Backlight Voltage Control for LED Lamp String Thermal Loss
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Solution Overview
Problem
The existing backlight drive systems for liquid crystal displays face inefficiencies due to multiple voltage conversions, leading to high power consumption, thermal loss, and reduced reliability, particularly when using AC to DC converters with many LED lamp strings, which results in unstable voltage distribution and increased heat generation.
Innovation Solution
A backlight drive voltage control device that includes a detecting unit and a controller connected to an AC to DC converter, which adjusts voltage output based on feedback signals from lamp strings, selectively disabling feedback signals for strings with excessive voltage adjustments to ensure stable operation at rated current, thereby reducing thermal loss and improving system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output voltage of the AC to DC converter is enhanced to 14.4V to ensure all LED lamp strings work at rated current, then the reliability of lamp string operation is improved, but the thermal loss increases significantly to 48W
Solution Approach 1:
The patent dynamically changes the output voltage parameter of the AC to DC converter based on the detected voltage characteristics of LED lamp strings. Instead of using a fixed high voltage (14.4V) for all lamp strings, the system adjusts the voltage to match each lamp string's actual requirements, thereby reducing thermal loss while maintaining reliable operation.
Solution Approach 2:
The patent implements a feedback mechanism where the voltage of each LED lamp string is detected and fed back to the AC to DC converter. The converter then adjusts its output voltage based on this feedback information, ensuring that each lamp string operates at its optimal voltage without excessive thermal loss.
2Reliability
If multiple AC to DC converters are used to improve voltage distribution stability, then the reliability is improved, but the device complexity and occupied space increase greatly
Solution Approach 1:
The patent makes a single AC to DC converter serve multiple LED lamp strings by implementing individual voltage detection and feedback control for each lamp string. This multi-functional approach eliminates the need for multiple separate converters, reducing device complexity and occupied space while maintaining voltage distribution stability.
Solution Approach 2:
The patent combines the function of multiple AC to DC converters into a single converter by implementing individual feedback control channels for each LED lamp string. This merging approach reduces the number of hardware components while maintaining the ability to independently control voltage for each lamp string.
3Ease of manufacture
If the forward voltage of LED lamp strings is allowed to float within a certain range due to process influence, then the manufacturing cost is reduced, but the voltage difference between lamp strings increases greatly
Solution Approach 1:
The patent uses feedback control to detect the actual voltage of each LED lamp string and adjusts the AC to DC converter's output accordingly. This compensates for the voltage variations caused by process influences, maintaining voltage uniformity across all lamp strings without increasing manufacturing costs.
Solution Approach 2:
The patent dynamically changes the output voltage parameter of the AC to DC converter based on the detected voltage characteristics of each LED lamp string. This allows the system to accommodate the natural voltage floatation caused by manufacturing variations while maintaining overall voltage uniformity.
Data Source
AI summary
A backlight drive voltage control device, comprising: a detecting unit connected to a controller, which detects the current states of the lamp strings of the divisions of the backlight sources of a liquid crystal screen, sends feedback signals to the controller; the controller which sends a voltage adjustment control signal to an AC to DC converter according to the feedback signals, and acquires the voltage adjustment amount of each lamp string according to the voltage adjustment control signal, selects lamp strings which voltage adjustment amounts are larger than the threshold, and sends the closing feedback control signal to the detecting unit; and the AC to DC converter which outputs corresponding voltages to the lamp strings according to the voltage adjustment control signal.