Be careful when choosing LED driver power supply

How to wisely choose the right LED driver is a question that every engineer is concerned about. Here we have compiled the opinions of netizens in the forum for your reference.

　　According to the characteristics of power consumption of the power grid, the requirements of LED characteristics and related LED products, three general principles should be followed when considering the selection of LED driver power supply:

　　1. According to the characteristics of LED current and voltage, it is ideal to use constant current drive. It can avoid the change of LED forward voltage causing current fluctuation, and the constant current can stabilize the brightness of LED.

　　2. In addition, the luminous flux of LED is inversely proportional to the temperature, so the power supply heating should be reduced as much as possible and a good heat dissipation system should be designed during use, thereby reducing the working temperature of the LED. 

　　3. In order to ensure the overall life of the LED, the LED temperature must be controlled within a certain range.

　　The following are ten things to pay attention to when choosing an LED driver :

　　1. High reliability: LED products are mainly composed of LED chips and power supplies, heat dissipation shells, control circuits, etc. The quality of the LED power supply directly affects the quality of the product. Especially LED street lamp products, because they are installed at high altitudes, maintenance is inconvenient and costly.

　　2. High efficiency: LED is an energy-saving product, and the driving power supply must also meet the requirements of energy saving. In particular, the structure where the power supply is installed in the lamp is particularly important. Because the luminous efficiency of LED decreases as the temperature of the LED increases. The power supply has high efficiency, its power consumption is small, and the heat generated in the lamp is small, which also reduces the temperature rise of the lamp. It can delay the light decay of LED.

　　3. Constant current drive mode: In order to match the VI characteristics of LED, the LED power supply must use constant current drive mode.

　　4. Surge protection: LEDs have poor impact resistance, so it is necessary to strengthen this protection. Especially for some products installed outdoors, due to the startup of the grid load and lightning, the LED driver power supply must be able to suppress the intrusion of surges and protect the LED from damage.

　　5. Temperature protection function: In addition to the conventional protection function of the power supply, it is best to add negative feedback of LED chip temperature in the constant current output to prevent the PN junction temperature of the LED chip from being too high.

　　6. LED power supply life: The life of the driving power supply should be matched with the life of the LED chip as much as possible.

　　7. Working environment: Due to the different environments in different places, it is important to consider the working environment of the LED lamps, such as temperature, humidity, installation location, etc. Considering the working mode of the power supply, if there is no soft start circuit, there will be a voltage spike at the output at the moment of power on. In order to better protect the LED, a soft start circuit is required. This is a key factor in the stability of the driving power supply.

　　8. Power factor of LED driver power supply: The power factor varies greatly when the same product is used in a large area, which is also a key point to consider for energy-saving products.

　　9. It is best to use a non-electrolytic capacitor design for LED driver power supply: Under normal use conditions, electrolytic capacitors are the shortest-lived devices on the circuit board. Generally, the life span is about 5,000 hours at rated temperature. The good ones can be 10,000 hours, and the bad ones may only be 2,000 hours. At present, the entire social environment is unprincipled in the pursuit of reducing product manufacturing costs, so if you don't get a relatively high price, the chance of choosing good materials is not great. The life of LED can reach 30,000-50,000 hours when the heat dissipation conditions are relatively good. If you want the driver source to match the life of the light source, a driver source without electrolytic capacitors is a better choice. We choose to design a driver source without electrolytic capacitors in underground explosion-proof LED tunnel lights, which is very effective.

　　10. Set current limiting: When the driving source drives multiple LED cores, pay attention to the series and parallel relationship between each channel. In addition to constant current, current limiting should also be set to prevent accidents.