Backlight Module LED String Voltage Distribution
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Solution Overview
Problem
Conventional backlight modules with LED light strings experience uneven power loss due to unclassified forward voltages, leading to inefficiencies in constant current control circuits, and using separate DC/DC converters for each string is costly and impractical.
Innovation Solution
The backlight module averages the forward voltages of LEDs across light strings by arranging them in series with a minimum and maximum voltage range, ensuring each string has a progressive increase in voltage from the minimum to the maximum, with a DC/DC converter connected to the first ends and a constant current control circuit to the second ends, reducing power loss differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light emitting diodes are arranged in light strings without classification by forward voltage, then the manufacturing cost is reduced and the production process is simplified, but the power loss in the constant current control circuit increases due to voltage differences among LEDs
Solution Approach 1:
The patent changes the parameter distribution strategy by deliberately designing light strings with progressive voltage sequences (minimum to maximum forward voltages) rather than using uniform voltage classification. This parameter arrangement reduces the voltage difference across each constant current control circuit while avoiding the need for expensive classification processes.
Solution Approach 2:
The patent applies local quality by creating different voltage distribution patterns in different light strings. Each light string is designed with a specific sequence of forward voltages from minimum to maximum, allowing each string to have optimized power characteristics tailored to its position and requirements in the backlight module.
2Loss of energy
If separate DC/DC converters are used for each light string to provide different driving voltages, then the power loss is reduced, but the device cost and complexity increase significantly
Solution Approach 1:
The patent makes a single DC/DC converter universal by designing it to handle multiple light strings with different voltage requirements. The converter is configured to sequentially or simultaneously drive multiple light strings with progressively increasing voltages, eliminating the need for separate converters for each string while maintaining optimal power efficiency.
Solution Approach 2:
The patent merges multiple DC/DC converter functions into a single converter unit. By combining the voltage conversion and regulation functions for all light strings into one converter with progressive voltage output capability, the system achieves the power efficiency of individual converters without the cost and complexity of multiple separate units.
3Ease of manufacture
If light emitting diodes with different forward voltages are used in the same light string, then the manufacturing process is simplified, but the constant current control circuit experiences higher power loss due to voltage feedback requirements
Solution Approach 1:
The patent transforms the parameter distribution approach by arranging LEDs in light strings with progressive voltage sequences rather than uniform voltages. This deliberate parameter arrangement reduces the total voltage difference that the constant current control circuit must compensate for, thereby reducing power loss while maintaining manufacturing simplicity.
Data Source
AI summary
The present invention provides a backlight module, and the backlight module has an LED module which has a plurality of light emitting diodes averagely divided into a plurality of light strings. Forward voltages of the light emitting diodes are between a minimum forward-voltage value and a maximum forward-voltage value, and each of the light strings at least has one first light emitting diode and one second light emitting diode. The first light emitting diode has the minimum forward-voltage value and the second light emitting diode has the maximum forward-voltage value. The backlight module is contributive to lower power loss on a constant current control circuit.