Application information

L6599A

20/35

Doc ID 15308 Rev 7

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

Figure 26.

How the L6599A can switch off a PFC controller at light load