Universal LCD Backlight Signal Generator for CCFL and LED Compatibility
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Solution Overview
Problem
Current LCD controllers are not compatible with both cold cathode fluorescent lamps (CCFLs) and light emitting diodes (LEDs), requiring separate controllers for each type of backlight unit, which limits flexibility and convenience.
Innovation Solution
A backlight driving signal generator that outputs two pulse signals, adjustable for either CCFLs or LEDs, using a combination of pulse width modulation units and a voltage supply unit with a primary and secondary winding to control the backlight unit, allowing for compatibility with both types of backlight sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate controllers are used for CCFLs and LEDs, then each controller can be optimized for its specific backlight type, but the overall system complexity increases and flexibility decreases
Solution Approach 1:
The patent implements a universal backlight driving signal generator that can control both CCFL and LED backlight units using the same controller. The generator includes switching circuitry that can generate different driving signals (AC for CCFL, DC for LED) based on the detected backlight type, thereby eliminating the need for separate controllers while maintaining optimized control for each backlight type.
2Adaptability or versatility
If a unified controller is used for both CCFLs and LEDs, then flexibility and convenience are improved, but the controller design becomes more complex
Solution Approach 1:
The patent employs dynamic switching mechanisms within the backlight driving signal generator that can adapt its output based on the detected backlight type. The generator dynamically switches between AC driving mode for CCFLs and DC driving mode for LEDs, allowing a single controller to serve multiple functions without requiring complex dedicated circuits for each backlight type.
Solution Approach 2:
The patent changes key driving parameters (current direction, voltage level, signal frequency) based on the detected backlight type. By detecting whether the connected backlight is CCFL or LED, the controller adjusts its output parameters accordingly - generating alternating current signals for CCFLs and direct current signals for LEDs - thereby achieving universal compatibility through parameter adaptation rather than structural complexity.
3Illumination intensity
If AC power is used to drive CCFLs, then luminance uniformity is improved, but the driving circuit complexity increases compared to DC driving
Solution Approach 1:
The patent merges the AC driving circuit functionality into the existing backlight driving signal generator by adding switching circuitry that can generate alternating current signals. This integration allows the same controller to provide both AC driving for CCFLs (achieving luminance uniformity) and DC driving for LEDs, without requiring separate dedicated AC driving circuits.
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
Enables a single LCD controller to manage the luminance of both CCFLs and LEDs, enhancing flexibility and convenience by providing a unified solution for different backlight units.
Implementation Method 1
The voltage supply unit comprises a primary winding for inducing an induced voltage so as to drive the backlight unit
Data Source
AI summary
The present invention discloses a backlight driving signal generator used in a liquid crystal display (LCD) controller. The backlight driving signal generator is coupled to a backlight driving circuit of the LCD and capable of issuing a first pulse signal and a second pulse signal to control the backlight driving circuit to function accordingly. In a preferred aspect, the backlight signal generator is capable of being adapted for the backlight driving circuit of cold cathode fluorescent lamps (CCFLs) or that of light emitting diodes (LEDs).