KB4540 Datasheet, PDF (1/15 Pages) Kingbor Technology Co – Li-Ion Battery Charger

Kingbor Technology Co.,Ltd
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KB4540
Li-Ion Battery Charger
FEATURES
■ _{Programmable Charge Current Up to 800mA}
■ _{No MOSFET, Sense Resistor or Blocking}
Diode Required
■ _{Complete Linear Charger in SOT Package for}
Single Cell Lithium-Ion Batteries
■ _{Constant-Current/Constant-Voltage Operation with}
Thermal Regulation to Maximize Charge Rate
Without Risk of Overheating
■ _{Charges Single Cell Li-Ion Batteries Directly}
from USB Port
■ _{Preset 4.2V Charge Voltage with ±1% Accuracy}
■ _{Charge Current Monitor Output for Gas}
Gauging
■ _{Automatic Recharge}
■ _{Charge Status Output Pin}
■ _{C/10 Charge Termination}
■ _{25µA Supply Current in Shutdown}
■ _{2.9V Trickle Charge Threshold (KB4540)}
■ _{Available Without Trickle Charge (KB4540X)}
■ _{Soft-Start Limits Inrush Current}
■ _{Available in SOT23-5 Package}
■ _{Cellular Telephones, PDAs, MP3 Players}
■ _{Charging Docks and Cradles}
■ _{Bluetooth Applications}
DESCRIPTION
The KB 4540 is a complete constant-current/constant-
voltage linear charger for single cell lithium-ion batteries.
Its ThinSOT package and low external component count
make the KB4540 ideally suited for portable applications.
Furthermore, the KB4540 is specifically designed to work
within USB power specifications.
No external sense resistor is needed, and no blocking
diode is required due to the internal MOSFET architecture.
Thermal feedback regulates the charge current to limit the
die temperature during high power operation or high
ambient temperature. The charge voltage is fixed at 4.2V,
and the charge current can be programmed externally with
a single resistor. The KB4540 automatically terminates
the charge cycle when the charge current drops to 1/10th
the programmed value after the final float voltage is
reached.
When the input supply (wall adapter or USB supply) is
removed, the KB4540 automatically enters a low current
state, dropping the battery drain current to less than 2µA.
The KB4540 can be put into shutdown mode, reducing
the supply current to 25µA.
Other features include charge current monitor, undervoltage
lockout, automatic recharge and a status pin to indicate
charge termination and the presence of an input voltage.
TYPICAL APPLICATION
330Ω
500mA Single Cell Li-Ion Charger
V_IN
4.5V TO 6.5V
1µF
4
V_{CC BAT} 3
KB4540-4.2
1
CHRG
5
PROG
GND
2k
2
500mA
4.2V
Li-Ion
BATTERY
I_CHG =
V_PROG
R _PROG
X 1000
(V _PROG =1V)
1