Introduction of factors to be considered when selecting and designing LED driving power supply
The following points should be considered when selecting and designing LED driving power supply: 1. High reliability, especially the driving power supply like LED street lamp, is installed at high altitude, which is inconvenient for maintenance and expensive for maintenance.
2. High efficiency LED is an energy-saving product, and the efficiency of the driving power supply is high.
For the installation of power supply, the structure of LED driving power supply in lamps 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 loss power is small, and the calorific value in the lamp is small, thus reducing the temperature rise of the lamp. It is beneficial to delay the light decay of LED.
3. The reason for high power is the requirement of the power grid for load.
Generally, there is no mandatory indicator for electrical appliances below 70 watts.
Although the low power of a single electrical appliance with low power has little effect on the power grid, it will cause serious pollution to the power grid if everyone lights up at night and the similar load is too concentrated.
For 30 watts ~ 40 w led drive power supply, it is said that in the near future, perhaps there will be a certain index requirements for power reasons.
4. There are two driving modes: one is a constant voltage source for multiple constant current sources, and each constant current source supplies power to each LED separately.
This way, the combination of flexible, all the way LED failure, does not affect the work of other LED, but the cost will be slightly higher.
The other is direct constant current power supply, LED series or parallel operation.
Its advantage is that the cost is lower, but the flexibility is poor, but also to solve a certain LED failure, does not affect the operation of other LED problems. 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. Perhaps the mainstream direction in the future.
5. The ability of surge protection LED to resist surge 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 lamps.
Due to the start-up of power grid load and the induction of lightning strike, various surges will invade from the power grid system, and some surges will cause LED damage.
Therefore, the LED driving power supply should have the ability to inhibit surge intrusion and protect the LED from damage.
6. Protection function, the power supply in addition to the conventional protection function, * Fortunately in the constant current output to increase the LED temperature negative feedback, to prevent the LED temperature is too high.
7. In terms of protection, the lamp is installed outside, 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 adapted to the life of the LED.
9. To meet the requirements of safety regulations and electromagnetic compatibility.