Rapidly developed in recent years, the LED application in various industries, control the power supply has become hotspot industry concern. The LED driver can be regarded as a special power supply power to the LED, and can according to need to drive series, parallel or series-parallel multiple leds, satisfy the requirement of drive current. In theory, the service life of the LED in the 100000 hours, but in the process of practical application, due to the design of the driving power and chi to incorrect way, the LED is easily damaged. In general, when the choose and design the LED driver in the general technical requirements are as follows.
High efficiency and high reliability. Leds are energy saving products, drive power efficiency is higher. For the structure of the power supply installed in the lamps and lanterns, this is especially important. Because the LED luminous efficiency with the rising of LED temperature drops, so the LED heat dissipation is very important. Power supply of high efficiency, small power consumption, in the lamps and lanterns of calorific value is small, also lower the temperature of lamps and lanterns, as well as reduce the droop of the led display, is helpful to extend the service life of the lamps and lanterns.

The work reliability of the LED driver must be high (for example, installation, maintenance and replacement of mechanical connection), the output power must be able to meet the requirements of lamps and lanterns (involving the scope of LED forward voltage, electric current and the LED arrangement), especially the LED street lamp driver power supply in high altitude, maintenance is not convenient, the cost of maintenance is also big.

High power factor. The power factor is the requirement of load of power grid. Generally no mandatory indicators for under 70 w electrical appliances. Though the power of the individual with the power factor of electric low a little impact on power grid is not big, but at night you light a lamp and its load is too concentrated, can produce serious pollution to grid. For 30 ~ 40 w LED drive power supply, perhaps in the near future will have certain indicators request for power factor.
Drive way. Led display adopt dc power supply, now the travel there are two kinds of driving mode, one of which is a constant voltage source to multiple constant current source, each constant-current source separately for each led power supply. Flexible combination, this way all the way LED failure does not affect the other LED work, but the cost will be slightly higher. The other is a constant current power supply directly, leds in series or parallel operation. It's a little bit has the advantage of low cost, but poor flexibility, but also solve a LED failure does not affect other LED running problem. These two forms will coexist in a period of time. Multi-channel constant current output power supply mode in terms of cost and performance will be better, it is possible that the mainstream of development direction in the future.
LED driver should be kept constant flow characteristics, especially in the power supply voltage should be remained 15% of the change of output current changes in the range of 10%. Drive should keep lower its power consumption at the same time, so that the system efficiency of LED always stay at a higher level.
Surge protection. LED the ability of anti surge voltage and current is relatively poor, especially the reverse voltage resistance, therefore, to strengthen the protection is very important. In outdoor LED lights, for example, as a result of the power grid load irregular starting and stopping, lightning induction, etc., from the grid system into the various surge voltage, current, some surge voltage, electric current will cause the damage of the LED. Therefore, the LED driver to stifle the surge voltage and current into technical measures, protect the LED from the surge voltage and current of accidental damage.
Protection function. Drive should set up perfect protection circuit, such as low-voltage latch, over-voltage protection, overheating protection, output open circuit or short circuit protection. LED drive, in addition to the conventional protection function, the best in the constant current output increase LED temperature negative feedback circuit, prevent LED temperature is too high.
Protective performance. For outside installation type lamps and lanterns, encapsulation structure of drive power supply to waterproof, moistureproof, shell to fast, resistance to ultraviolet radiation.
Functional requirements. Led display the maximum current can be set, in use process can adjust the brightness of led. Some occasions also requires drive with functions of luminous mode and effect change. Drive should comply with the safety standards and the requirements of electromagnetic compatibility, while working on other small electronic devices and the interference effect of the circuit.

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