Low power consumption and high power density integrated DC-DC converter for portable equipments

We developed an integrated buck type DC-DC converter for portable electronic equipments. A newly developed pulse frequency modulation (PFM) control integrate circuits (1 Cs), which includes output power MOSFETs, achieved a low quiescent current below 14 muA and small chip size of 1.4 times 1.1 mm² in 0.35 mum CMOS process. The integrated converter consisted of the PFM control 1Cs on a planar inductor and had a maximum efficiency of 90 % and a power density above 100 W/cm³.