CCFL Driving Circuit Phase Inversion for Water Ripple Elimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional high-voltage driving circuits for cold cathode fluorescent lamps (CCFLs) in flat panel displays generate abnormal water ripple images due to AC output power supplies with the same phases, leading to user discomfort and increased costs when attempting to rectify this with additional high-voltage AC power supplies.
Innovation Solution
A driving circuit that uses a power conversion unit with electromagnetic induction to generate two AC output signals with reverse phases from a single AC input signal, eliminating the need for additional high-voltage AC power supplies and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If AC output power supplies with the same phases are used to drive CCFLs, then the circuit structure is simple, but abnormal water ripple images are generated and user comfort deteriorates
Solution Approach 1:
The patent divides the single AC power supply output into multiple groups of AC output power supplies with different phases by using multiple transformers with different winding connections. This segmentation allows each group to drive different CCFLs with opposite phase signals, eliminating water ripple images while maintaining circuit simplicity.
Solution Approach 2:
The patent combines multiple transformers with different winding connections (Y-Δ, Δ-Y, Δ-Δ) to generate multiple groups of AC output power supplies with different phases from a single AC input power supply. This merging approach achieves phase diversity without requiring multiple independent power supplies.
2Object-affected harmful factors
If another high-voltage AC power supply is added to provide AC output power supplies with different phases, then water ripple images are eliminated, but the cost of the high-voltage driving circuit increases
Solution Approach 1:
The patent makes a single AC input power supply serve multiple functions by using it to generate multiple groups of AC output power supplies with different phases through multiple transformers. This multi-functionality eliminates the need for additional high-voltage AC power supplies, reducing cost while preventing water ripple images.
Solution Approach 2:
The patent changes the phase parameter of AC output power supplies by using transformers with different winding connections (Y-Δ, Δ-Y, Δ-Δ). This parameter change allows generation of AC outputs with different phases from a single AC input, eliminating water ripple images without increasing the number of power supplies.
3Object-affected harmful factors
If multiple high-voltage AC power supplies are used to provide AC output power supplies with different phases, then water ripple images are prevented, but the device complexity increases
Solution Approach 1:
The patent segments the power conversion function across multiple transformers with different winding connections, where each transformer processes the same AC input but produces outputs with different phase relationships. This segmentation achieves phase diversity without requiring multiple independent high-voltage power supplies.
Solution Approach 2:
The patent uses transformers with different winding connections as intermediaries to convert a single AC input power supply into multiple groups of AC output power supplies with different phases. These transformers act as mediators that create phase differences without requiring multiple input power supplies.
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
The solution effectively prevents abnormal water ripple images by generating AC output signals with reverse phases, improving display stability and reducing manufacturing costs by eliminating the need for additional high-voltage AC power supplies.
Implementation Method 1
The power conversion unit generates a first AC output signal and a second AC output signal using electromagnetic induction caused by the AC input signal, wherein phases of the first AC output signal and the second AC output signal are reverse to each other
Implementation Method 2
Each of the second side inductors cooperates with one of the first side inductors to generate electromagnetic induction
Data Source
AI summary
A driving circuit and lighting equipment using the same are provided. The driving circuit includes a first power receiving terminal, a second power receiving terminal and a power conversion unit. The first power receiving terminal receives an alternating current (AC) input signal. The second power receiving terminal is electrically coupled to a predetermined potential. The power conversion unit is electrically coupled to the first and second power receiving terminals for transforming the AC input signal into corresponding two AC output signals of different phases, wherein the two AC output signals are with the same current.