Review of current mode control schemes and introduction of a new digital current mode control method for the parallel module DC-DC converters

Abstract

Ever increasing demands for the development of compact, lightweight power supplies with more power density, higher efficiency and fast dynamics, often require power conversion through parallel connected converter. In order to realize the parallel module DC-DC converters, a current mode control scheme is essential for current sharing control among the modules. The general analog current mode control schemes, such as peak current mode control (PCM), charge current mode control (CC) and average current mode control (ACM), are reviewed and compared of their characteristics, in this paper. With recvent advances in digital systems, digital control has becmoe increeasingly visible even for high-frequency, low-to-medium power switching converters. However, digital current mode control for the parallel module converter is not easy because the switch or inductor current is a fast-changing waveform and the switching frequency is high. This paper introduces one of possible solutions for a digital current mode control employing nonlinear resistive current mode control as well.