application
INFO
UCC1919
UCC2919
UCC3919
available
3V to 8V Hot Swap Power Manager
FEATURES
DESCRIPTION
• Precision Fault Threshold
The UCC3919 family of Hot Swap Power Managers provide complete
power management, hot swap, and fault handling capability. The
UCC3919 features a duty ratio current limiting technique, which pro-
vides peak load capability while limiting the average power dissipa-
tion of the external pass transistor during fault conditions. The
UCC3919 has two reset modes, selected with the TTL/CMOS com-
patible L/R pin. In one mode, when a fault occurs the IC repeatedly
tries to reset itself at a user defined rate, with user defined maximum
output current and pass transistor power dissipation. In the other
mode the output latches off and stays off until either the L/R pin is re-
set or the shutdown pin is toggled. The on board charge pump circuit
provides the necessary gate voltage for an external N-channel power
FET.
• Charge Pump for Low RDSON High Side
Drive
• Differential Sense Inputs
• Programmable Average Power Limiting
• Programmable Linear Current Control
• Programmable Fault Time
• Fault Output Indicator
• Manual and Automatic Reset Modes
• Shutdown Control w/Programmable
Softstart
• Undervoltage Lockout
• Electronic Circuit Breaker Function
BLOCK DIAGRAM
13
OVERLOAD
CHARGE
VDD
CSP
VDD
4
CAP
COMPARATOR
PUMP
–
LINEAR
CURRENT
AMPLIFIER
+
14
+
OVERCURRENT
COMPARATOR
DRIVER
10 GATE
–
VDD
12
1
–
+
CSN
50mV
UVLO
UVLO
200mV
IMAX
+
VDD
1.5v
1X
36µA
2
1X
IBIAS
UVBIAS
SET
DOMINANT
S
Q
FLT
SD
UVBIAS
R
Q
FLT
9
8
PL
CT
7
FLT
+
S
R
Q
Q
–
1.5V
0.5V
S
R
Q
+
–
Q
11
GND
RESET
DOMINANT
1.2µA
SD
5
6
LR
SD
UDG-98123
Note: Pins shown for 14-pin package.
07/99
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