Analysis of PWM and PFM control schemes for integrated step-up DC-DC converters

Abstract

This paper studies and compares control schemes for fully-integrated step-up dc-dc converters. The paper analyzes both a pulse-width-modulated and a pulse-frequency-modulated control schemes, and discusses the differences in terms of load currents and output voltages. Both control schemes were designed and simulated in a CMOS 65-nm technology. The paper also compares the analytic models to simulation results for validation. The expected performance of dc-dc converter can be quickly assessed and the maximum achievable efficiency determined.