A switched-capacitor DC-DC converter with a low output voltage ripple and high efficiency is presented in this summary. To achieve a wide input and output voltage range, a 3-clock-phase operation is proposed to achieve 6 voltage conversion ratios (VCRs) with only two discrete flying capacitors. A digital ripple reduction scheme is utilized to achieve up to four times reduction in output voltage ripple. The digital design also improves the design flexibility. The converter can deliver a 250mW maximum power to a wide output range of 0.5 V to 3 V with an input range of 1.6 V to 3.3 V, and achieves a peak efficiency of 91%.