| On the basis of the project Theoretical Research and Design of Key Technique for Deep-submicron Power Management IC and Mixed IC , the principle and circuit design of Buck converter integrated circuit is analyzed, and a high voltage high efficiency peak current mode synchronous Buck converter is presented.Firstly, the development situation and trend of domestic and foreign power management technology are introduced. Then the basic structure and operational principle of Buck DC-DC converter are introduced. In addition, the system of converter is researched and designed, including introduction of electrical characteristics, analysis of system power dissipation and mode selection, research of the system stability. Besides, design and simulation of the key sub-circuits are presented. Finally, the whole chip simulation and layout are given.The synchronous PWM/PSM peak current mode is chosen, effectively improving the efficiency and the transient response speed. The converter works in PWM mode at heavy load and PSM mode at light load, which maintains high efficiency over the wide load range. The efficiency of the converter is up to 95%. To improve the temperature coefficient, a bandgap reference with a piecewise curvature compensated circuit is presented. A piecewise linear slope compensation circuit is designed, reducing the effect of slope compensation on load capability. In addition, perfect function blocks as over current protection, thermal shutdown, input under voltage lockout and output over voltage protection are also integrated in the chip, which can ensure the chip is stable and reliable.The design and simulation of XD1281 are completed by using Cadence software based on the 0.6μm BCD process. The simulation results show that the function and performance of the converter can meet the prospective requirements. |
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