Dependence of Continuous-Discontinuous Conduction Mode Boundary on Gate Pulse Shift in Coupled Inductor Single-Input Dual-Output Boost Converter

Abstract

The coupled inductor single-input dual output (SIDO) converters can supply two different output voltages from one input voltage with reduced component counts, reduced losses, and increased efficiency. Inversely coupled inductors enhance the advantages by reducing the core and overall converter sizes. The CI-SIDO boost converters operate in three modes– continuous conduction mode (CCM), discontinuous conduction mode (DCM) and CCM/DCM boundary. Due to simple load-independent control, the CCM is preferred more for operating CI-SIDO converters. This paper introduces the method of lowering the CCM/DCM boundary, thus, widening the CCM range of the converter by shifting the gate pulse. The commonly used method of reducing the CCM/DCM boundary current is increasing the inductance values, which is not preferred due to the increased size of the core and the converter. The paper presents the shift of gate pulses to reduce the boundary current of the CI-SIDO boost without changing inductance or any other circuit element. The gate pulse shift where maximum reduction takes place is found analytically. The proposed method is experimentally verified for all possible voltages and coupled inductor parameters. The presented experiments observed the percentage reduction in CCM/DCM boundary current is up to 91.67%.