LED drive power classification you know how much?
First, let's talk about what is the LED driver power supply. It can convert the power supply to a specific voltage and current to drive the LED to light the voltage converter. Normally: The input of the LED drive power supply includes high voltage power frequency AC (ie mains), low voltage direct current, high voltage direct current, low voltage high frequency AC (Such as the output of electronic transformers) and so on. While the LED drive power output is mostly with the LED forward voltage drop to change the voltage constant current source.
LED power supply core components include switch controller, inductor, switch components (MOSfet), feedback resistor, input filter, output filter and so on. According to different occasions, but also have input overvoltage protection circuit, input undervoltage protection circuit, LED open circuit protection, overcurrent protection and other circuits.
Sorted by drive
(1) constant current
Constant current drive circuit output current is constant, and the output of the DC voltage with the load resistance of the size of a change in a certain range, the load resistance is small, the output voltage is low, the greater the load resistance, the output voltage The higher the height
Constant current circuit is not afraid of load short circuit, but the load is strictly prohibited open;
Constant current drive circuit to drive LED is ideal, but relatively high prices;
It should be noted that the maximum withstand current and voltage values are used, which limits the number of LEDs used.
(2) regulator type
When the parameters in the regulator circuit are determined, the output voltage is fixed, and the output current changes with the load increases or decreases;
Voltage regulator circuit is not afraid of load open circuit, but the load is strictly prohibited short circuit;
To drive the driver circuit to drive the LED, each string need to add the appropriate resistance to each string of LED display brightness average;
The brightness will be affected by the voltage change caused by rectification.
LED drive power characteristics
(1) High reliability
Especially as LED lights drive power, installed at high altitude, maintenance is not convenient, maintenance costs are also large.
(2) High efficiency
LED is energy-saving products, drive power efficiency is higher. It is very important for the power supply to be installed in the fixture. Power efficiency is high, its power consumption is small, in the lamp heat is small, it will reduce the lamp temperature. To delay the LED light failure beneficial.
(3) High power factor
The power factor is the load on the grid. Generally less than 70 watts of household appliances, there is no mandatory indicators. Although the power is not a single power factor lower power factor little effect on the power grid, but the use of large amount of light at night, the same type of load is too concentrated, the grid will produce more serious pollution. For 30 watts to 40 watts of LED drive power, it is said that in the near future, may have a certain degree of power factor requirements.
(4) Drive mode
Now there are two kinds of traffic: one is a constant pressure source for a number of constant current source, each constant current source to each LED power supply. 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 a direct constant current power supply is "in the Division Huibao" to use the drive mode, LED series or parallel operation. Its advantage is a little lower cost, but the flexibility is poor, but also to solve an LED failure, does not affect the other LED operation problems. These two forms coexist for a period of time. Multi-channel constant current output power supply, in terms of cost and performance will be better. Perhaps the future direction of the mainstream.
(5) Surge protection
LED anti-surge capability is relatively poor, especially anti-reverse voltage capability. It is also important to strengthen this protection. Some LED lights installed in the outdoors, such as LED lights. Due to the load of the grid load and lightning induction, from the grid system will invade a variety of surges, and some surge will lead to LED damage. Therefore, the analysis of "in the Division Huibao" drive power in the surge protection should have a certain lack of, and as the frequent replacement of power and lighting, LED drive power to suppress the surge of intrusion, the protection of LED is not damaged capacity.
(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 comply with safety and electromagnetic compatibility requirements.
The overall constant current and the way of constant current work advantages and disadvantages
Compared with the overall constant current, the road constant current although the shortcomings are more cost is relatively high. But it can really play a protective LED and extend the life of the LED, so the road is the future trend of constant current.