LED driver power supply introduction

LED driver power is a voltage converter that converts power supply into a specific voltage and current to drive LEDs to emit light. Usually, the input of LED driver power includes high-voltage power frequency AC (i.e. mains), low-voltage DC, high-voltage DC, low-voltage high-frequency AC (such as the output of electronic transformers), etc. The output of LED driver power is mostly a constant current source that can change voltage as the forward voltage drop of the LED changes.

Features

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

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

2. High efficiency LED is an energy-saving product, and the efficiency of the driving power supply must be high. This is especially important for the structure where the power supply is installed in the lamp. Because the luminous efficiency of LED decreases as the temperature of the LED increases, the heat dissipation of the LED is very important. The high efficiency of the power supply means that its power consumption is small, and the heat generated in the lamp is small, which reduces the temperature rise of the lamp. This is beneficial to delaying the light decay of the LED.

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

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 LEDs have poor surge resistance, especially reverse voltage resistance. It is also important to strengthen this protection. 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 LEDs. Therefore, the LED driver power supply must have the ability to suppress the intrusion of surges and protect the LEDs from damage.

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

7. In terms of protection, the lamp should be installed outside, the power supply structure should be waterproof and moisture-proof, and the outer 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 comply with safety regulations and electromagnetic compatibility requirements.

As LEDs are increasingly used, the performance of LED driver power supplies will become more and more suitable for LED requirements.