Apple Inc.
Active burst ZVS boost PFC converter

Abstract:

A power converter can be configured to convert an AC input voltage into a regulated DC output voltage while maintaining the input current in phase with the rectified AC input voltage. A control circuit of the power converter may be configured to selectively enable switching of at least one switching device of the power converter responsive to a determination that the input voltage is greater than a threshold voltage and to selectively disable switching of the at least one switching device responsive to a determination that the rectified AC input voltage is less than the threshold voltage. The control circuit may be configured to selectively enable and disable switching using an active burst mode signal having a frequency lower than a switching frequency of the converter. The control circuit may be still further configured to operate at least one switching device of the converter in a zero voltage switching condition.