ltc4414ems8-trpbf Linear Technology Corporation, ltc4414ems8-trpbf Datasheet - Page 11

• Manufacturer Part Number: ltc4414ems8-trpbf
• Description: 36v, Low Loss Powerpath Controller For Large Pfets
• Manufacturer: Linear Technology Corporation

Battery Load Sharing
Figure 5 illustrates an application circuit for dual battery
load sharing with automatic switchover of load from
batteries to wall adapter. Whichever battery can supply 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 according 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 MOSFETs will turn off
and no load current will be drawn from the batteries. The
STAT pins provide information as to which input is supply-
ing the load current. This concept can be expanded to
more power inputs.
Multiple Battery Charging
Figure 6 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 charged simultaneously, the
higher capacity battery will get proportionally higher cur-
rent from the charger. For Li-Ion batteries, both batteries
will achieve the float voltage minus the forward regulation
voltage of 20mV. This concept can apply to more than two
batteries. The STAT pins provide information as to which
batteries are being charged. For intelligent control, the
TYPICAL APPLICATIO S
ADAPTER
BAT1
BAT2
INPUT
WALL
Figure 5. Dual Battery Load Sharing with Automatic
Switchover of Load from Batteries to Wall Adapter
7
3
2
7
3
2
*DRAIN-SOURCE DIODE OF MOSFET
V
GND
CTL
V
GND
CTL
LTC4414
IN
LTC4414
IN
SENSE
SENSE
GATE
GATE
STAT
STAT
6
8
1
6
8
1
*
*
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.
WHEN BOTH STATUS LINES ARE
HIGH, THEN BOTH BATTERIES ARE
SUPPLYING LOAD CURRENTS. WHEN
BOTH STATUS LINES ARE LOW, THEN
WALL ADAPTER IS PRESENT
V
V
CC
CC
U
47k
47k
4414 F05
C
OUT
TO LOAD
STATUS IS HIGH
WHEN BAT1 IS
SUPPLYING
LOAD CURRENT
STATUS IS HIGH
WHEN BAT2 IS
SUPPLYING
LOAD CURRENT
CTL pin input can be used with a microcontroller and
back-to-back MOSFETs as shown in Figure 4. This allows
complete control for disconnection of the charger from
either battery.
High Side Power Switch
Figure 7 illustrates an application circuit for a logic con-
trolled high side power switch. When the CTL pin is a
logical low, the LTC4414 will turn on the MOSFET. Be-
cause the SENSE pin is grounded, the LTC4414 will apply
maximum clamped gate drive voltage to the MOSFET.
When the CTL pin is a logical high, the LTC4414 will turn
off the MOSFET by pulling its gate voltage up to the supply
input voltage and thus deny power to the load. The
MOSFET is connected with its source connected to the
power source. This disables the drain-source diode from
supplying voltage to the load when the MOSFET is off. Note
that if the load is powered from another source, then the
drain-source diode can forward bias and deliver current to
the power supply connected to the V
CHARGER
BATTERY
0.1µF
INPUT
Figure 7. Logic Controlled High Side Power Switch
SUPPLY
0.1µF
INPUT
LOGIC
INPUT
Figure 6. Automatic Dual Battery Charging
from Single Charging Source
*DRAIN-SOURCE DIODE OF MOSFET
7
3
2
7
3
2
*DRAIN-SOURCE DIODE OF MOSFET
V
GND
CTL
V
GND
CTL
LTC4414
IN
LTC4414
IN
7
3
2
V
GND
CTL
SENSE
SENSE
LTC4414
IN
GATE
GATE
STAT
STAT
SENSE
GATE
STAT
6
8
1
6
8
1
*
*
P-CHANNEL
4414 F07
6
8
1
MOSFET
*
V
V
CC
CC
470k
470k
IN
C
pin.
LTC4414
OUT
BAT1
BAT2
4414 F06
TO LOAD
TO LOAD OR
PowerPath
CONTROLLER
STATUS IS HIGH
WHEN BAT1 IS
CHARGING
TO LOAD OR
PowerPath
CONTROLLER
STATUS IS HIGH
WHEN BAT2 IS
CHARGING
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