The interleaved dc/dc boost converter (IBC) has been widely used to interface the solar photovoltaic panels and fuel cells to dc microgrids. With the penetration of self-regulated power electronic loads, which tend to consume constant power, the stability of dc microgrids is severely challenged. To guarantee the large signal stability of IBC fed dc microgrids with constant power loads, this article proposes a novel data-driven linear quadratic regulator. It provides model-free online control optimization with very low computational burden. To verify the effectiveness of the proposed method, experiments are carried out using the low cost Texas Instrument C2000 series digital signal processor.