Research And Design Of High Precision Current Mode DC-DC Buck Converter With Synchronous Rectification Technology

In recent years, the portable electronic products are becoming more and more popular, which makes a rapid growth of power management IC. With the purpose of providing more functions and high performance, as far as saving energy, these electronic products need switching power supply chip with high conversion efficiency and high precision.This thesis proposes a high precision monolithic buck DC-DC converter. The chip adopts the current PWM control mode, and uses slope compensation and synchronous rectification. In the chip, both of the switching MOSFET and rectification MOSFET are integrated. This chip is characterized by high precision, high dynamic-responding speed and small strike-voltage and surge-current at starting stage.Spectre simulations are done on each cell and the whole system in cadence with the parameter of CSMC 0.6um Bi-CMOS process. It works at 3.3V to 5.5V supply voltage, and provides 1.8V to 3.3V output voltage with a maximal output current of 600mA. Simulation indicates that the output ripple is only 5mV ,and the power efficiency is 86% with 5V supply voltage,2.5V output voltage and 10Ωload resistor. Also,in other typical simulations, the respective values are achieved.