Power Supply Unit Three-Wire Analog Interface for LED Lighting
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Solution Overview
Problem
Existing interfaces for Power Supply Units and Light Engine Modules in LED-based lighting systems are unable to efficiently support multiple module connections while minimizing wire count and maintaining thermal derating capabilities, leading to complex current adjustments and increased costs.
Innovation Solution
A three-wire analog interface where the Power Supply Unit measures the equivalent resistance of current set resistors across Light Engine Modules, using an operational amplifier to inversely set the output current and incorporate a temperature-dependent current generator for thermal derating, allowing multiple modules to be connected in parallel with reduced wire usage and simplified electronics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple Light Engine Modules are connected to a single Power Supply Unit, then the system can support more LEDs and higher light output, but the complexity of current adjustment increases
Solution Approach 1:
The Power Supply Unit is designed with a universal current adjustment mechanism that automatically adapts to any number of connected Light Engine Modules. The control unit measures the total current draw and dynamically adjusts the driving current accordingly, eliminating the need for manual reconfiguration or complex switching mechanisms when modules are added or removed.
Solution Approach 2:
The system implements a feedback loop where the control unit continuously monitors the current drawn by the connected Light Engine Modules and automatically adjusts the driving current to maintain optimal operation. This closed-loop control simplifies the interface by eliminating the need for manual current setting while ensuring proper current distribution across multiple modules.
2Measurement precision
If the Power Supply Unit is programmed at manufacturing for specific current requirements, then the current adjustment is precise, but the adaptability to different configurations is reduced
Solution Approach 1:
The Power Supply Unit transitions from a static, pre-programmed current setting to a dynamic, automatically adjustable current control system. The control unit continuously adapts the driving current based on the actual number of connected Light Engine Modules and their real-time power requirements, maintaining precision while maximizing versatility.
Solution Approach 2:
The system performs self-configuration by automatically detecting the number of connected modules and adjusting its output current accordingly. The control unit measures the total current draw and autonomously determines the appropriate driving current level, eliminating the need for manual programming or external configuration while maintaining precise current control.
3Loss of information
If additional wires are used for interfacing between Power Supply Unit and Light Engine Modules, then more information can be exchanged, but the wire count and system complexity increase
Solution Approach 1:
The system combines multiple functions into existing wiring by having the control unit derive both power and configuration information through the same electrical connection. The existing power delivery wires also serve as communication channels, allowing the control unit to measure current draw and determine module configuration without requiring separate communication wires.
Solution Approach 2:
The electrical interface is designed to perform multiple functions simultaneously: power delivery, current measurement, and configuration detection all occur through the same wiring harness. This multi-functional approach eliminates the need for dedicated communication wires while maintaining full system control and information exchange capability.
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
Enables efficient current adjustment and thermal derating across multiple Light Engine Modules with reduced wire count, ensuring reliable operation and cost-effectiveness by using a simple resistor-based system with a temperature-controlled current generator, while maintaining accuracy and flexibility in system design.
Implementation Method 1
the Power Supply Unit is configured to determine the value of the current set resistor by clearing out the voltage drop on said common ground line by applying via the voltage source two different voltages to the communication line
Implementation Method 2
incorporate a temperature-dependent current generator for thermal derating
Data Source
Figure 1~3
Figure 4a~4b
Figure 5
AI summary
The invention is conducted to a Power Supply Unit and a lighting system consisting of said Power Supply Unit with at least one Light Engine Module and an inventive interface. The Power Supply Unit (PSU) comprises an output providing electrical power between a positive power supply line (LED+) and a common ground line (LED-), and a communication line (CL). An adjustable current generator (CG) responsive to an internal measurement signal (Vout) generates an output current (Iout) at the output, and a voltage source (Vk) is coupled to the communication line. A current measurement unit (CMU) measures a current through the communication line (CL) and generates the internal measurement signal (Vout) depending on the measured current through the communication line (CL). Specifically, the Power Supply Unit (PSU) is configured to determine the voltage drop on the common ground line by applying via the voltage source (Vk) two different voltages to the communication line (CL).