Apple Inc.

Evan D Ragsdale

Roderick Brian Hogan

Nathan Alan Johanningsmeier

Kavitha Srinivasan

A power converter produces power at a greater voltage than provided by a power source, while drawing power from the power source, wherein the power converter has a variable input current limit or a variable input power limit. One or more audio amplifiers are configured into i) drawing power from the power source bypassing the power converter and ii) drawing power from the power converter, according to audio signal amplitude, during audio playback and in accordance with an audio signal being amplified. A load of each amplifier is determined for when the amplifier is drawing power from the power source bypassing the power converter. The variable input limit of the power converter is adjusted in accordance with the determined load, during the audio playback. Other aspects are also described and claimed.

Amplifier power converter input current/power limit adjustment using amplifier load determinations

A power converter provides a first output voltage and a second output voltage in accordance with a control input, wherein the first output voltage is higher than the second output voltage. A switch that is series coupled between i) an energy reservoir node and ii) a power supply node or a power return node. A charge maintenance circuit is coupled to the energy reservoir node, and when the switch is closed can maintain a selected amount of charge in or a selected voltage across an energy reservoir element that may be coupled to the energy reservoir node. Other aspects are also described and claimed.

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Milpitas, CA, United States of America

Evan D Ragsdale