Patent ID: 11894779
Assignee: APPLE INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 11:
12. An AC-DC converter comprising:
a rectifier coupled to an AC input of the AC-DC converter;
a flyback converter having an input coupled to the rectifier and an output coupled to an output of the AC-DC converter;
an active power buffer coupled to the output of the AC-DC converter, the active power buffer further comprising:
an energy storage capacitor; and
one or more switching devices selectively coupling the energy storage capacitor to the output of the AC-DC converter so as to alternately store energy in and discharge energy from the energy storage capacitor; and

control circuitry including:
a first control loop, having a bandwidth less than twice the line frequency of the AC input, that operates the flyback converter to regulate an average voltage across the energy storage capacitor of the active power buffer while providing unity power factor at the AC input of the AC-DC converter; and
a second faster control loop that operates the one or more switching devices of the active power buffer to regulate an output voltage of the AC-DC converter.