LED Driver Feedback Control Using Global Minimum Voltage
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Solution Overview
Problem
Conventional LED systems face inefficiencies in power management due to a wide dynamic range for power supply when the number of LEDs is large, requiring numerous DC/DC converters for each LED driver.
Innovation Solution
An LED system with a comparator circuit in each driver to determine local minimum voltage, a global voltage register to store the lowest voltage across all subarrays, and a feedback circuit using an I2C bus to adjust the power supply voltage, ensuring efficient voltage control across the LED array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If each LED driver has one DC/DC converter to efficiently manage power, then power management efficiency is improved, but device complexity and cost increase significantly
Solution Approach 1:
Multiple LED drivers share a single DC/DC converter through a feedback mechanism. The feedback circuit monitors the cumulative current consumption of all LED drivers and adjusts the DC/DC converter's output to maintain efficient power delivery across the entire array, eliminating the need for individual converters at each driver.
Solution Approach 2:
A feedback circuit acts as an intermediary between the LED drivers and the shared DC/DC converter. This feedback circuit sums the current consumption signals from all drivers and provides adjustment signals to the DC/DC converter, enabling coordinated power management without direct individual connections.
2Device complexity
If a single shared DC/DC converter is used for multiple LED drivers, then device complexity is reduced, but power management precision deteriorates due to wide dynamic range
Solution Approach 1:
A feedback circuit continuously monitors the cumulative current consumption from all LED drivers and provides real-time adjustment signals to the DC/DC converter. This closed-loop feedback mechanism maintains precise voltage control despite the wide dynamic range caused by varying numbers of active LEDs across different drivers.
Solution Approach 2:
The feedback circuit performs multiple functions: it sums current consumption signals from all drivers, determines the total power requirement, and generates appropriate feedback signals for the DC/DC converter. This multi-functional approach enables precise control with a single shared converter.
3Device complexity
If conventional simple analog feedback is used, then device complexity is low, but power control capability deteriorates for large numbers of LEDs
Solution Approach 1:
The feedback circuit uses digital signal processing to sum current consumption from multiple drivers and provides precise feedback to the DC/DC converter. This digital feedback approach maintains relatively simple circuitry while significantly improving power control capability for large LED arrays compared to conventional analog feedback.
Data Source
AI summary
An LED system includes an LED array, a plurality of driver circuits, a power supply, a bus and a feedback circuit. Each of the plurality of driver circuits is connected to and driving one of a plurality of LED subarrays in the LED array. Each of the plurality of driver circuits includes a comparator circuit, a local voltage register, and a global voltage register. The comparator circuit determines, as a local minimum voltage, a lowest voltage in the corresponding LED subarray. The global minimum voltage is determined by comparing all the local minimum voltages. The feedback circuit provides the power supply with a feedback signal reflecting the global minimum voltage and causes the power supply to adjust the voltage output to the LED array.