CPC H02M 1/0058 (2021.05) [H02M 1/0012 (2021.05); H02M 3/33507 (2013.01)] | 16 Claims |
1. A power conversion apparatus supplying power to a load, the power conversion apparatus comprising:
a power switch,
a transformer having a primary side coupled to the power switch, and a resonance voltage generated on the primary side when the power switch is turned off, and
a control module coupled to the power switch, and configured to alternately turn on and turn off the power switch to convert an input voltage into an output voltage through the transformer, and an auxiliary winding of the transformer configured to sense an auxiliary voltage and configured to provide a level signal corresponding to a voltage level of the output voltage according to the auxiliary voltage, so as to set a predetermined counting threshold according to the level signal, and set a blanking time interval according to a feedback signal related to the load;
wherein, after the blanking time interval ends, the control module counts a number of oscillation turning points presented during an oscillation of the resonance voltage, and turns on the power switch when the number reaches the predetermined counting threshold.
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