Power supply with a magnetically uncoupled phase and an odd number of magnetically coupled phases, and control for a power supply with magnetically coupled and magnetically uncoupled phases

Abstract

An embodiment of a power supply includes an input node that receives an input voltage, an output node on which a regulated output voltage is provided, an odd number of magnetically coupled phase paths each coupled between the input and output nodes, and a first magnetically uncoupled phase path coupled between the input and output nodes. Such a power supply can improve its efficiency by activating different combinations of the coupled and uncoupled phase paths depending on the load conditions. For example, the power supply may activate only an uncoupled phase path during light-load conditions, may activate only coupled phase paths during moderate-load conditions, and may activate both coupled and uncoupled phase paths during heavy-load conditions and during a step-up load transient.