Design Of Buck Switching Power Supply Management IC In Current Mode

With the rapid development of IC industry, as an indispensable part of electronic system, the demand of PMI (Power Management IC) becomes more and more huge. The BCD process finds extensive application because of its high efficiency, low noise, high precision and low quiescent current. Thus, it is very necessary for us to do research on the BCD process DC-DC converter.The paper is based on the project"Theoretical research and design of key technique for power management IC". The detail system design and the circuit designs of the key sub-blocks of XD2160 are given. And the simulation of all functions and electrical characteristics are presented. Possessing all dynamic functions of a buck switching voltage regulator, this chip has the ability to provide 3A output driving current. Operating at a switching frequency of 340 KHz, it allows smaller sized filter components than what would be needed with lower frequency switching voltage regulators. By using the synchronous switch to substitute the Schottky diodes, the efficiency of the chip has been enhanced considerably. In addition, lots of protection circuits are integrated in the chip, such as thermal shutdown, under voltage lockout, over current protection, and so on.The design of XD2160 is based on the 0.5um BCD process, and simulated by Cadence and Hspice. According to the simulation results, the function and performance of XD2160 has met the requirements.