Digital Current Regulator for Solid State Lighting
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Solution Overview
Problem
Existing LED drivers for high brightness LEDs have low efficiency, leading to excessive power consumption and potential damage, especially in portable devices, due to the requirement of external loop compensation and analog current regulation.
Innovation Solution
A digital current regulator that provides power to LEDs without external compensation, using a controller to independently control the on and off times of a switching switch to maintain constant peak and minimum current levels, thereby reducing power losses and utilizing fewer components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external loop compensation with current sense resistor is used for peak current control, then current regulation accuracy is improved, but power efficiency deteriorates due to excessive power consumption
Solution Approach 1:
The patent extracts the current sensing function from the external loop compensation circuit and integrates it into the controller's internal circuitry. The controller directly monitors the current through the switching element, eliminating the need for external current sense resistors and their associated power losses while maintaining accurate current measurement and control capability.
2Ease of operation
If analog current regulators are used for LED driving, then continuous current control is achieved, but device complexity and cost increase due to additional components
Solution Approach 1:
The patent merges the analog current regulation functionality with the digital switching control in a single integrated controller. The controller uses pulse-width modulation (PWM) to regulate LED current digitally, combining the switching element control and current regulation functions in one device, thereby reducing the number of external components while maintaining effective current control capability.
3Illumination intensity
If high peak current is provided to high brightness LEDs, then light output intensity is improved, but reliability deteriorates due to potential damage from excessive current
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the current through the switching element and adjusts the switching duty cycle accordingly. This closed-loop control ensures that the LED current remains within safe operating limits while delivering the required light output intensity, preventing damage from excessive current peaks.
Solution Approach 2:
The patent uses periodic switching of the current through the LED at a high frequency, controlling the duty cycle to deliver the appropriate average current. This periodic action allows the system to provide high peak currents for brief intervals to achieve high brightness while maintaining overall reliability by limiting the average current and providing recovery periods.
Data Source
AI summary
A method of providing power to solid state lighting is disclosed. The method includes starting a first cycle by providing current to the solid state lighting system, monitoring a solid state lighting system current level, and reducing the solid state lighting system current level when a predetermined peak current level is reached. A second cycle is commenced by increasing the solid state lighting system current level when a predetermined minimum current level is reached. Corresponding apparatus and computer-readable medium are also disclosed.