Programmable Linear LED Current Driver With Dynamic Voltage Tuning
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Solution Overview
Problem
Linear current drivers in multispectral illuminators face inefficiencies and heat generation due to inefficient power conversion, which wastes energy and requires valuable PCB space for cooling, while maintaining tight current control and spectral stability is crucial.
Innovation Solution
A scalable linear current driver system with programmable voltage regulators that dynamically adjust supply voltage based on LED forward voltage and real-time conditions, incorporating current sink and source drivers with fault detection and group-level voltage tuning to minimize thermal dissipation and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear current drivers are used to drive LEDs with widely varying forward voltages, then current control precision is maintained, but power loss and thermal dissipation increase
Solution Approach 1:
The patent implements dynamic voltage adjustment where the supply voltage is continuously adapted to match the actual forward voltage of the LED load. This is achieved through feedback control circuits that monitor LED voltage drops and adjust the driver output accordingly, eliminating excessive voltage headroom and reducing power dissipation while maintaining precise current control.
Solution Approach 2:
The system changes the operating parameters of the current driver by adjusting the supply voltage level based on the specific LED forward voltage characteristics. Different driver configurations are used for different LED types, and the driver parameters are optimized for each application to minimize power loss while maintaining control precision.
2Stability of the object's composition
If linear current drivers operate with higher supply voltage to ensure regulation, then current control stability is improved, but thermal dissipation and PCB space requirements increase
Solution Approach 1:
The driver circuit dynamically adjusts the supply voltage to the minimum necessary level for stable operation. Feedback mechanisms continuously monitor the LED voltage and driver operating conditions, adjusting the supply voltage in real-time to maintain stability while minimizing thermal dissipation, rather than operating at fixed high voltage.
Solution Approach 2:
The patent applies different voltage levels and driver configurations to different LED groups based on their specific forward voltage characteristics. Each LED group receives the optimal local voltage level needed for stable operation, rather than a uniform high voltage across all groups, thereby reducing overall thermal dissipation.
3Device complexity
If fixed supply voltage is used for all LED groups, then device complexity is reduced, but power efficiency decreases due to voltage overhead
Solution Approach 1:
The LED array is divided into multiple groups based on their forward voltage characteristics, with each group receiving a dedicated voltage regulation circuit. This segmentation allows each group to operate at its optimal voltage level, minimizing voltage overhead and improving power efficiency while keeping the complexity manageable through modular design.
Solution Approach 2:
The system implements dynamic voltage regulation for each LED group, where the supply voltage is continuously adjusted to match the actual forward voltage. This dynamic approach eliminates fixed voltage overhead and maximizes power efficiency across all LED types in the array.
Data Source
AI summary
A light emitting diode (LED) driving system comprises at least one linear current driver configured to regulate current to a plurality of LEDs in a multi-spectral application independently of an electrical load affected by voltage fluctuations across the LEDs; and a programmable input configured to receive a current setpoint signal from a digital-to-analog converter (DAC), which defines a target current through the LEDs. The LED driving system further comprises a programmable voltage regulator configured to output a supply voltage to the least one linear current driver that includes a saturation voltage sufficient for the at least one linear current driver to regulate the current delivered to the plurality of LEDs.