Validation and Improvements of an RGB LED temperature compensation algorithm for Automotive Interior Lighting applications

Innovations and technological developments in modern society have shaped various areas of everyday life; the scientific progress is nowadays a firm base on which almost all industries and general workplaces are built. In the automotive sector, interior lighting has become a key factor when it comes to driver experience: Light Emitting Diodes are used not only for exterior but also for interior applications and many different colors can be set using RGB LEDs inside the vehicle. However, self heating or external influences as ambient temperature can affect color emission accuracy; hence, a compensation process should be performed in order to reduce the error to a proper range not perceived by human eyes. Besides, the Red, Green, Blue emitted colors do not always match with the specified datasheet targets due to the production spread and so a calibration of the RGB LED is necessary in advance. Moreover, the aging process is also a non-negligible factor in light emission performances, cause it has an impact not only on the luminous flux but also on the emitted spectrum, leading to a wavelength shift. Unfortunately, “aging” is a natural and irreversible process which can only be delayed to a certain extent: indeed, during LEDs operation, several external and internal factors influence the reliability and lifetime. This thesis work focuses on the simulation and validation of a temperature compensation algorithm for automotive applications, and on the presentation of important improvements obtained in terms of timing, structure and memory. After a short introduction on the color mixing theory, the calibration procedure and the temperature compensation solution will be discussed together with an explanation of the adopted measurements setup; afterwards, the most important results and code sections will be provided.