Parallel LED Driver Voltage Droop Control for Load Balancing
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Solution Overview
Problem
Existing LED driver systems with parallel-connected drivers face imbalances due to component variations, leading to overdimensioning and inefficient load balancing, especially at maximum power output.
Innovation Solution
A driver system with control circuits that regulate DC voltage using drooping output curves and adjust voltage offsets based on temperature thresholds to achieve self-calibration and improved load balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If parallel-connected LED drivers are used to supply high-power LED loads, then the system can handle higher power requirements, but load balancing becomes imbalanced due to component variations and miscalibration
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage of each parallel-connected LED driver is monitored and fed back to its control circuit. Based on this feedback, the control circuit dynamically adjusts the output voltage of individual drivers to compensate for variations in output characteristics. This ensures that all drivers share the load equally and prevents any single driver from exceeding its nominal power specification, thereby resolving the load balancing issue while maintaining high power handling capability.
2Productivity
If LED drivers operate at maximum power output, then the system achieves highest efficiency, but load imbalance causes some drivers to exceed nominal power specifications
Solution Approach 1:
The patent employs dynamic voltage adjustment where the output voltage of each LED driver is not fixed but continuously adapted based on real-time monitoring of the overall system output voltage and individual driver temperature. The control circuit dynamically modifies each driver's drooping output voltage curve by applying voltage offsets, enabling the system to operate at maximum power output while ensuring no individual driver exceeds its nominal power specification. This dynamic adaptation resolves the contradiction between productivity and reliability.
3Ease of manufacture
If voltage droop control is used to enable parallel connection of LED drivers, then output ports can be easily connected in parallel, but variations in output characteristics prevent congruent operation
Solution Approach 1:
The patent changes the operating parameters of each LED driver dynamically by adjusting the drooping output voltage curve through voltage offsets. Instead of requiring precise manufacturing tolerances to achieve congruent output characteristics, the system allows for parameter variations and compensates for them through real-time voltage adjustment. This approach maintains the ease of parallel connection while achieving effective output characteristic congruency through parameter adaptation rather than manufacturing precision.
Data Source
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AI summary
Disclosed is a driver system (1) for supplying an LED load (2) with a DC voltage (21). The driver system (1) comprises a plurality of LED drivers (11), having respective control circuits (12) and parallel-connected output ports (13). The control circuits (12) are respectively configured to regulate the DC voltage (21) in accordance with a respective drooping output voltage curve (14, 15); and to shift the respective output voltage curve (14, 15) by a negative voltage offset (16) if a respective driver temperature exceeds a maximum temperature threshold. This avoids imbalanced power supply in particular at maximum power output, overdimensioning of the drivers (11), and additional external sensors.