One type: LED energy saving lamp, made of straw hat type small power LED, and the power supply adopts the resistance resistance and depressurization circuit. Use the LED package form hat type indicator LED, epoxy resin packaging, in which the LED chip will not radiate heat, light, a lot of white LED, after a period of use, the temperature becomes high, gradually into the blue side, dim. There are also manufacturers straw hat type LED is committed to the development of low light decay, but without changing the package form, light is still not big change. This kind of LED energy saving lamp product is a transitional product with low price and poor quality.
Two class: LED energy-saving lamps made of 3528 or 5050 patches of small and medium power LED, power supply is generally used by resistance capacitance step-down circuit, there are some manufacturers to adopt constant current circuit, compared strawhat type LED, SMD LED cooling slightly better, with a heat conducting substrate, in aluminum plate, can be a part of the heat. But due to the LED or ignore the heat, many power SMD LED energy-saving lamp, no radiator, still use plastic shell, light is still serious. The low end power supply with resistance and pressure reduction is used, because the voltage is unstable, the current fluctuates, the brightness also fluctuates, the price is moderate, and the quality is slightly better.
Three class: LED energy-saving lamps made of high power chip LED, power supply generally uses constant current isolation circuit, which has a constant current, such as 5W LED, usually with 5 1 watt LED chip series, powered by the current source of constant current 300mA, wide voltage, make power fluctuation current, flux is not changed, the brightness is maintained constant, 5 piece of LED welding in aluminum plate, aluminum plate based on the radiator, the use of heat can be quickly dispersed, ensure that the LED chip LED allows the temperature below the junction temperature, so as to ensure real and effective life of LED energy-saving lamp. This kind of LED lamp is high in price and good in quality. It is also the direction of the development of LED energy saving lamp.
A good LED energy saving lamp should consist of four parts: high quality LED chip, constant current isolated power supply, suitable radiator for relative lamp power, light diffusion effect and soft light source.