Datasheet
LTC4416/LTC4416-1
9
4416fa
APPLICATIO S I FOR ATIO
W UU
U
This configuration would be used where V1 is a 12V power
supply and the V2 power supply is a 4-cell Li-Ion battery
pack. When V1 is 12V, E2 disables the V2 source from
being connected to V
S
through Q2A and Q2B by forcing
G2 to V2, H2 is open circuit. E1 is connected to a voltage
greater than the V
REF
to keep the V1 to V
S
path active. The
V
S
output can be shut completely off by grounding the E1
input. The LTC4416 takes its power from the higher of V1,
V2 and V
S
. This configuration will provide power from V1
to V
S
until the V1 supply drops below 9V.
When V1 drops below 9V, the H2 pin closes to GND, G2
drops to a V
CLAMP
below V2 and G1 rises to the V
S
volt-
age level. V2 will supply current to V
S
until V1 rises above
10.8V. The H1 output will be open until the E1 input drops
below the V
REF
voltage level.
The V1 V
FAIL
is determined by:
V V
R A R C
R C
V
k k
FAIL ETH
=
+
=
+
•
. •
.
.
2 2
2
1 222
158 24 9
24 9kk
V= 8 98.
The V1 V
RESTORE
is determined by:
V V
R A R C R E
R C R E
V
RESTORE ETH
=
+
( )
( )
=
•
. •
2 2 2
2 2
1 222
1558 24 9 105
24 9 105
10 81
k k k
k k
V
+
( )
=
.
.
.
V1 is Greater Than V2
Figure 3 illustrates the external resistor configuration for
this case.
This configuration would be used where V1 is a 12V power
supply and the V2 power supply is a 3-cell Li-Ion battery
pack. When V1 is 16V, E1 enables the V1 source as being the
primary supply, thus disabling the V2 supply since V1 > V2.
When E1 > V
REF
, the H1 output is open. The V
S
output can be
shut completely off by grounding the H1 input and forcing
E2 > V
REF
. The LTC4416 takes its power from the higher of
V1, V2 and V
S
. This configuration will provide power from
V1 to V
S
until the V1 supply drops below 12V.
When V1 drops below 12V, the H1 pin closes to GND,
G2 drops to a V
CLAMP
below V2 and G1 rises to the V1
voltage level. V2 will supply current to V
S
until V1 rises
above 13.5V. The H2 output will be shorted to GND until
the E2 input goes above the V
REF
voltage level.
The V1 V
FAIL
is determined by:
V V
R A R C
R C
V
k k
FAIL ETH
=
+
=
+
•
. •
.
.
1 1
1
1 222
221 24 9
24 9kk
V= 12 07.
The V1 V
RESTORE
is determined by:
V V
R A R C R D
R C R D
V
RESTORE ETH
=
+
( )
( )
=
•
. •
1 1 1
1 1
1 222
2221 24 9 187
24 9 187
13 51
k k k
k k
V
+
( )
=
.
.
.
Load Sharing
Figure 4 illustrates the configuration for this case.
This configuration would be used where V1 and V2 are
relatively the same voltage. In this case the LTC4416 acts
as two interconnected ideal diode controllers. V
S
will be
supplied by the higher of the two supplies, V1 and V2. If
V1 and V2 are exactly the same, then 50% of the current
for V
S
will be supplied by each supply. As the two supplies
LTC4416
PRIMARY SUPPLY
BACKUP SUPPLYV2 = 10.8V
V1 = 12V (FAIL)
V1 = 13.5V (RESTORE)
SUP75P03_07
Q1 Q2
Q3
SUP75P03_07
E1
GND
E2
H2
H1
V1
G1
V
S
G2
V2
R1D
187k
R1C
24.9k
R1A
221k
V1
GND
V2
V
S
4416 F03
Figure 3
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