Abstract: A voltage conversion apparatus, a control method, and a power supply device. The voltage conversion apparatus includes a control circuit. The control circuit is configured to: obtain a first sampling voltage and a second sampling voltage; detect a resonant period based on the second sampling voltage when it is determined, based on the first sampling voltage, that a voltage range of an output voltage of the voltage conversion apparatus changes and a voltage threshold is exceeded; and output a drive signal based on the detected resonant period. The drive signal is used to control turn-on and turn-off of a first switching transistor and a second switching transistor.

Abstract: A control circuit for a switch-mode power supply, a power circuit, and an electronic device. The control circuit outputs a control signal to control a switching frequency of the switch-mode power supply. The control circuit adjusts, in a plurality of cycles, a frequency of the control signal based on a plurality of ranges, and controls, in each cycle, the frequency of the control signal to change with time in a range corresponding to each cycle. In the embodiments, a frequency-domain energy dispersion degree of the control signal output by the control circuit can be increased, electromagnetic interference generated by the control signal output by the control circuit is reduced, and finally, it is ensured that the power circuit and the electronic device including the power circuit can pass a related security test.