A control method for a first synchronous rectifier and a second
synchronous rectifier in a switching power converter is presented. The
switching power converter includes a transformer, and a first switching
device and a second switching device connected in series and in parallel
with an input voltage source. The first synchronous rectifier is
connected with a low end of a secondary winding of the transformer. The
second synchronous rectifier is connected with a high end of the
secondary winding of said transformer. The first switching device is
connected with a high end of the input voltage source, and the second
switching device is connected with a low end of the input voltage source.
The control includes the steps of driving the first switching device to
an on state and the second switching device to an off state; and driving
the second synchronous rectifier to an off state after the second
switching device has been driven to an on state, such that a power is
delivered from the primary winding to the secondary winding.