s Very Low Power Dissipation: 350mW at 1A
s Complete Standalone Pulse Charger for 1-Cell
s Requires No Microcontroller, MOSFET or
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
s Handheld Computers
s Cellular Telephones
s Cradle Chargers
Pulse Charger with
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.
Single Cell 4.2V, 1A, Standalone Li-Ion Battery Charger
VIN = 4.5V TO 10V
LTC4052 Charge Profile
0 0.5 1.0 1.5 2.0 2.5 3.0
4052 • TA01b