MCU-Based LED Driver Control Using External Transistor
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Solution Overview
Problem
Existing LED array control systems require a separate LED driver IC, limiting the microcontroller's visibility and flexibility, with increased complexity and cost due to multiple components, and requiring hardware changes for modifications.
Innovation Solution
A system and method where a microcontroller controls an LED array using an external transistor, with access to relevant voltages, allowing for dimming and post-manufacturing changes via firmware updates, eliminating the need for a separate LED driver IC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate LED driver IC is used to control the LED array, then the LED array can be regulated, but the circuit complexity increases and the microcontroller loses visibility and flexibility
Solution Approach 1:
The patent merges the LED driver functionality directly into the microcontroller unit by integrating the FET control circuitry and current regulation logic into the MCU itself. This eliminates the need for a separate LED driver IC, reducing circuit complexity while maintaining LED array regulation capabilities. The MCU now directly monitors sense resistor voltages and controls the FET gate, consolidating multiple functions into a single integrated component.
Solution Approach 2:
The microcontroller is designed to perform multiple functions: it serves as both the control unit for the FET and the monitoring unit for the LED array current. By integrating the LED driver functions into the MCU, the system achieves multi-functionality where a single component handles both general control tasks and specific LED regulation, reducing the overall component count and circuit complexity.
2Ease of operation
If a separate LED driver IC is used, then current control is achieved, but hardware changes are required for modifications and cost increases
Solution Approach 1:
By combining the LED driver functionality into the microcontroller, the system allows software-based control of current regulation. This integration enables modifications to be made through firmware updates rather than hardware changes, significantly improving adaptability and versatility while maintaining ease of current control operation.
Solution Approach 2:
The patent implements dynamic control of the FET gate voltage through PWM signals generated by the microcontroller. This allows flexible adjustment of LED array current in real-time based on software commands, enabling easy modification of control parameters and behavior without requiring hardware changes. The system transitions from static hardware-based control to dynamic software-based control.
3Ease of operation
If an external LED driver IC is used with a microcontroller, then LED array control is achieved, but the system requires multiple components increasing cost and complexity
Solution Approach 1:
The patent merges the LED driver IC functionality into the microcontroller unit, eliminating the need for a separate external driver component. The MCU internally integrates the FET control circuitry, current sensing logic, and regulation algorithms, reducing the component count from multiple discrete parts to a single integrated microcontroller, thereby lowering cost and complexity while maintaining full LED array control capability.
Data Source
AI summary
A system and method for controlling the current to an LED array is disclosed. The system comprises a microcontroller and an external transistor. The microcontroller has access to the relevant voltages in the circuit, including the voltage across the sense resistor, the voltage at the drain of the external transistor and the high voltage input. By monitoring these voltages, the microcontroller may be able to control the gate input to the external transistor so as to control the current in the LED array. Further, the microcontroller includes provisions to allow for dimming of the LED array, if desired. This configuration allows for post-manufacturing changes to the operation of the system without any hardware modifications.