Active Thermal Management for LED Lighting Systems
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Solution Overview
Problem
Conventional lighting systems require over-engineering for worst-case ambient temperatures, leading to inefficient heat management and reduced light intensity, as they are designed to protect the product rather than maximize intensity.
Innovation Solution
An active thermal management system that uses a non-linear equation to proportionally adjust power based on dimming input, predicting LED die temperature and reducing power before reaching maximum thresholds, allowing for discrete dimming without noticeable user impact and optimizing heat management for typical temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat sinks are designed for worst-case ambient temperatures, then product reliability is improved, but light intensity is reduced and heat management becomes inefficient
Solution Approach 1:
The patent implements dynamic thermal management by continuously monitoring LED junction temperature and adjusting drive current in real-time. The system transitions from static worst-case design to dynamic adaptation, allowing the heat sink to operate efficiently across varying ambient conditions while maintaining reliability and maximizing light intensity at each moment.
Solution Approach 2:
The system employs temperature feedback through junction temperature sensing that continuously monitors thermal conditions and adjusts drive current accordingly. This closed-loop control enables the system to respond to actual thermal states rather than predetermined worst-case scenarios, resolving the contradiction between reliability and light intensity.
2Reliability
If heat sinks are designed for worst-case ambient temperatures, then product protection is improved, but excessive heat sinking is required
Solution Approach 1:
The patent replaces static over-engineered heat sinks with dynamic thermal management that adapts to actual operating conditions. By monitoring junction temperature and adjusting drive current in real-time, the system achieves adequate product protection without requiring excessive heat sinking capacity designed for rare worst-case scenarios.
Solution Approach 2:
The system changes the operating parameter (drive current) dynamically based on junction temperature measurements. This allows the LED to operate at optimal current levels for each thermal condition, preventing the need for oversized heat sinks designed for maximum ambient temperatures that occur rarely.
3Temperature
If power is reduced to prevent overheating, then temperature control is improved, but light intensity is reduced
Solution Approach 1:
The patent implements closed-loop thermal control where junction temperature is continuously measured and drive current is adjusted in response. This feedback mechanism allows the system to maintain optimal light intensity by reducing power only when and where thermal limits are approached, rather than preemptively dimming for all high-temperature conditions.
Solution Approach 2:
The system takes preliminary thermal protection action by monitoring junction temperature and adjusting drive current before damage occurs. Rather than reactive cooling, the control system proactively manages thermal conditions by modulating power input, maintaining both temperature control and light intensity.
Data Source
AI summary
The present disclosure is directed to a solution providing active thermal management that has multiple innovations and advantages. In some aspects, the design of the active thermal management (ATM) device is not a threshold clamp and instead, is a non-linear equation that proportionally changes relative to the dimming input. In some aspects, the innovation of the ATM design is how ATM works while the light is being dimmed. The design anticipates overheating by reducing power before the product gets to the maximum temperature threshold. The design also may include an equation that predicts the LED die temperature as a function of product case temperature. The ATM may operate responsive to one or more of a plurality of profile or power curves.