According to the power rules of the power grid and the characteristic requirements of the LED drive power supply, the following points should be considered when selecting and designing the LED drive power supply: 1. High reliability It is especially like the driving power supply of LED street lamp, installed at high altitude, it is inconvenient to maintain, and the maintenance cost is also high. 2. High-efficiency LEDs are energy-saving products, and the efficiency of the drive power supply should be high. For power supply installation, the structure of the LED drive power supply in the lamp is particularly important. Because the luminous efficiency of the LED decreases with the increase of the LED temperature, the heat dissipation of the LED is very important. The efficiency of the power supply is high, its power consumption is small, and the heat generated in the lamp is small, which reduces the temperature rise of the lamp. It is beneficial to delay the light decay of LED. 3. High power factor The power factor is the requirement of the grid on the load. Generally, there are no mandatory indicators for electrical appliances below 70W. Although the power factor of a single electrical appliance with low power is lower, it has little effect on the power grid, but if everyone lights up at night, the similar loads are too concentrated, which will cause serious pollution to the power grid. For LED drive power supplies of 30 watts to 40 watts, it is said that in the near future, there may be certain index requirements for power factors. 4. There are two common driving methods: one is a constant voltage source for multiple constant current sources, and each constant current source individually supplies power to each LED. In this way, the combination is flexible, and the failure of one LED will not affect the work of other LEDs, but the cost will be slightly higher. The other is direct constant current power supply, with LEDs running in series or parallel. Its advantage is that the cost is a bit lower, but the flexibility is poor, and it must solve the problem of one LED failure without affecting the operation of other LEDs. These two forms coexist for a period of time. Multi-channel constant current output power supply mode will be better in terms of cost and performance. Maybe it will be the mainstream direction in the future. 5. Surge protection The ability of LEDs to resist surges is relatively poor, especially the ability to resist reverse voltage. It is also important to strengthen protection in this area. Some LED lights are installed outdoors, such as LED street lights. Due to the onset of the grid load and the induction of lightning strikes, various surges will invade from the grid system, and some surges will cause damage to the LED. Therefore, the LED drive power supply must have the ability to suppress the intrusion of surges and protect the LED from damage. 6. Protection function In addition to the conventional protection function of the power supply, it is best to add negative feedback of LED temperature to the constant current output to prevent the LED temperature from being too high. 7. In terms of protection, the lamp is externally installed, the power supply structure should be waterproof and moisture-proof, and the shell should be light-resistant. 8. The life of the driving power supply should be matched with the life of the LED. 9. To meet the requirements of safety regulations and electromagnetic compatibility. With the increasing application of LEDs, the performance of LED driving power will be more and more suitable for LED requirements.
