\title{Development of a 30W SEPIC LED Driver for High and Low Beam Lighting Applications}

In recent years, rapid advancements in LED (Light Emitting Diode) technology have enabled high-brightness white LEDs—with superior features such as energy efficiency and long lifespan—to replace incandescent, halogen, and fluorescent lamps. However, with this transformation, the requirements for high power factor (PF) and low total harmonic distortion (THD) have become prominent to achieve energy savings and reduce environmental impacts. In this paper, the development of low-cost and highly efficient power converter topologies has emerged as a valuable research area. The SEPIC (Single-Ended Primary-Inductor Converter), which offers a single-stage structure, stands out as an ideal solution in non-isolated applications due to its ability to perform both boost and buck operations. Operating the SEPIC topology in discontinuous conduction mode (DCM) allows the input current too closely follow the input voltage, thereby reducing harmonic distortion and enabling a high-power factor. In this study, A 30W SEPIC-based LED driver for automotive lighting systems is designed and implemented, achieving an output voltage of 21V from a wide input voltage range of 9V to 36V. Experimental results show a high efficiency of 91.3% at full load, 94.6% at half load, and up to 95.2% during low-beam dimming operation. This study introduces a robust and efficient reference design for LED drivers supporting high-beam, low-beam, daytime running light (DRL) functions, offering valuable insights for both academic and industrial applications.