AN3180 Datasheet, PDF (1/39 Pages) STMicroelectronics – A 200 W ripple-free input current

AN3180
Application note
A 200 W ripple-free input current
PFC pre-regulator with the L6563S
Introduction
A major limitation of transition-mode-operated PFC pre-regulators is their considerable input
ripple current, which requires a large differential mode (DM) line filter to meet EMI
requirements. The ripple-steering technique, with its ability to reduce an inductor ripple
current, theoretically to zero, can be very helpful in reducing the need for DM filtering in any
offline switching converter and in PFC pre-regulators in particular, where DM noise is an
issue as there is no electrolytic capacitor just after the bridge. This application note
illustrates the use of this technique, providing both the theoretical base and practical
considerations to enable successful implementation. Furthermore, it shows the bench
results of the EVL6563S-ZRC200 demonstration board, a 200 W ripple-free PFC pre-
regulator based on an L6563S controller, designed according to the criterion proposed in
this application note.
Figure 1. EVL6563S-200ZRC 200W PFC demonstration board
September 2010
Doc ID 17273 Rev 1
1/39
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