Research And Design Of Buck DC/DC Converter

In this paper a Buck DC/DC converter have been designed for portable applications powered from one cell Li-ion or three cell NiCd batteries. The device in an adjustable output voltage from 0.9 to 2.4V is able to deliver up to 1A. It uses synchronous rectification to increase efficiency. Also automatic switching PWM/PFM mode offers improved system efficiency. The device has a built-in 1.7MHz oscillator which reduces component size by allowing a small inductor and capacitor. Additional features include thermal shutdown protection and under voltage lockout protection.This system contains many functional blocks, such as the bandgap reference, the LDO regulator, the amplifier, the current sensing circuit, the PWM comparator, the oscillator and the slope compensation circuit. Under Cadence design environment, the simulation of the circuit and system is completed based on TSMC0.18 process. These results of simulation indicate the circuit design according with the requirement.