LED Current Control Circuit with Temperature Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing circuits for regulating current to LEDs are complex and expensive, requiring accurate analog circuit electronics to manage temperature-dependent current derating effectively, which is crucial for maintaining the safe operating area and preventing damage.
Innovation Solution
A circuit comprising a temperature sensor, a compensation unit, and a control unit that adjusts the current based on a difference between a reference signal and an electrical signal from the compensation unit, ensuring operation within the safe operating area by derating current linearly or non-linearly with temperature, thereby preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accurate analog circuit electronics are used to control current depending on ambient temperature, then current regulation precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex analog circuit electronics with a microcontroller-based digital control system. The microcontroller reads temperature from a sensor and calculates appropriate current levels through software algorithms, substituting mechanical/electrical analog computation with digital processing. This reduces hardware complexity while maintaining or improving regulation precision through programmable control logic.
Solution Approach 2:
The invention changes the control parameter from direct analog voltage/current regulation to digital parameter control. The microcontroller converts temperature readings into discrete current control levels, transforming continuous analog regulation into stepped digital control. This parameter transformation simplifies the control architecture while enabling flexible adjustment of current characteristics through software.
2Illumination intensity
If current is increased to maintain luminous flux at higher temperatures, then light output is improved, but thermal runaway risk increases
Solution Approach 1:
The patent implements a closed-loop feedback control system where the microcontroller continuously monitors temperature via a temperature sensor and adjusts the LED current accordingly. When temperature rises, the system automatically reduces current to prevent thermal runaway, while maintaining luminous flux within acceptable ranges. This feedback mechanism creates a self-regulating system that balances light output with thermal safety.
Solution Approach 2:
The invention applies preliminary anti-action by proactively reducing current before critical temperature thresholds are reached. The control algorithm predicts thermal trends and preemptively adjusts current levels to counteract potential thermal runaway, rather than reacting after damage occurs. This preventive approach maintains luminous flux while eliminating thermal hazards.
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
The solution provides a cost-effective and reliable method to regulate current, ensuring LED operation within safe temperature limits, extending its lifetime by avoiding thermal runaway and maintaining controlled luminous flux.
Implementation Method 1
a compensation unit (3) comprising a temperature sensor (32) and providing an electrical signal at an output (302), the electrical signal depending on the current applied to the electrical load (4) and on a temperature measured by the temperature sensor (32)
Data Source
AI summary
Circuit for regulating a current applied to an electrical load, comprisinga compensation unit comprising a temperature sensor and providing an electrical signal at an output, the electrical signal depending on the current applied to the electrical load and on a temperature measured by the temperature sensor,a reference unit providing a reference electrical signal, anda control unit regulating the current applied to the electrical load depending on a difference between the electrical reference signal and the electrical signal provided at the output of the compensation unit.