Mix-voltage conversion for single-inductor dual-output buck converters

A single-inductor dual-output (SIDO) buck converter has recently found applications in hand-held battery-powered electronic devices. The circuit operation and the functional interdependencies among basic converter parameters such as DC voltage gains, transistor duty cycles, and load current levels are much more complicated than those of the single-output counterpart. In this paper, a rigorous analysis was conducted to develop DC equations for the converters. More importantly, from the analysis results, a possibility of a new mode of operation, dubbed “mix-buck” operation, will be pointed out. In the so-called “mix-buck” operation, the converter is capable of working even when the input voltage is lower than one of the two output voltages. In the past, a SIDO buck converter has been used for providing “pure-buck” outputs, i.e., both output voltages are lower than the input voltage. Therefore, this possibility not only opens up new applications but also may extend the operating battery range in existing applications. Experimental results confirmed the DC equations and the “mix-buck” operation of SIDO converters.

[1]  M. Ghioni,et al.  Novel control technique for single inductor multiple output converters operating in CCM with reduced cross-regulation , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[2]  Paolo Mattavelli,et al.  Digital Control of Single-Inductor Multiple-Output Step-Down DC–DC Converters in CCM , 2008, IEEE Transactions on Industrial Electronics.

[3]  Wing-Hung Ki,et al.  Single-inductor multiple-output switching converters , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[4]  P. Mattavelli,et al.  FPGA control of SIMO DC-DC converters using load current estimation , 2005, 31st Annual Conference of IEEE Industrial Electronics Society, 2005. IECON 2005..

[5]  Kun-Yu Lin,et al.  Modeling and design of feedback loops for a voltage-mode single-inductor dual-output buck converter , 2008, 2008 IEEE Power Electronics Specialists Conference.

[6]  Franco Maloberti,et al.  A 200mA 93% Peak Efficiency Single-Inductor Dual-Output DC-DC Buck Converter , 2007, 2007 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[7]  Franco Maloberti,et al.  On the design of single-inductor double-output DC-DC buck, boost and buck-boost converters , 2008, 2008 15th IEEE International Conference on Electronics, Circuits and Systems.

[8]  Amit Patra,et al.  On-chip implementation of a multi-output voltage regulator based on single inductor Buck Converter topology , 2007, 20th International Conference on VLSI Design held jointly with 6th International Conference on Embedded Systems (VLSID'07).

[9]  Chi-Ying Tsui,et al.  Single-inductor multiple-output switching converters with time-multiplexing control in discontinuous conduction mode , 2003, IEEE J. Solid State Circuits.

[10]  Dirk Killat,et al.  Design of single-inductor dual-output switching converters with average current mode control , 2008, APCCAS 2008 - 2008 IEEE Asia Pacific Conference on Circuits and Systems.