Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - PFC 20 mA SOIC 20

UCC28070

SLUS794E – NOVEMBER 2007–REVISED APRIL 2011

www.ti.com

Recommended PCB Device Layout

Interleaved PFC techniques dramatically reduce input and output ripple current caused by the PFC boost

inductor, which allows the circuit to use smaller and less expensive filters. To maximize the benefits of

interleaving, the output filter capacitor should be located after the two phases allowing the current of each phase

to be combined together before entering the boost capacitor. Similar to other power management devices, when

laying out the PCB it is important to use star grounding techniques and to keep filter and high frequency bypass

capacitors as close to device pins and ground as possible. To minimize the possibility of interference caused by

magnetic coupling from the boost inductor, the device should be located at least 1 inch away from the boost

inductor. It is also recommended that the device not be placed underneath magnetic elements.

References

1. O’Loughlin, Michael, “An Interleaving PFC Pre-Regulator for High-Power Converters”, Texas Instruments,

Inc. 2006 Unitrode Power Supply Seminar, Topic 5

2. Erickson, Robert W., “Fundamentals of Power Electronics”, 1st ed., pp. 604-608 Norwell, MA: Kluwer

Academic Publishers, 1997

3. Creel, Kirby "Measuring Transformer Distributed Capacitance", White Paper, Datatronic Distribution, Inc.

website: http://www.datatronics.com/pdf/distributed_capacitance_paper.pdf

4. L. H. Dixon, "Optimizing the Design of a High Power Factor Switching Preregulator", Unitrode Power Supply

Design Seminar Manual SEM700, 1990. Texas Instruments Literature Number SLUP093

5. L. H. Dixon, "High Power Factor Preregulator for Off-Line Power Supplies", Unitrode Power Supply Design

Seminar Manual SEM600, 1988. Texas Instruments Literature Number SLUP087

REVISION HISTORY

Changes from Revision C (June 2009) to Revision D Page

• Changed 30 kHz to 300 kHz ................................................................................................................................................. 1

Changes from Revision D (June 2010) to Revision E Page

• Changed PWM switching frequency ..................................................................................................................................... 4

• Changed Figure 8 ............................................................................................................................................................... 12