An embodiment of a coupled-inductor core includes first and second members and first and second forms extending between the first and second members. The first form has a parameter (e.g., length) of a first value, and is operable to conduct a first magnetic flux having a first density that depends on the first value of the parameter. The second form is spaced apart from the first form, has the parameter (e.g., length) of a second value different from the first value, and is operable to conduct a second magnetic flux having a second density that depends on the second value of the parameter. Because two or more of the forms of such a core may have different values for the same parameter, the core may be suitable for use in a multiphase power supply where the currents through the phases are unbalanced.