An Independently Controlled Single-Input-Dual-Output Buck Converter with Coupled Inductor Having 1:1 Turns Ratio

Abstract

Thanks to the favorable advantage of reduced magnetic components, single-inductor multi-output DC-DC converters are attractive in low-cost industrial applications. However, when the converters work in continuous conduction mode (CCM), a severe dynamic cross-regulation problem will occur due to the current multiplex of the same inductor. To solve this problem, an improved single-input-dual-output (SIDO) buck converter is proposed in this paper, which employs one coupled inductor with 1:1 turns ratio as a substitution for the inductor. In the proposed converter, the two output voltages can be controlled independently while the advantage of fewer magnetic cores is retained. Moreover, reduced number of semiconductor components is achieved, leading to a lower cost. Besides, because of the 1:1 turns ratio, the magnetizing current is also effectively decreased to the one output current rather than the sum of two output currents, which will reduce the volume of magnetic core.