In this paper, a novel buck-boost converter with the voltage gain of 2D - 1/1 - D is proposed. Output voltage is positive and the voltage stresses on the power switches and the diodes are low. Suggested topology is based on conventional boost converter. Proposed converter can provide a large step down voltage conversion ratio. Control of converter can be done with a simple I-type (Integrator) controller. (C) 2017 The Authors. Published by IASE. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).