I've been looking for a toroid with a cross section area (one side) of
probably 2 or 3 square centimeters and an id of about 10 or 12 mm. The
intended inductor is about 14 micro henries and will handle between 40 to 80
amps in a flyback power supply at, again probably, 100 kc.
Fair-Rite, Micrometals, and Magnetics show, at the desired id, cross
sections typically less than 1 sqcent. Greater cross sections show greater
id's and consequently greater lengths. These toroids would result in windings
using only a portion of available space with the rest of the toroid doing
nothing but dissipating power.
Anyone know of some suppliers that have the bulky type of toroids that are
required in this case? Or, perhaps, another approach to limit the dissipation?