Television Backlight Driving Device AC-DC LED Control
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Solution Overview
Problem
Existing television backlight driving methods require two transformations from AC to DC, resulting in low efficiency and high costs due to the need for multiple power components and complex circuit topologies.
Innovation Solution
A television backlight driving device comprising an AC-DC module and an LED driving module, where the AC-DC module transforms AC power to DC power, and the LED driving module adjusts the duty ratio or feeds back current to control the DC voltage, eliminating the need for a second DC-DC transformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant-current driving source is used to drive LED backlights through AC-DC and DC-DC transformations, then the LED current can be maintained constant, but the transformation efficiency is low and the system cost is high
Solution Approach 1:
The patent removes the DC-DC module from the traditional AC-DC-DC two-stage transformation system, extracting only the necessary AC-DC transformation function. This simplification eliminates the energy loss associated with the second DC-DC conversion stage while maintaining constant-current output through direct AC-DC controlled rectification
Solution Approach 2:
The patent combines the AC-DC rectification and constant-current control functions into a single integrated system. By merging these functions and eliminating the separate DC-DC stage, the system achieves both high efficiency (reducing energy loss) and reliable constant-current output for LED backlighting
2Reliability
If a DC-DC module is added to ensure constant-current output, then the LED current stability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts and removes the DC-DC module from the system, keeping only the essential AC-DC transformation and control functions. This reduction in components directly decreases device complexity and system cost while maintaining the core functionality of constant-current LED driving
Solution Approach 2:
The patent designs the AC-DC module to perform multiple functions: AC power rectification, voltage regulation, and constant-current control. This multi-functionality eliminates the need for a separate DC-DC module, thereby reducing device complexity and component count while ensuring stable LED current output
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
This solution improves efficiency and reduces system costs by eliminating the second DC-DC transformation, stabilizing current output, and simplifying the circuit structure while maintaining high reliability.
Implementation Method 1
the AC-DC module transforms an input supplied AC power into a DC power
Implementation Method 2
the second feedback circuit regulates the transformed voltage before filtering and outputting a DC voltage
Implementation Method 3
a constant-current output for LED current is controlled by adjusting the duty ratio
Implementation Method 4
the second feedback circuit generates a corresponding control signal to the main control circuit according to the detection current feedback from the LED driving module, the main control circuit then adjusts the DC voltage according to the control signal
Data Source
AI summary
The present invention discloses a television backlight driving device and the driving method thereof, the said television backlight driving device comprises: an AC-DC module and an LED driving module; when a power is on, the said AC-DC module transforms an input supplied AC power into a DC power before supplying to the backlight LED lightstrip; comparing to the existing backlight driving methods, there is no second process of DC-DC needed, saving a system cost of the power, and improving an efficiency of the system; when the LED driving module determines the detection current larger than the preset current but smaller than the first threshold, a constant-current output for LED current is controlled by adjusting the duty ratio; when the detection current is larger than the first threshold or smaller than the preset current, the LED driving module feeds back the detection current to the AC-DC module; the AC-DC module then controls the DC voltage according to the detection current; different methods for adjustment may save a power consumption, as well as achieving an effect of stabling the current output; it owns a simple circuit structure, and a high system reliability.