Design of Low Power Monolithic DC-DC Buck Converter with Integrated Inductor

This paper presents the design and fabrication of monolithic buck converter using standard CMOS process. As the Q-factor of planar spiral inductor is low in standard CMOS process, this work uses an in-plane inductor built using a CMOS compatible MEMS based technique called PDMA (plastic deformation magnetic assembly). The fabrication process for integrating this air-core, in-plane PDMA inductor is outlined. Optimization of MOS transistors to minimize losses in the buck converter is presented. The design of a 75-mW monolithic buck converter, using AMIS ABN 1.5 mm CMOS process and in-plane PDMA inductor, is outlined. Experimental results from this buck converter are presented