Fully Integrated Switched-capacitor DC-DC Down Converter

In recent years,portable electronic devices have become more and more popular among consumers,resulting in a general demand for electronic products of smaller size and lower power consumption.As integrated circuit processed continue to advance,the power consumption and area of the circuit on signal link is significantly optimized.However,for the power management unit,the required PCB board are cannot be reduced due to the off-chip devices.This has created a need for the fully integrated power management units,especially the fully integrated DC-DC buck converters(down converters).Switched-capacitor DC-DC uses only capacitors as energy storage devices,which is easy to integrate.This paper mainly studies fully-integrated switched-capacitor DC-DC down converter.The fundamental contradiction in the design of the fully integrated switched-capacitor DC-DC down converter is the contradiction between high efficiency and high power density.This paper aims to study and implement a fully integrated switched-capacitor DC-DC down converter with cold-start function and high input voltage under the TSMC-40nm CMOS process.The proposed DC-DC down converter adopts the 1:2 fixed voltage conversion ratio structure which is able to work at high input voltage with the help of stacked switches.At the same time,this paper proposed a new design of the storage capacitor,which alleviates the contradiction between high efficiency and high power density.The multi-phase technology is used in the proposed design to reduce the output voltage ripple in the proposed DC-DC design.The proposed design realized a fully integrated switched-capacitor DC-DC down converter with 3.3V voltage input,1.5V voltage output and 76.1%peak conversion efficiency with 0.174W/mm~2 power density.