LED Backlight Driving Circuit Voltage Balancing
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Solution Overview
Problem
In liquid crystal display (LCD) devices with LED backlights, the voltage differences between LED lightbars cause increased temperature of the control chip in the converter, leading to higher costs due to the need for thermal management solutions like thermal pads or bare copper.
Innovation Solution
A driving circuit for the LED backlight with a converter module that includes a digital potentiometer to balance voltage differences and adjust resistance via an electric signal, ensuring constant voltage across all pins of the control chip, reducing power consumption and heat production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple LED lightbars are connected in parallel to a single converter, then the backlight coverage is improved, but voltage differences between lightbars cause increased temperature of the control chip
Solution Approach 1:
The patent divides the parallel LED lightbars into groups, with each group connected to a separate converter. This segmentation ensures that voltage differences between lightbars are contained within each group, preventing excessive voltage variations from reaching the control chip and causing temperature rise. Each converter handles a subset of lightbars with more uniform voltage characteristics.
Solution Approach 2:
The patent introduces a converter as an intermediary component between the LED lightbars and the control chip. The converter includes voltage regulation mechanisms that mediate the voltage differences between parallel lightbars, ensuring stable voltage delivery to the control chip while maintaining the benefits of parallel lightbar configuration for extended backlight coverage.
2Temperature
If thermal pads or bare copper are added to reduce control chip temperature, then the temperature problem is solved, but the manufacturing cost increases
Solution Approach 1:
The patent extracts the voltage difference problem from the control chip by introducing separate converters for each LED lightbar group. This extraction eliminates the need for additional thermal management components like thermal pads or bare copper, as the voltage regulation is handled at the converter level rather than requiring thermal intervention at the control chip level.
Solution Approach 2:
The patent uses standard, readily available converter components that can be easily manufactured and replaced. By using conventional voltage regulation technology in modular converter units, the solution avoids the need for expensive specialized thermal management materials while maintaining effective temperature control through electrical rather than thermal means.
3Device complexity
If voltage differences between LED lightbars are not balanced, then the circuit simplicity is maintained, but current is generated causing increased temperature and potential damage
Solution Approach 1:
The patent segments the LED lightbars into multiple groups, each connected to its own converter. This segmentation isolates voltage differences within each group, preventing them from propagating to the control chip. The circuit remains relatively simple within each group, while the overall system achieves better voltage matching through the modular converter architecture.
Solution Approach 2:
The converter acts as an intermediary that processes voltage differences before they reach the control chip. It includes voltage regulation and balancing mechanisms that mediate the electrical characteristics, ensuring that only balanced and safe voltages are delivered to the control chip, thereby protecting reliability without requiring complex voltage matching circuitry throughout the entire system.
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 reduces the temperature of the control chip by eliminating voltage differences and allowing for automatic resistance adjustments, thereby lowering energy consumption and heat production, while also simplifying maintenance through the use of an isolating switch and connector.
Implementation Method 1
The converter module is configured with a digital potentiometer balancing a voltage difference between LED lightbars and adjusting a resistance by an electric signal
Data Source
AI summary
The driving circuit for a light emitting diode (LED) backlight includes at least two lightbars arranged in parallel connection. An output end of each of the LED lightbars is coupled with a converter module, and the converter module is configured with a digital potentiometer balancing a voltage difference between the LED lightbars and adjusting a resistance by an electric signal. In the present disclosure, the digital potentiometer adjusting the resistance by the electric signal is arranged in the converter module connected with the LED lightbar in series, and the resistance of the digital potentiometer is dynamically adjusted according to the resistance of different LED lightbars during use. Thus, the total voltage of each LED lightbar and the digital potentiometer connected with the LED lightbar in series is constant.