Patent ID: 11888410
Assignee: APPLE INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A system comprising:
a transformer including one or more secondary windings;
a rectifier, including a set of switches, that connects taps of the one or more secondary windings to a first terminal and a second terminal;
a battery connected between the first terminal and the second terminal; and
a processing apparatus that is configured to control the set of switches to rectify a multilevel voltage signal on the transformer, including:
selecting a modulation scheme from among two or more modulation schemes based on a measured voltage level of the battery, wherein each of the two or more modulation schemes is a periodic sequence of multiple modulation states with a period that corresponds to a whole number of periods of the multilevel voltage signal on the transformer, wherein a modulation state specifies which of the set of switches is in an on state, and wherein a first modulation scheme of the two or more modulation schemes includes at least one modulation state that is different than the modulation states of a second modulation scheme of the two or more modulation schemes.