Because of the incomparable features of LED lighting fixtures: environmental friendly, long lifetime, high photoelectric efficiency (the average luminous efficiency of white-ray LEDs has reached up to 100lm/W), LED lighting technology received rapid development in various industries. Theoretically, the average lifetime of LED chips is around 100,000 hours. But this value has never been approved by practical applications. Some LED lamp designers is lack of knowledge of LED power supplies. In order to reduce production cost, they tended to choose cheap LED drivers, without knowing that drivers are one the most important parts of LED lighting devices.
LED drivers, also known as LED power supplies, are a type of converter output special voltage and current. The normal input modes of LED drivers include high-voltage low-frequency AC, low-voltage DC, high-voltage DC and low-voltage high-frequency AC (such as electronic transformer) and so on. The output of LED power supplies is normally constant current sources, which can change voltage with the variations of LED internal forward voltage drop. Core components of LED drivers include: switch controllers, inductors, switching components (MOSFET), feedback resistors, input filter components, output filter pieces. According to the requirements of different occasions, output over-voltage protection circuit, input under-voltage protection circuit, G24 LED open-circuit protection, over-current protection circuit are also needed in some cases.
Key sections of making a good LED lighting product are cooling sections, drivers and light sources. The heat dissipation is particular important. And the cooling effect is a direct impact on the quality and the lifetime lighting products. The lifetime of LED drivers, the stability of output current/voltage also have significant impacts on the service life of the entire lamp. Light source is the core part of LED lighting fixtures.
Because of the particularity of LED manufacturing technologies, different makers (different products from one makers) will produce LED drivers with huge individual differences in current and voltage. Take 1W high-powered white-ray LED chips for example: generally, the forward working voltage of 1W white-ray LEDs is around 3-3.6V. In another word, suppose the internal current flow of one 1W LED white-ray LED is 350mA, voltage across it may 3.1V, 3.2V or 3.5V. When the internal current flow within LEDs reached 350mA, any tiny fluctuations of input voltage will cause huge increase of forward current, and consequently working temperature, which, as we all know, will speed up the light attenuation of LED chips.