Introduction to the characteristics of LED driver

According to the power utilization rules of the power grid and the characteristic requirements of LED drive power supply, the following points should be taken into consideration when selecting and designing LED drive power supply: 

1. High reliability, especially the drive power supply for LED street lamps, is installed at high altitude, which is inconvenient to maintain and expensive to maintain. 

2. High-efficiency LED is an energy-saving product, and the efficiency of driving power should be high. For power supply installation, the structure of LED drive power supply in the lamp is particularly important. Because the luminous efficiency of LED decreases with the increase of LED temperature, the heat dissipation of 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 also reduces the temperature rise of the lamp. It is beneficial to delay the light decay of LED. 

3. High power factor Power factor is the requirement of power grid for load. Generally, there are no mandatory indicators for electrical appliances below 70 watts. Although the low power factor of a single electric appliance with small power has little impact on the power grid, when everyone lights up at night, the same kind of load is too concentrated, which will cause serious pollution to the power grid. It is said that in the near future, there may be certain index requirements for the power factor of the 30-40W LED drive power supply. 

4. There are two driving modes: one is that one constant voltage source supplies multiple constant current sources, and each constant current source supplies power to each LED separately. In this way, the combination is flexible. The failure of one LED will not affect the operation of other LEDs, but the cost will be slightly higher. The other is direct constant current power supply, LED series or parallel operation. It has the advantage of low cost, but poor flexibility. It also needs to solve the problem of one LED fault, which will not affect 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. It may be the mainstream direction in the future. 

5. The anti-surge capability of the surge protection LED is relatively poor, especially the anti-reverse voltage capability. It is also important to strengthen protection in this regard. Some LED lights are installed outdoors, such as LED street lights. Due to the start and drop of power grid load and the induction of lightning stroke, various surges will intrude from the power grid system, and some surges will cause LED damage. Therefore, LED drive power supply should have the ability to suppress the invasion of surge and protect LED from damage. 

6. In addition to the conventional protection function, it is better to add negative feedback of LED temperature in the constant current output to prevent the LED temperature from being too high. 

7. In terms of protection, the lamp shall be installed outside, the power supply structure shall be waterproof and moisture-proof, and the shell shall be sunproof. 

8. The life of the drive power supply should match the life of the LED. 

9. It shall meet the requirements of safety regulations and electromagnetic compatibility. With the increasingly extensive application of LED, the performance of LED driving power supply will be more and more suitable for the requirements of LED.