max5924deubt Maxim Integrated Products, Inc., max5924deubt Datasheet - Page 13

• Manufacturer Part Number: max5924deubt
• Description: 1v To 13.2v, N-channel Hot-swap Controllers Require No Sense Resistor
• Manufacturer: Maxim Integrated Products, Inc.

Bilevel fault protection is disabled in startup mode, and
is enabled when V
end of the startup period.
When no R
parator is active during startup because the high
RD(ON) of the MOSFET when not fully enhanced would
signal an artificially-high V
ing prior to startup insures that the output is not short cir-
cuited.
When R
abled during startup while the fast comparator remains
active. The overcurrent trip level is higher than normal
during the startup period because the ICB is temporarily
doubled to ICB,SU at this time. This allows higher than
normal startup current to allow for output capacitor
charging current.
The slow comparator is disabled during startup while
the external MOSFET turns on.
If the slow comparator detects an overload condition while
in normal operation (after startup is complete), it turns off
the external MOSFET by discharging the gate capaci-
tance with I
depends on the external MOSFET gate-to-source volt-
age, V
ately following a fault and decreases as the MOSFET
gate is discharged (Figure 8a).
Figure 8a. Gate Discharge Current vs. MOSFET Gate-to-Source
Voltage
GS
1V to 13.2V, n-Channel Hot-Swap Controllers
SENSE
. The discharge current is strongest immedi-
60
50
40
30
20
10
SENSE
0
Bilevel Fault Protection in Startup Mode
GATE,PD
0
V
is detected, the slow comparator is dis-
CC
1
is detected, neither slow nor fast com-
= 13.2V
______________________________________________________________________________________
GATE-VOUT
2
. The magnitude of I
Bilevel Fault Protection
IN
3
V
GS
-V
(V)
SENSE
4
exceeds V
5
voltage. Load prob-
Slow Comparator
6
CB,EN
7
GATE,PD
at the
Require No Sense Resistor
The fast comparator is used for serious current overloads
or short circuits. If the load current reaches the fast com-
parator threshold, the device quickly forces the MOSFET
off. The fast comparator has a response time of 280ns,
and discharges GATE with I
comparator is disabled during startup when no R
is detected
The MAX5924A, MAX5924B, MAX5925A, and MAX5925B
latch the external MOSFET off when an overcurrent fault
is detected. Following an overcurrent fault, the
MAX5924C, MAX5924D, MAX5925C, and MAX5925D
enter autoretry mode. The MAX5926 can be configured
for either latched or autoretry mode (see Table 1).
In autoretry, a fault turns the external MOSFET off then
automatically restarts the device after the autoretry
delay, t
EN1 low to restart the device. In latched mode, pull EN
or EN1 low for at least 100µs to clear a latched fault
and restart the device.
The power-good output(s) are open-drain output(s) that
deassert:
PGOOD/PGOOD asserts only if the part is in normal
mode and no faults are present.
Table 1. Selecting Fault Management
Mode (MAX5926)
Latched and Autoretry Fault Management
When V
During t
When V
During load probing
When disabled (EN = GND (MAX5924/MAX5925),
EN1 = GND or EN2 = high (MAX5926))
During fault management
During t
MAX5924B, MAX5925A, MAX5925B, or MAX5926
(LATCH = low)).
LATCH
High
Low
RETRY
CC
GS
D,UVLO
RETRY
. During the autoretry delay, pull EN or
< V
< V
Autoretry mode
Latched mode
THPGOOD
UVLO
or when latched off (MAX5924A,
FAULT MANAGEMENT
GATE,PD
Power-Good Outputs
(Figure 8a). The fast
Fast Comparator
SENSE
13