A flyback converter includes a primary-side circuit to receive an input voltage, a secondary-side circuit to generate an output voltage, a transformer coupling the primary-side circuit to the secondary-side circuit, a main switch coupled to a primary winding of the transformer, and a converter controller having a primary-side controller in signal communication with the main switch to control an on time and an off time of the main switch and to detect one or more valleys of a resonant waveform developed at the main switch during the off time of the main switch. The primary-side controller is configured to operate in a valley reduction mode of operation upon determining that the output voltage is less than a reference voltage minus a predetermined threshold value. The valley reduction mode of operation includes decrementing, for each switching cycle of the main switch, a number of valleys occurring during that switching cycle.
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