LED Driver Assembly Error Detection via Current Source Voltage Drop
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Solution Overview
Problem
Conventional driver assemblies for lighting units with LEDs face challenges in detecting error conditions, such as short circuits or disconnected strands, due to high or low voltages at measurement points, requiring additional components for voltage protection and increased design complexity, which can lead to unsafe operating conditions and potential damage.
Innovation Solution
A driver assembly with a control unit that measures voltage drops at the current source's second terminal, allowing for error detection without additional circuitry, by adjusting control values and determining line statuses to identify potential errors in strands, enabling the detection of short circuits or bypassed diodes without requiring voltage protection at high voltage terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage is tapped at the connecting point between the series circuit of LEDs and the current source to detect error conditions, then error detection capability is improved, but the design complexity and cost increase due to high voltage processing requirements
Solution Approach 1:
The patent introduces a mediator element (resistor) connected between the current source and reference potential terminal. This resistor serves as an intermediary that converts the current information into a measurable voltage drop at a safe location (second terminal of current source), allowing error detection without directly measuring high voltages at the LED connection point.
Solution Approach 2:
The patent creates a copy of the current information through the voltage drop across the resistor. Instead of measuring the actual high voltage at the LED connection point, the system measures a copied representation (voltage drop) at the second terminal of the current source, which contains the same diagnostic information but at a safe voltage level.
2Object-affected harmful factors
If additional external components are provided to lower high measured voltage to a processable level, then safety is improved, but the device complexity and cost increase
Solution Approach 1:
The current source itself provides the voltage drop measurement function through its second terminal connection to the resistor. The system uses the existing current source structure and its inherent voltage characteristics to provide safe measurement points, eliminating the need for separate voltage division or protection circuits that would add complexity.
Solution Approach 2:
The patent establishes a reference potential terminal connected to ground through a resistor, creating a safe equipotential reference point. The voltage drop measurement is taken relative to this reference, ensuring that all measurement points remain at safe voltage levels while still providing accurate error detection capability.
3Measurement precision
If measurement is performed at the first terminal of the current source, then error detection accuracy is improved, but the risk of damage and safety hazards increase due to high voltage exposure
Solution Approach 1:
The resistor connected to the reference potential terminal acts as an intermediary that provides indirect access to the current information. By measuring the voltage drop across this resistor at the second terminal, the system obtains accurate error detection data without exposing measurement circuitry to high voltages at the first terminal.
Solution Approach 2:
The voltage drop across the resistor creates a safe copy of the electrical state information. This copied signal at the second terminal contains the same diagnostic value as a direct measurement would provide, but without the safety risks associated with high voltage exposure at the first terminal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for efficient and safe error detection in lighting units, reducing the risk of damage and user safety hazards by analyzing voltage drops at the current source's second terminal, thereby enabling the identification of error conditions without additional circuit components and maintaining safe operating ranges.
Implementation Method 1
measured values are acquired at the second terminal of the current source of each strand in order to detect a potential error condition in one or more strands based on the measured values as well as adjusted control values or control signals. The measured values correspond, for example, to the respective voltage drop through the resistor of the strand.
Data Source
AI summary
A driver assembly (100) for a lighting unit (230) comprises a control unit (110). The lighting unit (230) comprises a plurality of strands (240, 250, 260), wherein each strand comprises a series circuit (242, 252, 262) of light-emitting diodes and a current source (243, 253, 263) with a first and a second terminal (246, 256, 266), and wherein the series circuit (242, 252, 262) of diodes is connected between a supply voltage input (231) of the lighting unit (230) and the first terminal of the current source (243, 253, 263) and the second terminal (246, 256, 266) of the current source is connected to a reference potential terminal via a resistor (245, 255, 265). The control unit (110) is designed for generating a corresponding control signal for a voltage converter (210) from a respectively adjusted control value, wherein said voltage converter is designed for making available an output voltage at the supply voltage input (231) of the lighting unit (230) based on the control signal, for acquiring a measured value at each of the second terminals (246, 256, 266) of the current sources (243, 253, 263), for storing an adjusted control value for each strand (240, 250, 260) based on the acquired measured values and for detecting whether an error condition exists in one of the strands (240, 250, 260) based on the stored control values.