A low-ripple switched-capacitor DC-DC up converter for low-voltage applications

This paper describes a switched-capacitor type DC-DC up converter with high efficiency and low-ripple output. Identical charge pumps operating sequentially in the proposed DC-DC converter reduce the magnitude of output voltage ripples to 20% of the conventional converters. A new charge pump adopting PMOS switches near the output stage improves the power efficiency of the DC-DC converter by 10%. The proposed DC-DC converter is applied, as a test vehicle, to a phase-locked loop circuit which is sensitive to power supply noise. All circuits are simulated and fabricated in a 0.65-/spl mu/m CMOS process.