LTC4411ES5 Linear Technology, LTC4411ES5 Datasheet - Page 7

• Manufacturer Part Number: LTC4411ES5
• Description: 2.6A Low Loss Ideal Diode in ThinSOT
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
tion mode, the forward voltage will be kept low by control-
ling the gate voltage of the internal MOSFET to react to
changes in load current. Should the wall adapter input be
applied, the Schottky diode will pull up the output voltage,
connected to the load, above the battery voltage. The
LTC4411 will sense that the output voltage is higher than
the battery voltage and will turn off the internal MOSFET.
The STAT pin will then sink current indicating an auxiliary
input is connected. The battery is now supplying no load
current and all load current flows through the Schottky
diode.
Microcontrolled PowerPath Monitoring and Control
Figure 6 illustrates an application circuit for microcontroller
monitoring and control of two power sources. The
microcontroller’s analog inputs, perhaps with the aid of a
resistor voltage divider, monitors each supply input and
commands the LTC4411 through the CTL input. Back-to-
back MOSFETs are used so that the parasitic drain-source
diode will not power the load when the MOSFET is turned
off (dual MOSFETs in one package are commercially
available).
Load Sharing
Figure 6 illustrates an application circuit for dual battery
load sharing with automatic switchover of load from
batteries to wall adapter. Whichever battery is capable of
supplying the higher voltage will provide the load current
until it is discharged to the voltage of the other battery. The
load will then be shared between the two batteries accord-
ing to the capacity of each battery. The higher capacity
battery will provide proportionally higher current to the
load. When a wall adapter input is applied, both LTC4411’s
Figure 5. Automatic Switchover of Load Between a
Primary and an Auxiliary Power Source with External
Dual P-Channel MOSFETs
C1: C0805C106K8PAC
C2: C1206C475K8PAC
AUXILIARY
PRIMARY
SOURCE
SOURCE
POWER
POWER
MICROCONTROLLER
C1
10 F
U
1
2
3
IN
GND
CTL
U
AUXILIARY P-CHANNEL
LTC4411
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
MOSFETS
STAT
OUT
R1
470k
5
4
W
4.7 F
C2
4411 F06
LOAD
STATUS
U
turn off and no load current will be drawn from the
batteries. The STAT pins provide information as to which
input is supplying the load current. This concept can be
expanded to more power inputs.
Multiple Battery Charging
Figure 7 illustrates an application circuit for automatic dual
battery charging from a single charger. Whichever battery
has the lower voltage will receive the charging current until
both battery voltages are equal, then both will be charged.
When both are charging simultaneously, the higher ca-
pacity battery will get proportionally higher current from
the charger. For Li-Ion batteries, both batteries will achieve
the float voltage minus the forward regulation voltage of
40mV. This concept can apply to more than two batteries.
The STAT pin provides information as to which batteries
are being charged. For intelligent control, the CTL pin input
can be used with a microcontroller as shown in Figure 5.
Figure 6. Dual Battery Load Sharing with Automatic
Switchover of Load from Batteries to Wall Adapter
CHARGER
BATTERY
INPUT
C
1 F
C
1 F
IN
IN
Figure 7. Automatic Dual Battery Charging
from a Single Charging Source.
ADAPTER
BAT1
BAT2
INPUT
WALL
1
2
3
1
2
3
IN
GND
CTL
IN
GND
CTL
1
2
3
1
2
3
LTC4411
LTC4411
IN
GND
CTL
IN
GND
CTL
LTC4411
LTC4411
STAT
STAT
OUT
OUT
STAT
STAT
OUT
OUT
5
4
C
C
IN
OUT
5
4
: C0805C105K8PAC
: C1206C475K8PAC
BAT1
BAT2
V
V
CC
CC
470k
470k
V
V
CC
CC
470k
470k
ARE SUPPLYING LOAD CURRENT.
WHEN BOTH STATUS LINES ARE
WHEN BOTH STATUS LINES ARE
PRESENT AND SUPPLYING FULL
LOW, THEN WALL ADAPTER IS
HIGH, THEN BOTH BATTERIES
C
4.7 F
OUT
TO LOAD OR
PowerPath
CONTROLLER
STATUS IS HIGH
WHEN BAT1 IS
CHARGING
TO LOAD OR
PowerPath
CONTROLLER
STATUS IS HIGH
WHEN BAT2 IS
CHARGING
TO
LOAD
STATUS IS HIGH WHEN
BAT1 IS SUPPYLING
LOAD CURRENT
STATUS IS HIGH WHEN
BAT2 IS SUPPLYING
LOAD CURRENT
LOAD CURRENT
LTC4411
4411 F08
4411 F07
7
4411f