LED Driver Controller with Automatic Voltage Adaptation
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Solution Overview
Problem
Electrical power converters, particularly those controlling LED chains, face challenges in maintaining consistent current and voltage across a wide range of operating conditions without requiring programming of input or load voltages, often resulting in non-linear illumination responses and flicker.
Innovation Solution
An electronic driver system that automatically generates a target average output current using control logic, measuring input and load voltages to determine a reference current and off-time for a switching signal, thereby ensuring reliable and efficient current flow with minimal ripple, regardless of input or load voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If analog control is used for LED driver, then simplicity and fast response time are achieved, but illumination response is non-linear and color changes with brightness
Solution Approach 1:
The patent replaces the analog control system with a digital control system that uses a microcontroller to regulate LED current. The digital controller measures input voltage and load voltage, then calculates appropriate PWM duty cycles to maintain constant current through the LED chain, eliminating the non-linear response and color shifting inherent in analog control while keeping the overall system complexity manageable.
2Stability of the object's composition
If digital DC-DC current converter controller is used, then illumination linearity and color stability are improved, but device complexity increases
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the PWM duty cycle based on measured input voltage and load voltage conditions. The microcontroller modifies control parameters in real-time to compensate for voltage variations, maintaining stable LED operation across different operating conditions without requiring complex additional hardware.
Solution Approach 2:
The system implements feedback control by continuously measuring the input voltage and load voltage using ADC channels, then using these measurements to adjust the PWM output duty cycle. This closed-loop feedback mechanism ensures stable current regulation through the LED chain while keeping the controller architecture relatively simple and cost-effective.
3Measurement precision
If voltage programming is required for driver, then precise control is achieved, but adaptability to different voltage conditions is reduced
Solution Approach 1:
The driver circuit performs self-configuration by automatically measuring the input voltage and LED chain forward voltage when powered up, then calculating and storing the appropriate PWM duty cycle parameters internally. This self-service capability eliminates the need for external voltage programming while maintaining precise control, allowing the same driver to adapt to various input voltages and LED chain configurations without manual intervention.
Data Source
AI summary
Methods, devices, techniques, and circuits are disclosed for current control of a buck converter. In one example, a device is configured to receive a selected average current value for a current driver. The device is further configured to determine a set of parameters for the current driver. The device is further configured to generate an output to the current driver to cause the current driver to output a switching signal with an average current that corresponds to the selected average current value.