FAN4868

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8

the regulation point, the boost switch remains off as long as

Fault State

The regulator enters the FAULT state under any of the

following conditions:

from LIN state to SS state

from SS state to BST state

limit during the BST state

Once a fault is triggered, the regulator stops switching and

After waiting 480 CLK counts, a restart is attempted.

Soft−Start and Fault Timing

The soft−start timing for each state, and the fault times, are

determined by the fault clock, whose period is inversely

cycle in current limit.

Figure 15. Fault Response into Short Circuit

ILIN2

VOUT

0

64

16

ILIN1

EN

0 V

480

8

Figure 16.

illustrated in Figure 17

.

Over−Temperature Protection (OTP)

The regulator shuts down when the thermal shutdown

threshold is reached. Restart, with soft−start, occurs when

the IC has cooled by about 30

°C.

Over−Current Protection (OCP)

During Boost Mode, the FAN4868 employs a

cycle−by−cycle peak current limit to protect switching

elements. Sustained current limit, for 32 consecutive fault

clock counts, initiates a fault condition.

immediately switched off and a fault condition is declared.

Automatic restart occurs once the overload/short is

removed and the fault timer completes counting.