Research And Design Of A Very Low-voltage BUCK Convertor Based On Hysteresis Control Mode

During the last few years,the huge improvement of modern electronic technology and the consumers’ keen need promote the development of smart cellphones, tablet PC, latptops and other portable electronic products.As the most basic support to guarantee electronic products to operate normally,power supply has a huge effect on the battery life and operational life.However,with the increasing integration level,and the CPU,GPU.etc tend to become more core and high frequency,in addition,the display device is becoming biger and has higher resolution,all in all,the power consumption increases greatly. But the stored energy of the single cell available is very limited,the power management chip with more excellent performance and higher efficiency is most effective method to satisfy the urgent need of the modern electronic products.What’s more,semiconductor technology is still developing rapidly along the trend which is known as the Moor Law,20 nm technology has been used in advanced integrated circuits whose supply voltge also scale down to even below 1V. Clearly,low-voltage power management chips would have great research value.As an important branch in the field of power management, DC-DC converter can make flexible adjustment according to the input DC voltage, and can realize the incrasing,reducing,both at the same time or inverting of the DC voltage.So, DC-DC converter has been widely used in various electronic products,such as digital camera, smart phones, tablet PC and so on.A low-voltage BUCK converter based on hysteresis contol mode with fast transient response performance is provided in this thesis,which is designed based on 0.18 um BCD(Bipolar,Cmos.Dmos) process.The converter can operate normally under the 1v-input-voltage,so it can be used for 1.2-V Ni-Mh or Ni-Cd battery,and its output voltage can range from 0.5V to 0.9V so that it can supply the integrated circuits whose minimum operational voltage is below 1V.Also the converter adopt the way of supply switch,in order to broaden its highest input voltage to 12 V. In addtion,some adaptive design is used to improve the performance of transient response.This thesis fistly introduces basic related knowledge about Switching power supply,and then more detailed theory about BUCK converter is talked about.Secondly, the design idea of the provided converter is present.To be next,detailed analysis to the key sub-circuits is deployed and present the corresponding simulation results including the simulation to the whole converter by H-spice.Finally, a summary to the whole design is made.