Synchronous rectifier
AssigneeNXP B.V.
InventorsJeroen KLEINPENNING, Jan DIKKEN
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Abstract
Disclosed is a method to control the synchronous rectification in a power converter including a primary winding and a secondary winding, including detecting a peak current in a secondary winding, determining a blanking threshold based on the peak current, and blanking a turning off of a synchronous rectifier (SR) switch for a blanking time based on the blanking threshold.
Claims20
A method to control the synchronous rectification in a power converter including a primary winding and a secondary winding, comprising:
- detecting a peak current in a secondary winding;
- determining a blanking threshold based on the peak current;
- and
- blanking a turning off of a synchronous rectifier (SR) switch for a blanking time based on the blanking threshold.
The control method of claim 7, where the zero blanking time is applied for a SR gate voltage just above the threshold of a logic level FET in low voltage applications and for a SR gate voltage just above the threshold of a standard level FET in high voltage applications.
A power converter, comprising:
- a secondary current winding having a peak current;
- a synchronous rectifier (SR) switch to rectify current in the secondary winding, the SR switch having a source, drain and gate;
- an SR controller to control the SR switch, the SR controller comprising:
- a peak current detector configured to produce an output signal related to the peak current value of a secondary current;
- and
- a blanking circuit configured to set a blanking time based upon the output gate signal related to the peak current value.
The power converter of claim 13, wherein the peak current is obtained by measuring a drain to source voltage of the SR switch with the SR gate charged such that a defined VDS voltage is reached.
A power converter, comprising:
- a secondary winding having a peak current;
- a synchronous rectifier (SR) switch to rectify current in the secondary winding,;
- an SR controller to control the SR switch, the SR controller comprising:
- a detecting circuit to detect a peak current in the secondary winding;
- regulation circuitry to determine a blanking time based on the peak current;
- and
- a blanking circuit to blank the SR switch for the blanking time.
Dependencies are inferred from the claim text.