LED Array Control Circuit for Equal Current and Light Uniformity
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Solution Overview
Problem
Existing LED array control circuits face challenges in achieving homogeneous light output due to process and production variability, temperature changes, and limited diagnostic capabilities, often resulting in unequal current distribution and inefficient system protection.
Innovation Solution
A parallel control approach with current measurement circuits for each LED strand, selectable via a multiplexer, and a processor-controlled system that includes independent switches and current limiting circuits, enabling accurate current regulation and continuous diagnostic monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a parallel control approach with independent current measurement circuits for each LED strand is implemented, then current regulation accuracy and light output homogeneity are improved, but device complexity increases
Solution Approach 1:
The control circuit is divided into multiple independent current measurement circuits, each dedicated to a specific LED strand. This segmentation allows precise current regulation for each strand while maintaining overall system manageability through modular architecture.
Solution Approach 2:
The current measurement circuits use a unified parallel control architecture that can be selectively activated for different LED strands. The multiplexer enables a single control circuit to serve multiple functions by switching between different measurement circuits based on which LED strand is currently being controlled.
2Stability of the object's composition
If independent current measurement and control circuits are used for each LED strand, then light output homogeneity is improved, but device complexity and cost increase
Solution Approach 1:
The system divides the LED array into multiple independently controllable strands, each with its own current measurement circuit. This ensures that each strand maintains consistent current and produces uniform light output, while the segmentation allows for manageable complexity through modular design.
Solution Approach 2:
Each current measurement circuit provides real-time feedback on the current flowing through its associated LED strand. This feedback is used by the control circuit to adjust and maintain precise current levels, ensuring homogeneous light output across all strands while using a standardized feedback mechanism to control complexity.
3Reliability
If current limiting circuits with independent predetermined current limits are implemented for each output terminal, then system protection capability is improved, but device complexity increases
Solution Approach 1:
The protection system is segmented into multiple current limiting circuits, each associated with a specific output terminal and LED strand. Each circuit independently monitors and limits current to predetermined safe levels, providing robust protection while the modular segmented architecture prevents excessive overall complexity.
Solution Approach 2:
The current limiting circuits are pre-configured with predetermined current limits that act as safety thresholds. These limits are established beforehand to prevent over-current conditions before they can cause damage, providing proactive protection rather than reactive response.
4Measurement precision
If multiple current measurement circuits are used for accurate current determination, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The measurement system is divided into multiple dedicated current measurement circuits, each responsible for measuring current in a specific LED strand. This segmentation provides accurate measurements for each strand while the modular structure keeps individual measurement circuits simple and manageable.
Solution Approach 2:
The current measurement circuits are designed with universal functionality to measure current across different LED strands. Through the multiplexer, a single measurement circuit can be configured to measure different strands, reducing the need for completely separate measurement systems and thereby controlling complexity while maintaining precision.
Data Source
AI summary
Devices and techniques for individual control of multiple light emitting diodes (LEDs) in a LED array. A LED array may include multiple strands of LEDs with each strand including a single LED or multiple LEDs. The techniques of this disclosure include a parallel approach to controlling a LED array with a current measurement circuit in each LED strand. The current measurement circuits may be selectable by a controller via a multiplexer (MUX). The arrangement of circuit elements provides for an improved initialization phase and operating phase and may achieve an accurate and substantially equal current at all LEDs. The current control may ensure a homogenous light output that accounts for process and production variability, as well as changes in operating conditions. A LED control circuit of this disclosure may also include system safety features including temperatures sensing, and over voltage and over current sensing and protection.