The thesis deals with the development of the power supply for automotive LED headlamps, from idea and concept to the testing of electronic circuit and the final product.
The first chapter is devoted to the review of the history of automotive headlamps. Described are the light-emitting diodes (LEDs) and their functions. On the car there are more lights for different applications, so relevant is also color of LED. We will let in the operation, structure and characteristics of white LEDs, because all of these data are required to design a power supply.
In the second chapter we will get to know many different ways to drive an LED. We focus on switching power supplies. We explain their operation and advantages. The development of switching power supply for LED headlamp is described in next chapter. We start by selecting the appropriate integrated circuit based on our requirements and start with making schematics. Under the more complex requirements belong additional protections, such as overvoltage and thermal protection. In order to achieve the usage of the headlamp in the two applications, such as daytime runing lamp and the position lamp with the single LED, the pulse-width modulation is used to adjust luminous intensity. After the schematic is created, we devote to detail design and realization of PCB (printed circuit board) layout. The PCB must be systematically drawn so that the LED driver is working properly and meets the electromagnetic compatibility (EMC) without any interference. For easier design, we follow the layout guideline for chosen integrated circuit which can be found in datasheet of integrated circuit. On produced printed circuit board we perform electrical tests and tests of electromagnetic compatibility. Since switching converters have a very good efficiency we won’t deal with temperature problems but problems of electromagnetic compatibility, which are always present.