LED Driving Circuit Thermistor Current Stabilization
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Solution Overview
Problem
LED lamps experience unstable current and reduced service life due to voltage fluctuations in the driving circuit, which existing methods like feedback circuits and capacitors fail to adequately stabilize.
Innovation Solution
Incorporating first and second thermistor units with positive temperature coefficient resistances in the LED driving circuit to convert voltage fluctuations into resistance changes, stabilizing the driving current passing through the LED light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback circuits or capacitors are used to stabilize current, then current stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the current stabilization function from complex feedback circuits and capacitors, implementing it instead through the inherent positive temperature coefficient characteristics of thermistors. This simplifies the circuit structure while maintaining current stability by using the thermistors' natural resistance-temperature relationship to compensate for voltage fluctuations.
Solution Approach 2:
The patent replaces expensive and complex feedback circuits with simple, inexpensive thermistor units. The thermistors provide adequate current stabilization at a lower cost and with simpler circuitry, accepting that they are passive components that operate without active control mechanisms.
2Reliability
If feedback circuits or capacitors are used to stabilize current, then current stability is improved, but manufacturing cost increases
Solution Approach 1:
The patent adopts inexpensive thermistor units to replace costly feedback circuits and capacitors. The thermistors achieve current stabilization through their passive positive temperature coefficient characteristics, eliminating the need for expensive active components and complex circuitry, thereby reducing overall manufacturing cost.
Solution Approach 2:
The patent removes the expensive feedback control mechanisms and capacitor components, retaining only the essential current stabilization function through thermistors. This extraction of the core function from costly components significantly reduces manufacturing expenses while maintaining adequate performance.
3Adaptability or versatility
If voltage conversion is performed, then voltage adaptation is improved, but energy loss increases
Solution Approach 1:
The patent uses thermistors to dynamically change resistance parameters based on temperature, which changes based on power dissipation. This allows the circuit to adapt to different input voltages and maintain stable output current while minimizing energy loss through the inherent self-regulating characteristics of the thermistor units.
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 ensures stable luminescence and extends the service life of LED lamps by maintaining consistent driving current despite input voltage fluctuations.
Implementation Method 1
the resistance of the first thermistor unit is positively correlated to its sensed temperature, and the resistance of the second thermistor unit is positively correlated to its sensed temperature
Implementation Method 2
a voltage conversion unit that is coupled to the power input unit and converts the input voltage into a conversion voltage
Data Source
AI summary
An LED driving circuit and an LED lamp are provided. The driving circuit comprises a power input unit coupled to an input voltage; a voltage conversion unit coupled to the power input unit and converting the input voltage into a conversion voltage; a power output unit coupled to the LED light source; a first thermistor unit connected between the power input unit and the voltage conversion unit; a second thermistor unit connected between the voltage conversion unit and the power output unit, where the second thermistor unit and the conversion voltage generates a driving current passing through the LED light source; where the resistance of the first thermistor unit is positively correlated to its sensed temperature, and the resistance of the second thermistor unit is positively correlated to its sensed temperature to stabilize the driving current.