LED lighting LED driver power supply

Do a LED lighting products, the key lies in the heat, power supply, heat source, and is particularly important, the cooling effect directly affects the life quality of lighting products, the stability of driving life and output current and voltage of the power supply has a great influence on the whole life of product quality, light source is the key part of the whole product the.

LED driver power supply is also a supporting products, the current market power quality is uneven, the following provides some knowledge of LED driver power supply.

1, what is the LED driver power supply

LED drive power to the power supply is converted to voltage and current to drive the LED specific light voltage converter, typically LED drive power input includes high voltage AC (i.e., electric), low voltage DC, high voltage DC and low frequency AC (electronic transformer output) etc.. The output of the LED drive power supply is mostly a constant current source which can be changed with the change of the forward voltage drop of LED. The core components of LED power supply include switch controller, inductor, switch component (MOSfet), feedback resistor, input filter, output filter and so on. According to the requirements of different occasions, but also the input over-voltage protection circuit, input undervoltage protection circuit, LED open circuit protection, over-current protection circuit.

2, the characteristics of LED power supply

(1) high reliability particularly like LED lamp drive power, installed at high altitude, convenient maintenance, maintenance costs are high.

(2) high efficiency LED is energy-saving products to the high efficiency of the drive power. It is very important to install the power supply in the lamp. The efficiency of the power supply is high, the power consumption is small, the heat in the lamp is small, and the temperature rise of the lamp is reduced. Favorable to delay the LED attenuation.

(3) high power factor

Power factor is the requirement of power grid to load. General 70 watts of electrical appliances, there is no mandatory indicators. Although the power of a single power factor is low, little impact on the power grid, but the use of large lighting at night, the same load is too concentrated, will have a more serious pollution to the grid. For 30 watts ~40 watts LED power supply, it is said that in the near future, there may be some aspects of the power factor requirements.

(4) drive

Now there are two kinds: one is a constant voltage source for multiple constant current source, each constant current source to each LED power supply. In this way, the combination of flexible, all the way LED fault, does not affect the work of other LED, but the cost will be slightly higher. The other is the direct current power supply that is, in the Department of Hui Bao to change the use of the driver, LED series or parallel operation. It has the advantage of low cost, but the flexibility is poor, but also to solve a LED fault, does not affect the operation of other LED problems. These two forms coexist over a period of time. Multi channel constant current output power supply, in terms of cost and performance will be better. Perhaps the main direction in the future.

(5) surge protection

LED anti surge capability is relatively poor, especially the ability to reverse voltage. Strengthen the protection of this area is also very important. Some LED lights are installed outdoors, such as LED street lamps. Due to the load shedding and lightning induction, from the grid system will invade a variety of surge, some surge will cause LED damage. The analysis of "driving power of HB" in surge protection should have certain defects, and for power and lighting frequent replacement, LED drive power to invade to suppress the surge, the ability to protect LED from being damaged.

(6) protection function

Power supply in addition to the conventional protection function, it is best to increase the constant current output LED temperature negative feedback, to prevent the LED temperature is too high to meet the requirements of safety and electromagnetic compatibility.

3, according to the driving mode classification

(1) constant current constant current drive circuit output is constant, while the output DC voltage is different with the size of the load resistance in a certain range, the load resistance is small, the output voltage is low, the greater the load resistance, the output voltage is higher; the constant current circuit is not afraid of a shorted load but the non load fully open; constant current drive circuit LED is ideal, but relatively higher prices; should be noted that the use of the maximum withstand current and voltage, it limits the number of the use of LED.

(2) when the voltage stabilizing regulator to determine the parameters in the circuit, the output voltage is fixed, while the output current but increase or decrease with load change; voltage regulator circuits are not afraid of open load, but not completely to load short circuit; voltage drive circuit to drive the LED, each string to add the appropriate resistor the brightness of each string of LED display the average brightness; voltage change by the rectifier to influence.

4. The advantages and disadvantages of the overall constant current and constant current mode

Compared with the overall constant current, constant flow by road, although the shortcomings are more, the cost is relatively high. But it can really play a role in the protection of LED and prolong the life of LED, so the constant current is the future trend.

5, LED power shortage

The production of LED lighting technical personnel and related products for the company to understand the switching power supply is not enough, make the power can work normally, but some of the critical assessment and electromagnetic compatibility is not enough, there are still certain risks; most of the LED power production enterprises are switching power supply from the general transformation over the LED power supply the characteristics of LED and the use of knowledge is not enough; the current standard about LED almost no, mostly reference switching power supply and electronic rectifier standard; now most of the LED power supply is not uniform, so most are relatively small. Small purchase price