A High Performance Voltage Reference Based On BICMOS Technology

All electrical equipments require power supply to keep normal operation. According to different requirements of equipments, all sorts of power supply were developed successively from early linear regulator to present switching regulator. Power management ICs are always applicable in portable products. In recent years, this kind of products makes tracks with high productivity, new function and high quality, and it is inevitable to present more demands. With the upgrade of portable products and development of semiconductor technology, power management ICs trend to high efficiency, low power, low voltage, high precision, low noise and high integrated in the future.This thesis delves into voltage reference which is a significant block cell of the most popular power management ICs, and designs a bandgap reference applicable to power management IC. The research produce is supported by National Science Foundation of China and Sichuan Province Academic and Technologic Leaders Foundation.Temperature independence and high stability of output voltage are essential characteristics, which can influence on stability of output voltage and other performance indexes of power management IC. The thesis analyzes the basic theory of bandgap reference, presents an introduction to academic studies condition on it and then gives a summary of advantage and disadvantage in several circuit structures. On the basis of comparing some popular structures of bandgap reference, we have successfully designed a high performance bandgap voltage reference satisfying main performance indexes which are required by power management IC.The main contributions lie with designing a bandgap reference based on 0.6 um BICMOS technology which is characteristic of low temperature coefficient and high power supply rejection ratio over wide band. The object of low temperature coefficient is realized by avoiding operational amplifier to eliminate temperature drift due to operational amplifier offset. By using common-gate MOS transistor and compensation capacitor, high power supply rejection ratioover wide band and low noise are achieved. A long start-up time is avoided by designing a charge circuit which is controlled accurately for compensation capacitor.