LTC4090 Datasheet, PDF (1/28 Pages) Linear Technology – USB Power Manager with 2A High Voltage Bat-Track Buck Regulator

FEATURES
■ _{Seamless Transition Between Power Sources: Li-}
Ion Battery, USB, and 6V to 36V Supply (60V Max)
■ _{2A Output High Voltage Buck Regulator with Bat-}
Track^TM Adaptive Output Control (LTC4090)
■ _{Internal 215mΩ Ideal Diode Plus Optional External}
Ideal Diode Controller Provides Low Loss Power
Path When External Supply / USB Not Present
■ _{Load Dependent Charging from USB Input Guaran-}
tees Current Compliance
■ _{Full Featured Li-Ion Battery Charger}
■ _{1.5A Maximum Charge Current with Thermal Limiting}
■ _{NTC Thermistor Input for Temperature Qualified}
Charging
■ _{Tiny (3mm × 6mm × 0.75mm) 22-Pin DFN Package}
APPLICATIONS
■ _{HDD-Based Media Players}
■ _{Personal Navigation Devices}
■ _{Other USB-Based Handheld Products}
■ _{Automotive Accessories}
LTC4090/LTC4090-5
USB Power Manager with
2A High Voltage Bat-Track
Buck Regulator
DESCRIPTION
The LTC^®4090/LTC4090-5 are USB power managers plus
high voltage Li-Ion/Polymer battery chargers. The devices
control the total current used by the USB peripheral for
operation and battery charging. Battery charge current is
automatically reduced such that the sum of the load current
and the charge current does not exceed the programmed
input current limit. The LTC4090/LTC4090-5 also accom-
modate high voltage power supplies, such as 12V AC/DC
wall adapters, FireWire, or automotive power.
The LTC4090 provides a Bat-Track adaptive output that
tracks the battery voltage for high efficiency charging from
the high voltage input. The LTC4090-5 provides a fixed 5V
output from the high voltage input to charge single cell
Li-Ion bateries. The charge current is programmable and an
end-of-charge status output (^⎯C^⎯H^⎯R^⎯G) indicates full charge.
Also featured are programmable total charge time, an NTC
thermistor input used to monitor battery temperature while
charging and automatic recharging of the battery.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Bat-Track is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
TYPICAL APPLICATION
HIGH (6V-36V)
VOLTAGE INPUT
5V WALL
ADAPTER
USB
59k
270pF
HVIN
1μF
IN
4.7μF
V_C
TIMER
BOOST
0.47μF
SW
LTC4090
HVOUT
HVPR
OUT
BAT
6.8μH
22μF
1k
LOAD
4.7μF
RT
CLPROG
0.1μF
40.2k
2k
GND PROG
100k ⁺
Li-Ion BATTERY
V_OUT (TYP)
V_BAT + 0.3V
5V
5V
V_BAT
AVAILABLE INPUT
HV INPUT (LTC4090)
HV INPUT (LTC4090-5)
USB ONLY
BAT ONLY
4090 TAO1
LTC4090/LTC4090-5 High Voltage
Battery Charger Efficiency
90 _{FIGURE 12 SCHEMATIC}
80
WITH R_PROG = 52k
NO OUTPUT LOAD
70
60
LTC4090
LTC4090-5
50
40
HVIN = 8V
30
HVIN = 12V
HVIN = 24V
HVIN = 36V
20
2.0 2.5 3.0 3.5 4.0 4.5
V_BAT (V)
4090 TA01b
4090fa
1