Application information
L6599A
the no load consumption of this stage (0.5 1 W). There is no compliance issue in that,
because EMC regulations on low-frequency harmonic emissions refer to nominal load, no
limit is envisaged when the converter operates with light or no load.
To do so, the L6599A provides pin 9 (PFC_STOP): it is an open collector output, normally
open, that is asserted low when the IC is idle during burst mode operation. This signal is
externally used for switching off the PFC controller and the pre-regulator, as shown in
Figure 26. When the L6599A is in UVLO, the pin is kept open to let the PFC controller start
first.
Figure 25. Load-dependent operating modes: timing diagram
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Figure 26. How the L6599A can switch off a PFC controller at light load
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Doc ID 15308 Rev 7
STMICROELECTRONICS [ ST ]
