LTC4414 Datasheet, PDF (1/12 Pages) Linear Technology – 36V, Low Loss PowerPathTM Controller for Large PFETs

FEATURES
■ _{Designed Specifically to Drive Large QG PFETs}
■ _{Very Low Loss Replacement for Power Supply}
OR’ing Diodes
■ _{3.5V to 36V AC/DC Adapter Voltage Range}
■ _{Minimal External Components}
■ _{Automatic Switching Between DC Sources}
■ _{Low Quiescent Current: 30µA}
■ _{3V to 36V Battery Voltage Range}
■ _{Limited Reverse Battery Protection}
■ _{MOSFET Gate Protection Clamp}
■ _{Manual Control Input}
■ _{Space Saving 8-Lead MSOP Package}
U
APPLICATIO S
■ _{High Current Power Path Switch}
■ _{Industrial and Automotive Applications}
■ _{Uninterruptable Power Supplies}
■ _{Logic Controlled Power Switch}
■ _{Battery Backup Systems}
■ _{Emergency Systems with Battery Backups}
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
LTC4414
36V, Low Loss PowerPath^TM
Controller for Large PFETs
DESCRIPTIO
The LTC^®4414 controls an external P-channel MOSFET to
create a near ideal diode function for power switchover.
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 typi-
cally 20mV. For applications with a wall adapter or other aux-
iliary power source, the load is automatically disconnected
from the battery when the auxiliary source is connected.
Two or more LTC4414s may be interconnected to allow
switchover between multiple batteries or charging of mul-
tiple batteries from a single charger.
The wide supply operating range supports operation from
one to eight Li-Ion cells in series. The low quiescent
current (30µA 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 micro-
controller that an auxiliary supply is connected. The con-
trol (CTL) input enables the user to force the primary
MOSFET off and the STAT pin low.
The LTC4414 is available in a low profile 8-lead MSOP
package.
TYPICAL APPLICATIO
Automatic Switchover of Load Between a Battery and a Power Supply
POWER
SUPPLY
INPUT
BATTERY
CELL(S)
UPS840
SUP75P03_07
LTC4414
V_IN SENSE
GND GATE
CTL STAT
NC
NC
C_OUT
V_CC
TO LOAD
470k _{STATUS OUTPUT}
LOW WHEN POWER
4414 TA01 _{SUPPLY PRESENT}
LTC4414 vs Schottky Diode Forward Voltage Drop
8.0
CONSTANT
R_ON
3.6
LTC4414
CONSTANT
VOLTAGE
SCHOTTKY
DIODE
0
0.02
FORWARD VOLTAGE (V)
0.5
4414 TA01b
4414fc
1