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© Semiconductor Components Industries, LLC, 2012
June, 2012 − Rev. 1
1 Publication Order Number:
AND9064/D
AND9064/D
Safety Tests on a
NCP1611-Based PFC Stage
Introduction
Housed in an SO−8 package, the NCP1611 is an
innovative controller designed to drive PFC boost
converters. It features a unique Current Controlled
Frequency Fold−back (CCFF) mode and skip capability to
optimize the efficiency of your PFC stage throughout the
load range. It also helps the design of the downstream
converter thanks of the Dynamic Response Enhancer and
Soft OVP functions.
In addition, when developing the part, particular care and
effort was carried on the addressing the ruggedness and
safety aspects of the power supply. In fact, the NCP1611
features make the PFC stage extremely robust. Among these
protective functions, we can mention the Brown−Out
Detection block that stops operation when the ac line is too
low and the 2−level Current Sensing, that forces a low
duty−ratio operation mode in the event that the current
exceeds 150% of the current limit due to inductor saturation
or by a short of the bypass or boost diode.
Also, the intent of the NCP1611 is to ease the
manufacturing and compliance with safety requirements.
Elements of the PFC stage can be accidentally shorted, badly
soldered or damaged as a result of manufacturing or
handling incidents, excessive operating stress or other
troubles. In particular, adjacent pins of controllers can be
shorted together or a pin can be grounded or badly
connected. It is common to expect that such open/short
situations do not cause fire, smoke nor loud noise.
The enhanced functions of the NCP1611 help address
such requirements, for instance, in case of an improper pin
connection or of a short of the boost or bypass diode. To
illustrate this ability, safety tests were performed on the
NCP1611 evaluation board. The results are reported in the
application note.
This report is not intended to guarantee that the part
can pass all safety tests in all boards and conditions since
the performance can vary with respect to the application
and test conditions. The purpose of this application note
is to illustrate in detail the typical behavior of the part
under particular fault situations using the NCP1611
demo−board, highlighting the protection functions that
help pass the safety tests. It remains, nonetheless, the
responsibility of the NCP1611 user to check that the
system he builds using the NCP1611, properly meets the
safety requirements it must be compliant with.
http://onsemi.com
APPLICATION NOTE
Verzeichnis
- ・ Teilenummerierungssystem on Seite 20
- ・ Markierungsinformationen on Seite 20
- ・ Blockdiagramm on Seite 3
- ・ Anwendungsbereich on Seite 3
