Available values are:
•
0
•
320
•
384
•
448
•
512
•
640
•
768
•
896
•
1024
•
1280
•
1536
•
1792
•
2048
•
2560
•
3072
•
3584
Use
This parameter can be used to improve efficiency at the power levels at which harmonic contents are not subject
to regulation (e.g. below 75 W).
To tune the parameter, run the system at the desired threshold level and Vac value, read the input power raw
value from the GUI and use it as the threshold (see
It is suggested to keep a 20% margin to take into account variations from unit to unit (e.g. set the threshold to 60
W to assure it is out of this mode at 75 W).
Test the exit point from the skipping area mode at the nominal mains voltages to check that the system returns in
the continuous switching mode below 75 W.
Setting this parameter to “0” disables the skipping area feature, in case good THD and PF are required even at
very low loads.
3.3.16
PFC Vout target
Size: 3 bits
Sets the nominal PFC output voltage.
Available values are:
•
1.946 V - 377 V
•
1.965 V - 381 V
•
1.985 V - 385 V
•
2.004 V - 388 V
•
2.024 V - 392 V
•
2.063 V - 400 V
•
2.102 V - 407 V
•
2.141 V - 415 V
This is the voltage level at which the PFC stage regulates its output, in all operating conditions.
Use
Set the PFC output voltage according to the application specs.
The values on the left are referred to the PFC_FB pin, that corresponds to values on theright if the bulk voltage
divider is designed with the standard ratio k = 5.16 · 10
-3
(i.e. 484.5 V on the bulk voltage correspond to 2.5 V on
the PFC_FB pin).
If other bulk voltage dividers are used, the values on the left can be used to set the outputvoltage. In this case,
consider that the PFC HW OVP comparator has a fixed threshold of 2.3 V.
UM3002
PFC parameters
UM3002
-
Rev 1
page 17/42