamic Threshold Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 3D LED backlight displays, the high peak currents used to minimize crosstalk lead to overheating in the LED driving circuit, which existing Over-Temperature Protection (OTP) systems fail to prevent effectively, resulting in potential fires due to the high threshold temperature settings that do not align with the limit temperatures of circuit elements.
Innovation Solution
A backlight unit and method that includes a control unit to measure the internal temperature of the LED driving circuit, interrupting its operation when the temperature exceeds a preset threshold, and a threshold temperature adjustment unit that changes the threshold based on the limit temperatures of circuit elements, using a resistor unit and comparator to manage the temperature and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Over-Temperature Protection (OTP) with high threshold temperature Tjmax is used to prevent integrated circuit overheating, then the integrated circuit is protected, but the LED driving circuit elements (inductor, transistor) overheat and cause fuming or fire before OTP activates
Solution Approach 1:
The patent segments the temperature protection function into two independent protection mechanisms: one for the integrated circuit (using OTP with Tjmax) and another for the LED driving circuit elements (using a separate temperature sensor with threshold Ts). This allows each component to be protected at its appropriate temperature threshold, preventing the inductor and transistor from overheating while the IC is protected at its higher threshold.
Solution Approach 2:
The patent introduces a separate temperature sensor as an intermediary device that specifically monitors the temperature of the LED driving circuit elements (inductor and transistor). This intermediary sensor detects temperature changes in the driving circuit before they reach dangerous levels, enabling early protection action independent of the IC's internal OTP mechanism.
2Illumination intensity
If high peak current is used to compensate for luminance decrease in 3D mode, then luminance is maintained, but the LED driving circuit overheats due to increased power dissipation
Solution Approach 1:
The patent implements a feedback mechanism where a temperature sensor continuously monitors the temperature of the LED driving circuit elements and feeds this information to the control unit. When the temperature approaches the threshold Ts, the control unit adjusts the driving current or duty cycle to reduce power dissipation, thereby maintaining luminance within acceptable ranges while preventing overheating during high-current 3D operation.
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
Prevents overheating of the LED driving circuit elements by dynamically adjusting the threshold temperature, thereby reducing the risk of damage and accidents such as fires, ensuring the normal operation of the LED driving circuit.
Implementation Method 1
a control unit which measures a temperature of the LED driving unit
Implementation Method 2
The control unit may include a resistor unit which has a resistance value that changes according to the temperature of the LED driving unit
Data Source
AI summary
A backlight unit is provided, which includes a light-emitting diode LED, an LED driving unit which drives the LED, a control unit which measures a temperature of the LED driving unit, and, if the temperature exceeds a preset threshold temperature, interrupts an operation of the LED driving unit, and a threshold temperature adjustment unit which changes the preset threshold temperature based on a limit temperature of a circuit element included in the LED driving unit.