Datasheet
LTC4416/LTC4416-1
10
4416fa
differ by more than 100mV, 100% of the load will come
from the higher of V1 or V2.
The user has the option of using E1 and E2 to disable
one of the two supplies by connecting them to a digital
controller. If E1 is brought low, V1 will no longer supply
current to V
S
. If E2 is brought high, V2 will no longer sup-
ply current to V
S
. If E1 is brought low and E2 is brought
high, V
S
will be disabled.
Figure 5 shows the same application without the shut-
down option. It has one-half the losses of Figure 4 and is
configured for 5V rails.
disabled. This rapid turn-off feature is desirable when the
supply cannot tolerate certain voltage excursions under
load, or when the load is being protected from a rapidly
changing input supply.
Under and Overvoltage Shutdown
Refer to Figure 6 for an application circuit which disables
the power to the load when the input voltage gets too low
or too high. When V
IN
starts from zero volts, the load to
the output is disabled until V
IN
reaches 5.5V. The V1 path is
enabled and the load remains on the input until the supply
exceeds 13.5V. At that voltage, the V2 path is disabled. As
the input falls, the voltage source will be reconnected to
the load when the input drops to 12V and the V2 path is
enabled. Finally, the load will be removed from the input
supply when the voltage drops below 5V.
APPLICATIO S I FOR ATIO
W UU
U
LTC4416
V2 = 12V
V1 = 12V
Si7483ADP
Si7483ADP
E1
H1
GND
E2
H2
V1
G1
V
S
G2
V2
V1
GND
TO HOST
CONTROLLER
E1
E2
V2
V
S
Q3 Q4
Q1 Q2
4416 F04
LTC4416
SUPPLY 2
SUPPLY 1
Q2
Si7495DP
Q1
Si7495DP
H1
E1
GND
E2
H2
V1
G1
V
S
G2
V2
V1
5V
V2
5V
V
S
5V
4416 F05
Figure 4
Figure 5. Dual PowerPath for Current Sharing
LTC4416-1
The LTC4416-1 will support all three of the LTC4416
applications without the “soft-off” feature. The only dif-
ference in the two designs is the LTC4416-1 will rapidly
switch off the load from a supply whenever a channel is
LTC4416-1
H1
E1
GND
E2
H2
G1
V1
V
S
V2
G2
R1D
182k
R1C
24.3k
R2C
24.9k
GND
V
IN
R2E
187k
V
TH1
WITH
HYSTERESIS
V
TH2
WITH
HYSTERESIS
V
OUT
TO
LOAD
4416 F06
R1A
75k
R2A
221k
UV ENABLED AT 5V, V
IN
RESTORED TO LOAD WHEN V
IN
RISES TO 5.5V
OV ENABLED AT 13.5V, V
IN
RESTORED TO LOAD WHEN V
IN
FALLS TO 12V
Figure 6
Undervoltage
V V
R A R C
R C
V
k k
k
FAIL ETH
=
+
=
+
•
. •
.
.
1 1
1
1 222
75 24 3
24 3
== 4 99. V
V V
R A R C R D
R C R D
V
RESTORE ETH
=
+
( )
( )
=
•
. •
1 1 1
1 1
1 222
755 24 3 182
24 3 182
5 497
k k k
k k
V
+
( )
=
.
.
.