LTC4230_15 Datasheet, PDF (19/36 Pages) Linear Technology – Triple Hot Swap Controller with Multifunction Current Control

LTC4230
APPLICATIO S I FOR ATIO
RESETTING THE ELECTRONIC CIRCUIT BREAKER
Once the LTC4230’s circuit breaker is tripped, FAULT is
asserted low and the GATEn pin is pulled to ground. The
LTC4230 remains latched OFF in this fault state until the
external fault is cleared. To clear the internal fault detect
circuitry and to restart the LTC4230, its ON pin must be
driven low (V_ON < 1.234V) for at least 30µs, after which
time FAULT goes high. Toggling the ON pin from low to
high (V_ON > 1.314V) initiates a restart sequence in the
LTC4230. The timing diagram in Figure 10 illustrates a
CHECK FOR GATEn < 0.25V
12
CHECK FOR FILTER LOW (< V_REF)
CHECK FOR FAULT HIGH (> V_REF + 50mV)
FAST COMPARATOR
ARMED
345
SLOW COMPARATOR
ARMED
CIRCUIT BREAKER TRIPS,
ALL GATEn PINS PULL
6
7 ^{LOW IMMEDIATELY}
ON
TIMER
20µA PULL-UP
GATEn
V_OUTn
20µA PULL-UP
GATEn
V_OUTn
1.6µA PULL-DOWN
CHECK FOR TIMER < 0.3V
8
9
FAULT
I_OUTn
LOAD CURRENT < 50mV/R_SENSEn
LOAD CURRENT > 150mV/R_SENSEn
FILTER
4230 F08
Figure 8. Output Short Circuit Causes Fast Comparator to Trip the Circuit Breaker
4230f
19