Two of the largest and most powerful LED lighting applications are the large-screen LCDTV display with rear lighting and automotive headlamps. Take a look at the standard LED car headlamps used by Cadillac Escalade from Lexus, Audi, and even GM. The overall lighting structure of all these cars is very similar. Each car headlamp includes five LED power supply beams optimized for a variety of lighting requirements, including: low beam, high beam, turn assist lamp, daytime running light and turn signal light.
Standard LED lighting beams typically require 35W to 50W of power supply. This may not seem to be a lot of power; however, the brightness of the LED is up to 10 times the HID halogen lamp, so the LED light output is equivalent to 500W halogen lamp. The power required for the high beam is generally the same or slightly higher than the standard illumination beam, while the power required for the turn assist lamp, daytime running light, and turn signal light is low. However, the overall car headlamps will consume more than 200W of electricity, which may have a significant heat dissipation problem. This is really not a good thing, because with the increase in operating temperature, LED light output and working life will be rapidly reduced.
There are many ways to deal with this cooling problem. One is to add a lot of heat sinks to remove heat from the lights. However, this creates another set of problems, including an increase in the cost and weight due to the use of the heat dissipation material. The most effective way to solve this problem is to use a highly efficient drive (efficiency> 93%) to minimize the heat dissipation of the LED driver circuit. This is not as difficult as it sounds, because a 50W high beam can usually consist of 14 series 1ALEDs. Since the forward voltage drop across the entire temperature range is about 4V per LED, the boost converter LED driver topology boosts the nominal 12V nominal battery voltage to just over 56V at 93% efficiency, which makes it easy to dissipate 3.5W power, for the power dissipation value, in the installation of LED car headlamps printed circuit board layout of low-grade copper radiator can easily meet the requirements.