Step-down Output Research Articles

Integrated Dual-Output Converter

This paper presents a family of single-input-multiple-output (SIMO) dc-dc converter topologies, which can provide one step-up and multiple step-down outputs. These topologies are synthesized by replacing the control switch of a boost converter topology with series-connected switches and using the additional switch nodes to generate step-down dc outputs. Compared with separate converters, these topologies utilize a lower number of switches and are more reliable due to their inherent shoot-through protection. Analysis shows that the topologies exhibit similar dynamic behavior as individual buck and boost converters. Hence, the control system methodology is the same as that of separate converters, with each output being precisely regulated. The behavior of these converters has been illustrated in this paper using the integrated dual-output converter (IDOC), which has a step-up and a step-down output. The steady-state characteristics and dynamic behavior of the converter have been studied. An analog closed-loop control system for the converter has been described for regulation of both the outputs. The operating principles have been experimentally validated using a 120-W prototype. Results show that the proposed converter has very good cross-regulation to step load change as well as dynamic reference change in either output. The measured efficiencies of the IDOC prototype are around 90%.

An Integrated One-Cycle Control Buck Converter With Adaptive Output and Dual Loops for Output Error Correction

An integrated adaptive-output switching converter is presented. This converter adopts one-cycle control for fast line response and dual error correction loops for tight load regulation. A dc level shifting technique is proposed to eliminate the use of negative supply and reference voltages in the controller and make the design compatible with standard digital CMOS process. The design accommodates both continuous and discontinuous conduction operations. To further enhance the efficiency, dynamic loss control on the power transistors is proposed to minimize the sum of switching and conduction losses. The design can be extended to other dc-dc and ac-dc conversions. The prototype of the buck converter was fabricated with a standard 0.5-/spl mu/m digital CMOS process. Experimental results show that the converter is well regulated over an output range of 0.9-2.5 V, with a supply voltage of 3.3 V. The tracking speeds are 12.25 /spl mu/s/V for a 1.6-V step-up output change and 13.75 /spl mu/s/V for a 1.6-V step-down output change, respectively, which are much faster than existing counterparts. Maximum efficiency of 93.7% is achieved and high efficiency above 75% is retained over an output power ranging from 10 to 450 mW.