LED lighting circuit design based on market demand

LED lighting industry although the potential value, also put a lot of effort in the field of LED chip, but the circuit design, it is still an important role in driving the LED light source, even if the chip and package as well, circuit design is poor in vain, in general, the circuit design of LED lighting is still off the volume and the cost of a few basic points, but is also an important reference index of PFC.

From the LED lighting system to the overall observation, LED chip and packaging industry accounted for the overall cost quite high proportion, but the circuit design although the proportion is not high, but after all is the pursuit of such carbon, how to reduce the power of a system industry must consider the subject in power, but on the other hand, LED lighting is also facing to cost, service life and volume etc. the design requirements, at the same time facing many requirements, system operators will also pressure onto the semiconductor industry, also let the semiconductor industry in providing solutions also face some challenges. A Morimi semiconductor arithmetic and consumer products business group marketing manager Lin Zhiyan pointed out that his own observation, lighting industry for circuit design is quite strange, this kind of problem, usually by the semiconductor industry to think of the solution, and the lighting industry to be able to spend more effort in the mechanism, optical and the heat dissipation and the exterior design, to achieve a multiplier effect.

Lin Zhiyan further pointed out that the lighting industry quite strange for circuit design, but in order to cope with the appearance or mechanism design requirements, the semiconductor industry must stand in the angle of the cooperation as much as possible to help customers to solve all the problems, and also need fast production, in the design and development of circuit board, but also as far as possible towards to "the immediate shipment" as the goal, in the shortest possible time to enter the delivery process.

Application of different circuit design concept also slightly different

LED lighting applications can be divided into indoor and outdoor lighting and vehicle types, although these three areas still quite a lot of subdivision categories, but the total return, difference circuit design is not much, with differences, mostly in the operation temperature, system volume, reliability and cost other factors. For example, indoor lighting applications, such as household or commercial areas will be more attention to cost and volume of the system, if the outdoor lighting, may need to take into account the cost, but the operation temperature and reliability will be relatively more important. As for the use of automotive lighting, although without the help of AC-DC components, but after all, with a high degree of personal safety, reliability and life expectancy will be particularly demanding.

Indoor and outdoor requirements are different

Compared with indoor outdoor lighting, the working environment is strict, the level of industry supply gap is large, and at this stage of the outdoor lighting also has a clear standard, expected future outdoor lighting market to further grow, still need a period of time. But left away in the environment not to talk, in fact, outdoor lighting power demand is high, the main reason is that the LED lamp series, more power will increase, if carried out in parallel, will also face the problem of the turn-on voltage, so if we want to solve the development of outdoor lighting. Plan must be relatively complete, can meet the design requirements.

Indoor and outdoor lighting will need to convert AC-DC components, AC and DC, but still need the assistance of DC-DC to light the LED light source, although the two components are very important, but the former high voltage must be carrying 110V or 220V, it is not easy to enter the threshold, the entry threshold is low, competition is more fierce.

IR (International Rectifier) LED Department Manager Peter Green said, indoor and outdoor LED lighting will choose Offline circuit, and generally depends on the size of the power and security requirements of the application. In low power applications, it is not necessary to use a buck converter in the absence of isolation, but the need to isolate the flyback converter. External devices may be more isolated because they must be able to protect against the risk of electric shock.

In larger LED lighting appliances, such as street lighting, the power is generally more than 50W, the associated isolation design will likely use a front-end and back-end level two power supply architecture. The front-end stage will provide power factor correction, and the latter will provide isolation and regulation of current to drive the LED load.

On the circuit design, there is no much difference between outdoor and indoor lighting, the main difference is in the operation temperature, about 85 degrees Celsius to 105 degrees Celsius, but if Japan, may be as high as 125 degrees, visible to the outdoor temperature operating requirements, the door sill is quite high. In addition to working temperature of outdoor lighting requirements, the safety is almost comparable to the industrial grade, whether in reliability, product life or prevent thunder presses, these are also the outdoor lighting needs to take into account the place. Vehicle lighting requirements are different security is still the primary consideration

As for in car lighting, will also have the temperature requirements, National Semiconductor (NS) Asia Pacific market senior engineer Chen Guangji said, without the use of AC lighting vehicle (AC), is the direct use of 12V DC (DC), the circuit design is relatively easy, but the general vehicle lighting temperature requires approximately 105 degrees Celsius, with the change of temperature will affect the stability of the power supply. Moreover, the application environment is belongs to the vehicle field, also want to