Inventory of LED headlamp driving technology of th

  • Detail

Inventory of automotive LED headlamp drive technology

now most models still use ordinary halogen headlamps, and better models will use xenon headlamps. At most, we should make some innovations in the structure of the lamp group, carefully study and judge the industrial development trend, and use the optical principles of lens and reflector to improve the efficiency of lighting, but the technical innovation of the lamp group itself is insufficient. LED car light refers to the light sources inside and outside the car adopt LED technology for external and internal lighting. LED car lights can be widely used to create the interior environment, with a service life of 50000 hours. The LED structure is solid, not easy to be affected by vibration, and the brightness of light output will not decrease significantly during use

led's continuous penetration in automotive exterior lighting applications is increasingly replacing traditional lighting solutions. A more efficient, robust and cost-effective electronic device and driver IC is needed to give full play to the advantages of LED in such applications. This important component in LED lighting system points out the factors that need to be considered in the development of LED external lamp drive electronic architecture. LED car lights are suitable for various lighting applications of automotive electronics, including headlights (high beam and low beam), fog lights, taillights, brake lights, turn signal lights, daytime running lights, pedal lights, instrument lights, license plate lights, door lights, interior lights, side lights, navigation, entertainment systems, backlights and indicators. These features include LED cooling management, flexible drive of different LED configurations, and cost-effective system design. Light emitting diodes (LEDs) have been used in the automotive field for more than 15 years. In the past, the available color and power levels limited the application of LEDs to dashboard, interior lighting and some low-power tail lamp hybrid lighting functions

led lamps are increasingly widely used in these automotive front lighting applications. The main reason is that compared with conventional incandescent lamps or high intensity discharge (HID) lamps, LED lamps have unique advantages in style and design, and recently they benefit from the characteristics of low power consumption. However, it is also important that with the continuous development of LED technology, the need to immediately add pressure can provide a higher power level and a wider color gamut. At present, in the application of automotive front lighting, the performance of LED lamps is no less than that of incandescent lamps

led in automotive lighting

for automotive manufacturers, the style advantage is still one of the main reasons for using LED lights. Clearly, automakers see an opportunity to further consolidate their car brands. Many lighting designs have benefited from the greater design freedom provided by LED lamps. Famous early cases include Audi a8/a6. However, the focus is shifting to other advantages that led lamps bring to automotive lighting applications. These include lower power consumption, longer service life and faster startup time

the University of Michigan School of Transportation Research (umtri) evaluated the energy consumption level of the lighting function of conventional incandescent lamps and led solutions during daytime driving. They found that for equivalent functions, the energy consumption level of LED solutions was 50% lower (23W vs. 46W). This savings can be directly converted into fuel efficiency, while reducing passenger car carbon dioxide emissions by 50%

this fuel efficiency is very important for automakers preparing to develop all electric vehicles. For consumers, an important purchase standard is the distance that electric vehicles can travel when fully charged. To this end, car manufacturers are looking for appropriate ways to improve the energy consumption level of various functions, so as to improve the endurance of cars. LED lamps obviously have great energy-saving advantages, so they are increasingly becoming the natural choice of lighting design engineers

another important factor that has made indelible contributions to the improvement of LED efficiency and the penetration of LED in automotive lighting applications is the lighting efficiency of LED, that is, lumens per watt (lm/w). This indicator measures the light output generated by each watt of energy consumed by LED lamps. The higher the value, the more efficient the LED is in converting input power into optical output. Today's high brightness LED lamps can achieve lighting efficiency of lm/w, while a 60W incandescent lamp is only lm/w. The improvement of this indicator has greatly expanded the application range of LED lamps and extended to the automotive front lighting system based entirely on LED lamps. In particular, headlights based entirely on LED, including high beam and low beam adjustment and other functions. The next section will describe some of the challenges faced by using LED lights in automotive applications

led application in automotive electronics

automotive environment has brought great challenges to LED. Led must be able to provide stable light output. Even if the electrical conditions and heat dissipation conditions around the headlamp are constantly changing, the light flux and color point must remain constant. Because the light output of LED is proportional to the current applied to LED, and led adopts diffusion production process, even the products of the same batch may have different light output under the same driving current. In order to avoid this adverse difference, LEDs are often selected according to certain parameters. Through screening, it can ensure that the LED of the same batch is more consistent in light output and color dots

led must also ensure that the light output meets the minimum legal luminous flux requirements for specific applications within the ambient temperature range of -40 ℃ to +125 ℃. The luminous flux of the headlamp needs to reach about 1000 lumens, and can provide the required minimum light output within the operating temperature range. In order to meet this luminous flux requirement, several LEDs may be connected in series or in parallel. The combination of multiple high brightness LED lights puts forward high requirements for heat dissipation management at the same time, because with the increase of LED temperature, the light output of LED will decrease significantly, and the color dots will shift. Therefore, the heat emitted by LEDs in the process of producing light of this magnitude must be transmitted through the radiator. In some extreme cases, it may be necessary to reduce the drive current of the led to avoid overheating and damage. The automotive industry also puts forward strict requirements for the reliability of LED. The LED solution must be able to meet the strict requirements of aec-q100 standard. This means that led and driver electronic devices must pass the certification of this standard

led7 advantages

for cars, LED light sources (not limited to headlights) have the following seven advantages: 1. Energy saving and low cost: the luminous efficiency of LEDs reaches 80% - 90%. If we use our daily energy-saving lamps to draw an analogy, energy-saving lamps save 4/5 energy than incandescent lamps, while LEDs save 1/4 energy than energy-saving lamps. In cars, the energy consumption of LED components of the same daytime running lamp is only 1/20 of that of halogen lamps. The cost of LED components has also been significantly reduced year by year, and at present, the cost and price are still declining by more than 20% every year

2. Long service life: LED components used in cars can basically reach the level of 50000 hours, while well-known automotive lighting suppliers have been able to provide LED components with a service life of 100000 hours, which is equivalent to 11 years. Considering the use frequency of light, basically in the design life of the whole vehicle, LED components do not need to be replaced. In contrast, the life of xenon lamp is only about 3000 hours. Moreover, led makes the shape and lines of headlights richer, and the recognition at night is also higher

3. Good durability: LED components have simple structure, excellent impact resistance and seismic resistance, are not easy to break, and can well adapt to various environments

4. LED components are small, compact and convenient for layout and shape design: This is a huge advantage of LED. This advantage fully caters to the evolutionary needs of automobile manufacturers in design, breaks the shackles of the past lighting system on shape innovation, and lets us have more creative automobile products

5. Fast response speed: the lighting of led only needs microseconds. When used in tail lamps and cornering lamps, it can light up quickly to achieve better warning effect. When used in headlights, it has higher response speed than xenon lamps and halogen headlights, and better guarantee driving safety

6. Low brightness attenuation: the brightness of LED is high, and the brightness attenuation of light is far lower than that of halogen lamp, which is suitable for lighting and warning lights such as brake lamp and turn signal lamp

7. It can be driven by low-voltage DC, with small load, weak interference, low requirements for the use environment and good adaptability. Unlike xenon lamps, pressure boosting devices are also required

with the increasing scale of the automotive LED market, more and more new suppliers are bound to join, and the competition is intensified. The uneven product quality of suppliers is bound to affect the market reputation, thus affecting the final consumer demand. As long as the cost of LED is reduced to the same level as that of incandescent lamp, all cars except economy cars will apply led on a large scale There is no doubt that the use of high brightness LED lighting will become the main feature of cars in the future, thanks to the many basic advantages of LED compared with the traditional incandescent lighting scheme. In addition, the use of LED lighting can also drive changes in automotive design technology and design style. However, just like any innovative technology, LED is widely used "At present, the biggest problem is that recycling still needs to overcome many difficulties before it can be used for automotive lighting.

automotive LED headlights schemes

for example, NXP, ansenmey, Infineon, Fairchild, etc. have LED headlights schemes for automotive, which provide automotive manufacturers with more energy-saving options to meet consumers' requirements for fuel economy, improve energy, reduce emissions of CO2 and SO2 by more than 64 million tons in China, and improve safety Reduce or avoid the incidence of traffic accidents, create a personalized vehicle atmosphere, and meet consumers' expectations for the unique shape of the car. In the future, the overall annual compound growth rate of the vehicle lighting system will reach 10%, and the market development potential is huge

Copyright © 2011 JIN SHI