This paper shows DC and small-signal circuit models for the PWM DC to DC buck, boost and back/ boost converters with the equivalent series resistance of the inductor. The DC voltage transfer function and the efficiency of the converter are derived from the DC model. Small-signal open-loop characteristics are derived from the small-signal model based on a state variable model. A design example proves the performance of the circuit and verification of the model.
 Kazimierczuk, M. and Cravens, R. (1994) Open-Loop DC and Small-Signal Characteristics of PWM Buck-Boost Converter for CCM. Aerospace and Electronics Conference, Proceedings of the IEEE, 1, 226-233.
 Wang, J.H., Zhang, F.H. and Gong, C.Y. and Chen, R. (2011) Modeling and Analysis of a Buck/ Boost Bidirectional Converter with Developed PWM Switch Model. 2011 IEEE 8th International Conference on Power Electronics and ECCE Asia (ICPE & ECCE), May 2011, 705-711.
 Neacsu, D., Bonnice, W. and Holmansky, E. (2010) On the Small-Signal Modeling of Parallel/Interleaved Buck/Boost Converters. 2010 IEEE International Symposium on Industrial Electronics (ISIE), July 2010, 2708-2713. http://dx.doi.org/10.1109/ISIE.2010.5637070
 Wang, Q., Shi L.X. and Chang, C.Y. (2008) Small-Signal Transfer Functions for a Single-Switch Buck-Boost Converter in Continuous Conduction Mode. 2008 ICSICT 9th International Conference on Solid-State and Integrated-Circuit Technology, Beijing, 20-23 October 2008, 2016-2019.
 Ortiz, C. (2005) Circuit Oriented Average Modeling of Switching Power Converters. 2005 European Conference on Power Electronics and Applications, 1-10. http://dx.doi.org/10.1109/EPE.2005.219694