Datasheet
Application information ST1S14
30/46 DocID17977 Rev 2
Figure 16. Minimum V
FB
for effective pulse-by-pulse protection over V
IN
As a consequence of V
IN
> 12 V the pulse-by-pulse current protection (in the worst case
scenario which is the minimum V
OSET
) may not be effective to limit the inductor current to
the peak current limitation over the entire FB range 300 mV < V
FB
< 1.22 V.
In fact, at higher input voltage,
ΔI
L TON
may be higher than ΔI
L TOFF
and so the inductor
current could escalate. The system typically meets Equation 31 at a current level higher
than the nominal value thanks to the voltage drop across stray components.
Figure 17. I
L
diverging triggers hiccup protection (V
IN
= 48 V)
In most of the application conditions the pulse-by-pulse current limitation is effective in
limiting the inductor current.
Whenever the current escalates, a second level current protection called “hiccup mode” is
enabled. In case the hiccup current level (6.2 A typ.) is triggered the switching activity is
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