Parallel LED Driver Feedback for Dynamic Supply Voltage Control
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Solution Overview
Problem
Conventional light source driving systems face issues such as excessive power consumption, inefficiency, and dark patches due to thermal protection thresholds, particularly in large-area backlighting applications and High Dynamic Range (HDR) scenarios, which are exacerbated by the need for multiple controllers and dedicated processors.
Innovation Solution
A light source driving system with multiple light source driving devices that operate in parallel, adjusting supply voltage based on real-time power demand without a dedicated controller, incorporating thermal foldback functions to prevent overheating and dark patches, and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target voltage value is set to the maximum supply voltage required across the operating temperature range to ensure sufficient power supply, then the light source can operate reliably at all temperatures, but excessive power consumption and energy waste occur
Solution Approach 1:
The patent implements dynamic voltage adjustment where the power converter continuously adapts the supply voltage to the actual needs of the light source. The controller receives feedback from driving devices and adjusts the target voltage in real-time based on actual operating conditions, transforming the static maximum-voltage approach into a dynamic adaptation mechanism that matches supply voltage to demand, thereby reducing energy waste while maintaining reliability
Solution Approach 2:
The patent establishes a feedback loop where driving devices monitor the actual power supply status and communicate this information to the controller. The controller uses this feedback to adjust the target voltage value dynamically, ensuring the power converter supplies exactly the voltage needed at any given moment rather than continuously supplying the maximum voltage, thus resolving the contradiction between reliability and energy consumption
2Measurement precision
If a dedicated controller or processor is used to read data from driving devices and calculate target voltage values, then voltage adjustment accuracy is improved, but system cost and power consumption increase
Solution Approach 1:
The patent merges the control function into the existing driving devices rather than using a separate dedicated controller. The driving devices themselves perform the data reading and target voltage calculation, consolidating multiple functions into unified components. This integration maintains the required calculation accuracy while eliminating the need for additional controller hardware, thereby reducing system complexity and cost
Solution Approach 2:
The driving devices are empowered to autonomously read their own operational data, perform the necessary calculations for target voltage determination, and communicate results to the power converter. This self-service capability eliminates dependency on external dedicated controllers, simplifying the system architecture while preserving the precision needed for accurate voltage regulation
3Object-affected harmful factors
If conventional thermal protection shuts down driving devices when temperature exceeds the protection threshold, then device overheating is prevented, but dark patches appear on the display
Solution Approach 1:
The patent replaces the static thermal protection threshold with a dynamic thermal foldback mechanism. Instead of abruptly shutting down at a fixed temperature point, the driving device gradually reduces its output current as temperature approaches the threshold, then restores operation when temperature decreases. This dynamic response prevents complete shutdowns that cause dark patches while still protecting against overheating, maintaining display brightness uniformity
Solution Approach 2:
The thermal foldback mechanism operates in periodic cycles: as temperature rises, the driving device reduces current output; when temperature drops below the threshold, operation resumes. This periodic modulation of current rather than complete shutdown prevents the formation of persistent dark patches while continuously managing thermal conditions, resolving the contradiction between protection and display quality
Data Source
AI summary
A light source driving system is configured to drive multiple sets of LEDs sharing common power supply terminal. The light source driving system includes a feedback node and multiple light source driving devices coupled to the feedback node. The feedback node is configured to provide a power-supply adjustment signal to adjust a supply voltage at the power supply terminal. The multiple light source driving devices are configured to generate multiple feedback output signals to control the power-supply adjustment signal in parallel. Each light source driving device of the multiple light source driving devices is configured to drive a set of LEDs of the multiple sets of LEDs, and to generate a feedback output signal of the multiple feedback output signals based on power supply status of the set of LEDs.