System Modeling And Design Of High Performance Peak Current Mode DC-DC Buck Converter

With the development of Internet of things(IoT) and portable electronics devices, designing of green power system is becoming increasingly popular, and the requirement of power management system is becoming more and more critical. A new nonideal small-signal model for synchronous converter is presented in this dissertation. This is achieved by separately considering the power and control stage. And a peak current mode synchronous converter with light load high efficiency for portable devices applications is implemented based on the model in previous.In this work, system modeling and design of high performance peak current mode DC-DC buck converter was discussed. The power and control stage model of converter system was presented with circuit averaging and averaged switch modeling method. Based on the model, the layout and designing of main block circuits in converter system was implemented.The main research works and innovations include:1. As a guidance to the circuit designing, a nonideal small-signal model of converter system was presented with circuit averaging and averaged switch modeling method.2. With the help of gm/Id method in analog integrated circuits design, the main block circuits in converter system was implemented and optimized. Moderate performance and low-power was achieved, which improves the conversion efficiency of the converter system. The blocks include CMOS voltage reference with subthreshold region MOSFETs, ultra-low power relaxation oscillator and adaptive slope compensation circuits.3. A high performance converter system with light-load high efficiency mode was implemented using TSMC 0.13 um Mixed-signal CMOS process, the switching frequency is 2M Hz, range of input is 2.5 to 4.5V, the output is 1.2 to 1.8V according to the feedback resistor loop. The performance of converter system presented in this dissertation was verified with the aid of CADENCE IC616 tools. The results shows that system is stabled in different input voltage, output voltage and load current conditions, the design specs was meted. A peak power efficiency 98.4% is achieved at ILOAD=100mA, VIN=2.7, VOUT=1.2V.