LED Lamp Temperature Control Circuit with Magnetic Ballast
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Solution Overview
Problem
LED lamps using a magnetic ballast can experience excessively high internal temperatures when replacing fluorescent or high-pressure gas discharge lamps, leading to reduced service life due to excessive heat generation, as existing solutions lack adaptive power adjustment mechanisms.
Innovation Solution
A temperature control circuit is integrated with the LED lamp, featuring a negative temperature coefficient thermistor and a phase cut circuit that adjusts the output power by decreasing resistance when internal temperatures exceed a threshold, thereby reducing drive current and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a magnetic ballast is used to drive LED light source, then the LED lamp can replace fluorescent or high-pressure gas discharge lamps, but the internal temperature of the LED lamp becomes excessively high
Solution Approach 1:
The patent implements a feedback control mechanism using a temperature sensing module that continuously monitors the internal temperature of the LED lamp and feeds this information back to the control module. Based on the temperature feedback, the control module dynamically adjusts the drive current through PWM dimming control, thereby resolving the contradiction between maintaining LED operation and preventing excessive heat accumulation.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities through the control module that can vary the drive current to the LED light source based on real-time temperature conditions. This dynamic control allows the system to adapt its operating parameters, reducing current when temperature rises, thus preventing thermal overload while maintaining operational flexibility.
2Power
If drive current is not reduced when temperature is high, then LED can operate at full power, but service life of LED lamp is reduced
Solution Approach 1:
The temperature sensing module provides continuous feedback on the internal temperature conditions to the control module. When high temperature is detected, the control module responds by reducing the drive current through PWM dimming control, thereby protecting the LED from thermal damage and extending service life while maintaining near-full power operation under normal temperature conditions.
Solution Approach 2:
The patent implements preventive protection mechanisms by continuously monitoring temperature and proactively reducing drive current before thermal damage can occur. The control module is designed to detect temperature rises and adjust power delivery in advance, cushioning the LED against potential thermal stress and extending its operational lifespan.
3Reliability
If dedicated LED drive circuit is developed, then LED can be driven properly, but device complexity increases
Solution Approach 1:
The control module serves multiple functions: it acts as a dimming control module for PWM dimming control, a temperature control module for thermal management, and a drive circuit for powering the LED. By integrating these functions into a single multi-functional module, the patent achieves proper LED drive compatibility without significantly increasing overall device complexity.
Solution Approach 2:
The patent combines the temperature sensing module, control module, and LED drive circuit into an integrated system. The control module integrates both dimming control and temperature management functions, reducing the number of separate components needed and simplifying the overall circuit architecture while maintaining reliable LED operation.
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 effectively maintains internal temperatures within a safe range, extending the service life of the LED lamp by adaptively reducing output power and drive current when high temperatures are detected.
Implementation Method 1
a thermal sensitive module having a negative temperature coefficient thermistor
Implementation Method 2
adjusts the output power of the LED unit by decreasing a resistance of the negative temperature coefficient thermistor
Data Source
AI summary
The present invention provides an LED lamp and a temperature control circuit applied to the LED lamp. The LED lamp includes at least one LED unit, a magnetic ballast, and an LED drive circuit. The magnetic ballast is coupled to a power and configured to limit and stabilize a received alternating current. The LED drive circuit includes a temperature control circuit. The temperature control circuit is coupled to the magnetic ballast and connected in parallel with the LED unit, is configured to detect an internal temperature of the LED lamp and adjust an output power of the LED unit, and includes a thermal sensitive module having a negative temperature coefficient thermistor and a phase cut circuit. The phase cut circuit is coupled to the thermal sensitive module, and adjusts the output power of the LED unit by decreasing a resistance of the negative temperature coefficient thermistor when the negative temperature coefficient thermistor detects that the internal temperature of the LED lamp is higher than a specified temperature threshold.