LED Driving Apparatus Time-Dividing Feedback Control
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Solution Overview
Problem
Conventional LED driving apparatuses for large-sized liquid crystal display devices require a large number of electronic elements and complex wiring, leading to increased costs and circuit size due to the need for separate drivers and feedback control units for each divided backlight region.
Innovation Solution
A LED driving apparatus with a time-dividing feedback control unit that compensates and outputs constant voltages to multiple LED lamps connected in series, reducing the number of necessary electronic elements and simplifying the circuit configuration by integrating feedback control for all LED lamps into a single unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate drivers and feedback control units are provided for each divided backlight region, then independent luminance control of each region is achieved, but the number of electronic elements increases and circuit complexity increases
Solution Approach 1:
The patent merges multiple separate feedback control units into a single integrated feedback control unit that can sequentially control multiple LED strings. This single unit receives feedback signals from all LED strings, processes them centrally, and generates appropriate drive signals, thereby reducing the number of electronic elements while maintaining independent luminance control capability through time-division multiplexing
Solution Approach 2:
The feedback control unit is designed with multi-functionality to handle control of multiple LED strings sequentially. It can switch between different LED strings, process feedback from each string, and adjust drive signals independently for each string, making a single unit perform the functions that would otherwise require multiple separate units
2Adaptability or versatility
If separate drivers and feedback control units are provided for each divided backlight region, then independent luminance control of each region is achieved, but the cost increases
Solution Approach 1:
The patent combines multiple separate feedback control units into one integrated unit, directly reducing the bill of materials and assembly costs. By sharing common components such as microcontrollers, ADCs, and communication interfaces among multiple LED strings, the manufacturing cost is reduced while preserving the capability for independent luminance control of each LED string
3Adaptability or versatility
If multiple separate feedback control units are used, then each LED string can be controlled independently, but the PCB wiring becomes complicated
Solution Approach 1:
The patent consolidates feedback control functions into a single unit with centralized signal processing. Multiple LED strings share common feedback signal lines, control signal lines, and power supply lines, dramatically simplifying PCB routing. The single control unit sequentially samples feedback from different strings and adjusts drive signals, eliminating the need for separate dedicated wiring for each control unit
Data Source
AI summary
There are provided a LED driving apparatus and a liquid crystal display apparatus using the same, in which a circuit configuration of the LED driving apparatus can be simplified and the cost of the LED driving apparatus can be saved in employing a LED as a light source of the liquid crystal display apparatus. The LED driving apparatus comprises a plurality of n LED lamps, constant voltage providing units that provide constant voltages to the plurality of LED lamps, respectively, a Pulse Width Modulation (PWM) control signal providing unit that provides PWM signals to the constant voltage providing units, respectively, and a feedback control unit that receives voltages feedbacked through the plurality of LED lamps, compensating for the voltages as constant voltages suitable for constant current driving of each of the LED lamps, and sequentially outputs the constant voltages to the constant voltage providing units, respectively, based on time-dividing.