
Use
The above values are intended as a positive delta with respect to the “PFC Vout target” parameter.
In fact, the SW OVP threshold is defined as:
Equation 11
"PFC SW OVP threshold" = "PFC Vout target" − "PFC SW OVP threshold delta "
(11)
The values on the left are referred to the PFC_FB pin, that corresponds to values on the right 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 output voltage. It is suggested
to keep the SW OVP enabled with the maximum value 105 mV - 20 V, especially if the “PFC boost exiting burst”
feature is enabled.
3.4
LLC parameters
3.4.1
Soft ACP feature
Size: 1 bit
Enables / disables the soft ACP management.
Available values are:
•
Enabled
•
Disabled
Soft ACP is the protection that is triggered when the system is approaching the capacitive mode (i.e. the time
between the MOSFET turn-on and tank current zero crossing becomes smaller than the value programmed with
the parameter “Soft ACP entering threshold”).
The feature will try to recover the capacitive mode, reducing the LLC time shift value of a quantity defined by
the “Soft ACP TS decrement”, every time the protection is triggered, for a maximum number of occurrences of
“Maximum soft ACP occurrences”.
Every time the system triggers the soft ACP feature, the STNRG011A will move to the softstart state, to smoothly
recover the regulation.
The system will shut down for the soft ACP fault if the minimum time shift or the maximum number of soft ACP
occurrences is reached. The fault can be latched or not latched depending on the “LLC ACP behavior”.
3.4.2
LLC HVG first Ton
Size: 4 bits
Sets the total on-time of the first LLC HVG.
Available values are:
•
133.3 ns
•
200 ns
•
266.7 ns
•
333.3 ns
•
400 ns
•
466.7 ns
•
533.3 ns
•
600 ns
•
666.7 ns
•
800 ns
•
933.3 ns
•
1067 ns
•
1200 ns
•
1333 ns
•
1467 ns
•
1600 ns
UM3002
LLC parameters
UM3002
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Rev 1
page 19/42