On the Use of Buck ICs in the Implementation of the Non-Inverting Buck-Boost Topology

The first goal of this paper is to show that an integrated circuit implementing a buck converter without a maximum duty cycle limitation, which is thus able to provide 100% duty cycle, can be safely used in a four-switches non-inverting buck-boost topology provided that the inductor current-limit is suitably implemented. The second goal is to experimentally verify that such inexpensive buck device can be used in non-inverting buck-boost converters where the efficiency degradation, due to a sub-optimal switching pattern, can be accepted. This 'enhancement' of an original buck integrated circuit to operate as a buck-boost is cost-competitive against dedicated buck-boost solutions. Theoretical analysis, numerical simulations and experimental results show the effectiveness of the design choices.