LED power supply is also a supporting products currently on the market power quality is poor, the following businesses entering the bank to provide some knowledge of the LED drive power.
The characteristics of the LED drive power
(1) high reliability
Especially as the drive power of the LED lights installed in the high altitude, inconvenient repairs and maintenance spend.
(2) high efficiency
LED energy-saving products, the higher the efficiency of the drive power. Results cooling power installed in the fixture is very important. High efficiency power supply, the loss power, heat in the fixture, and reduces the temperature rise of the lamps. Beneficial to delay the LED light failure.
(3) high power factor
The power factor is the grid load requirements. Appliances generally less than 70 watts, there is no mandatory targets. Power is not a single electrical power factor on the grid has little effect, but the use of large amount of lighting at night, focus too much on similar load, the grid will produce a more serious pollution. 30 watts to 40 watts of LED drive power, said that in the near future, will power factors may have certain specifications.
(4) drive way
Now common, there are two: one is a constant voltage source for the constant current source, each constant current source separately to each LED power supply. In this way, the combination of flexible, all the way to the LED fault, does not affect the other LED’s work, but the cost will be slightly higher. The other is a direct constant current power supply is in the Division Hui Bao “to drive the LED in series or parallel operation. Its advantage is low cost, but the flexibility is poor, but also to solve a LED fault, does not affect other LED running. These two forms co-exist within a certain period of time. Multi-channel constant-current output power supply, in terms of cost and performance. May be a future direction of the mainstream.
(5) Surge Protection
LED anti-surge capacity is relatively poor, especially the anti-reverse voltage capability. Is also important to strengthen this protection. Some LED lights installed in the outdoors, such as LED street lights. Kai rejection grid load and the induction of lightning from the grid system will invade a variety of surge, some surge can cause damage to the LED. Therefore, the analysis in Section Hui Bao “drive power in the surge protection should have a certain lack of frequent replacement as for power and lighting, LED drive power have to inhibit the intrusion of surge, the ability to protect the LED is not damaged.
(6) protection
Power in addition to conventional protection functions, the best increase in the constant current output LED temperature negative feedback to prevent the LED temperature is too high; to comply with the requirements of the safety and electromagnetic compatibility.
3, according to the drive mode.
(1) constant flow
Constant current drive circuit output current is constant, and the output DC voltage with the change of load resistance of different sizes within a certain range, load resistance is small, the output voltage, the greater the load resistance, the output voltage higher;
Not afraid of the constant current circuit load short circuit, but is prohibited to load completely open;
Constant current drive circuit driving the LED is an ideal, but the relatively higher prices;
Should be noted that the Maximum current and voltage values, which limits the number of the LED.
(2) The regulator type
When the parameters identified in the regulator circuit, the output voltage is fixed, the output current changes with changes in load;
The regulator circuit are not afraid of open-circuit load, but it is prohibited to load completely short-circuit;
Regulator drive circuit drives LED strings with a suitable resistor before each string of LED display brightness average;
The brightness will be affected by the rectifier from the voltage change.
4, the overall constant current and constant current work by road advantages and disadvantages
-By-channel constant current shortcomings more, the cost is relatively high compared with the overall constant current. But it can truly protect LED and extend the life of the LED-by-channel constant current is the future trend.
5, LED power less than
LED driver power supply shortage of reasons:
Production of LED lighting and related products, the company’s technical staff is not enough understanding of the switching power supply to make the power supply is working properly, but some of the critical assessment and electromagnetic compatibility consideration is not enough, or there must have hidden;
Most of the LED power producers are come to do transition from ordinary switching power supply LED power supply, not enough understanding of the characteristics of LED and use;
LED standard little, mostly refer to the standard switching power supplies and electronic ballasts;
Now most of the LED power supply is not unified, so the amount of most of the are relatively small. Small purchases, the price is high, and component suppliers uncooperative;
LED power supply stability: wide input voltage, high and low temperatures, overtemperature, overvoltage, etc. have no problem to solve;
First, the drive circuit as a whole life, especially the key devices such as: the life of capacitance at high temperatures directly affect the power of life;
LED driver should challenge the higher conversion efficiency, especially in the drive of high power LED high bay lights, because all is not as light output power as heat dissipation, the power conversion efficiency is too low, the impact of the LED energy-saving effect play;
Less power (1-5W) applications, the proportion of the cost of constant current drive power is close to 1/3 the cost of the light source has been close to a certain extent, affected the marketing.