Design of LED system thermal management is an important part, and through the circuit to realize the function of temperature compensation for thermal management is an economical and reliable method. Most of the current LED lighting manufacturers will be the driving current of the LED design does not change with temperature constant current source, therefore, when the LED surrounding temperature is higher than the safety temperature point,
Viribright LED globe lamp dab8d29ck the working current is not in the safety zone, this will cause the LED 's life is far lower than the specification numerical even direct damage. While the LED surrounding temperature is too high by LED fever causes, there are two ways to solve this problem.
One approach is the use of thermal conductivity and better heat radiating device, reducing the LED chip to a thermal resistance, control LED internal temperature not higher than ambient temperature too much, but it needs high cost. In addition, it is difficult to avoid the problem is, when the heat dissipation device is used for a period of time in the body of the heat sink of settled dust, and aluminum base copper clad plate is connected to the copper layer and the aluminum substrate dielectric layer aging degumming will lead to resistance greatly rise, resulting in an overall thermal performance decline.
Another approach is to make LED work in the area of security margin, which meet in a safe temperature points within the output current, output power work in rated condition and constant, and above the safety temperature output current proportional drop negative compensation,
Viribright LED Bulb Brand ensure that LED service life, this is the definition of temperature compensation.
Radiation detection function is also very important. We could be detected by NTC voltage to detect LED lamp temperature changes. The detected voltage and temperature of NTC directly, while NTC resistance varies with NTC and its peripheral circuit temperature rising and falling. Use the NTC to determine the temperature there are two basic methods.
Methods: in a system of mandatory implementation of a known voltage divider circuit used in NTC, and subsequently measuring NTC node voltage. NTC temperature increase, decrease of resistance. Resistance reducing the amount lead divider ratio. NTC node voltage also decreases as the temperature increases.
Method two: compulsory known current through NTC, and measuring the voltage across NTC. NTC temperature increase, decrease of resistance. According to the Ohm's law,
hk-car resistance reducing the amount change of NTC node voltage. Such as resistance decreases while the current remains constant, NTC node voltage will drop too.
PR
