公开(公告)号：US10855192B1

公开(公告)日：2020-12-01

申请号：US16538963

申请日：2019-08-13

Applicant: Apple Inc.

Inventor： Zaohong Yang ,  Marco A. Davila, Jr. ,  Joao L. Andres ,  Poornima Mazumdar ,  Bogdan T. Bucheru

IPC: H02M3/335 ,  H02M1/00

Abstract: A transformer-based switching power converter can include a slew rate limiter coupled to the switching stage and configured to limit rate of change of voltage across one or more switching devices of the switching stage, thereby reducing voltage spikes appearing on the secondary winding. The slew rate limiter may be configured to selectively operate to limit rate of change of voltage across one or more switching devices of the switching stage during startup of the switching stage, upon waking from burst mode, or at any time when zero voltage switching of the one or more switching devices is unavailable. The slew rate limiter can include at least one circuit element configured to selectively alter a time constant of a gate drive circuit of at least one switching device in the switching stage to increase a turn-on transition time of the at least one switching device.