A power supply circuit and a control method for a control circuit, where the control circuit is coupled to the voltage buck-boost adjustment circuit. The control circuit is configured to: when a voltage value of a first enable signal of the voltage buck-boost adjustment circuit is greater than or equal to a first predetermined value, control the output voltage of the voltage buck-boost adjustment circuit to be a first output voltage, and is further configured to: when the voltage value of the first enable signal of the voltage buck-boost adjustment circuit is less than or equal to a second predetermined value, control the output voltage of the voltage buck-boost adjustment circuit to be a second output voltage or a zero voltage.