Method of forming a synchronous rectifier controller and structure therefor
AssigneeSemiconductor Components Industries, LLC
InventorsLukas Olivik, Roman Stuler, Tomas Tichy
Life of this patent
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Abstract
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.
Claims20
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.
A method of forming a synchronous rectifier controller comprising:
- configuring the synchronous rectifier controller to initiate disabling a synchronous rectifier responsively to a voltage on a winding of a transformer that is coupled to the synchronous rectifier becoming a first value;
- configuring an off-time control circuit to form an off-time interval for a first period of time wherein the synchronous rectifier controller maintains the switching signal in the disable state for at least the off-time interval;
- and
- configuring the off-time control circuit to increase the off-time interval by increasing the first period of time to a second period of time responsively to the voltage becoming a different value prior to termination of ringing of the voltage and prior to expiration of the off-time interval.
A method of forming a synchronous rectifier controller comprising:
- configuring the synchronous rectifier controller to initiate a disable state a synchronous rectifier responsively to a voltage of the synchronous rectifier becoming a first value;
- configuring an off-time control circuit to form an off-time interval responsively to the first value of the voltage;
- and
- configuring the off-time control circuit to one of increase the off-time interval or reinitiate forming the off-time interval prior to termination of ringing of the voltage and prior to expiration of the off-time interval wherein the synchronous rectifier controller maintains the switching signal in the disable state for at least a portion of the off-time interval.
Dependencies are inferred from the claim text.