Datasheet

AN3180 Zero-ripple current phenomenon: theory
Doc ID 17273 Rev 1 9/39
To summarize the main results of this brief analysis:
1. Ripple-current can be reduced to zero in either winding of a two-winding coupled
inductor, but not simultaneously
2. The only conditions imposed on the voltages that excite the windings, in order to get
ripple current steering, is that they are proportional, with the same frequency and
phase
3. Provided the above condition on the terminal voltages is met, the zero-ripple current
occurrence in one winding depends on a proper choice of the leakage inductance
associated with the other winding only
4. As a winding where zero-ripple current occurs is virtually open for AC currents, the
inductance seen at the terminals of the other winding is exactly equal to its self-
inductance.