Abstract: Usually basic dc-dc boost converters are unable to provide high step up voltage gain due to the effect of power switches, rectifier diodes and equivalent series resistance of inductors and capacitors and the voltage stresses on the power switches are high. This paper proposes a simple transformerless dc-dc converters to achieve high step up voltage gain without an extremely high duty ratio. The structure of the proposed converters is very simple. This paper proposes three transformerless Dc-Dc converters with switched inductor technique, the duty ratio and the voltage stresses in the active switches of the proposed converters is compared with basic boost converter. The experimental results confirm that the voltage stresses in the active switches is reduced without an extremely high duty ratio in the proposed converters. Finally a prototype circuit is simulated to verify the performance.