LED-Driver with Integrated Dimming Feature and its Influence on Chromaticity Values

摘要

In this paper, different methods of dimming white high brightness LEDs with miscellaneous LED current waveforms are investigated to determine their influence on LED color-stability. A boost converter with integrated LED dimming feature has been built for an automotive daytime running light system. In comparison to the conventional approach, the proposed solution achieves cost reduction by saving the external switches and drivers without generating additional color deviations. Experimental results of the prototype converter show only small color shifts for typical white LEDs. Performance and design issues of the converter are presented. Finally the color stability of the complete prototype during dimmed operation is shown.