[high tech products] comprehensive report
LED lighting in the near future has been a leap in the development of LED as a clean light source of green environmental protection has been widely recognized. LED light source has the advantages of long service life, energy saving, simple and convenient application, low cost and so on, so it will be used in the future. At this stage, China's LED lighting industry output value of more than 150 billion yuan; Guangdong currently LED lighting accounted for 70% of the national market, the industrial output value of 85 billion 300 million yuan in Guangdong province last year, yuan. Professionals is expected, the fastest in 2015, LED lighting in China lighting market share will reach 20%, driven by industrial scale will reach 5000 billion yuan, then our country will enter the top three global LED lighting market.
LED lamp using LED light source power and small power (IF=15-20mA) (IF>200mA)) second, small power led many to do LED fluorescent lamp, decorative lamp, grille lamp; high power led to do home lighting, lamp, underwater lamp, wash wall lamp, street lamp, tunnel lamp, working lamp for car. The high power LED light source is driven by low voltage and high current device and the luminous intensity is determined by current flowing through the LED size, too strong an electric current will cause LED light attenuation, the current weak will affect the LED's luminous intensity.
And under normal circumstances lighting with LED light source VF voltage is very low, generally =2.75-3.8V IF, VF in 15-1400mA; therefore LED drive IC output voltage is X N VF or X VF 1, IF constant current in 15-1400mA.
In summary, the LED driver needs to provide a constant current power supply, to ensure the safety of the use of high power LED, while achieving 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, not a good driver IC matching, LED lighting can not reflect the advantages.
Now due to the needs of the green LED lighting market, to promote LED lighting power drive chip to the development of innovative design, LED lamps and lanterns, the mass market demand to all IC design companies another chance to flex its muscles.
We all know that the LED lighting power supply is inseparable from the driver chip, so the need for a variety of functions of the LED light source IC. LED lamp selection of 36V AC power supply can consider non isolated power supply, such as the use of 220V and 100V AC power supply should consider the isolation of power supply. As for the direct use of AC100-220V driver chip, due to the application of the volume of demanding, in the technical requirements of higher, more difficult, the current efforts are in the development of.
LED lighting power supply for low voltage drive the relevant requirements of the chip, as follows:
1. Drive chip nominal input voltage range shall satisfy the DC8-40V, to cover the surface of the application need and pressure can be better than 45V; AC 12V or 24V input simple bridge rectifier output voltage will with the voltage fluctuations, especially high voltage when the output DC voltage will be high, the driver IC such as can not adapt to the wide voltage range, often in the grid voltage rise will be breakdown, LED light source has therefore been burned.
2. Chip driven nominal output current is greater than 1.2-1.5A, LED light source for lighting, 1W power LED light source for the nominal operating current of 350mA, Power 3W LED light source the nominal operating current of 700mA. High power needs more current, therefore led lighting lamps and lanterns choose to use the driver IC must have enough current output, product design must drive IC operating at the optimal working zone of 70-90% of full load output. Use of full negative output current drive IC in the narrow space of the lamp heat dissipation, easy fatigue and early failure.
3. Drive chip output current must be constant for a long time, LED light source can be stable luminescence, brightness will not blink; with a number of driver chip used in the same conditions, the size of the output current is to be as consistent as possible, is discrete to small, so in automatic production line for mass production can be effective and orderly; the current output have certain discrete driving chip required in front of the factory or put into production line tranches, adjust the PCB plate current setting resistor (RS) the resistance size, the production of LED lamps and lanterns constant current drive plate for similar LED light source luminous brightness consistency, maintain the consistency of the final product.
4. Drive chip package should be conducive to the driver IC tube core of rapid heat dissipation, such as the tube core (die) by directly binding in copper, and a pin direct extension to the outside of the package, for welding heat quickly on a PCB copper foil. Such as in a similar 4X4mm silicon wafer, to a long time through the 300-1000mA of the current, there is bound to have power consumption, will inevitably heat, the chip itself is also essential to the physical cooling structure.
5. Drive chip anti EMI, noise, high pressure is also related to whether the LED lighting products passed the CE, UL certification, so that the drive chip itself at the beginning of the design to choose excellent topological structure and high production technology.
6 drive chip power requirements are less than 0.5W, the switching frequency is greater than 120Hz, so as to avoid power frequency interference and produce visible flicker.