A noninverting buck-boost converter with reduced components using a microcontroller

This paper presents a simple method for the microcontroller implementation of a noninverting buck-boost converter. The converter requires two switches, but only one set of controls. As compared to a cascaded buck converter/boost converter topology, the noninverting buck-boost converter requires one less capacitor and inductor. The system operates as a buck converter for duty cycles between 0-50% in the microcontroller, and as a boost converter (up to a gain of twice the input voltage) for duty cycles between 50-100%. The system is therefore also advantageous because the microcontroller algorithm prevents a dead short from occurring during operation in the boost converter mode. Experimental and PSpice results prove that both buck and boost operation are possible using this topology. The effect of the load resistance on the results is discussed.