According to the characteristics of the grid electricity, led feature requirements and relevant led products, when choosing led drive power supply should consider the following:
1, according to the LED current and voltage characteristics, ideal is to use a constant current driver. It can avoid the LED forward voltage caused by the change of the current change, at the same time that the brightness of the LED constant current stability.
2, in addition, the LED luminous flux is inversely proportional to the temperature, so use in the design should try to reduce the power of fever and good cooling system. To reduce the LED working environment temperature.
3, in order to guarantee the whole life of LED products, the LED junction temperature must be controlled in a certain range, which is to control the work environment temperature of the LED products.
LED feature requirements
1, high reliability
LED products mainly have LED chips and power supply, cooling case, control circuit, etc. Which led the built-in driving power supply quality directly affect the quality of the product. Especially the LED street light products, because in a high altitude, maintenance is not convenient, the cost of maintenance is also big.
2, high efficiency
Leds are energy saving products, driving power supply also want to accord with the requirement of energy conservation. The structure of the power supply installed in the lamps and lanterns, in particular, is especially important. Because the LED luminous efficiency with the rising of LED temperature drop. Power supply of high efficiency, its power consumption is small, in the lamps and lanterns of calorific value is small, also lower the temperature of lamps and lanterns. Good for delaying the LED light failure.
3, constant current drive mode
To cooperate the volt-ampere characteristics of leds, so LED built-in drive power supply must use constant current drive way.
4, surge protection
LED impact resistant ability is poor, so should strengthen the protection of this aspect. In particular, some in outdoor products, power grid load start-stop and lightning strike will have impact on the power supply. So the LED driver power supply input terminal to stifle the surge protection circuit, avoid switch instant damage the LED.
5, the temperature protection function
Power supply in addition to conventional protection function, it is better to add the LED chip temperature in the constant current output feedback, to prevent the LED chip p-n junction temperature is too high.
6, LED power life
To improve the life of LED drive power supply, we need from several aspects to improve: capacitance with higher life, improve the efficiency of power supply, do a good job in the power of the cooling function, optimize the thermal design of lamps and lanterns. NiuBao power points out that the built-in led drive power belongs to the switching power supply, switching power supply quality and reliability depends on the circuit design, manufacturing process, and the quality of the device. Electrolytic capacitor is indispensable part of the high-power switching power supply. And the normal working life depends on the power supply of switch power supply used by the life of the electrolytic capacitor, electrolytic capacitor of life and is determined by the life and working temperature of the capacitor, electrolytic capacitor in its working life under different temperature difference is very big.
7, the work environment
, due to the different environment in different region to focus on the LED lamps and lanterns in the workplace environment, such as temperature, humidity, such as installation location.
Considering the power works, if not add soft start circuit, current moment, output would have a voltage spikes. To better protect the LED, so you need to add soft start circuit. This is a key factor driving power supply stability.