SWITCHING POWER CONVERTER WITH PRIMARY-SIDE DYNAMIC LOAD DETECTION AND PRIMARY-SIDE FEEDBACK AND CONTROL

摘要

A switching power converter provides regulated voltage to a load. The switching power converter comprises a transformer including a first primary winding coupled to an input voltage, a second primary winding, a secondary winding coupled to an output of the switching power converter, and an auxiliary winding, a first switch coupled to the first primary winding, and a second switch coupled to the secondary primary winding. A controller generates a first control signal to turn the first switch on or off at a first switching frequency, and a second control signal to turn the second switch on or off at a second switching frequency that is higher than the first frequency. During off cycles of the switches, feedback voltage representing the output voltage of the power converter is generated across the auxiliary winding. The controller controls switching of the first switch to regulate the output voltage based on the feedback.

主权项

1. A switching power converter comprising:
a transformer including a first primary winding coupled to an input voltage, a second primary winding, a secondary winding coupled to an output of the switching power converter, and an auxiliary winding on a primary side of the transformer, output voltage across the secondary winding being reflected as feedback voltage across the auxiliary winding; a first switch coupled to the first primary winding of the transformer, current in the primary winding being generated responsive to the first switch being turned on and not generated responsive to the first switch being turned off, the feedback voltage being generated across the auxiliary winding during off-cycles of the first switch; a second switch coupled to the second primary winding of the transformer, current in the second primary winding being generated responsive to the second switch being turned on and not being generated responsive to the second switch being turned off, the feedback voltage being also generated across the auxiliary winding during off-cycles of the second switch; and a controller coupled to the first switch and the second switch, the controller being configured to generate a first control signal to turn on or turn off the first switch at a first switching frequency and a second control signal to turn on or turn off the second switch at a second switching frequency that is higher than the first frequency.