A method for operating PFC rectifier circuit, a control circuit for operating a PFC rectifier, and a power converter circuit are disclosed. The method includes: operating the rectifier circuit (2) in a PFC mode, wherein operating the rectifier circuit (2) in the PFC mode comprises operating the rectifier circuit (2) in a first operating mode or a second operating mode, wherein operating the rectifier circuit (2) in the first operating mode comprises operating a switch (26) in the rectifier circuit (2) at a predefined fixed first switching frequency (fswl), wherein operating the rectifier circuit (2) in the second operating mode comprises operating the switch (26) in the rectifier circuit (2) at a second switching frequency (fsw2) higher than the first switching frequency (fswl), and wherein the method further includes adjusting the second switching frequency (fsw2) dependent on a current ripple parameter (|Iac bf |).