Design of the DC-DC buck Converter for mobile applications using PWM/PFM mode

초록

This paper presents a high efficiency DC-DC buck converter for mobile device. The circuit employs simplified compensation circuit for its portability and for high efficiency at stand-by mode. This device operates at PFM mode when it enters stand-by mode (light load). In order to place the compensation circuit on chip, the capacitor multiplier method is employed, such that it can minimize the compensation block size of the error amplifier down to 30%. The simulation results show that the buck converter provides a peak efficiency of 93% on PWM mode, and 92.3% on PFM mode. The converter has been fabricated with a 0.35um CMOS technology. The input voltage of the buck converter ranges from 2.5V to 3.3V and it generates the output of 3.3V.