Technical details of the hottest LED lighting that

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Technical details of LED lighting that cannot be ignored

LED lighting fixtures have been developed by leaps and bounds in recent years. As a green and environmentally friendly clean light source, LED has been widely recognized. LED light source has the advantages of long service life, energy saving and power saving, simple and convenient application, and low use cost, so it will be widely used in home lighting. OSRAM optical semiconductor company investigated and calculated in 2008 that the global annual shipment of home lighting lamp holders is about 50billion

led light source technology is becoming more and more mature, and the luminous lumens per watt are growing rapidly, prompting it to reduce prices year by year. Taking 1W LED light source as an example, the price in the spring of 2008 has been one third of that in the spring of 2006, and will drop to one quarter of that in the spring of 2009

the massive market of LED green lamps and the continuous and stable growth demand for several years will be a super tsunami in the consumer electronics market of the integrated circuit industry after VCD, DVD, MP3! LED lamps are widely recognized for their superior performance of high energy saving, long life and environmental protection

led high energy saving: DC drive, ultra-low power consumption (single tube 0.03 watt -1 Watt) electro-optical power conversion is close to 100%, and the same lighting effect is more than 80% energy saving than traditional light sources

led long life: LED light source is called long life lamp. The solid cold light source is encapsulated with epoxy resin, and there is no loose part in the lamp body. There are no shortcomings such as easy burning, thermal deposition and fast light decay of the filament. The service life can reach 50000 to 100000 hours, which is more than 10 times longer than that of the traditional light source. Time waits for no man! Cui Lixin said

led is beneficial to environmental protection: LED is a green light source with better environmental protection benefits. There are no ultraviolet and infrared rays in the spectrum, low heat, no stroboscopic, no radiation, and the waste can be recycled, no pollution, no mercury, cold light source, can be safely touched, which is a typical green lighting source

led light source working characteristics VF voltage of LED light source for lighting is very low, generally VF =2 8V, if in Ma; Therefore, the output voltage of LED drive IC is VF x n or VF x 1, and if constant current is ma. There are two kinds of LED light sources used in LED lamps: low power (if=ma) and high power (if 200mA). Low power LED is mostly used as LED fluorescent lamp, decorative lamp and grille lamp; High power LED is used to make home lights, spotlights, underwater lights, wall washing lights, street lights, tunnel lights, car work lights, etc. Power LED light source is a device driven by low voltage and high current. Its luminous intensity is determined by the current flowing through the LED. Too strong current will cause the attenuation of LED light, and too weak current will affect the luminous intensity of LED. Therefore, the driving of LED needs to provide constant current power supply to ensure the safety of high-power LED and achieve the ideal luminous intensity at the same time

in the field of LED lighting, to reflect the characteristics of energy saving and long life, it is very important to choose a good LED Driver IC. Without a good driver IC matching, the advantages of LED lighting cannot be reflected. The technical details of LED lighting design need attention

led lamps' requirements for low-voltage drive chip:

1 The nominal input voltage range of the drive chip should meet the needs of DCV to cover the application surface. If the withstand voltage can be greater than 45V, it is better; When AC12V or 24 V is input, the output voltage of the simple bridge rectifier will fluctuate with the electrical voltage, especially when the voltage is high, the output DC voltage will also be high. If the drive IC cannot adapt to a wide voltage range, it will often be broken down when the electrical voltage rises, and the LED light source will be burned out

2. The nominal output current of the drive chip is required to be greater than 1 Establish strategic cooperative relationship with key customers 5A, as the LED light source for lighting, the nominal working current of the 1W LED light source is 350mA, and the nominal working current of the 3W LED light source is 700mA. Higher power requires greater current. Therefore, the drive IC selected for LED lighting fixtures must have sufficient current output. When designing products, the drive IC must work in the optimal working area of% of the full negative output. The driving IC with full negative output current has poor heat dissipation in the narrow space of the lamp, which is easy to fatigue and early failure

3. The output current of the driving chip must be constant for a long time, so that the LED light source can emit light stably and the brightness will not flicker; When the same batch of drive chips are used under the same conditions, the output current should be as consistent as possible, that is, the discreteness should be small, so that the production can be effective and orderly on the mass automatic production line; For the drive chip with a certain discreteness of output current, it must be selected before leaving the factory or being put into the production line, and the resistance value of the current setting resistance (RS) on the PCB board must be adjusted to make the LED lamp constant current drive board produced by it have the same luminous brightness to the similar LED light sources, so as to maintain the consistency of the final product

4. The packaging of the drive chip should be conducive to the rapid heat dissipation of the drive chip die. For example, the die is directly bound to the copper plate, and a pin is directly extended to the outside of the package, which is convenient for direct welding on the copper foil of the PCB board for rapid heat conduction. For example, on a silicon chip die similar to 4x4mm, if you want to pass the ma current for a long time, there must be power consumption and heat generation. The chip itself, from the international perspective, has a low physical heat dissipation sampling rate structure, which is also crucial

5. The ability of anti EMI, noise and high voltage of the drive chip itself is also related to whether the whole LED lamp product can successfully pass the CE, UL and other certifications. Therefore, the drive chip itself should choose excellent topological structure and high-voltage production technology at the beginning of design

6. The power consumption of the drive chip itself is required to be less than 0.5W, and the switching frequency is required to be greater than 120Hz to avoid visible flicker caused by power frequency interference

led green lighting promotes the development of driver chips to innovative design. LED lamp lighting is inseparable from driver chips, so a multi-functional LED light source driver IC is required. If the AC power supply below 36V is selected for LED lamps, non isolated power supply can be considered. If 220V and 100V AC power supply is selected, isolated power supply should be considered. Driving chips that directly use ACV have higher requirements and greater difficulties in technology due to the demanding application volume. At present, countries are working hard to develop them. The massive demand market for LED lamps gives all IC design companies a chance to succeed again, with rapid transformation and early production, and many opportunities to win

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