LTC4211IMS8TRPBF View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC4211IMS8TRPBF Datasheet PDF : 40 Pages
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LTC4211
APPLICATIONS INFORMATION
OVERVOLTAGE
IF ANY FAULT HAPPENS
AFTER THIS POINT, THE
CIRCUIT BREAKER TRIPS
AND FAULT LATCHES LOW
IF OVERVOLTAGE GOES
AWAY, SECOND CYCLE
CONTINUES
12
2A
34
5
6
VCC
ON
SLOW COMPARATOR ARMED
OVERVOLTAGE CIRCUIT BREAKER
TRIPS, GATE PULLS DOWN AND
FAULT LATCHES LOW
78
ABC
TIMER
GATE
VOUT
RESET
FILTER
>VREF – 80mV
GATE
VOUT
POWER GOOD
VFB > VREF
FPD
POWER BAD
VFB < VREF
>VREF
FAULT
FAULT IS PULLED LOW (BUT NOT LATCHED)
DUE TO A START-UP OVERVOLTAGE PROBLEM
Figure 24. High Side Overvoltage Protection
4211 F24
FAULT
LATCHED LOW
Low Side (Output) Overvoltage Protection
A Zener diode can be used in a similar fashion to detect/
protect the system against a supply overvoltage condition
on the load (or low) side of the pass transistor. In this
case, the Zener diode is connected from the load to the
LTC4211’s FILTER pin, as shown in Figure 25. An additional
diode, D1, prevents the FILTER pin from pulling low during
an output short-circuit. Figure 26 illustrates the timing
diagram for a low side output overvoltage condition. In
this example, VCC starts up in an overvoltage condition
but the LTC4211 can only sense the overvoltage supply
condition at Time Point 6 when the GATE pin has ramped
up. At Time Point 6, VFILTER is greater than 1.236V, the
circuit breaker is tripped, the GATE pin voltage is pulled
to ground and FAULT is asserted low and latched.
4211fb
32
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