Backlight Lamp Current Balance Feedback Mechanism
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Solution Overview
Problem
Existing backlight systems for large LCD devices face issues with current leakage and non-uniform light output due to high-voltage operation and parameter discrepancies, leading to inaccurate image display and increased costs for high-voltage components.
Innovation Solution
A backlight system with a lamp current balance and feedback mechanism, utilizing transformers, capacitors, and a feedback circuit to balance currents and generate uniform light outputs, eliminating the need for expensive high-voltage capacitors and preventing damage from system malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If high-voltage operation is used to drive longer lamps in large LCD devices, then the lamp can be driven with sufficient voltage, but current leakage becomes more serious and costly high-voltage capacitors and transformers are required
Solution Approach 1:
The patent divides the single high-voltage driving system into two separate low-voltage driving systems. Each transformer (first transformer 220a and second transformer 220b) operates at low voltage and drives one end of the lamp independently. This segmentation eliminates the need for expensive high-voltage capacitors and reduces current leakage while still providing sufficient total voltage for driving longer lamps in large LCD devices.
2Reliability
If double-side driving mode is used with two transformers, then current can be supplied to both ends of the lamp, but parameter discrepancies cause current inconsistency and non-uniform light output
Solution Approach 1:
The patent introduces a feedback mechanism where a feedback circuit (350) monitors the actual current flowing through the lamp and sends feedback signals to the driving circuit (360). The driving circuit adjusts the driving voltages in real-time based on this feedback to compensate for parameter discrepancies in the transformers and capacitors. This ensures consistent current distribution and uniform light output from both ends of the lamp, resolving the manufacturing precision issue.
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 system achieves balanced lamp currents for uniform light output, reduces costs by eliminating the need for expensive high-voltage capacitors, and protects the system from damage through feedback mechanisms.
Implementation Method 1
A first induced voltage Vba is generated by inducing a feedback current Ifb through a second winding 334 of the second transformer 330b. A second induced voltage Vca is generated by inducing a balance current Ibal through a third winding 353 of the first transformer 330a
Implementation Method 2
The second winding 222 of the transformer 220a in conjunction with the first capacitor 280a performs a resonant operation for generating a first AC voltage Va having a high peak-to-peak voltage
Data Source
AI summary
A lamp current balance and feedback system and related method are disclosed for balancing the input and output currents of a lamp by making use of a lamp current balance and feedback mechanism. The operation of the lamp current balance and feedback mechanism includes coupling the input current of the lamp for generating a first balance current by a first transformer, coupling the output current of the lamp for generating a second balance current by a second transformer, coupling the first and second transformers for substantially equalizing the first and second balance currents, generating a feedback signal based on the first or second balance current by a feedback circuit, generating a pulse width modulation signal based on the feedback signal by a pulse width modulation signal generation circuit, and driving the input and output currents of the lamp based on the pulse width modulation signal by a driving circuit.