First, profiles, structures
There are basically two types of profiles on the market: all-plastic, semi-plastic semi-aluminum tubes.
1. All-plastic tube: The early LED tube used is a full-plastic tube. Because it mainly uses non-isolated power supply, in order to avoid electric shock, it is more desirable to use a full-plastic tube. Inside is a φ5 straw hat tube LED. The biggest problem with this kind of fluorescent lamp is the heat dissipation problem. Since the heat is completely sealed in the tube, it can't be dissipated at all, the light decay is very serious, and the life of the straw hat tube is very short, and it will be broken in less than 2000 hours.
2, semi-plastic semi-aluminum tube: LED fluorescent lamps sold on the market are basically half of this PC half aluminum alloy, the plastic used in the half that needs light transmission, the half that needs heat dissipation without the need of light transmission Made of aluminum alloy. The power supply is of course placed inside the aluminum tube, so that the heat generated by the LED plus the heat generated by the power supply is quite large, because the power of the lamp is usually around 20W. The power is bigger, and the half-aluminum tube does not solve its heat dissipation problem. Therefore, another heat-dissipating aluminum tube structure is proposed: a fan-shaped aluminum tube. The fan-shaped aluminum tube adopts a fan-shaped heat dissipation structure, which greatly increases the heat sink area. It puts the power supply outside the tube so that the half-sided aluminum shell can be completely made into a heat sink. Compared with semi-circular aluminum tubes, its heat dissipation area has increased by at least three times. In addition, the power is not placed in the tube, and the heat can be reduced, which greatly extends the life of the LED. (The picture can't be put in, please forgive me)
Second, the power supply
The power of LED fluorescent lamps is divided into built-in and external. The so-called built-in means that the power supply can be placed inside the lamp. The biggest advantage of this built-in type is that it can be used to directly replace existing fluorescent tubes without any circuit changes. So the built-in shapes are made into a strip shape so that they can be inserted into a semi-circular tube.
1. Non-isolated constant current power supply: Non-isolated means that there is a direct connection between the load end and the input end, so there is a danger of electric shock when the touch load is applied. The advantage of the non-isolated constant current source is that the circuit design is simple and the manufacturing cost is not high. The disadvantage is that the high voltage of the AC power source is introduced to the load end, which may cause electric shock.
2. Isolated constant current power supply: Isolated type means isolated transformer isolation at the input and output terminals. But both can isolate the input and output. The advantage of isolating the constant current source is that the circuit design is complicated and the risk of electric shock can be avoided. The disadvantage is that the efficiency of the power supply will be reduced, the manufacturing cost is high, and the volume is relatively large. It can be put into the T10 tube, but the tube placed in the T8 is relatively tight.
3. Centralized external power supply: A centralized external power supply is best used for maximum performance. Because the main places to promote LED fluorescent lamps are government agencies, offices, shopping malls, schools, underground parking garages, subways, etc., often more than one fluorescent lamp is used in one room, and there may be more than 10. At this time, a centralized external power supply should be used. The so-called centralized type refers to the use of a high-power AC/DC switching power supply for unified power supply, and each fluorescent lamp uses a separate DC/DC constant current module. This gives the highest efficiency and maximum power factor. The advantages of centralized power supply are obvious. Moreover, it is also an isolated power supply, and this structure is also easy to implement various dimming schemes.
Third, the chip
There is basically nothing to say about this. In general, the quality of first-line brands such as CREE, Osram, Hewlett-Packard (HP), Nichia, and Toyota Synthetic Lumileds is definitely better than that of second-tier or Taiwanese. Currently used in fluorescent lamps are 3528, 3020, 3014 and other specifications, these are mainly the size and size of the chip, the heat dissipation method of the chip is not the same. The same brand of chips, packaging manufacturers are not the same, the quality is not the same.
--Shenzhen Toplight lighting Co. Ltd.(led tube light/LED linear light
/led high bay light/led tri-proof light/Toplight/Toplight Lighting)