LED lighting can not be ignored technical details

LED lighting in the near future by leaps and bounds, led as a green clean light source has been widely recognized. LED light source, long service life, energy saving, easy to use, low cost, and thus in the home lighting will be massive application, statistical survey of 2008 OSRAM optical semiconductor company, global annual household lighting lamp shipments of approximately 50 billion.

The technology of LED light source is mature day by day, the luminous lumen per watt is increasing rapidly, which makes it decrease year by year. 1W LED light as an example, in the spring of 2008 price is the price of 1/3 in the spring of 2006, the spring of 2009 will be reduced to 1/4 in 2006. Led green lighting mass market and steady growth for several years after the demand will be VCD, DVD, mobile phone, MP3 consumer electronics market integrated circuit industry super tsunami!

LED lamp high energy saving, long life, excellent performance and the environmental protection was universally accepted.

LED high energy: DC drive, ultra low power (0.03 watt -1 single Watt) electro-optical power conversion close to 100%, the same lighting effect than traditional light energy saving more than 80%. Led: LED long-life light source is called longevity lamps. Solid-state light, epoxy resin packaging, light body and no loose parts, there is no filament burnability, thermal deposition, fast decay etc..

LED life: service life of up to 50 thousand to 100 thousand hours, longer than the traditional light source life more than 10 times.

Led Li environmental protection: LED is a kind of green light source, environmental protection is better. No ultraviolet and infrared spectrum, low heat and no stroboscopic, no radiation, no pollution and waste Recyclable, no mercury, cold light, safe touch, which belongs to the typical green lighting source.

LED light source characteristics of lighting VF voltage LED light source is very low, generally VF =2.75-3.8V, IF in 15-1400mA; thus LED driver output voltage of IC is VF X N or VF X 1, IF constant current in 15-1400mA. LED light LED lamp with low power (IF=15-20mA) and high power (IF>200mA) two), low power LED for LED fluorescent lamp, decorative lamp, grille lamp; high power LED used for family lights, spotlights, underwater lamp, wall lamp, street lamp, tunnel lamp, automobile working lamp etc.. Power LED light source device is low voltage and high current drive, the luminescence intensity is determined by the current flowing through the size of LED, the current is too strong will cause LED light attenuation, weak current will affect the luminescence intensity of LED, therefore, LED driven by the need to provide a constant current power supply, to ensure the safety of large power LED use, and achieve the ideal luminous intensity. In the field of LED lighting, to reflect the characteristics of energy saving and long life, choose a good LED driver IC is essential, there is no good driver IC match, LED lighting can not reflect the advantages of. Need attention to the technical details of LED lighting design

Requirements of LED lamps for low voltage drive ic:

1 driver chip nominal input voltage range shall satisfy DC8-40V, to cover the needs of application, such as pressure can better than 45V; AC 12V or 24 V input simple bridge rectifier output voltage with voltage fluctuation, especially the output DC voltage of high voltage is high, such as drive IC wide the voltage range can not, often in the voltage rise will be breakdown, LED light source has therefore been burned.

2 drive chip nominal output current is more than 1.2-1.5A, the LED light source for lighting, led 1W power source the nominal operating current is 350mA, the LED 3W power source the nominal operating current is 700mA, high power needs more current, so the selection of the LED lighting driver IC must have current output enough, the design of products need to drive the IC in full load output 70-90% the best working area. The use of full negative output current drive IC narrow space in the lamp poor heat dissipation, easy fatigue and early failure.

The output current required long constant 3 driver chip, LED light source can be stable luminescence brightness will not flicker; the same driver chip used in the same conditions, the size of the output current should be as consistent as possible, which is discrete is smaller, so in mass production of automatic production line can be effective and orderly; for output current a discrete driver required in the factory or into the production line before stepping on the PCB board, adjust the current setting resistor (Rs) the resistance value of LED lamps to produce constant current drive plate for similar LED light source luminous brightness consistency, consistency of the final product.

4 driver chip package should be conducive to the rapid cooling tube driver chip core, such as the tube core (Die) directly binds to copper, and there is a direct extension to the Pin package, can be directly welded heat quickly in the PCB board on the copper foil (Figure 1). Such as in a similar 4X4mm silicon core, to a long time through the 300-1000mA current, there will be power consumption, will inevitably heat, the chip itself is the most important physical heat dissipation structure.

5 driver chip itself anti EMI, noise and high capacity but also to the LED lighting products can pass CE, UL certification, so that the drive chip itself at the beginning of the design to the topological structure of excellent and high production technology.

6 drive chip power consumption is less than 0.5W, the switching frequency is more than 120Hz, in order to avoid the interference caused visible flicker. Led green lighting to drive chip to the development of innovative design, LED lighting is cannot do without the driver chip, so we need a variety of functional LED light