Apple Inc.
Combined Buck-Boost Converter Using a Single Inductor

Abstract:

A DC-DC converter that provides both buck and boost voltages using a single inductor is disclosed. The DC-DC converter includes an H-bridge circuit having an inductor having first and second terminals, and a number of switches. The switches include a first switch coupled between the second inductor terminal and a boost voltage node, a second switch coupled between the second inductor terminal and a buck voltage node, and a third switch coupled between the first inductor terminal and an input voltage node. A control circuit is coupled to activate the switches in accordance with a number of different phases such that a buck voltage (e.g., less than the input voltage) is provided on the buck voltage node, while a boost voltage (e.g., greater than the input voltage) is provided on the boost voltage node.