Method of forming a synchronous rectifier controller and structure therefor

摘要

In one embodiment, a synchronous rectifier controller is configured to initiate forming an off-time interval for a first period of time responsively to the controller forming a disable state of a switching signal wherein the control circuit maintains the switching signal in the disable state for at least the off-time interval. The controller is also configured to restart forming the off-time interval responsively to a voltage of a synchronous rectifier becoming a first value prior to expiration of the first period of time.

主权项

1. A synchronous rectifier controller comprising:
a control circuit configured to form a switching signal with an enable state to enable a synchronous rectifier and with a disable state to disable the synchronous rectifier; a sync input configured to receive a sync signal that is representative of a voltage drop across the synchronous rectifier; a first circuit configured to initiate the enable state of the switching signal responsively to the sync signal becoming a first value; a second circuit configured to initiate the disable state of the switching signal responsively to the sync signal becoming a second value that is greater than the first value; an off-time control circuit having a first timer circuit that is configured to initiate forming an off-time interval for a first period of time wherein the control circuit maintains the switching signal in the disable state for at least the off-time interval; and the off-time control circuit configured to restart forming the off-time interval responsively to the sync signal becoming a third value prior to expiration of the first time period.