Research And Design Of Low Loss DC/DC Converter

With the amazing development of the SoC(system on chip) technology, the SoC had became the prime focus of the IC field. It can be safe to say that it has been come to the time of SoC. Integrating the digital circuits, analog circuits, the signal sample modules, converse circuits and the storage devices on a single slice of silicon to form a system. But all of these modules need power supply, which is the foundation for the system to work. The common solution is to provide the SoC chip power,by using one or more power supply IC. But in order to reduce the power consumption, the volumes of the total system, and the cost, the designers want to also integrate the power supply module. With the development of semiconductor process and the overspreading of the portable devices, the digital devices request the power supply much better. The large scope of output current, low loss is the prime point for researchers. Step-up DC/DC converter is also very important.For the above circumstance, and considering that digital CMOS process is the main process in SoC designing, the topic of this thesis will to be: The analysis and design of step-up, low loss DC/DC converter based on standard digital CMOS process (SMIC 0.18um CMOS process).This thesis analyzes and compares the advantage and disadvantage of DC/DC converters and feedback controlling methods, and then determines that realizing the DC/DC converter by using Boost circuit and voltage mode PWM feedback controlling method. Designing and optimizing the parameter of Boost circuit according to the SPEC of the design. Then design a low power reference source, to ensure low wave of output voltage; a stable frequency Saw Wave Generator by using reference current charge and discharge to capacitance; a low-power wide-band error amplifier; and a low loss driver.This thesis analyzes the problem of the converter system, liking the phenomenon of no start, current surge when starting, and the instability of system. Accordingly, we add Soft Start Circuit, Over Current Protection Circuit and Feedback Compensation Net in converter system. These designs had been tested and modified. Finally, with the technologies of synchronous rectifier which could lower rectifying loss of the converter and improve the system's efficiency, the converter had been simulated and modified on system level. Furthermore, this converter had been simulated functionally in various conditions.