网上棋牌LED drive circuit directly aff
LED driver power supply operat
Difficulties in LED drive power drawing
a. Power description. Although LED has high light efficiency, there is still 80-85% of heat loss, resulting in a temperature rise of 20-30 degrees inside the lamp. If the room temperature is 25 degrees, the inside of the lamp has 45-55 degrees, and the power supply is always in a high temperature environment. Under the operation, the power margin must be increased to ensure longevity, usually leaving 1.5-2 times the margin.
b. Component selection. When the internal temperature of the luminaire is 45-55 degrees, the internal temperature rise of the power supply is still about 20 degrees, and the temperature of the adjacent element reaches 65-75 degrees. Some components will drift in the parameters of high temperature, and some life will be shortened, so the equipment should be selected to be used at a higher temperature for a long time, with special attention to electrolytic capacitors and wires.
c. Electrical features are depicted. The parameter description of the switching power supply to the LED is mainly constant current parameters. The magnitude of the current determines the brightness of the LED. If the batch current error is large, the brightness of the entire batch of lamps is not uniform. And temperature changes can also cause the power supply output current to shift. The
e. Certification challenges. At present, there is no standard for LED lamps in China. The relevant parts of the country are being studied and formulated. The domestic sales of lamps and lanterns certification is based on the specification of lighting lamps, the export is done by CE or UL certification, and some also refer to foreign LED lamp specifications. . Therefore, in line with this situation, the description of the switching power supply must be satisfied with the above specifications are more difficult, we can only aim at different requirements not the same as the certification.