LTC4090/LTC4090-5
USB Power Manager with
2A High Voltage Bat-Track
Buck Regulator
FEATURES
DESCRIPTION
The LTC®4090/LTC4090-5 are USB power managers plus
highvoltageLi-Ion/Polymerbatterychargers. Thedevices
control the total current used by the USB peripheral for
operation and battery charging. Battery charge current is
automaticallyreducedsuchthatthesumoftheloadcurrent
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.
■
Seamless Transition Between Power Sources: Li-
Ion Battery, USB, and 6V to 36V Supply (60V Max)
■
2A Output High Voltage Buck Regulator with Bat-
TrackTM 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
■
The LTC4090 provides a Bat-Track adaptive output that
tracksthebatteryvoltageforhighefficiencychargingfrom
the high voltage input. The LTC4090-5 provides a fixed 5V
output from the high voltage input to charge single cell
Li-Ionbateries.Thechargecurrentisprogrammableandan
■
1.5A Maximum Charge Current with Thermal Limiting
■
NTC Thermistor Input for Temperature Qualified
Charging
■
Tiny (3mm × 6mm × 0.75mm) 22-Pin DFN Package
⎯
⎯
⎯
⎯
end-of-charge status output (CHRG) indicates full charge.
Alsofeaturedareprogrammabletotalchargetime, anNTC
thermistorinputusedtomonitorbatterytemperaturewhile
charging and automatic recharging of the battery.
APPLICATIONS
■
HDD-Based Media Players
■
Personal Navigation Devices
■
Other USB-Based Handheld Products
Automotive Accessories
, 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
0.47μF
6.8μH
LTC4090/LTC4090-5 High Voltage
Battery Charger Efficiency
BOOST
SW
HIGH (6V-36V)
HVIN
IN
22μF
VOLTAGE INPUT
1μF
90
80
70
60
50
40
30
20
HVOUT
5V WALL
ADAPTER
FIGURE 12 SCHEMATIC
WITH R = 52k
LTC4090
PROG
HVPR
NO OUTPUT LOAD
4.7μF
USB
LTC4090
1k
V
C
OUT
LOAD
LTC4090-5
4.7μF
TIMER
BAT
R
CLPROG
2k
GND PROG
T
59k
+
40.2k
100k
270pF
0.1μF
Li-Ion BATTERY
HVIN = 8V
HVIN = 12V
HVIN = 24V
HVIN = 36V
V
(TYP)
+ 0.3V
5V
5V
AVAILABLE INPUT
HV INPUT (LTC4090)
HV INPUT (LTC4090-5)
USB ONLY
OUT
V
BAT
2.0
2.5
3.0
3.5
(V)
4.0
4.5
V
BAT
V
BAT ONLY
BAT
4090 TAO1
4090 TA01b
4090fa
1