Positive buck-boost converter

• Main Author: Hong, Zu Xin.
• Other Authors: Luo Fang Lin
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Power electronics
• Online Access: http://hdl.handle.net/10356/17310
• Institution: Nanyang Technological University

Through the increasing advancement in technologies, more devices are designed with better efficiency and additional functionality. With the increasing demand for low-voltage devices, superior and efficient power management techniques are entrenched into these devices. The most common choice of voltage source for these devices is the Li-ion battery. A single Li-ion battery voltage output ranges from 4.2V to 2.7V. A positive DC/DC Buck-Boost converter is used to sustain the fluctuating voltage of the Li-ion battery to a constant value of 3.3V. The DC/DC converter will be operating in three modes: Buck mode (Step-down), Buck-Boost mode and Boost mode (Step-up).The basic requirement for a prolonged life of the Li-ion battery is a smooth transition from the buck to boost mode. The positive buck-boost converter is incorporated with two switches, which controls the converter mode action depending on the input and output voltage in the project. A control circuitry has been designed for the purpose of this project. Creation of control circuitry will be presented in this report. Simulation and experiment will be conducted to verify results. In addition, a smooth transition from buck to boost mode techniques will be discussed in the paper.