Improving the control strategy for a four-switch buck-boost converter

Abstract

The four-switch buck-boost converter, such as implemented with the Linear Technology LTC3440 integrated circuit, is useful in many applications. While this topology can be highly efficient, new strategies for controlling it could decrease power losses even more. The strategy proposed for this thesis involves the use of level shifted triangle waves and high speed comparators to achieve a narrower buck-boost region than achieved in previous control IC's such as the LTC3440. Reducing the amount of operation in this regime is desirable because it is the most inefficient mode of operation of the converter. This potentially simpler solution will allow for resources to be used to improve the performance of other elements of the circuit, allowing for potential increases in efficiency.