Controlling an adapter transformer voltage

摘要

Embodiments of an adapter are disclosed that include a transformer with a primary coil coupled to an H-bridge. The H-bridge is controlled by a control circuit that controls a voltage across the primary coil using the H-bridge, and the control circuit is configured to control the H-bridge so that during each of one or more intervals, a first voltage pulse is applied across the primary coil in a start direction, wherein the start direction alternates between a first direction and a second direction each interval. Then, a direction of subsequent voltage pulses across the primary coil is alternated between the first direction and the second direction a predetermined number of times. After the predetermined number of times, a last voltage pulse is applied across the primary coil; then, voltage across the primary coil is reduced to zero for a predetermined time.

主权项

1. A method for controlling a voltage across a primary coil in an adapter transformer, comprising:
during each of one or more intervals, applying a first voltage pulse across the primary coil in a start direction, wherein the start direction alternates between a first direction and a second direction each interval; applying a predetermined number of subsequent voltage pulses across the primary coil, wherein the subsequent voltage pulses alternate between the first direction and the second direction; applying a last voltage pulse voltage across the primary coil; and reducing the voltage across the primary coil for a predetermined time; wherein at least one of a frequency at which the direction of the predetermined number of subsequent voltage pulses across the primary coil is alternated, the predetermined number of times the direction of the voltage pulse across the primary coil is alternated, and the predetermined time that the voltage across the primary coil is reduced is changed based on a power demand from the adapter transformer.