This work applies unequal duty cycle to switched-capacitor (SC) dc-dc converters to improve its output ripple as well as the power conversion efficiency. By adjusting the duty cycle, the capacitor charge and discharge states are reasonably balanced. Therefore, we effectively reduce the output ripple and the charge redistribution loss, improving the efficiency. A SC converter verifies this scheme with voltage conversion ratios (VCRs) of 1/4 and 1/3, in a 65 ​nm CMOS low-power process. Operating with a switching frequency of 33 ​MHz, an input voltage of 2.4 ​V, an output range of 0.5–25 ​mA, and a VCR of 1/4, the peak efficiency increases by 1.0% and the output ripple drops by 43.6%, when compared with the equal duty cycle mode. With the input voltage equal to 1.8 ​V and the VCR ​= ​1/3, the peak efficiency increases by 0.7% and the output ripple reduces by 48.0%, compared to the equal duty cycle mode.

这项工作将不相等的占空比应用于开关电容器（SC）的DC-DC转换器，以改善其输出纹波以及功率转换效率。通过调整占空比，可以合理地平衡电容器的充电和放电状态。因此，我们有效地减少了输出纹波和电荷再分配损失，提高了效率。SC转换器在65 nm CMOS低功耗工艺中以1/4和1/3的电压转换比（VCR）验证了该方案。以33 MHz的开关频率，2.4 V的输入电压，0.5-25 mA的输出范围以及1/4的VCR工作时，峰值效率提高了1.0％，输出纹波下降了43.6与等占空比模式相比时，％。在输入电压等于1.8伏且VCR等于1/3的情况下，峰值效率提高了0。