Research And Design Of Dynamic Output DC/DC With High Efficiency And High Current

Based on the project of "Theoretical Research and Design of Key Techniques for Power Management IC", a dynamic output DC/DC converter IC characterized by high efficiency and high current is designed in this paper.A dynamic output DC/DC converter IC XD6927 characterized by high efficiency and high current is designed to perform this function after an in-depth systemic study on the fundamental principles and key techniques employed in current-mode Buck converter. The efficiency of this design can be as high as 96% by adopting the technologies of synchronous rectification, dual operation modes and bypass P-channel FET. A novel slope compensation scheme is introduced into XD6927 to provide stability by preventing the sub-harmonic oscillations at high duty cycles and avoid the occurrence of over compensation at low duty cycles, improve the loading capacity of the system. XD6927 provides DC/DC conversion from single lithium-ion cell voltages down to a dynamic output 0.3V～3.5V, which can be easily modulated by driving the REF pin. Finally, to solve the test of the chip, the relevant test circuit is designed by the muti-function of the pad, which can shorten the research cycle and improve the benefit of the chip.Detailed theoretical analysis of system and main sub-blocks of XD6927 are made in the paper and based on 0.5μm CMOS process, the schematic design, pre-layout simulations and verifications have been completed using the EDA tools of Workview and Hspice. The simulation results turn out to be that all the functions have been implemented and electrical characteristics are consistent with the design specification.