A Dual-Output Step-Down Switched-Capacitor Voltage Regulator With a Flying Capacitor Crossing Technique for Enhanced Power Efficiency

This paper presents a dual-output switched-capacitor voltage regulator (DOSCVR) with a new flying capacitor crossing technique (FCCT) to improve power efficiency. With the FCCT, the power loss of the DOSCVR is reduced by 28%, increasing the power efficiency by 7% compared with the power efficiency of the conventional method that generates two voltages using independent single-output SCVRs. This enhanced efficiency results in no area penalty since the total flying capacitance remains unchanged. A prototype is then implemented in a 0.13- $\mu \text{m}$ CMOS process to validate the proposed scheme. The prototype simultaneously produces two regulated voltages of 0.44 and 0.88 V from an input voltage of 1.5 V. The output voltages are regulated by low-bound regulation with frequency modulation. The maximum output current is 12 mA with a total flying capacitance of 0.98 nF, and the measured peak efficiency is 78%.