LED constant current driver

Due to the LED's features sensitive semiconductor devices, but also has negative temperature characteristic, therefore in the process of application need to be stable working status and protection, to produce the concept of drive. LED devices near demanding of drive power supply, LED, unlike ordinary incandescent bulbs, can be directly connected to the 220 v ac mains. LED is 2 ~ 3 v low voltage driver, must want to design complex conversion circuit, different USES of LED lights, with different power adapter. Foreign clients in the international market for the LED drive power conversion efficiency, effective power, accuracy of constant current, the power life, electromagnetic compatibility requirements are very high, design a good power supply must be considering these factors, because of the role of power in the lamps and lanterns is as important as the heart of the people.

the LED constant current drive

with LED as a monitor or other lighting equipment or back light, need to be constant current drive, the main reason is that the

1. Avoid drive current exceed the maximum rating, affect its reliability.

　　2. To obtain the desired brightness requirements, and ensure the consistency of the LED brightness, chroma

3. Can effectively avoid lightning, surge of power grid, over current, over voltage protection, the LED life

there is a problem to deal with good heat dissipation problem, heat problem affecting the service life of the LED without a handle, improve the efficiency of

the leds are driven by dc, therefore between the mains and the LED need to add a power adapter or the LED driver power supply. Its function is to convert the ac mains to fit the LED of direct current. According to the rules of the grid electricity and LED driver feature requirements, to consider when choosing and design LED drive power supply to the following

1. High reliability,

special like LED street lamp driver power supply, in a high altitude, maintenance is not convenient, the cost of maintenance is also big.

　　2.

the LED is energy saving products with high efficiency, the efficiency of the driving power supply. For the structure of the power supply installed in the lamps and lanterns, is particularly 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, 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. High power factor

power factor is the requirement of load of power grid. Generally below 70 watts of electrical appliances, there is no mandatory indicators. Though the power of a single use lower electric power factor, the impact on the 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 watts of the LED drive power supply, it is said that in the near future, may be the index of power factors have certain requirements.

　　4. Drive way

now there are two general one is a constant voltage source for multiple constant current source, each constant-current source separately for each LED power supply. This way, flexible combination, LED failure all the way, don't affect the work of other leds, but the cost would be slightly higher. The other is a constant current power supply directly, leds in series or parallel operation. It 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, for a period of time. Multi-channel constant current output power supply way, in terms of cost and performance will be better. Maybe the mainstream direction of the future.

　　5. Surge protection

LED the ability of anti surge is relatively poor, especially the reverse voltage resistance. Strengthening the protection is also very important. Some LED lights installed outdoors, such as the LED street light. As a result of the power grid load and sling and lightning induction, into the various surge from the grid system and some surge can cause the damage of the LED. So the LED drive power to suppress surge intrusion, ability to protect the LED was damaged.

　　6. Protection function

power supply in addition to the conventional protection function, the best in the constant current output increase LED temperature feedback, prevent LED temperature is too high.

　　7. Protection

type lamps and lanterns is installed outside, power supply structure to waterproof, moistureproof, shell to fast.

　　8. Drive power supply to match the LED life life

9. To conform to the requirements of the safety and electromagnetic compatibility

to assist

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