LTC4052-4.2_15 Datasheet, PDF (1/12 Pages) Linear Technology – Lithium-Ion Battery Pulse Charger with Overcurrent Protection

FEATURES
s _{Very Low Power Dissipation: 350mW at 1A}
s _{Complete Standalone Pulse Charger for 1-Cell}
Lithium-Ion Batteries
s _{Requires No Microcontroller, MOSFET or}
Blocking Diode
s _{Sense Resistor Limits Maximum Current for Safety}
s _{Programmable Charge Termination Timer for}
Maximum Capacity Charging
s _{±1% Float Voltage Accuracy}
s _{Near End-of-Charge (C/10) Detection Output}
s _{AC Wall Adapter Present Output}
s _{Low Battery Drain when Input Supply Is Removed}
s _{Automatic Trickle Charge for Low Battery}
s _{Automatic Battery Refresh}
s _{Thermal Shutdown Protection}
s _{Tiny Thermally Enhanced MSOP Package}
U
APPLICATIO S
s _{Handheld Computers}
s _{Cellular Telephones}
s _{Cradle Chargers}
LTC4052-4.2
Lithium-Ion Battery
Pulse Charger with
Overcurrent Protection
DESCRIPTIO
The LTC^®4052 is a complete standalone pulse charger
with integrated MOSFET for 1-cell lithium-ion batteries.
An external sense resistor provides overcurrent limiting as
a safety precaution against a user connecting a wall
adapter with the incorrect or no current limit. The internal
MOSFET prevents reverse battery current from flowing if
the input voltage is shorted to ground, eliminating the
need for a blocking diode.
As the battery accepts charge and approaches the
programmed float voltage, the internal MOSFET begins
switching off and on with the duty cycle gradually decreas-
ing as the battery approaches a fully charged condition.
A programmable timer terminates the charge cycle. The
near end-of-charge C/10 condition is indicated at the
CHRG pin when the average charge current falls to one-
tenth of the wall adapter current. Removing the input
voltage puts the LTC4052 into a sleep mode, dropping the
battery current drain to less than 1µA.
The LTC4052 is available in a tiny 8-pin thermally
enhanced MSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Single Cell 4.2V, 1A, Standalone Li-Ion Battery Charger
V_IN = 4.5V TO 10V
WITH 1A
CURRENT LIMIT
4.7Ω
1µF
1k
CHARGE STATUS
AC PRESENT
3
1k
V_IN
LTC4052
6
CHRG
GATE ⁷
2
ACPR
TIMER
5
C_TIMER
0.1µF
1
SENSE
8
BAT
GND
4
10k
0.047µF
R_SENSE
0.05Ω
0.022µF
1-CELL 4.2V
Li-Ion
BATTERY
4052 TA01
LTC4052 Charge Profile
4.5
4.0
3.5
3.0
CONSTANT
CURRENT
1.0
CHARGE
CYCLE
ENDS
PULSING
CURRENT
0.5
0
C/10
5
0
0 0.5 1.0 1.5 2.0 2.5 3.0
TIME (HOURS)
4052 • TA01b
405242f
1