Backlight Driving Circuit Voltage Protection Sub-Circuit
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Solution Overview
Problem
The reliability of backlight driving circuits in liquid crystal display devices is compromised by abnormal negative terminal voltages of light-emitting diodes, leading to increased triode temperatures and potential damage.
Innovation Solution
A backlight driving circuit with a voltage protection sub-circuit that includes a voltage detection module, comparison module, and processing module to identify abnormal negative terminal voltages and output a feedback signal to stop the power supply chip, preventing excessive temperature and ensuring circuit reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing backlight driving circuit is used without voltage detection, then the circuit structure is simple, but the reliability deteriorates when negative terminal voltage is abnormal
Solution Approach 1:
The voltage detection module proactively monitors the negative terminal voltage of light-emitting diodes before abnormal conditions can cause damage. By detecting voltage abnormalities in advance and triggering protective action, the system prevents triode temperature rise and potential circuit failure, thereby improving reliability without requiring complex response mechanisms
Solution Approach 2:
The voltage protection sub-circuit acts as an intermediary between the power supply chip and the light-emitting diodes. It includes detection, comparison, and processing modules that monitor voltage conditions and control the power supply chip's operation. This intermediary layer isolates the potential harmful effects of voltage abnormalities from the main circuit components, protecting them while maintaining relatively simple overall structure
2Reliability
If voltage protection sub-circuit is added to detect negative terminal voltage, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The voltage protection function is segmented into three independent modules: voltage detection module (with multiple diodes for parallel detection), voltage comparison module (comparing detected voltage with reference), and voltage processing module (controlling power supply chip). This segmentation allows each module to perform a specific function with simple structure, making the overall protection system manageable and maintainable while providing comprehensive voltage monitoring
Solution Approach 2:
The voltage protection sub-circuit is designed to be universally applicable to backlight driving circuits with multiple light-emitting diodes. The detection module uses parallel diodes that can be configured for different numbers of LEDs, and the comparison module uses a reference voltage that can be adjusted for different operating conditions. This multi-functionality allows the same protection circuit structure to serve various backlight configurations without requiring complete redesign
Data Source
AI summary
The present disclosure discloses a backlight driving circuit and a display device. The backlight driving circuit includes a power supply chip, light-emitting diodes connected to the power supply chip, and a voltage protection sub-circuit connected to both the light-emitting diodes and the power supply chip. By adding the voltage protection sub-circuit, when a negative terminal voltage of the light-emitting diode is abnormal, the voltage protection sub-circuit will output a feedback signal to the power supply chip to stop the power supply chip from working, thereby improving reliability of the backlight driving circuit.