A Multi-Channel LED Driver with Selective Dimming

摘要

A multi-channel LED driver consisting of front-end AC-DC boost Power Factor Correction (PFC) converter followed by a DC-DC power conversion stage with selective dimming capability for LED based lighting is proposed in this paper. Selective dimming of groups of output channels of a multi-channel LED driver comprising of a symmetric half bridge non-resonant DC-DC converter, high frequency transformer and symmetric voltage multiplier output rectifier with purely capacitive output is accomplished. The proposed driver has the advantages of low device count, high efficiency and can handle high power. Primary switches control the peak current of primary side which is proportional to LED peak current. The brightness based on average current of each group LEDs is controlled by duty ratios of four secondary switches, respectively. In this paper, the proposed selective dimming multi-channel LED driver is analyzed and validated on a 150W test setup.