Nine factors to consider when choosing LED driver power design

According to the power consumption rules of the power grid and the characteristics of LED driver power supply, the following 9 performance characteristics should be considered when selecting and designing LED driver power supply:

1. High reliability, especially for the driver power supply of LED street lamps, which is installed at high altitude, inconvenient to maintain and the maintenance cost is also high.

2. High power factor, the power factor is the load requirement of the power grid. Generally, there is no mandatory index for electrical appliances below 70 watts. Although the low power factor of a single electrical appliance with low power has little impact on the power grid, when everyone lights up at night, the same load is too concentrated, which will cause serious pollution to the power grid. For 30 watt to 40 watt LED driver power supplies, it is said that in the near future, there may be certain index requirements for power factor.

3. High efficiency, LED is an energy-saving product, and the efficiency of the driver power supply should be high. It is especially important for the structure where the power supply is installed in the lamp. Because the luminous efficiency of LED decreases with the increase of LED temperature, the heat dissipation of LED is very important. The high efficiency of the power supply means that its power loss 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.

4. There are two common driving modes: one is that a constant voltage source supplies multiple constant current sources, and each constant current source supplies power to each LED separately. This mode has flexible combination, and the failure of one LED does not affect the operation of other LEDs, but the cost will be slightly higher. The other is direct constant current power supply, and the LEDs are operated in series or parallel. Its advantage is that the cost is lower, but the flexibility is poor, and the problem of a certain LED failure not affecting the operation of other LEDs must be solved. These two forms coexist for a period of time. The multi-channel constant current output power supply mode will be better in terms of cost and performance. Perhaps it will be the mainstream direction in the future.

5. Surge protection, the ability of LED to resist surges is relatively poor, especially the ability to resist reverse voltage. 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-up 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 driver 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, it is best 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, for external installation of lamps, the power supply structure should be waterproof and moisture-proof, and the shell should be sun-resistant.

8. The life of the driving power supply should be compatible with the life of the LED.

9. It must meet the requirements of safety regulations and electromagnetic compatibility.