Inverter Circuit Single Sampling Unit for LCD CCFL Voltage Stabilization
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Solution Overview
Problem
The complexity and high cost of traditional inverter circuits for liquid crystal displays (LCDs) are exacerbated by the need for multiple sampling units to stabilize voltages for multiple cold cathode fluorescent lamps (CCFLs), leading to increased structural complexity and expense.
Innovation Solution
An inverter circuit design featuring a full-bridge circuit, main inverse transformers, over-voltage protective circuits, and a simplified feedback circuit with a secondary inverse transformer, sampling unit, and integral circuit unit, which converts DC voltage to AC low voltage and stabilizes voltage output by integrating sampling voltages, reducing the need for multiple sampling units regardless of the number of CCFLs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sampling units are used to stabilize voltages for multiple CCFLs, then voltage stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple sampling units into a single sampling unit that can sample voltages from multiple CCFLs sequentially. The feedback circuit integrates voltage sampling, rectification, and control functions into one unified structure, eliminating the need for separate sampling units for each CCFL while maintaining voltage stability through centralized feedback control.
Solution Approach 2:
The single sampling unit is designed with multi-functionality to handle voltage sampling from multiple CCFLs, perform rectification through integrated diodes and resistors, and provide feedback control. This universal structure replaces multiple specialized sampling units, reducing complexity while maintaining the ability to stabilize voltages across all CCFLs.
2Manufacturing precision
If multiple sampling units are used for each CCFL, then voltage control precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple sampling units into one integrated feedback circuit that can precisely control voltages for multiple CCFLs. The single sampling unit with integrated rectification components (diodes, resistors) and feedback mechanisms provides sufficient voltage control precision without requiring multiple separate units, thereby reducing component count and manufacturing cost.
Solution Approach 2:
Instead of physically copying multiple sampling units for each CCFL, the patent uses a single sampling unit that sequentially samples and controls voltages for all CCFLs. The feedback circuit creates a virtual copy of the sampling function for each CCFL through time-division multiplexing, maintaining control precision while avoiding the cost of physical duplication.
3Reliability
If a traditional feedback circuit with multiple sampling units is used, then voltage stabilization is achieved, but the inverter circuit structure becomes complicated
Solution Approach 1:
The patent merges the feedback circuit structure by integrating voltage sampling, rectification, and control functions into a single unified circuit. The feedback circuit receives voltage signals from multiple CCFLs, processes them through integrated components (diodes, resistors, capacitors), and provides centralized feedback to the full-bridge circuit, simplifying the overall inverter structure while maintaining effective voltage stabilization.
Solution Approach 2:
The feedback circuit is segmented into functional modules within a single unit: voltage sampling section, rectification section with diodes and resistors, integration section with capacitors, and feedback control section. This modular segmentation within a unified structure allows complex voltage stabilization functionality to be achieved without increasing overall circuit complexity.
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 design simplifies the inverter circuit structure, reduces costs, and enhances feedback efficiency by stabilizing voltage output effectively across multiple CCFLs with a single sampling unit, ensuring stable operation and protection against over-voltage.
Implementation Method 1
The full-bridge circuit is configured for converting an external direct current (DC) voltage into an alternating current (AC) low voltage
Implementation Method 2
The main inverse transformers are configured for converting the AC low voltage into an AC high voltage
Implementation Method 3
The secondary inverse transformer is configured for converting the AC low voltage outputted by the full-bridge circuit into an AC high voltage
Implementation Method 4
The sampling unit is configured for sampling the AC high voltage outputted by the secondary inverse transformer and outputting a sampling voltage
Implementation Method 5
The integral circuit unit is configured for integrating the sampling voltage and outputting an integrated sampling voltage to the full-bridge circuit
Data Source
AI summary
An exemplary inverter circuit (2) includes a full-bridge circuit (21) for converting a DC voltage into an AC low voltage, main inverse transformers (22) for converting the AC low voltage into an AC high voltage, and a feedback circuit (25). The feedback circuit includes a secondary inverse transformer (250) for converting the AC low voltage into an AC high voltage, a sampling unit (254) for sampling the AC high voltage and outputting a sampling voltage, and an integral circuit unit (205) for integrating the sampling voltage and outputting an integrated sampling voltage to the full-bridge circuit. When the AC low voltage outputted by the full-bridge circuit fluctuates, the feedback circuit sends a feedback voltage to the full-bridge circuit, and the full-bridge circuit stabilizes the AC low voltage according to the feedback voltage. The feedback voltage is in direct proportion to the fluctuation of the AC low voltage.