SC824 Datasheet, PDF (1/29 Pages) Semtech Corporation – Single-cell Li-Ion Charger Tri-Mode with Timer and NTC

SC824
POWER MANAGEMENT
Features
„ Single input 30V protected charger
„ Adapter, USB High, USB Low modes
„ Charging by current regulation, voltage regulation,
and thermal limiting
„ Programmable currents from 70mA to 1A
„ Fast-charge current regulation — 15% at 70mA,
9% at 700mA
„ Constant voltage — 4.2V, 1% regulation
„ Input voltage protection — 30V
„ Current-limited adapter support capability — reduces
power dissipation in charger IC
„ USB modes automatically reduce charge current if
needed to prevent USB Vbus overload
„ Instantaneous CC-to-CV transition for faster charging
„ Battery temperature NTC thermistor interface
„ Multi-stage charge timer for safety and alternative
termination, IEEE Std. 1725-2006 compliant
„ Termination on current or timer — first to occur
„ Soft-start reduces adapter or USB load transients
„ High operating voltage range permits use of
unregulated adapters
„ Complies with CCSA YD/T 1591-2006
„ High-current USB Dedicated Charger compatible
„ Ultra-thin 2×2×0.6 (mm) MLPD package
„ Lead-free and halogen-free
„ WEEE and RoHS compliant
Applications
„ Mobile phones
„ Personal Media Players
„ Personal Navigation Devices
Single-cell Li-Ion Charger
Tri-Mode with Timer and NTC
Description
The SC824 is a single input triple mode (adapter/USB High,
USB Low) linear single-cell Li-Ion battery charger in a 10
lead 2×2 (mm) MLPD ultra-thin package.
Charging begins automatically when an input source is
applied to the charging input. The input is designed to
survive sustained input voltage up to 30V to protect
against hot plug overshoot and faulty charging adapters.
Thermal limiting protects the SC824 from excessive power
dissipation.
The SC824 provides three modes of charging: adapter
mode, USB low power mode, and USB high power mode.
Adapter mode charges up to 1A with the charging adapter
operating either in voltage regulation or in current limit to
obtain the lowest possible power dissipation. A single
current programming pin is used to program precharge
current, termination current, and fast-charge current in
fixed proportions. The USB modes provide low and high
power fast-charge currents. The two USB modes dynami-
cally limit the charging load if necessary to automatically
prevent overloading the USB Vbus supply.
The SC824 provides a battery NTC thermistor interface to
disable charging when the battery temperature exceeds
programmed thresholds. An optional programmable
multi-stage charge timer protects against a faulty battery,
or terminates charging on timeout if the system load is
too great to terminate charging on current. A 45 minute
top-off period following termination ensures a fully
charged battery. The monitor state restarts a charge cycle
if the battery discharges after the charger has turned off.
Typical Application Circuit
VADAPTER
MODE SELECT
CPU GPIO
1μF
2.2μF
SC824
RNPU
VIN
VSYS
MODE
RTIME
GND
EN_NTC
BAT
IPRGM
STAT0
STAT1
RIPRGM
2.2μF
RNTC
Thermistor
Battery
Pack
Device
Load
October 30, 2009
© 2009 Semtech Corporation
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