Currently, LED fluorescent lamps market is very active. Manufacturers can be divided into three types: a. original LED chip manufacturers, started to penetrate to downstream packaging and application business, having little knowledge in circuit and power supply; b. ordinal general lighting application manufactures, entering a new field, having little knowledge in circuit; c. new comers, they just started their new venture in the field of LED lighting business, having no knowledge in LED power supply. LED power supply (LED driver) is the most important part of LED fluorescent lamps. Improper selection of LED drivers will reduce the performance of LED tubes or even disable the normal work of them.
Why must be a constant current: characteristics of LED semiconductors seriously influenced by the environment: LED current will increase with the raise of temperature and input voltage. Working under over-rated current for a long time, the service life of LEDs will be declined drastically. Constant current can fix the internal working current in diverse temperatures and voltages.
The match between LED fluorescent lamps and lighting boards: some customers are accustomed to design lighting boards before finding matched power supplies. It is rather difficult: too much current Vs too small voltage (I>350mA, V<40V); otherwise too much voltage Vs too small current (I<40mA, V>180V), leading to a result of over-heated, low efficiency, insufficient input voltage range. The best solution is to choose an optimal connection mode (series/parallel), making current/voltage on each LED chip remain the same. By doing so, LED power supplies can get the best performance.
The operation current: the general LED rated operating current is 20mA. Some makers would set the initial current as 20mA. In fact, working under such current, LED Tunnel Light chips will generate a large amount of heat. After numerous comparison tests, 17mA is an ideal value. The total current of N-way parallel branches is 17*N.
The operation voltage: generally, the suggested operation voltage of LED chips is 3-3.5V. According to measurements, most of LED chips will work under 3.125V voltage, which has been proved a relative ideal value. The total voltage of M-way series branches is 3.125*M.
Dimensions: height is the main restriction factor. LED chips used for LED T6/T8 tubes should have a height no more than 9 mm, and no more than 15 mm for T10 tubes. Long in length can help to conduct heat.