Microsoft-Word-06-林永裁-Integrated-CMOS-龙华.pdf

Integrated CMOS Buck DC-DC Converter with On-Chip PWM Circuit Integrated CMOS Buck DC-DC Converter with On-Chip PWM Circuit 1, 2 2 2 1 Yeong-Tsair Lin , Mei-Chu Jen , Dong-Shiuh Wu , Wen-Yaw Chung , and Hung-Chan Wang1 1Department of Electronic Engineering, Chung Yuan Christian University 2Department of Electronic Engineering, Lunghwa University of Science and Technology Abstract An integrated CMOS voltage-mode buck dc-dc converter with on-chip pulse-width modulation (PWM) technique of switching control is presented in this paper. Also, a micro-power bandgap voltage reference generator is developed for the dc-dc converter. The PWM scheme employs a pseudo hyperbola curve current-compensation technique, by which the duty cycle of the oscillation signal is controllable, and the oscillation frequency can be remained constant approximately. The proposed dc-dc converter with a chip area of 0.915 mm2 is designed and fabricated with a 2P4M 0.35-μm CMOS process. The experimental results show that the converter is well regulated over an output range from 1.0 V to 2.5 V, with an input voltage of 3.3 V. The maximum efficiency of the converter is 87 %, and its efficiency is kept above 81 % over an output power ranging from 60 mW to 410 mW. Keywords: pulse-width modulation (PWM), voltage-controlled duty-cycle (VCDC), dc-dc converter, ring oscillator.