Although the potential value of mini led light bars after, industry also LED chips in input in many heart, but is circuit design is concerned, it is still drive LED light source important role, even if chip and packaging for better, circuit design is not in vain, summarized to see, LED lighting circuit design is still not to take off a volume, cost of several basic points, but also is the important reference PFC indexes.
From the whole LED lighting system of to observe, LED chips and assembly field accounts for the overall cost quite high proportion, however, although the proportion of circuit design is not high, but, after all, is the relationship between the carbon save energy demand, how in power consumption can reduce power consumption on the system operators must become thinking subject, but on the other hand, the LED illumination also faces to the cost, service life and volume, and many other design requirements, at the same time are facing many requirements of the situation, the system operators will also pressure on to the semiconductor industry, also let semiconductor company in solutions also faced some provide challenge. Asian beauty semiconductor operations and consumer product marketing manager LinZhiYan career group of technology that he himself observation, lighting operator for circuit design is quite strange, this kind of problem, usually are passed on to the semiconductor industry to think of a way to solve, and lighting industry can spend more heart in institutions, optical, heat dissipation and appearance design, with twice effect.
Further points out that, because the lighting operator for circuit design is quite strange, but in order to match the exterior or institutions design requirements, the semiconductor industry to stand in the Angle of with as much as possible to help customers solve all the problems, and needs rapid mass production, in the development of the circuit board design, also as far as possible to the “immediate shipment” as the goal, as far as possible in the shortest time into the flow of the shipment.
Use different circuit design concept also vary slightly
The application field of high watt led lights in general can be divided into indoor and outdoor and vehicle lighting type etc, although these three fields can still subdivision quite a number of categories, but to view, circuit design and without too much difference, and the differences are more, mostly during the operation temperature, system volume, reliability and cost, and other factors. For example, indoor lighting applications, such as household or commercial field, will more attention to cost and system volume problem, if outdoor lighting, may be less need to consider the cost, but in homework temperature and reliability, etc, it’s relatively more important. As for automotive lighting, although no AC-DC component help, but after all the personal safety and high association, in the reliability and life on the also will be especially requirements.
Indoor and outdoor different demand
Outdoor and indoor lighting in the operation environment is more tough, supply the level of large companies fall, and the current stage of the outdoor lighting is also a more explicit standard, the expected future outdoor lighting to further growth market, still needs a period of time. But despite the external environment don’t talk about, in fact, outdoor lighting power demand is higher, the main reason is that LED lamp is more, after in series, power will also increased in parallel manner if, upon meeting conduction voltage problem, so if you are going to outdoor lighting development, the solution must relatively complete, can meet the design requirements.
Indoor and outdoor lighting will need AC, DC component, to the transformation of the AC/DC electricity, but still need the help of DC-DC to lit LED light source, although two types of components are important, but the former must carry up to 110 V or 220 V of high voltage, into the threshold for relatively not easily, the latter into low threshold, competition is more intense.
IR (international rectifier Company) LED are the department manager Peter Green says, indoor and outdoor LED lighting will choose offline circuit, and depends on the size and power of general application safety requirements. In the low power applications, not in need not use isolation antihypertensive converter, just need to separate but the return chi type converter. External devices may need more isolated, because they must be able to moisture proof, to prevent the risk of electric shock.
In the larger LED Fluorescent Replacement appliances, such as street lighting, the general power more than 50 W, related isolation type design will likely adopt a front end and back end level including the level 2 power structure. The front end level will provide power factor correction, and then the isolation and adjust level will provide current to drive LED load.
On the electric circuit design, outdoor and indoor lighting and not have too big differences, the main difference is in operation temperature, is about to 85 degrees Celsius to around 105 degrees, but if Japan region, may be as high as 125 degrees level, visible to the temperature outdoor work demand, the gateway is quite high. Outdoor lighting in addition to the special requirements of operation temperature, in safety hardly can compare with industry level, both in the reliability, product life or prevent thunder eager, etc, they are all needed to be considered outdoor lighting place.
Automotive lighting requirements has security is still a top priority
As for the automotive lighting, also can have temperature requirements, and the national semiconductor (NS) Asia Pacific senior market ChenGuangJi said engineers, automotive lighting without the use of AC (AC), is directly used 12 V DC (DC), circuit design relatively easy, but the rule of automotive lighting temperature requirements for roughly around 105 degrees Celsius, and the change of the temperature will influence the stability of power supply, moreover, the application of the environment is to belong to automotive field, also want to consider to safety, reliability, service life and stability and related requirements, so the difficulty of the circuit design is not less than other application fields.
Peter Green also added that the points out. LED by low drive car use DC power, the application in the tail light, in the front, and display a backlight is between respectively. Part of the application for, low current LED to use simple linear adjustment is enough. In other cases, such as in power relatively high headlights applications, you need a switch mode power supply, and can use several potential circuit topology, including booster, step-down-or step SEPIC. This LED drive needs to withstand car of possible high surge voltage.
PFC different requirements but direction to the agreement
Be worth what carry is, because (power factor correction) PFC also become LED lighting is one of the means reference values, the higher the value PFC, will let the circuit design more and more complicated, also in virtually increase costs, but this practice, also can sacrifice system area, this to home and commercial lighting lighting system has a high design difficulty, especially in Japan, PFC numerical requirement also has been on the rise, and this will allow semiconductor industry wits.
NXP semiconductors (NXP) the greater China area lighting products marketing senior managers ChenRong thinks, different countries formulate policies and regulations of each have differences, like a Japanese policy running time is earlier, whether T5, T8 started to import in LED light source, and at the same time will be LED lighting and intelligent or radio frequency, and other functions, in order to improve the LED illumination additional value, but also because of this, plus the Japanese have long been holds the key to all LED patent, if foreign companies to enter Japan semiconductor market, it will inevitably face compatibility problems, this is not all a line of semiconductor industry can do.
Chechen also further points out, recently in South Korea LED lighting, also have quite a few describes, in the standards set forth on PFC must also up to 0.9 above, the move, but also increased into the threshold, but because of the Asian region LED lighting development condition, mostly by government to lead, the improvement of PFC value, means that the circuit will also increase the cost, overall development, it is not very good, the future the government’s attitude is still Asia LED lighting of the development of the market observation indexes.
On from the application perspective, PFC LED lighting is indeed one of the focal points of circuit design, power perspective, 15 tile the following lighting applications need high value whether PFC, even can need not into consideration, this still depends on the needs of customers, but her understanding, even if it is 3 to 5 watts of industrial lighting, have begun to have the requirement of PFC, and its numerical requirements as high as 0.9 or so.
This shows, LED lighting circuit design, although the proportion of the whole system in cost is not high, but with the challenge of the ascension of no less LED the luminous efficiency, although different applications, and considering the design conditions also different, but can know is, the existence of PFC, has LED lighting is indispensable to the future of the elements of the circuit design.