There is an increase in renewable energy sources, which are regarded as current sources, where DC-DC converters are widely used which require more suitable loads for driving current type loads. This paper uses a duality approach to show that the converter circuit can apply to the current type loads without too much voltage variation. It illustrates the derived steps for a conventional buck converter by using graph formation. To validate the duality approach, five original switching converters are detailed. A current source with an R-L load (CSRL) converter is used for current-based applications, such as electrical motors, electromagnetic relays, or light-emitting diodes (LEDs). This study proposes a two-phase non-inverting buck-boost converter with an R-L load which is suitable for driving currentbased applications. The design procedure and steady-state analysis are presented. SIM-PLISTM software is used to simulate the topologies. This method for operation mode and formula derivation is like in voltage type circuit structures, and this study has sufficient mathematical analysis capabilities. For demonstration, a 650 W VSRL converter is implemented to verify the feasibility of the method. The corresponding circuit topology of the conventional circuit can be illustrated by using the duality approach rapidly.