LTC4412
Low Loss PowerPath™
Controller in ThinSOT
Features
Description
Very Low Loss Replacement for Power Supply
OR’ing Diodes
nn Minimal External Components
nn Automatic Switching Between DC Sources
nn Simplifies Load Sharing with Multiple Batteries
nn Low Quiescent Current: 11µA
nn 3V to 28V AC/DC Adapter Voltage Range
nn 2.5V to 28V Battery Voltage Range
nn Reverse Battery Protection
nn Drives Almost Any Size MOSFET for Wide Range of
Current Requirements
nn MOSFET Gate Protection Clamp
nn Manual Control Input
nn Low Profile (1mm) ThinSOT™ Package
The LTC®4412 controls an external P-channel MOSFET to
create a near ideal diode function for power switchover
or load sharing. This permits highly efficient OR’ing of
multiple power sources for extended battery life and low
self-heating. When conducting, the voltage drop across
the MOSFET is typically 20mV. For applications with a
wall adapter or other auxiliary power source, the load is
automatically disconnected from the battery when the
auxiliary source is connected. Two or more LTC4412s
may be interconnected to allow load sharing between
multiple batteries or charging of multiple batteries from
a single charger.
nn
Applications
Cellular Phones
Notebook and Handheld Computers
nn Digital Cameras
nn USB-Powered Peripherals
nn Uninterruptible Power Supplies
nn Logic Controlled Power Switch
nn
The wide supply operating range supports operation
from one to six Li-Ion cells in series. The low quiescent
current (11µA typical) is independent of the load current.
The gate driver includes an internal voltage clamp for
MOSFET protection.
The STAT pin can be used to enable an auxiliary P-channel
MOSFET power switch when an auxiliary supply is
detected. This pin may also be used to indicate to a microcontroller that an auxiliary supply is connected. The
control (CTL) input enables the user to force the primary
MOSFET off and the STAT pin low.
nn
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
The LTC4412 is available in a low profile (1mm) ThinSOT
package.
Typical Application
LTC4412 vs Schottky Diode
Forward Voltage Drop
1
WALL
ADAPTER
INPUT
TO LOAD
LTC4412
VIN SENSE
GND
GATE
CTL
STAT
COUT
VCC
470k
4412 F01
STATUS OUTPUT
LOW WHEN WALL
ADAPTER PRESENT
CURRENT (A)
BATTERY
CELL(S)
CONSTANT
RON
Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter
LTC4412
CONSTANT
VOLTAGE
0
SCHOTTKY
DIODE
0.02
FORWARD VOLTAGE (V)
0.5
4412 F01b
4412fb
For more information www.linear.com/LTC4412
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