LED application domain and mart of technology of LED drive IC are analysed

LED gets be admissived extensively as the clean illuminant of green environmental protection. LED service life is long, energy-saving province report, application is simple convenient, use cost is low, be in consequently camera of number of mobile phone, MP3, MP4, PMP, DSC() , computer of plane of PDA, GPS, PND, sport, study machine, notebook the LCD that holds a product is in a poor light; LED flashlight, miner’s lamp is portable illume; Building illume, adornment illume, label card illume; In the instrument of the car | Dashboard is in a poor light, lamp of around fog lamp, the 3rd brake, direction lamp, taillight; And apply what can get magnanimity in domestic illume. LED drive IC is current IC of drive of market demand LED is current market demand is divided by application have 3 kinds big basically, use at consuming sexual electron product, its apply a characteristic is it is the sources of energy with batteries, it is 4.2-8.4V commonly, the LED driver of because this is low voltage, small electric current is the product with quantity at present wide bedding face; 2 it is to be used at car illume product, because of its power source | Manostat comes from car accumulator, it is 48V commonly, need the LED drive IC of taller voltage step-down so; 3 it is building adornment illume and domestic illume, need the LED drive IC that AC can direct commutation becomes DC, main function is alternating voltage changeover is constant current power source, finish the voltage with LED and electric current at the same time match. Consequently the LED drive IC that different applying is completely different. The LED driver that consumes sexual electron product has more mature technology, product and relatively mature market. Market of global mobile phone used LED drive IC to amount to 600 million 2007, will continue to grow 2008. The measure that the car takes the LED that bright product uses to wait is more, it is to string together mostly, shunt-wound drive, need taller voltage, to taking it is very convenient for the power source of 48V car accumulator oneself. At present the LED driver of ability 60V high pressure is tasted newly roll out more already. The dashboard that uses LED directly in market of the costume before the car consequently is in a poor light, the market of lamp of around fog lamp, the 3rd brake, direction lamp, taillight very value and hopeful. The building decorates illume and domestic illume, need the LED drive IC that AC can direct commutation becomes source of DC constant current, return the integrated circuit product that cannot offer individual SOC at present, great majority is module circuit. Building adornment illume is in home each big city application is very wide already, energy-saving effect is distinct. The society needs a capacity with LED floodlight to the family will be astronomical, but current family leaves big batch production to still have certain space with LED floodlight technology and manufacturing cost, still need hard. IC of drive of commonly used LED consumes product of consumptive sex electron of screen of Lcd of sexual electron product be in a poor light is 2-8 commonly LED lamp, shunt-wound or odd the application of a power supply is in the majority. Come from 2000, IC of drive of commonly used LED has product of consumptive sex electron DC/DC switch manostat (pump of Boost) , charge (source of ChargePump) , constant current (Constant) and low-pressure difference manostat (LDO) . DC/DC switch manostat is to use inductor to store of electric energy, and inductor emits switch frequency easily, be opposite easily radio frequency (the interference with RF) new happening, because this is used lesser in mobile phone product. Charge pump also is manostat of a kind of switch, but it is to use capacitor to make electric energy store can, won’t emit switch frequency consequently, the lion’s share was held in mobile phone product. Constant current of IF of LED glow requirement, constant current source is in the light of this market special design, production, 50% the price of constant current source is charge pump, gaining ground in recent years consequently model fair share also is owned in mobile phone product. Gain ground model hope for success of exacting of mobile phone product drops originally, the mobile phone carries what CD driver uses unit and passable oil expression on the back to reduce the cost of LED drive IC namely, of most mobile phone close Electromechanical to press a design to come in batteries voltage drop when 3.3V, because source of this constant current is designed,when 4.2V-3.3V constant current outputs 20-30mA, 3.3V outputs voltaic pelt below. Of charge pump selling a site is efficiency (η ) , but most charge pump is when 4.2V-3.3V its changeover efficiency is not tall, to its changeover when 3.0V-2.5V when batteries voltage drop efficiency can amount to 85-90% , be in regrettablly its advantage can be not produced in most mobile phone plan at present. LDO is the low-pressure difference manostat with one can very good individual character, output voltage is stable, when load is changeless, the electric current that it sheds overload is constant also, be based on this principle LDO also is a very good LED driver. Current the mobile phone uses LED drive IC and character, the price of a DC/DC(Boost) is USD0.12-0.15, the price of pump of a charge is USD0.20-0.25, the price of source of a constant current is 0.09-0.12, a LDO a few minutes of U.S. dollors, bear cost of optical driving unit to reducing a mobile phone, have certain space, come to many gaining ground this year model the mobile phone already was chosen. The mobile phone is in a poor light besides color screen IC of need LED drive, the clavier of the mobile phone is in a poor light, the flashlight of mobile phone camera also needs LED drive IC. Its characteristic is low voltage, small electric current, because be,be the sources of energy with batteries. The consumes electronic product LCD screen that does not have RF part is in a poor light drive can choose DC/DC switch manostat, LED is N series connection commonly N paralell connection is used, working voltage slightly tall, working electric current is lesser. The series-parallel connection of many LED can make bigger LCD screen carry illuminant on the back, be like box of lamp of graph 3LCD electron. In addition, still be like LED flashlight. Shift holds indication product to be in a poor light the choice shift of LED drive IC holds indication product to be in a poor light the choice of LED drive IC, the area that presses LCD comes a number of point light source of set need LED; The N that presses LED strings together N and illume the LED drive IC that means will come to choose capacity of different job principle, different output; 1.8 inches of ~3.5 inch the mobile phone uses point light source of LCM its LED is 2-4 LED; 3.5 inches of ~8.0 inch MP3/MP4/PDP/GPS/PND/DPF uses point light source of LCM its LED is 6-28 LED; 12.1 inches of ~15.4 inch notebook computer uses point light source of LCM its LED is 48-60-72 LED; The mobile phone has RF to be afraid of interference, because this great majority does not choose the DC/DCBoost that is electric energy packet with inductor; Without the consumptive electron product of RF, choose DC/DCBoost mostly, because its can output taller voltage, and have more efficient; IC of drive of commonly used LED has charge pump (source of ChargePump) , constant current (manostat of switch of step up of Constantcurrent) , inductance (DC/DCBoost) . The floodlight that the family uses with family of LED floodlight drive still does not have mature product at present, the above of power demand 10W of the floodlight that the family uses. The 1-5WLED lamp that at present city makes work can serve as wall lamp and auxiliary illume to use only in the family, because their brightness returns the requirement of fluorescent and short of incandescent lamp, energy-saving lamp, still cannot write as the book read illume to use. Price of present lamp of tall brightness LED is very high, be not ordinary common people to be able to be enjoyed. Advance rapidly of technology of Bai Guang LED, use as the sheet of floodlight source the LED of chip, its power does bigger more, already big batch produces those who put in the market to have 1W, 3W, 5W, 10W, 20W, 30W, 50W, 100W, glow brightness is the biggest already achieved 4400lm. High-power illume is used it is odd that its enclose LED to look from finished product of a chip, it is to use N actually LED is in charge of core to be enclosed in an unit (the 4) that be like a graph. Their permutation is combined is series-parallel connection, they are N series connection, again N is shunt-wound, next by at 2 o’clock connection power source. High-power illume produced final production illume to be created with LED lamp with the big batch of LED must condition and corporeal foundation. Tall brightness and high-power LED floodlight enter a family to be used on applied technology to still technical bottleneck is solved urgently, advocate if chip comes loose,heat up (management of quantity of heat) , glow brightness (lumen) with EMI/EMC, cost drops also is a crucial question. Domestic illume still is with technology of LED drive IC in assault fortified positions, drive chip needs to use technology of 700VBCD high pressure; The MOSFET inside chip should have done government of quantity of heat, want those who consider drive IC to come loose hot design; AC to source of DC constant current conformity of each function chip encloses the SOC inside to need to innovate in a pattern of new power source chip. If sample of floodlight of family expenses LED pursues 5. Source of constant current of type of switch power source may be AC compares one of effective methods to source of DC constant current. The efficiency of switch power source is as high as 65%-85% . Of power source efficiency rise make equipment manufacturer be able to the bit that will need machine electric current to reduce EnergyStar(the sources of energy) make with BlueAngEL(blue sky) the level that attestation place requires. The floodlight that the family uses uses the inevitable trend that Bai Guang LED is development of science and technology. The family gives off light with floodlight of Bai Guang LED tall, service life grows efficiency is the fact that does not dispute, the skill that still just needs to await industrialization to produce at present matures and drop of cost further. Fluorescent and energy-saving lamp is born to enter the time that family of innumberable families common people popularized to also be experienced almost 10 years from the product. If express,the family is compared with the glow efficiency of floodlight and mean life 2. Euramerican wait for a country to was mixed in Feburary 2007 will pass governmental resolution respectively in March, cancel incandescent lamp 2 years stage by stage in future, advocate use energy-saving lamp and LED floodlight. From this, LED floodlight enters an innumberable families to open prelusive, its market demand will be one astronomical. Integrated circuit and manufacturer of lamps and lanterns begin the operation in succession, run quickly to this huge market. High-power floodlight makes technical advance rapidly with LED, today already can big batch was produced, and in to increase LED glow efficiency (Lm/W) respect tries hard; The chip that from AC to output of source of DC constant current, economy effectively drive high-power floodlight uses LED still needs more integrated circuit to develop firm investment, the innovation design that caters to prospective market is the precondition that wins usury embellish get one’s own back, capture the creativity of good luck, play, concept that cooperating necessary financial resources and material resources is company success. Origin: Embedded online