Non-zero inductor current based DCM analysis for combined DC-DC converters

This paper aims to highlight the differences between DC-DC converters having one inductor or multiple inductors under discontinuous conduction mode (DCM) operation. A single inductor-based converter such as boost and two inductor-based converter such as zeta converter are analyzed to present the differences under DCM. This work reasserts that a DC-DC converter inductor current need not always be zero to enter into DCM. For multiple inductor-based converters it is shown that the equivalent inductance and the sum of the inductor current play a vital role in deciding the discontinuity. This is verified based on a Boost-Zeta combined converter which is analyzed and simulated for all possible cases under DCM. Moreover, the benefit of introducing phase shift between the gate pulses of switches in this combined converter is also presented.