LTC4060_15 Datasheet, PDF (1/20 Pages) Linear Technology – Standalone Linear NiMH/NiCd Fast Battery Charger

LTC4060
Standalone Linear NiMH/NiCd
Fast Battery Charger
FEATURES
■ _{Complete Fast Charger Controller for Single,}
2-, 3- or 4-Series Cell NiMH/NiCd Batteries
■ _{No Firmware or Microcontroller Required}
■ _{Termination by –∆V, Maximum Voltage or}
Maximum Time
■ _{No Sense Resistor or Blocking Diode Required}
■ _{Automatic Recharge Keeps Batteries Charged}
■ _{Programmable Fast Charge Current: 0.4A to 2A}
■ _{Accurate Charge Current: ±5% at 2A}
■ _{Fast Charge Current Programmable Beyond 2A with}
External Sense Resistor
■ _{Automatic Detection of Battery}
■ _{Precharge for Heavily Discharged Batteries}
■ _{Optional Temperature Qualified Charging}
■ _{Charge and AC Present Status Outputs Can Drive LED}
■ _{Automatic Sleep Mode with Input Supply Removal}
■ _{Negligible Battery Drain in Sleep Mode: <1µA}
■ _{Manual Shutdown}
■ _{Input Supply Range: 4.5V to 10V}
■ _{Available in 16-Lead DFN and TSSOP Packages}
U
APPLICATIO S
■ _{Portable Computers, Cellular Phones and PDAs}
■ _{Medical Equipment}
■ _{Charging Docks and Cradles}
■ _{Portable Consumer Electronics}
DESCRIPTIO
The LTC^®4060 is a complete fast charging system for NiMH
or NiCd batteries. Just a few external components are
needed to design a standalone linear charging system.
An external PNP transistor provides charge current that is
user programmable with a resistor. A small external capaci-
tor sets the maximum charge time. No external current
sense resistor is needed, and no blocking diode is required.
The IC automatically senses the DC input supply and bat-
tery insertion or removal. Heavily discharged batteries are
initially charged at a C/5 rate before a fast charge is applied.
Fast charge is terminated using the –∆V detection method.
Backup termination consists of a programmable timer and
battery overvoltage detector. An optional external NTC ther-
mistor can be used for temperature-based qualification of
charging. An optional programmable recharge feature au-
tomatically recharges batteries after discharge.
Manual shutdown is accomplished with the SHDN pin, while
removing input power automatically puts the LTC4060 into
sleep mode. During shutdown or sleep mode, battery drain
is <1µA.
The LTC4060 is available in both low profile (0.75mm) 16-
pin 5mm × 3mm DFN and 16-lead TSSOP packages. Both
feature exposed metal die mount pads for optimum ther-
mal performance.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
2-Cell, 2A Standalone NiMH Fast Charger with
Optional Thermistor and Charge Indicator
V_IN = 5V
330Ω
“CHARGE”
NTC
698Ω
V_CC
SHDN ACP
CHRG SENSE
NTC DRIVE
LTC4060
PROG BAT
ARCT TIMER
SEL0 CHEM
SEL1 PAUSE
GND
+
NiMH
BATTERY
1.5nF
4060 TA01
2-Cell NiMH Charging Profile
3.40
–∆V
TERMINATION
3.30
3.20
3.10
0
10 20 30 40 50 60
CHARGE TIME (MINUTES)
4060 TA01b
4060f
1