LED Voltage Adjustment Device for LCD Backlight Overheat Prevention
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Solution Overview
Problem
Existing LED voltage adjustment systems for LCD backlight modules face challenges in managing the negative terminal voltage, leading to potential overheat issues due to high voltage differences and direct voltage penetration into IC circuits, which can cause inefficiencies and reliability problems.
Innovation Solution
The proposed solution involves an LED voltage adjustment device comprising a PI regulator, integrator, subtractor, comparator, and IC module, which adjusts the duty cycle of the switch transistor in the boost converter based on the negative terminal voltage of the LED light bar, using a clock signal to control the conductivity of the switch transistor and prevent overcurrent protection, thereby regulating the voltage and reducing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a boost converter is used to drive the light bar, then the negative terminal voltage of the light bar can stay at high level, but this causes high voltage penetration issues that can damage IC circuits
Solution Approach 1:
The patent introduces an intermediary voltage adjustment device between the boost converter and the LED light bar. This device includes a controller that regulates the duty cycle of the switch transistor, effectively mediating the voltage transmission and preventing high voltage from reaching the IC circuits while still providing sufficient power to the light bar.
Solution Approach 2:
The patent dynamically changes the duty cycle parameter of the switch transistor based on real-time voltage detection. By adjusting this parameter, the system can adaptively control the negative terminal voltage level, maintaining it within a safe range for IC circuits while ensuring adequate power delivery to the LED light bar.
2Power
If the negative terminal voltage of the light bar is kept at high level, then the light bar can be driven effectively, but this leads to large voltage differences causing overheating
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the voltage across the switch transistor and adjusts the duty cycle accordingly. This closed-loop feedback system ensures that the voltage difference remains within safe limits, preventing overheating while maintaining effective light bar operation.
Solution Approach 2:
The patent makes the system dynamic by continuously adjusting the duty cycle based on real-time operating conditions. This dynamic adaptation allows the system to respond to changing load conditions and prevent overheating by adjusting the voltage levels to match actual operational requirements.
3Device complexity
If the duty cycle of the switch transistor is not adjusted, then the circuit is simpler, but the average switch period variation is not proportional to the control reference leading to performance issues
Solution Approach 1:
The patent implements a self-service control mechanism where the controller automatically adjusts the duty cycle based on feedback from the voltage detection circuit. This self-regulating system ensures precise switch period control without requiring complex external intervention, maintaining reliability while keeping the control architecture relatively simple.
Data Source
AI summary
The present invention provides LED voltage adjustment device and drive system thereof. The device includes PI regulator, with negative terminal connected to negative terminal of LED light bar to receive negative terminal voltage of light bar and positive terminal of PI regulator being for receiving reference voltage; integrator, for performing integral on output signal of PI regulator; a subtractor, with positive input terminal receiving output signal from PI regulator and negative terminal receiving overcurrent protection detection voltage from boost converter for driving light bar, and subtracting overcurrent protection detection voltage from output signal of PI regulator; comparator, with positive terminal receiving output signal from integrator and negative terminal receiving output signal from subtractor; and integrated circuit (IC) module, for receiving output signal from comparator and based on received output signal to control a control signal to conduct or cut off switch transistor of boost converter.