AN3180 datasheet(9/39 Pages) STMICROELECTRONICS

Part #	AN3180

Description	A 200 W ripple-free input current

PDF	39 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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9 / 39 page

AN3180

Zero-ripple current phenomenon: theory

Doc ID 17273 Rev 1

9/39

To summarize the main results of this brief analysis:

Ripple-current can be reduced to zero in either winding of a two-winding coupled

inductor, but not simultaneously

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

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

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.

AN3180 Datasheet(PDF) 9 Page - STMicroelectronics