Standalone Linear Li-ion Battery Charger with Thermal Regulation
FSP4054
FEATURES
Programmable charge current up to 800mA
No MOSFET, sense resistor or blocking diode
required
Complete linear charger in thin 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
25uA supply current in shutdown
2.9V trickle charge threshold
Soft-start limits inrush current
Space saving ThinSOT23-5L package
GENERAL DESCRIPTION
The
FSP4054
is
a
complete
constant-current/constant-voltage linear charger for
cell lithium-ion batteries. Its Thin SOT23-5L package
and low external component count make the FSP4054
ideally suited for portable applications. Furthermore,
the FSP4054 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 regulators 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
FSP4054 automatically terminates the charge cycle
when the charge current drops to 1/10
th
the
programmed value after the final float voltage is
reached.
When the input supply (wall adapter or USB supply) is
removed, the FSP4054 automatically enters a low
current state, dropping the battery drain current to less
than 2uA. The FSP4054 can be put into shutdown
mode, reducing the supply current to 25uA.
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.
(Top View)
1
2
3
4
5
APPLICATIONS
Cellular phones, PDAs
Bluetooth applications
Charging docks and Cradles
MP3 players
PIN CONFIGURATION
PIN DESCRIPTION
Pin Number
1
2
3
4
5
Pin Name
CHRG
GND
BAT
Vcc
PROG
Pin Function
Open-drain charge status output
Ground
Charge current output
Positive input supply voltage
Charge current program, Charge current monitor and shutdown pin
TYPICAL APPLICATIONS CIRCUITS
600mA single cell Li-ion charger
1/15
2007-7-3
FOSLINK [ FOSLINK SEMICONDUCTOR CO.,LTD ]
