Flicker and driver topology assessment of Extra Low Voltage LED lamps under DC supply

This paper addresses the flicker of LED lamps designed for ELV supply. In the first part the severity of the produced flicker under DC supply is measured in two connection modes - with and without the rectifying bridge - in order to investigate influence on lamps sensitivity to sinusoidal and rectangular amplitude modulation of the supply voltage. Second part of the paper introduces an approach to estimate the lamps' flicker response to non-harmonic supply voltage distortion based on the flicker caused by harmonic supply voltage distortion. The approach is demonstrated upon the tested lamps and its limitations are discussed.