Single-Inductor Dual-Input Triple-Output Buck–Boost Converter With Clockless Shortest Power Path Control Strategy for IoT Nodes

Abstract

A single-inductor dual-input triple-output buck–boost (SIDITOBB) converter with a novel clockless shortest power path (CSPP) control strategy is presented, which compares the output voltages with their respective reference voltages to obtain the states of each output, and compares the input voltages with their relaxation ranges of the ideal photovoltaic maximum power point voltage to judge the states of each input, and correspondingly selects the right input and output per period to achieve a shortest power path rather than the equivalent twice power conversion in the conventional control strategies. The CSPP control strategy contributes to the advantage of the high efficiency because of lower power consumption resulting from the eliminated clock module and less conversion times of current flowing through the power transistors and inductor, as well as more harvested energy resulting from the fractional open-circuit voltage maximum power point tracking. Besides, low power circuit design strategies are utilized to enhance the efficiency further, including using zero current switching, utilizing a low voltage as the supply of the control circuits, discontinuing the controllable comparators after each comparison, and making the transistors of CMOS voltage reference in the weak inversion or linear region. Finally, the proposed SIDITOBB converter with the CSPP control strategy is fabricated in the Central Semiconductor Manufacturing Corporation 0.18 μ m 1P6M technology.