LTC4088-1 Datasheet, PDF (1/24 Pages) Linear Technology – High Effi ciency Battery Charger/USB Power Manager with Regulated Output Voltage

LTC4088-1/LTC4088-2
High Efficiency Battery
Charger/USB Power Manager
with Regulated Output Voltage
FEATURES
n _{Switching Regulator Makes Optimal Use of Limited}
Power Available from USB Port to Charge Battery
and Power Application
n _{180mΩ Internal Ideal Diode Plus External Ideal Diode}
Controller Seamlessly Provide Low Loss Power Path
When Input Power is Limited or Unavailable
n _{Automatic Charge Current Reduction Maintains}
3.6V Minimum V_OUT
n _{Full Featured Li-Ion/Polymer Battery Charger}
n _{VBUS Operating Range: 4.25V to 5.5V (7V Absolute}
Maximum—Transient)
n _{1.2A Maximum Input Current Limit}
n _{1.5A Maximum Charge Current with Thermal Limiting}
n _Bat-Track^TM _{Adaptive Output Control}
n _{Slew Control Reduces Switching EMI}
n _{Low Profile (0.75mm)14-Lead 4mm× 3mm DFN Package}
U
APPLICATIO S
n _{Media Players}
n _{Digital Cameras}
n _GPS
n _PDAs
n _{Smart Phones}
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
PowerPath and Bat-Track are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6522118
DESCRIPTIO
The LTC^®4088-1/LTC4088-2 is a high efficiency USB
PowerPath^TM controller and Li-Ion/Polymer battery
charger. It includes a synchronous switching input regu-
lator, a full-featured battery charger and an ideal diode.
Designed specifically for USB applications, the
LTC4088-1/LTC4088-2’s switching regulator auto-
matically limits its input current to either 100mA, 500mA
or 1A via logic control. The LTC4088-1 powers-up with the
charger off; the LTC4088-2 powers-up with the charger on.
The switching input stage provides power to V_OUT where
power sharing between the application circuit and the
battery charger is managed. Charge current is automati-
cally reduced to maintain a regulated 3.6V V_OUT during
low-battery conditions. As the battery is charged, V_OUT
tracks V_BAT for high efficiency charging. This feature al-
lows the LTC4088-1/LTC4088-2 to provide more power to
the application and eases thermal issues in constrained
applications.
An ideal diode ensures that system power is available
from the battery when the input current limit is reached
or if the USB or wall supply is removed.
The LTC4088-1/LTC4088-2 is available in the low profile
14-Lead 4mm × 3mm × 0.75mm DFN surface mount
package.
TYPICAL APPLICATIO
High Efficiency Battery Charger/USB Power Manager
WALL
USB
10µF
3.3µH
V_BUS
D0
D1
D2
SW V_OUT
V_OUTS
LTC4088-1/LTC4088-2 ^GATE
CHRG
BAT
CLPROG PROG C/X GND NTC
8.2Ω
0.1µF
2.94k
499Ω
+
Li-Ion
SYSTEM
LOAD
10µF
408812 TA01a
Switching Regulator Efficiency to
System Load (P_OUT/P_BUS)
100
90
80
70 ^{BAT = 4.2V}
60
BAT = 3.3V
50
40
30
20
10
0
0.01
V_BUS = 5V
I_BAT = 0mA
10x MODE
0.1
I_OUT (A)
1
408812 TA01b
40881fb
1