Abstract: A DC/DC converter combines elements of a boost and a buck converter with synchronous switching and a single controller to provide a step-up or step-down regulator with continuous input and output currents. A boost converter composed of an inductor in series with the input, a switch to ground, and a diode to an intermediate voltage node provides an intermediate voltage that is greater than the input voltage. A buck converter composed of a switch in series with the intermediate voltage node, a diode to ground, and an inductor in series with the output provides an output voltage that is less than the intermediate voltage. The output is regulated by a single pulse width modulating controller which drives the boost switch and buck switch simultaneously. This technique provides a DC/DC converter that can operate with an input voltage greater than or less than the output voltage.